The Ecology of Tidal Freshwater Marshes of the - USGS National ...

LibraryNational Wetlands Restarch Center'ire S. F:s5 erit"lii&lliil Serarice70G C2ju:ldorne Doirle\;ardLahyette, La. 70506FWS/OBS-83/17January 1984THE ECOLOGY OF TIDAL FRESHWATER MARSHES OF THEUNITED STATES EAST COAST: A COMMUNITY PROFILEWilliam E. OdumThomas J. Smith I11John K. HooverCarole C. McIvorDepartment of Envi ronmental SciencesUniversity of VirginiaCharlottesvil le, VA 22903Project OfficerEdward C. PendletonNational Coastal Ecosystms TeamU.S. Fish and Wildlife Service1010 Gause BoulevardSl idel 1, LA 70458Performed forNational Coastal Ecosys tems TeamDivision of Biological ServicesResearch and DevelopmentFish and Wildlife ServiceU.S. Department of the InteriorNashington, DC 20240

DISCLAIMERThe findings in this report are not to be construed as an official U.S.Fish and Wildlife Service position unless so designated by other authorizeddocutnents .Library of Congress Card Number; 83-600579This report should be cited as:Mum, W.E., T.J. Sqith III, J.K. Hoover, and C.C. kIvor. 1984. The ecologyof tidal freshwater ~narshes of the United States east coast: a communityprofile. U.S. Fish Wildl. Serv. WS/OBS-83/27. 177 pp.

PREFACEThis report is part of a series of community profiles produced by theFish and Wildlife Service to provide up-to-date information on coastalecological communities of the tidal freshwater marsh community along theAtlantic coast from southern New England to northern Florida.Tidal freshwater marshes occupy the uppermost portion of the estuarybetween the 01 igohal ine or low salinity zone and nontidal freshwater wetlands.By combining the physical process of tidal flushing with the biota of thefreshwater marsh, a dynamic, diverse, and distinct estuarine community hasbeen created. The profile covers all structural and functional aspects of thecommunity: its geology, hydro1 ogy, biotic components, and energy, nutrientand biomass cycl i ng .A major purpose of the community profile series is to gather andsynthesize the diverse bits of ecological information existing on eachcommunity and, further, to condense this information into a coherent andpractical habitat guide. The following discussion has been a true syntheticeffort on the part of the authors. Their careful compilation and analysis ofavail abl e data represent an extensive compendium of know1 edge of thisimportant natural resource and wil dl ife habitat.Questions or comments concerning this publication or others in theprofile series should be directed to:Information Transfer Special istNational Coastal Ecosystems TeamU.S. Fish and Wildlife ServiceWSA-S1 idel 1 Computer Compl ex1010 Gause Boul evardSl idel 1 , LA 70458iii

CONTENTS.........................................................PREFACEFIGURES...................................................................................................................TABLESACKNOWLEDGMENTS .................................................CONVERSION FACTOR TABLE .........................................CHAPTER 1 . INTRODUCTION .......................................1.1 Definition and Location ..............................1.2 Geographical Distribution ............................1.3 Visual Appearance ....................................1.4 Horizontal. Temporal. and Regional Variations...........................................1.5 Geological History1.6 Marsh Developmental Stage ............................1.7 Substrates ...........................................1.8 Hydrology and Water Qua1 i ty ..........................CHAPTER 2. COMMUNITY COMPONENTS : PLANTS ......................2.1 Introduction .........................................2.2 General Speci es/Habi tat Descriptions .................2.3 Community Structure ..................................2.4 Factors Control ling Plant Demography .................2.5 Seasonal Succession ..................................2.6 Other Aquatic Vegetation .............................CHAPTER 3 . ECOSYSTEM PROCESSES ................................3.1 Primary Productivity .................................3.2 Decomposition and Li tter Production ..................3.3 Nutrient Cycling (Elenents other than Carbon) ........3.4 Carbon Flux ..........................................3.5 Energy Flow ..........................................CHAPTER 4 . COMMUNITY COMPONENTS : INVERTEBRATES ...............4.1 Zooplankton .........................................4.2 Benthic Invertebrates ................................4.3 Marsh Plant Insect Community .........................CHAPTER 5. COMMUNITY COMPONENTS: FISHES ......................5.1 Introduction ........................................*5.2 The Fauna: Affinities and Natural History ofImportant Species ....................................5.3 Community Structure ................................... 5.4 Function of Tidal Freshwater brsh for Fishes ........5.5 Trophic Associations .................................5.6 Seasonality ..................................,. ......5.7 Biogeography ................................, .......Pageiiiv ivi ivi i ii x

Page.......6.1 Species Composition ................................... 666.2 Latitudinal Distribution .............................. 676.3 Daily and Seasonal Variability ........................ 676.4 Ecological Relationships .............................. 68CHAPTER 6 COMMUNITY COMPONENTS: AMPHIBIANS AND REPTILES 66CHAPTER 7 . COMMUNITY COMPONENTS: BIRDS ........................ 71Introduction ..........................................Fl oating and Di ving Waterbi rds ........................Wading Birds ..........................................Rails and Shorebirds ..................................Birds of Prey .........................................Gulls. Terns. Kingfishes. and Crows ...................Arboreal Birds ........................................Ground and Shrub Birds ................................Energy Flow and Avian Community Dynamics ..............CHAPTER 8 . COMMUNITY COMPONENTS: MAMMALS ...................... 818.1 Species Occurrence .................................... 818.2 Roles in Marsh Ecology ................................ 818.3 Economic Value ........................................ 85CHAPTER 9 . VALUES. ALTERATIONS. AND MANAGEMENT PRACTICES ....... 869.1 Value to Man .......................................... 869.2 Connections with Adjacent Ecosystems .................. 889.3 Alterations by Man .................................... 889.4 Potential for Sewage Assimilation ..................... 899.5 Best Management Practices .............................. 90CHAPTER 10 . COMPARISON OF TIDAL FRESHWATER MARSHES ANDSALT MARSHES ....................................... 9110.1 A General Comparison ................... ., .......... 9110.2 Physical Cornpari sons .................................. 9110.3 Biological Comparisons ................................ 9110.4 Comparison with Nontidal Freshwater Marshes ........... 95REFERENCES ....................................................... 96APPENDIX A: PLANTS OF THE TIDAL FRESHWATER MARSH ................ 114APPENDIX B: FISH OF THE TIDAL FRESHWATER MARSH .................. 120APP.ENDIX C: AMPHIBIANS AND REPTILES OF THE TIDALFRESHWATER MARSH .................................a*. 142APPENDIX D: BIRDS OF THE TIDAL FRESHWATER MARSH ................. 149APPENDIX E: FIAMMALS OF THE TIDAL FRESHWATER MARSH 174...............

FIGURES.......................................The relationship between marsh type and averageannual sal i ni tyRepresentative areas with more than 200 ha (500acres) of tidal freshwater marsh ......................Tidal freshwater marsh on the Chickahominy River ......Tidal freshwater marsh on James River in earlyspring ................................................Tidal freshwater marsh on James River in late summer ..Spatterdock communi ty type ............................Arrow-arum pickerel weed comrnuni ty type ................Wild rice community type ..............................Cattail community type ................................Giant cutgrass community type .........................Mixed aquatic community type ..........................Big cordgrass community type ..........................Bald cypress /b1 ack gum cinnnuni ty type .................Profile of mid-At1 antic tidal freshwater narsh ........Profile of northeastern tidal freshwater marsh ........Winter and summer scenes of the same marsh onthe Potomac River .....................................Common submerged aquatic plants .......................Decomposition curves for high and 1 ow marsh plants ....Changes in N and P during decomposition ...............General node1 of nutrient cycl i ng ( N and P).............................Hypothetical pathways of energy flowGrazing by the amphipod. Gammarus fasciatus.....................................Seaward change in microfaunaDistributions of different types of fishes bysalinity zones..........................................Striped bassMoven~ent of es tuarine-dependent fish 1 arvae ...........Cornpari son of seasonal variation in fish numbersin three river systens ................................Mixed assernbl ages of geese and ducks in tidalfreshwater marshes..........................................................................Great blue heronWhite-tailed deer feeding in a tidal freshwatermarsh .................................................Beaver dam on tidal freshwater marsh stream ...........Abandoned rice fields .................................

TABLESNumber12345678910111213141516171819202 la2 1bPageAcreages of tidal freshwater marshes on the east coast ... 3Concentrations of chemicals in marsh soils andinterstitial water ....................................... 10Water qua1 i ty parameters ................................. 11Cominon tidal freshwater marsh plants ..................... 15Species composition of marshes along the Patuxent River .. 29Sal ini ty to1 erances of submerged aqua tics ................ 34Peak standing crop and annual production estimates ....... 38Twogroupsof plantsbased on rates of decomposition ..... 42Typical tidal freshwater zoopl ankton ..................... 43Representative benthic macrofauna from tidal freshwater .. 52Characteristics of anadromous and semianadromous fishes .. 57Patterns of use of tidal freshwater habitat by fishes .... 60Numerically dominantfishes in tidal freshwaters ......... 61Fishes reported to spawn in tidal freshwater ............. 62Fishes using tidal freshwaters as nurserygrounds ........ 63Popul ation densities and biomass of turtl es andother vertebrates ........................................ 68Efficiency of secondary production ....................... 69Distribution of waterfowl in various regions ofVirginia ................................................. 74Percentage of total species found in tidal freshwaterinupperChesapeakeBay .................................. 74Breadth of diet of waterfowl in tidal freshwater ......... 76Resident mammal s in tidal freshwater marshes ............. 81Mammal s using tidal freshwater marshes on feedingforays ................................................... 81Harvest of furbearers by marsh type ...................... 85Commercial fish harvest from the tidal Potomac River ..... 86Commercial fish harvest from the entire Potomac River .... 86Hypothetical comparison of tidal freshwater and sal tmarshes .................................................. 92vii

CHAPTER 1. INTRODUCTION1.1 DEFINITION AND LOCATIONTidal freshwater wetlands are a distinctivetype of ecosys tem 1 ocated upstreamfrom tidal saline wetlands (saltmarshes) and downstream from nontidalfreshwater wetlands (Figure 1). They arecharacterized by (1) near freshwater conditions (average annual sal ini ty of0.5 ppt or below except during periods ofextended drought), (2) plant and animalcommunities dominated by freshwaterspecies, and (3) a daily, lunar tidalfluctuation.In a classification system based onsalinity, these wetlands lie between the01 igohal ine zone and nontidal freshwater(Figure 1). The lack of dominance byestuarine marshgrasses (Spartina) differentiatestidal freshwater marshes from01 igohal ine and higher salinity marshes.01 igohal ine estuarine marshes tend to bedominated by big cordgrass (2.cynosuroi des) and sal tier estuarinemarshes by sal tmeadow hay (S. atens) andsmooth cordgrass (5. a1 ternifl ?-Tidalfreshwater marshes, on the other hand, arecharacterized by a large and diverse groupof broad-1 eafed pl ants, grasses, rushes,shrubs, and herbaceous plants (see Table4, Appendix A).This wetland type has been variouslyclassified as tidal freshwater (Odum etal. 1978; Lippson et al. 1979), freshwatertidal (Whigham et al. 1978), transitionmarsh combined with arrow-arum andpickerelweed marsh (Daiber et al. 1976),coastal shallow fresh marsh (Shaw andFredine 1956), fresh marsh combined withintermediate marsh (Chabreck 1972),estuarine river marsh (Stewart 1962), andpalustrine emergent wetl and (Cowardinet al. , 1979). All of these terms arebasically synonymous. We have chosen touse tidal freshwater marsh because it isconvenient and widely used.In the U.S. Fish and WildlifeService's classification system ofwetlands (Cowardin et al. 1979), tidalfreshwater marshes are cl assif ied aseither of the following: (1) system:palustrine; class: emergent wetl and; subclasses:persistent and nonpersistent, or(2) system: riverine; class: emergentwetl and; subclass: nonpersistent. Waterregime modifiers for either classificationare: permanently flooded-tidal , regularlyflooded, or seasonally flooded-tidal . Thesystem selected depends on the position ofthe marsh with respect to the river channel.High back marshes with persistentvegetation are more properly termed palustrine;fringing low marshes along riveredges are properly c1 assified as ri verine.1.2 GEOGRAPHICAL DISTRIBUTIONThe most extensive development oftidal freshwater marshes in North Americaoccurs on the United States east coastbetween Georgia and southern New England.The two regions with the greatest area ofthis type of wetland are in the mid-Atlantic States and South Carolina andGeorgia (Table 1).The distribution of extensive tractsof tidal freshwater marshes follows aninteresting pattern (Figure 2). Theyappear to be best developed in locationswhich have (1) a major influx of freshwater,usually a river, (2) a daily tidalamplitude of at least 0.5 m (1.6 ft), and(3) a geomorphological structure whichconstricts and magnifies the tidal wave inthe upstream portion of the estuary.In southern Mew England, where largeriver systems are relatively scarce, ex-

(DURINGLowFLOWCONMTIONS)Figure 1. The relationship between marsh type and average annual salinity (values areapproximate only). Terminology is based on Cowardin et a1 . (1979).tensive tidal freshwater marshes are uncommon.They occur along the Hudson River,Connecticut River, and a few smallerrivers such as the Mystic and the NorthRivers. In northern New England and rmchof eastern Canada, geornorphologi cal conditions(steep, rocky coastlines) are notconducive for tidal freshwater marshdevelopment on a large scale. One exceptionis the St. Lawrence River systemwhich has a tidal freshwater zone withmarsh areas as large as 400 ha (1,000acres) (Reed 1978).From New Jersey south to Virginia andthroughout the Chesapeake Bay region, tidalfreshwater marshes are abundant andoften extensive in size. A noteworthy gapin the distribution occurs through much ofNorth Carolina (Figure 2). In this regionmost estuaries lie behind closely spacedbarrier island systems (e.g., the OuterBanks). This results in a greatly dampenedtidal amplitude within the lower

Table 1. Conservative estimates of acreages of tidal freshwater marshes on the United States east coast.Fiyures in parentheses are hectares.State Estimated area References Commentsha (acres)FloridaNo re1 iable estimate or observations availableGeorgia 19,040 (47,047) Hi1 kes (1976) Estimate qay include some tidal swamn and non-Mathews et al. (1980)tidal freshwater marshSouth Carol ina 26,115 (64,531) Tiner (1977)North Carol i na 1,200 (3,000) U.S. Army Corps ofEngineers (1979);Wilson (1962)Virginia 16,000 (39,000) Gene Si 1 berhorn(unpubl ished data)(1954)w Mary1 and 10,345 (25,563) McCormick and Somes(1982)Delaware 823 (2,033) Daiber et al. (1976)South Carolina also has 28,511 ha (70,451 acres)of "coastal impoundments" which contain considerableacreage of tidal freshwater marsh18,600 ha (46,000 acres) of "shallow fresh marsh"re~orted hy Wilson are not tidal freshwater hvour definition; re~orted area is on the CaoeFear RiverPrecise estimate based on the Virginiawet1 ands inventorybnears to he an excellent estimate and animprovement on earlier State and Federal estimatesThere are an additional 1231) ha (10,452 acres) of"transition marsh" which is ver.y similar to tidalfreshwater marshPennsylvania 400 (1,000) Our observations Rough estimate; located along the Delaware QiverNew Jersey 89,000 (220,000) Sirnpson et al. (1983) Very rough estimate, mav be too hiqhNew York 400 (1,000) Our observations Rough estimate; located along Hudson RiverConnecticut 444 (1,097) Metzler and Rosza (1982) 471 ha (1,040 acres) associated with tQeConnecticut River and 23 ha (57 acres) along theHousatonic RiverRhode Island 40 (100) Our observations Very rough estimateMassachusetts 400 (1,000) Our observations A1 ong the North and Merrimack RiversNew Hampshi reand MaineNo estimate or observation availableTOTAL 164,000 (405,000) (an imprecise estivate)-

MERRIMACK RlVERNORTH RlVERCONNECTICUT RlVERHUDSON RlVERCA AND WADING RIVERSPOTOMAC RlVERRAPPAHANNOCK RIVERRK RlVER (MATTAPONI AND PAMUNKEY)JAMES AND CHICKAHOMINY RIVERSHARBOR (COOPER,NEW-WRIGHT RIVERSSAVANNAH RlVERFigure 2.marsh.Representative areas with more than 200 ha (500 acres) of tidal freshwater4

eaches of coastal rivers such as theNetlse and Pam1 ico. As a result, almostall North Carolina coastal river systemshave sections which are both tidal andfreshwater. However, the tidal range isslight; and tides are irregular, andgreatly affected by the wind. Therefore,in North Carolina the types of plant communities typical of most east coast tidalfreshwater sites (see Chapter 2) arerestricted in size and are replaced bytidal swamps. The one major exception inNorth Carol ina is the Cape Fear River system.It empties directly into the AtlanticOcean, has a one-meter tide, and hasextensive areas of typical tidal freshwatermarshes.South Carol ina and Georgia containnunierous and often extensive tidal freshwatermarshes. Many of these marshes andassociated swamps were diked, impounded,and converted to ricefields during thelath and first half of the 19th centuries.Sorne of these impoundments remain virtuallyintact. However, in others the dikeshave broken and the impoundments havereverted to tidal marsh. A difficultinanagement decision needs to be made as towhether the i ntdct impoundments should bernanaged for ~aterfowl or should be allowedto revert to tidal marsh (discussed inChapter 9).The mos t southern major river sys temon the coast, the St. Johns River inFlorida, has tidal influence for over 160kilometers (99 mi) inland (L. Gerry, Jacksonville Water Control District, Pal atka,Florida; pers. comm.). Due to its unusualmorphology (narrow mouth, broad upperreaches), the tidal amp1 i tude in the tidalfreshwater stretch is ninor, and typicalplant communities are absent or restrictedto small areas.Tidal freshwater envi ronments (includingsome mangrove areas) exist insouth Florida. However, they are generallytoo restricted in size or too seasonalin occurrence (e.g., the Evergladesestuary) to be included in this report.Similar types of tidal freshwatermarshes occur on other coasts of theUnited States. For example, Louisiana hasextensi ve stretches of tidal, freshwaterwetlands. However, these wetlands have atide that is irregular, of low amp7 i tude,and wind driven. This makes both the community structure and ecosystem processesappear to be somewhat different (Chabreck1972; Hopkinson et al. 1978). Tidalfreshwater marshes are relatively rare onthe Pacific coast. They do occur extensively,however, in Alaska (McRoy andGoering 1974), in California in associationwith several large river systemsincluding the Sacramento (Kelley 1966),and between Washington and Oregon in associationwith the Columbia River.(Clairain et al. 1978).1.3 VISUAL APPEARANCETidal freshwater marshes look stri k-ingly different from either salt marshesor nontidal freshwater marshes. Plantdiversity is much higher than that foundin higher salinity estuarine marshes. Theresult is a highly heterogeneous plantassembl age (Figure 3) quite different inappearance from the almost monospecif icSpartina marshes found nearer the mouth ofthe estuary. Zonation is oresent (discussedin Chapter 2) but is not assharply defined as in salt marshes. Theso-called low marsh is dominated by a fewbroad-leaved, fleshy plants such as spatterdock(Nuphar luteum) and pickerelweedand by wild ricemania aquatica) andgiant cutgrass (Zizaniopsis mil iaceae).The higher sections of the tidal freshwatermarsh contain aore species than thelow marsh and may be dominated by a varietyof plants including cattail (Typhaspp. ), smartweeds (Pol onums spp.) , rosemallow(Hibiscus moscheutos -7 , sweet flaq(Acorus calamus), and burrnarigold (Bidens . x Certain species such as arrow-arumare found throughout the marsh.The tidal freshwater marsh has plantsin flower through much of the spring andsummer. In the spring wild iris (Irisspp.) blooms in the high marsh. In earlysummer, pickerelweed sends up a spike ofpurple flowers. Rose-ma1 low, jewel weed(Impatiens capens is), and the spectacularyellow flowers of burmarigold bloom laterin the summer.One of the most striking features ofthe tidal freshwater marsh is the pronouncedseasonal sequence of vegetation

Figure 3,Tidal freshwater marsh on the Chickahominy River, Virginia, during midsummer.(discussed at length in Chapter 2). The1 ow marsh undergoes particularly extremechanges. There is a period of virtuallybare mud in late winter and early spring.Then there is a period of domination bybroad-leaved plants (e.g.,arrow-arum) inthe late spring, and finally in late summerthere is a period dominated by grassesand herbaceous pl ants ( Figures 4a ,b) .Conspicuous organisms in the tidalfreshwater marsh include freshwater snakesand turtles, adult and larval insects,ducks and geese, and muskrats. A casualexamination of the fauna of the tidalfreshwater marsh reveals few bivalves,crustaceans, or polychaetes, organi smswhich dominate the higher salinity marshesin the lower estuary.In summary. the tidal freshwatermarsh appears superficially different fromthe nearby salt marshes. In Chapter 10 wediscuss whether these apparent differencesactually exi'st and whether they includeaspects of communi ty structure and ecosystanprocesses.1.4 HORIZONTAL , TEMPORAL, AN0 REGIONALVARIATIONSTidal freshwater ecosyste~?~ form acomplex gradient with freshwater on oneside and 01 igohal ine and higher salinityesturine conditions on the other side.Concentrations of dissolved oxygen, particulateand dissol ved carbon, dissolvedheavy metals, nitrite, nitrate, ammonia,and other chemical and physical water andsediment parameters change dramatically assalinities increase from 0.1 to 1.0 ppt(Morris et al. 1978). Fish, plant, andinvertebrate communities change si gnif i -cantly as the salinity rises above 1 p ~t.Rarely are conditions homogeneous over avery great distance. For this reason,general statements about ti dal freshwatermarshes and associated bodies of watermust always be made with gradient conditionsin mind.Tidal freshwater wet1 ands vary temporally as well as spatially. Daily, seasonal,and long-term changes may occur ata given site in response to tidal or windinfluences and as a result of annual or

Figure 4a. Tidal freshwater marsh onJanes River in early spring.longer-term variations in freshwater runoff.A marsh that experiences highersal i ni ti es during periods of drought mayswitch to tidal freshwater characteristicsafter prolonged rains. A slight increasein salinity during one summer may changethe plant composition of a tidal freshwatermarsh for several years. Tidalfreshwater marshes lie in a dynamic transitionzone between freshwater and saltwater.A1 though we treat the tidal freshwatermarsh as a general wetland type onthe Atlantic coast, there are clear regionaldifferences in flora, fauna, andphysical characteristics. For example,New England marshes appear to have morepeat than mid-At1 antic marshes. The muskratis a plentiful herbivore in mid-Atlantic marshes but is absent in thecoastal marshes of South Carolina andGeorgia (discussed in Chapter 8). Tbebrackish water fiddler crab (Ilca minax)occurs throughout tidal freshwater inSouth Carolina and Georgia (J. Birch,Institute of Ecology, IJniversi ty ofGeorgia, Athens; pers. comm.), but isusual 1 Y found in 01 iqohal ine and hiqhersalinities in the - Chesapeake region(Kerwin 1971, and our personal observations).The bowfin and the pirate perchare plentiful members of the fish communitiesthroughout tidal freshwaters of SouthCarol ina and Georgia, but are generallyrestricted to nontidal freshwater in theChesapeake region (see Section 5.7).1.5 GEOLOGICAL HISTORYIt is difficult to generalize aboutthe geological history of tidal freshwaterenvironments on the Atlantic coast becauseconsiderable variabil i ty exists from oneregion to the next. New England riversystems such as the Connecticut and Hudsonare incised into highly resistant Paleozoicand Lower Hesozoic bedrock. (Frey andBasan 1978). Clay minerals are in relativelyshort supply. Further south, alongthe coasts of South Carolina and Georgia,coastal river systems have cut into bedrockwhich is mainly Upper Fksozoic andCenozic. Thick, well-developed saprol i tes(mineral soils) of the southern Piedmontprovide abundant clay for redistributionFigure 4b. Tidal freshwater marsh on into both tidal freshwater and estuarineJames River in late summer.marshes along the coast.7

In general the river systems of themid-At1 antic and south At1 antic CoastalPi ai ns tend to be more numerous, more extensive,and fed by greater quantities ofrunoff. For these reasons, the tidalfreshwater marshes in f,laryl and, Virginia,Georgia, and South Carolina are muchvaster than the states north of NewJersey.For a variety of reasons (e.g.,sl ower decomposition rates, freezing ofmarsh surfaces during the winter, anddifferences in vegetation), most NewEngland coastal marshes tend to have morepeat than southern coastal marshes (Freyand Basan 1978). Southern marshes, on theother hand, have sediments with a highercl ay and silt content.In spite of these regional differencesin geology and sediments, the recentgeological history of east coast tidalfreshwater marshes is similar. Virtuallyall conteinporary marshes are very recentin origin (Holocene). They lie in rivervall eys which were cut during Pleistoceneperiods of lowered sea level. As sealevel rose during the post-Wisconsin periodof the Holocene (5,000 to 15,000 BeforePresent [BPI), both tidal freshwater andestuarine marshes expanded rapidly as thelower stretches of drowned river systemswere inundated (El 1 i son and Nichol s 1976).There is excel lent evidence (Froomer1980a, 1980b) which suggests that coastalmarsh expansion has continued at a relativelyrapid rate to the present. Infact, Froomer (1980b) concluded that therate of coastal marsh building in themid-At1 antic reg ion has been accel eratedover the past three centuries due toincreased soil runoff associated withman's activities. He reported an averagevertical growth in marsh sediments of 27.4cmlcentury for estuarine and tidal freshwatermarshes in the northern portion ofChesapeake Bay. Because of these highrates of deposition, many tidal freshwatermarshes have started and have grown toconsiderable extent in only the last fewcenturies.The recent geological history oftidal freshwater marshes can be demonstratedby examining a vertical profile takenfrom corings through a contemporary marsh.A typical sequence through a mid-At1 anticmarsh could show (1) a hard bottom consistingof a Pleistocene erosion surface(bedrock) cut during a glacial period oflowered sea 1 evel ; (2) varying layers ofriver, estuarine, and narsh sediments; and(3) a cap of recent tidal freshwater marshsediments varying in thickness from lessthan 1 m (3 ft) to more than 10 m (30 ft).Of course, very young marshes might beunderlain by layers of sand or clay andhave only a thin 1 ayer of narsh sedimentson the top.Even though contemporary tidal freshwatermarshes are generally 1 ess than15,000 years of age and most are nuchyounger, this does not nean that this typeof wetland did not exist in earlier geologicalperiods. Certainly, during Pleistoceneperiods of reduced sea 1 evel, alltypes of coastal marshes were relativelyreduced in extent. There is ample evidencefrom coal deposits, however, whichshows that early equivalents of ourpresent-day tidal freshwater marshesexisted hundreds of mill ions of years ago.1.6 MARSH DEVELOPMENTAL STAGEIn the same way that all wet1 andspass through various stages of development,tidal freshwater marshes have certain geomorphol og i cal and ecol og i calcharacteristics which tend to ref1 ecttheir geological age. Frey and Basan(1978) have cl assif ied coastal estuarinemarshes into three categories: (1) youngmarshes which are largely low or intertidalmarsh, (2) mature marshes which area mixture of low and high marsh, and (3)old marshes which are largely high marsh.We feel that this classification system,while somewhat simp1 istic, is equallyuseful in studying tidal freshwatermarshes. Young tidal freshwater marshes,of a few hundred years of age or 1 ess, aretypically low-lying, largely intertidal,and dominated by vegetation of the lowmarsh (spatterdock, arrow-arum, and wildrice). Old marshes are generally all highmarsh (except along creek banks and arounddepressions), may not be flooded at all byneap tides, and are dominated by highmarsh vegetation (e.g., cattails, marshmallow, and iris). Mature marshes are

intermediate in appearance and have a mixtureof low and high marsh plants and geomorphology.Of course, the apparent age of aspecific marsh is influenced by >ore thani ts time of existence. Factors such aslocal physi ography, 1ati tude, rates oflocal subsidence, rates of local sea levelchange, degree of wave and current action,suspended sediment loadings, vegetationtype, a1 terations by man (e.g. , conversionto rice fields in South Carolina), andlocal rates of net primary production allinfluence the stage or age of the marsh.Takiny these factors into considerationand remembering that apparent chronologicalage ;nay be misleading, it is stillconvenient to use the concept of young,mature, and old in describing the visualstate of a specific marsh.1.7 SUBSTRATESSediments underlying most tidalfreshwater inarshes are typical ly darkcoloredand sticky with a high content ofsilt and clay. Usually, the marshes arelocated in the section of the estuary withthe highest rates of sediinentation(Nichols 1972). This accreting material,largely clays and silts, combines withlarge quantities of organic detritus toform a dark, mucky soil. From the viewpointof tile U.S. Fish and WildlifeService (Cowardin et al. 1979), the lowmarsh can generally be regarded as havinga mineral soil (less than 50% organic matter)and the high marsh a mixture ofmineral soi 1 s and organic soi 1 s (greaterthan 50% organic matter), depending on thelocation within the marsh.Peat may be present in the Typhadominatedhigh marsh in northern NewEngland marshes and in the giant cutgrassmarshes of the Southeast. However, it isnot as common as in sal t marshes . Becausetidal freshwater rnarsh sediments have alower biomass of plant roots and peat(particularly in the low marsh), they areinore erodable than estuarine marsh sediments(Garofalo 1980). Areas covered witharrow-arum and spatterdock appear to beparticularly vulnerable to winter erosion.Because of their erodible banks, tidalfreshwater creeks tend to have lowermeander amp1 i tudes (s i nuos i ty) than sal tmarsh creeks (see Chapter 10).Generally, tidal freshwater marshsedi~~lents have a hiqh organic contentwhich may vary considerably w~th depth andlocations. Whigham and Simpson (1975)found that the marsh soils along the tidalfreshwater portion of the Delaware Rivervaried from 13% to 40% organic natter on adry weight basis, Organic content was1 ower in the arrow-arum-dominated lowrnarsh (14% to 30%) compared to the sweetfla -cattail-dominated high marsh (30% to4043 . Volatile solids (a parameter relatedto organic content) from a James Riverlnarsh ranged from 10% to 20% (Lunz 1978).In other Virginia tidal freshwater marshes,we have found a range in soil organicmatter from 20% to 50%. The highest valueswere found in the high marsh (Hoover1983)' Bowden (1982) reported that thesoils of the North River marsh inMassachusetts had from 50% to 75% organicmatter; this difference from more southerlymarshes may reflect either a dominanceby different plant species or a slowerannual rate of decomposition.Water content tends to parallel organiccontent. For example, the JamesRiver marsh soils typically contain 50%water (Lunz 1978). On the other hand,water may compose as much as 88% of thefresh weight of North River marsh soils(Bowden 1982).The combination of ample organic matterand iron along with at least some sulfurproduces sediments which are usuallyanaerobic just below the surface. Thedegree of reducing conditions in tidalfreshwater marsh sediments is difficult todetermine. Since the reaction pairs forthe oxidation-reduction reactions are notas obvious as the sulfur reduction reactionsin salt marshes, classical redox(Eh) estimates have 1 i ttl e obvious meani ngfor tidal freshwater sediments. The scantevidence which is available from our ownresearch (presence of methanogens, negativeEh readings) has led us to concludethat tidal freshwater marsh sediments aremoderately to strongly reducing.Typical pH values for tidal freshwatersediments range from 6.0 to 6.5(Schwartz 1976, Lunz et al. 1978). Wetzel9

and Powers (1978) measured the cation exchangecapacity of sediments from a JamesRiver marsh and found values ranging from39.6 to 67.3 meg x 100 g dry weight. Thisis a relatively high value compared tocoastal plain and piedmont soils, but typicalfor highly organic, high clay wetlandsediments (personal observation). Thesehigh values of cation exchange capacitya1 so indicate a young, sl ightly weatheredsediment with high nutrient avail abil ity.A range of sediment nutrient concentrationsis shown in Table 2. It shouldbe noted that these limited data come frompolluted sites. It is possible that unpollutedsediments might have lower nutrientconcentrations.As in other wet1 and sediments, ammoniumis the most abundant form of inorganicnitrogen (Table 2). Nitrate and nitriteusually do not accumulate in anaerobicsoils. This is because nitrificationproceeds slowly while deni trification proceedsrapidly. Bowden (1982), who workedin the tidal freshwater marshes of theNorth River, Massachusetts, found that theamount of ammonium that is free in theinterstitial water is often less than theamount of ammonium adsorbed loosely ontosediment particles. Consequently, thepool of available ammonium is probablymuch greater than the pool of free ammonium.Bowden also presents evidence thatthe amount of ammonium in tidal freshwatermarsh sediments may be highest in midsummerand lowest in late spring, coincidentwith heavy demands for nitrogen from newvegetation. He found the highest concentrationsnear the surface (3.7 mg/l).Lower concentrations were found at 20-cm(8-inch) depth (0.9 mg/l), and an increase(2.0 mg/l ) was found at 60-cm (24-inch)depth.In summary, from 1 imi ted informationit appears that the sediments of tidalfreshwater marshes typically have (1) ahigh organic content, (2) a pH in the 6.0to 6.5 range, (3) moderate to strongreducing conditions, (4) a high cationexchange capacity, and (5) inters ti tialnutrient concentrations which are high inaiamonium and low in nitrate and nitrite.Sediment and water nutrients are discussedfurther in Section 3.3.Table 2. Concentrations of chemicals in the soils and interstitial water of threetidal freshwater marshes. na = not available, + = one standard deviation.Soi 1Interstitial waterLocation and Total N Total P NH NO + NO Total dissolved Preference (% dry wt.) (% dry wt.) (g/l) (9/1) (9/1)Herring Creek Marsh,James River, Va. (Lunz 1.5r0.8 0.7k0.4 1600t1200 look50 180k190et a1 . 1978)North River Marsh,Mass. (Bowden 1982) 1.6r1.9 0.1-0.3 900-3700 0-170 n aHami 1 ton and WoodburyCreek marshes. Delaware 0.5-1.0 0.04-0.2 na naRiver (Simpson et al.1981)Hami 1 ton marshes ,Delaware River(Whi gham et a1 . 1980)1.03-1.64 0.12-0.35 n a na

1.8 HYDROLOGY AND WATER QUALITYThe hydrology of tidal freshwatermarshes and associated streams and riversis poorly studied. Presumably, this environmentis more strongly influenced by theeffects of inflowing riverine freshwaterthan the lower part of the estuar,~ which,in most cases, is strongly influenced byoceanic tides. We have observed thatchanges in wind direction and velocityappear to have a greater effect on thedaily tides at tidal freshwater sites thanfurther down the estuary.Certainly, more information is neededon the relative effects on tidal freshwaterenvironments of upstream fl oods,droughts, ocean-induced tides, and wind.Perhaps nost important of all, we need toknow the extent to which the tidal freshwatermarsh zone is able to ahsorb andbuffer inputs of floodwater from upstream.Water qua1 i ty data from a variety oftidal freshwater sites are shown in Table3. Unfortunately, all but one of theselocations are highly eutrophic. The oneexception, the Ware Creek marshes on theYork River in Virginia, is a relativelypristine site, hut has salinities slightlyhigher (annual average = 7 ppt) than atypical tidal freshwater marsh. However,the Ware Creek data have been includedsince the vegetation in these marshes contains many freshwater species.Comparison of the nitrogen and phosphorousdata in Table 3 with the criteriapresented by Wetzel (1975) suggests thatthese tidal freshwater sites range fromeutrophic (Ware Creek) to hypereutrophic(the remaining sites), Certainly, thereare more than adequate nutrient levels tosupport high phytoplankton production.The generally high chlorophyll concentrations(Table 3) give further proof of aeutrophic envi ronment . !Inpub1 i shed data(T. Wolover, University of South Carolina,Seorgetown, pers . comm. ) confirm that evenTable 3. Water quality parameters from a variety of tidal freshwater locations arrangedin approximate order of increasing eutrophication. DOC = total dissolved organic carbon,POC = total particulate organic carbon, TKN = total Kjehldahl nitrogen. TP = total particulateand dissolved phosphorous, DO = dissolved oxygen, na = not available. Wheretwo values are given, one above the other, the upper value = summer, the lower value (inparentheses) = winter.A1 ka-Location and pH 00 Chlor. A linlty DOC POC NH' NO +N! TUN PO Total Preference (mgll) (gll) (meq/l) (mgll) (mgll) (gll) (dl) (g/l) (d1) (qll)Ware Creek Marsh,York River na na 2.2-23.6 na 5-10 1-5 15-20 20-30 na na 110-5')(Axelrad et al.1976)Hami 1 ton andWoodbury Creek 4-6marshes, Delarare na (10-17) na na na na 49-80 40-300 na 5-20 5-5"River (Simpsonet al. 1981)Herring Creek 7.3 6.9 13.9 na 3.8 na 470 500 4200 40 16nMarsh, James (8.0) (12.3) (0.9) (0.39) (9.11 (1.5) (460) (1600) (3300) (30) (180)River (Adams 1978)Tinicum Marsh,Delaware River na 0.6-11.2 na 0.8-2.0 na na 500-6000 300-10nn na na na(Grant and Patrick1970)Potomac River 4-6 5W na na na 230-500 350+ na na 40n-7W(Lippson et al. na (12-13)1979)

CHAPTER 2, COMMUNITY COMPONENTS: PLANTS2.1 I NTRODUCT I ONThe physical characteristics whichdistinguish tidal freshwater wetlands (seeSection 1.1) exert considerable influenceon plant communi ty development. Nearlyall of these wetlands are riverine. Thelack of stressful sal ini ty levels facil i-tates util ization of this habitat by manymore plant species than are found incoastal or inland brackish marshes. Suchhigh diversity produces a co~nplex andseasonally variable mixture of 1 ife forms.Unl ike nontidal riparian wet1 ands wheremarsh vegetation is confined to a narrowband para1 lel i ny channel s, regular inundationin tidal freshwater regions serves tolaterally extend habitat boundaries.Plant communities visibly stratify acrossthis broadened niche space, a1 though distinctzonation is not readily apparent.No known plant species appears exclusivelyin the tidal freshwater habitat.Most marshes are dominated by a combinationof annuals and perennial s, the majority of which are common to freshwater wetlandsover nuch of North America (Fassett1957, Cowardin et al. 1979; Silberhorn1982). Latitudinal differences in cl imateas well as local variation in physiographyand geology produce distinct heterogeneitywithin tidal freshwater marshes. Marshesin respective regions of the At1 anticcoast differ markedly in plant speciesconposi tion, re1 ative diversity, and community structure as a result of this variation.A1 though tidal freshwater marshesshare much in common with other wetlandsas a whole, only a limited amount ofavail able information pertains specificallyto the flora and ecology of thishabitat.The discussion which follows willfocus upon those plant species which mostcommonly occur in tidal freshwater marshes.Emphasis will be placed on descriptionsof community structure and thosephysical and ecological processes influencingplant demography and succession.Habitat vari abil i ty on a regional basiswill be discussed, a1 though in most instancesthe tidal marshes of the mid-Atlantic States will serve as a generalmodel. Plant species are addressed bycommon names in the text; scientific namesare listed in Appendix A.2.2 GENERAL SPECIESIHABITAT DESCRIPTIOI\ISThe bulk of tidal freshwater marshf1 ora consists of (1) broad-1 eaved emergentperennial macrophytes (spatterdock,arrow-arum, pickerelweed, arrowheads), (2)herbaceous annuals (smartweeds, tearthumbs,burmari go1 ds, jewelweed, giantragweed, water-henp, water-dock) , (3) annualand perennial sedges, rushes andgrasses (bulrushes, spi ke-rushes, umbrella-sedges,rice cutgrass, wild rice, giantcutgrass), (4) grass1 i ke plants or shrubformherbs (sweetflag, cattail ,. rosenallow,water parsnip), and (5) a handfulof hydrophytic shrubs (button bush, waxmyrtle,swamp rose) (Whigham et al. 1976;Tiner 1977; McCormick and Sornes 1982;Metzler and Rosza 1982; Sil berhorn 19821.Regional variations in species compositionand diversity persist, but havenever been described comparatively.Marshes of the %id-Atlantic and GeorgiaBight regions can contain as many as 50 to60 species at a single location, and arecomprised of a number of codominant taxa(Odum 1978; Sandifer et al. 1980). Amongthe more conspicuous species occurring inboth regions are arrow-arum, pickerelweed,wild rice, and cattails. However, thereare notable differences between the tidal

freshwater marshes of these respectiveregions. Bri efly, vegetation communitiesin South Carolina and Georgia are ofteneither a nearly monospecific stand ofgiant cutgrass or a mixed community dominatedby one or more of the aforementionedspecies plus sawgrass, a1 1 igatorweed,plumegrass, giant cordgrass or soft-stembulrush. In Virginia, Maryland, and NewJersey, giant cutgrass becornes 1 ess prevalent,and plants such as spatterdock,various smartweeds and tearthumbs, sweetflag, rice cutgrass, and burmarigoldsbecome more pro1 if i c .The vegetation communities in MewEngland tidal marshes general ly harborfewer species with perennial sedges andgrasses becoming more conspicuous consti t-uents. Important components of thesenorthern ma rshes include reed bentgrass,various rushes and sedges, arrowheads,cattails and spiked loosestrife (Kiviat1978a; Bowden '1982; Metzler and ' Rosza1982).Tidal freshwater swamps prevail a1 ongmany tidal rivers from Virginia south, andare often closely associated with tidalfreshwater marsh. Occurring primarilylandward of the marsh, these forestedareas are dominated by trees such as baldcypress, red maple, black gum, and tupelogum (Sil berhorn 1982). In addition, tidalswamps typically harbor an understory ofemergent herbs and shrubs, many of whichoccur in the marsh. Some of these speciesinclude arrow-arum, jewel weed, royal fern,1 izard's tail, Asiatic spiderwort, waxmyrtle,and alder.In areas where sal ini ties periodicallyextend into oligohaline ranges (0.5 to5 parts per thousand [ppt]), species suchas big cordgrass, common threesquare,narrow-1 eaved cattail , various smartweeds,arrow-arum, wild rice, marsh ma1 low, andwater-hemp become the most prevalent communitycomponents (Phillip and Brown 1965;Sandifer et al. 1980; Ferren et al. 1981;Si 1 berhorn 1982) .A survey of the 1 iterature on vascularplant populations in tidal freshwatermarshes indicates an inherent vari abil i tyin the composition and spatial distributionof plant communities. However, severaldozen species occur consistently atmany locations on the At1 antic CoastalPlain. A listing of common tidal freshwaterwetland species plus their generalcharacteristics and ha5i tat referencesare given in Table 4. A more extensive1 isting of common and rare species awearsin Appendix A.2.3 COMMUNITY STRUCTURESpeci es Compos i ti onPlant communities can be classifiedby a number of characteristics includinggrowth form dominance, speci es dominance,and species composition. Generally thesecharacteristics define arbitrary boundaries between communi ty types, but neverthelessare useful in describing vegetationpatterns (Whittaker 1975). A1 thoughtidal freshwater marsh flora is not particularlywell-suited to such a classificationscheme due to its unusually highdiversity, many attempts have been made todescribe marshes in this manner (McCormick1970; McCormick and Ashhaugh 1972; Whighamand Simpson 1975; Shima et al. 1976;Douml ele and Sil berhorn 1978; McCormi ckand Somes 1982). In most instances,species dominance has been used as a primarymeans of classification, usuallybecause vegetation units represented bynearly pure stands of a species are easilymapped. Our synthesis of this informationhas resulted in the classification ofeight major floristic associations occurringin tidal freshwater wetlands fromMassachusetts to northern Florida. Eachof these associations, or community types,presumably results from reponse to aspecific set of envi ronnntal conditions orseasonal changes (see Sections 2.4 and2.5) and can be described as follows:1) Spatterdock Community type - Spatterdockcan be found in distinctly purestands (Figure 5), especially in latespring, in areas of the marsh adjacent toopen water. Generally these areas arebelow the level of mean lokt water; therefore,during high tide, spatterdock standsare submerged rather deeply. Each periodof inundation can be extensive. Sproutingfrom thick underground rhizomes, thisspecies forms dense clonal colonies oftencovering suherged point bars on tidalcreek meanders. As the growing season

Table 4.Common species of vascular plants occurring in the tidal freshwater habitat.G e n e r a l H a b i t a t Sal ini ty AssociatedSpecies c h a r a c t e r i s t i c s p r e f e r e n c e to1 erance spcci esAcorus calamus(SweetmA1 ternanthera~hiloxeroidesA1 1 igatorweed)Ascle ias incarnataSwamp milkweed)- 7-4G --Bidens coronataBi dens 1 aevi s(Buiia3@3?f)Cal amagros t iscanadensi s-grass)- Carex spp.(Sedges)Echinochloa wal teri(Water's m i - wGrows in dense colonies propagating mainly Shallow water or wet soil;by 'rhizome; stemless plants up to 1.5 m with channel marginsFresh Pel tandra virginicaPol yqonum SDD .stiff, narrow basal leaves; cyl indrical in-Impatiens capensisflorescence emerges from side of stem (openspadi x) ; aromatic.Hollow stems with simple branches hearing Extreqely adaptable; often Fresh toopposite, 1 ance-shaped leaves; forms dense emersed oligohaline-------mats; flowers on long panicles; perennial.Erect, fleshy and stout; up to 2 m; leaves Common to levee sections of Fresh to Pel tandra virqinicalanceolate with blades as long as 20 cm; not the tidal marsh habitat; mesohal ine Pol onum spo.conspicuous until mid-summer when it towers tolerates periodic inundation*o .above other marsh forbs.Tall, leafy, pink-flowered herb growing Cosmopol i tan ; grows in many Fresh to High marsh herbssolitary or in small, loose groups; lance- wetland situations; high oligohalineshaped, opposite leaves; reproduces via seeds marsh speciesor rhizomes.Annual plants up to 1.5 m tall, solitary or Cosmopolitan, growing in the Freshin small scattered groups; loosely branched upper two-thi rds of the interabovewith opposite leaves; leaf shape vari- tidal zone on wet mud or inable but generally toothed or lance01 ate;shallow waterimpressive yellow bloom late in the growingseason.Slender grass up to 1.5 m, generally formingdense colonies; long, flat leaves;loose, ovoid panicle with purplish color;perenni a1 .Wet meadows and thicket5Grass1 ike sedges, culms mostly 3-angled,Low areas with frequentbearin several leaves with rough margins;up to ! m tall and usually in groups; perenfloodingor damp soilnial from long, stout rhizomes.Fresh?FreshPol yqonum sno.haranthus cannabinusother Bidens sop.-Tv~ha SDD.Acorus cal amus--Branched shrub up to 1.5 m tall with Upland margins and raised Freshto Hibiscussn~.leathery smooth opposite leaves and white hummocks of tidal freshwater 01 igohal ine Cornusnomumflowers crowded into dense, spherical, marshes; wet soilstalked heads; flowers June through Aug~~st;leaf petioles reddish.Grass up to 2 m, solitary or in small groups; Shallow water; moist areas, Fresh to -------long, moderately wide leaf blades; flowers in disturbed sites 01 igohal inea terminal panicle which is ovoid, greenishpurple, and appears in July/August.(continued)

Tab1 e 4.(Continued).G e n e r a l H a b i t a t Sal i ni ty 4ssociatedS p e c i e s c h a r a c t e r i s t i c s p r e f e r e n c e to1 erance soeciesHibiscus spp. Shrubform herbs up to 2 m, scattered or in Freshwater marshes or the up- Fresh to TyDha soo.large colonies; leaves wedge-shaped or land margin of saline marshes vesohaline S artina cynosuroidesrounded and a1 ternate; large, showy pink or with freshwater seepage h m son.white flowers appearing in midsummer;Impatiens capensi sperenni a1 .Eleocharis alustris Perennials with horizontal rootstocks; culms Channel margins or stream Fresh to Pontederi a cordataua ran stout, slender, and cylindrical or squarish banks in shallow water; muddy, ol igohal ine Scirous spp.with a basal sheath; flowers crowded ontotenninus of spikelet; between .5 and 1.5 in.organic substrates =s~o.Leersia oryzoidesIm atiens ca ensis Annual plants up to 2 m with succulent, Same as Bidens spp.; also grows Fresh Bidens son.-*eaf branched stems with swelling at the joints;colonial ; leaves a1 ternate and ovate orin shaded portions of marshes T_ypha spo.Polyqonum sno.orange and funnel-like, appearing in July/August.el 1 iptic with toothed margins; flowersIris versicolor Flat, swordlike leaves arising from a stout High, shaded portions of the Fresh None in oarticlrlar~ ~ u m creeping rhizome; large, purpl ish-blue intertidal zone in damp soi;4 flowers emerge in spring from a stiff upright will not tolerate long inundaa,stem; perennial. tions.Leersia or zoides Weak slender rass growin in dense, matted Mid-intertidal zones of Fresh toMany; none inc colonies. lea! sheaths a"j blades very rough; marshses; high diversity vege- 01 i gohal ine particularemerges tram creeping rhlzomes and oftentation patchessprawls on other vegetation.Lythrum salicaria Shrubform herbs forming large, dense colon- Moist portions of marshes; Fresh to Hihiscus snn.Decodon ies; aggressive; up to 1.5 iq in height with high intertidal or upland 01 iqohal ine Convolvulus son.verticillatus lanceolate leaves opposite or whorled; upper areas(Loosestri fe) axil s branched with small purplish-pinkflowers; terminal spikes pubescent; annual.-Mi kani a scandens Long, herbaceous vine forming matted tangles Open, wooded swamps and marshes; Fresh to(Climbingee) over other emergent plants; heart-sha3ed shrub thickets oligohalineleaves; dense, pinkish flower clusters;slender stem; propagates by both seed andrhizome; perenni a1 .M rica cerifera Compact, tall , evergreen shrub with leathery Most a1 1 coastal habitats; Fresh-k- wax-mjZiT)-alternate leaves; spicy aroma; waxy, berry- border between intertidal zonelike fruits; forms extensive thickets.and uplandsPlant with floating or emergent leaves and Constantly submerged areas up Freshflowers attached to flexible underwaterto 1.5 m deoth, or if tidal,stalks; rises from thick rhizomes imbeddednear or below mean low water inin benthic mds; flowers deep yellow, appear- deep organic mudsing throughout the summer.--Acer ruhrumspo.Taxodium rlistichuvUsually in ourestand

Nyssa sylvanticaN~s;;~;;uaticaMedium-sized tree (10 m) with numeroushorizontal, crooked branches; leaves crowdedat twig ends turning scarlet in fall; flowersappear in AprillMay.Panicum vir atum Perennial grass 1-2 m in height in largem h * bunches with partially woody stems; nest ofhairs where leaf blade attaches to sheath;large, open delicately branched seed headproduced in late summer; rhizomatous.Pel tandra vir inicaaStemless plants, 1-1.5 m tall, growing inloose colonies; several arrowhead-shapedleaves on long stalks; emerge in ratherdense clumps from a thick subsurface tuber;flowers from May to June.Phragmi tasTall, coarse grass with a feathery seedaustral ishead; 1-3 m in height; grows aggressively-reed ) from long, creeping rhizomes; perennial ;flowers from July to September.Polyqonum arifoll Plants with long, weak stems up to 2 m tall,Pol onum sa ittatum usually leaning on other vegetation; leaves[ ; : a r t h u e saqitate in shape and alternate; leaf midri6sand stems arined with recurved barbs;flowers small and appearing in late summer;-L annual.IJPolyqonum punctatum Upright plants growing from a fibrousPol onum densi- tuft of roots; narrowly to widelyT~%uT - lanceolate leaves with stalks basallyPolygonum hydropi-~ E es ) denclosed within a membranous sheath; upto 1 m; flowers at spike at end ofstalk.Pontederia cordata Rhizomatous perennial growing in dense or-(Pickexweed) loose colonies; plants up to 2 m tall ;fleshy, heart-shaped leaves with parallelveins and emerging from spongy stalks;flowers dark violet-blue, appearing June toAugust.Flarsh/upl and borders Fresh --Acer ruhrumMyrica ceriferam s n l .Dry to moist sandy soils or Fresh to -- Hi3iscus snn.the mid-i ntertidal portions nesohal ine Sci rpus snp.of tidal freshwater marshes; Eleocharis oalustrisdisturbed areasGrows predominantly as an Fresh to Pontederia cordataemergent on stream margins or 01 igohal ine Z izania aquaticaintertidal marsh zones on ~nanv other soeci~srich, loose siltExtrenely cos~noool itan, growing Fresh to Spartina cynosuroid-esintidal and nontidal marshes nesohaline Zizania ?qttaticaand often associated with disturbedareasShallow water or damp soil ; Fresh to Bidens sno.middle to upper intertidal 01 igohal ine Hihiscus spp.zoneIm~atiens canensis--- ---!Ipper three-quarters of inter- Fresh to Many s7eciestidal zone in freshwater marshes oligohalineon wet or damp soilLower intertidal zone of Fresh tc~ Nuphar lutpumtidal freshwater marshes oligohaline Pel tandra virqinicaSaqittnri3- latifol iaRosa alustris7 ~ a -Shrub up to 2 m growing in loose colonies;stems lack prickles except for those occurringat hases of leaf stalks; pinnatelycompound leaves with fine serrate margins;showy, pink flowers appearing JulyJAugust.High intertidal zones or wet Fresh to Cenhala~thus occidentmeadows01 igohal ine -alis- -Rumex verticil latus Erect, robust annual with dark-green, Wet meadows or pond margins Fresh tom t e r dock) lance-shaped leaves; stem swollen at nodes; on mud or in shallow water 01 igohal ineattains heights over 1.5 m.,and grows solitaror n oose colonies flower head i?evlrent in late spr~ng and can he 53 cm Inlength.(continued)

Table 4,(Concluded).G e n e r a l H a b i t a t Sal i ni ty AssociatedS p e c i e s c h a r a c t e r i s t i c s p r e f e r e n c e tolerance speciesSa ittaria latifolia Perennial herbs; stanless, up to 2 m in Borders of rivers or marshes Fresh to Peltandra virqinicah t a t o ) height and emerging from fibrous tubers; in low intertidal zones on 01 igohal ine ---- Pontederia cordataSa i ttarl falcata leaves arrowhead-shaped or lanceolate with organic, silty mud*~UFwhite flowers in whorls appearing on anaked stalk in July/August.Scir us val idus Medium to large rushes with cylindrical or Brackish to fresh shallow Fresh to Other rushes'&tzush) triangular stems; inconspicuous leaf sheaths; water or low to middle inter- snesohal ine wh~ spp.Scir us c erinusIusually grow in small groups; bear seed~1ustersonendorsideofstm;perennial.tidal zones on organic claysubstratesScir us americanus7- Common three square)Spa rqani um Stout upright forbs up to 1 m with limp, Partially submerged, shallow Fresh lizania aquaticaeur car umunderwater, emergent leaves attached basally water marsh areas; lower to Leersi a -ides(*cad)and a1 ternating up the stem; to~ards the middle intertidal zones Tf?7jGj5iiurn snn.-terminus, stems zig-zag bearing sphere-likeclusters of pistillate and staminate flowers.Spart ina Perennial grass attaining heights in excess Channel and creek margins in Fres!~ to Phragmi tes austral isof 3 m, having long, tapering leaves and tidal 01 igohaf ine marshes nesohaline -h~ spp.growing froin vigorous underground rhizomes;0)found in dense monospecific or mixed stands.Taxodium distichum Tall tree with straight trunk (40 m), conifer- Marsh/upland borders'-d'-cypress)1 ike but deciduous; light porous wood coveredby stringy bark; unbranched shoots originatingfrom roots as knees.Zizania a uaticaStout, upright reeds up to 3 m formingdense colanies; basal leaves, long andsword-like, appearing before stems; yellowirhmale flower disintegrates leavinga thick, velvety-brown swelling on thespike; rhizomatous; perennial.Annual or perennial aquatic grass, 1-4 mtall, usually found in colonies; shortunderground roots, stiff hollow stalk, andlong, flat, wide leaves with rough edges;male and female flowers separate along alarge terminal panicle in late sumner.Fresh?--Very cosmopol i tan, occurring Fresh to blany associatesin shallow water or uppernesohal ineintertidal zones; some disturhedareasFresh to slightly brackish Fresh to Peltandra --- virqinicamarshes and slow streams, 01 igohal ine many other speciesusual 1 y in shall ow water;requires soft ~nud and slowlycirculating waterZizaniopsis Perenni a1 by creeping rhizome; culms Swamps and margins of tidal Fresh?mi leacea 1-4 m high; long, rough-edged leaves genic- stream(Giant cutgrass) ulate at lower nodes; large, looseterminal panicles appearing in midsummer;aggressive.References: Fassett 1957; Fernald 1970; Beal 1977; Tarver et al. 1979; Magee 1951; Silberhorn 1982.

progresses, some pl ants wi 11 be overtopaedby other species commonly inhabiting thelow intertidal zone such as arrow-arum,pickerelweed, and wild rice.2) Arrow-arum1Pickerelweed CommunityType - Arrow-arum is an extremely cosmopoli tan species growing throughout theintertidal zone of many marshes. Thisspecies forms its purest stands in the lowintertidal portions of the marsh in springor early summer. Pickerelweed, a commonassociate, is equally as likely to dominateor codominate this lower marsh zone(Figure S), although its distribution isusual ly more cl unped than arrow-arum.Both species tolerate long periods of inundation.Other species associated withthis community type, especially in moreelevated sections of the marsh, includeburrnarigolds and wild rice, and less frequently,arrowhead, sweetfl ag, and smartweeds.3) Wild Rice Community Type - Wild rice isconspicuous and widly distributed throughoutthe Atlantic Coastal Dlain. This annualgrass can completely dominate a givenmarsh, producing plants which attainheights in excess of 4 m (13 ft) in Augustand September (Figure 7). Wild rice isnot noticable until midsummer when itbegins to overtop a discontinuous canopygeneral ly composed of arrow-arum,pickerelweed , spatterdock, arrowhead,smartweed, and burnarigolds.4) Cattail Community Type - Cattails areamong the most ubiquitous of wetlandplants and are princioal components ofmany tidal freshwater marshes. The cattailcommunity type (Fiqure 8), whichincludes several species of Typha in themid-Atlantic region, is qostly confined tothe upper intertidal zone of the marsh.Cattails are usually found with one ormore common associates---arrow-arum, rosema11 ow, snartweeds, jewelweed, and arrowhead---butwill a1 so form dense inonospecific stands. Cattail communities area1 so prevalent in disturbed areas, wherethey often are associated with commonreed.5) Giant Cutgrass Community T.yne - Giantcutgrass, also known as southern wildrice, is an aggressive perenni a1 confined~redorilinantlv to wetlands south of Virqin-Fi gure 5. Spatterdock cornrnuii ty type. i a and l4aryl and. This species dominated19

Wild RicePickerelweedArrow-ArumFigure 6.nity type.Arrow-arurn/pickerelweed commu-Figure 7. Elild rice community ty~e.

many of the tidal freshwater marshes ofthis region, often competing with otherplants to their exclusion. When not inpure stands, this grass associates with avariety of ot'ier emergent macrophytos includingsawgrass, cattails, wild rice, alli yator weed, water parsnip, and arrowarum(Figure 9).6) Mixed Aquatic Community Type - Themixed aquatic community consists of anextrenely variable conglomeration offreshwater marsh vegetation (Figure 10).Generally occurring in the upper intertidalzone of the marsh, it is comuosed ofa number of codominarlt species which forman intricate mosaic over the narsh surface.Important species include arrowarum,rose-ma1 1 ow, smart\.reecls, water-hemp,burrnarigolds, sweetflag, cattails, ricecutqrass, 1 oosestri fey arrowhead, and jewelweed.Certain comoonents of the mixedaquatic type dominate on a seasonal basis.7) Big Cordgrass Comrnunity Type - Bigcordyrass is often seen growing in nearlypure stands in narrow bands along tidalcreeks and sloughs, or on levee portionsof 01 igohal ine garshes (Figure 11).Arrow-arum and pickerelweed are associatedwith big cordgrass in these locales, butvdhon stands extend further up onto themarsh, this species will inter:nix withca ttai 1 s, cornr?ion reed, rice cutgrass, andwild rice.3) Bald Cypress/Black GUT Commuqity Ty~eThe bald cypress/black gum type (Figure12) generally represents an ecotonal communityforming the boundary between themarsh itself and wooded swam or up1 andforest. Situated in the most landwardportions of tile tidal freshwater marsh atapproximately the level of mean highwater, this comvunity consists of a mixtureof herbs, shrubs, and trees. Otheroverstory species include tupelo gum, redmaple, and ash, as well as shrubs such aswax-myrtl e and buttonbush. Understoryspecies include typical tnarsh plants, a7-tilough their diversity and density isreduced because of shading.Zonation-Figure 3. Cattail community type.The presence of reoccurring groups ofspecies which fom recognizable patternsin many wet1 and habitats has encouraged

Giant Cutgrass/ycrass community type.Hopkinson.the description of plant species distributionsin terns of zones. Zonation intidal freshwater marshes is 1 ess distinctthan in many other aquatic or wetlandenvironments. This is partially a functionof the complexity of the major tidalfreshwater community types. A number ofspecies consistently form pure or mixedstands which do not necessarily occur inregular patterns from marsh to marsh(Whigham et al. 1976, Wum 1978). In someinstances, individual species or groups ofspecies have little or no orqanizationalpattern, appearing to !)e distributed in arandom fashion over the marsh surface.The existence of zonation is supportedby some studies. In Virginia tidalmarshes on the Chickahominy River, cattai1 s and rose-ma1 1 ow regularly appear inthe landward half to one-third of themarsh profile. Precise surveying of someof these areas indicates that this naturalvegetation boundary coincides with a 20 to30 cm (8 to 12 inch) rise in the marshsurface (Hoover 1983). Parker and Leck(1979) described two major zones in a NewJersey rnarsh dominated by annuals. The1 ow marsh zone contained water smartweed,clearweed, and water-hemp, and the highmarsh zone contained tearthumb, burmarigold,and jewelweed. Seed1 ing transplantstudies indicated that higb marshspecies could not tolerate prolonqed periodsof inundation in the low marsh zone.Concurrently, competitive interactionsseemingly contributed to the exclusion ofthe low marsh dominates from the highmarsh zone.22Mhigham (Chesapeake Bay Center forEnvironmental Studies, Edgewater,Maryland, pers. comm.) notes that a varietyof annual species tend to congregatein the upper intertidal reaches of mid-Atlantic coast marshes. He postulatesthat the ability of many of these speciesto produce adventitious roots above themarsh substrate may be a rnechanisin allowinggreater species packing. As such,plants wit11 this adaptation (e.g., burmarigold)can avoid anaerobic substrateconditions yet exploit a low, humid, anddensely shaded layer just above the marshsurface.In a freshwater marsh habitat influencedby artificial water level fluctuationson the Connecticut River, van Raal te

Rose-Mallow \i':JewelweedFigure 10.Mixed aquatic community.(1982) found that plants grew in distinct herbivory all contributed to this obviouszones. Pickerelweed dominated the low zonation pattern. Cahoon (1982) di s-intertidal zone followed by \?lore landward covered that the biomass a11 ocation pat-Sands of arrowhead and rice cutgrass. tern of individual wse-mallow plants wasTransplant experiments indicated that ele- influenced by salinity, water depth, andvation, interspeci fic competition, and soi 1 temperature. The existence of vari-

Cordgrassii Wax-MyrtleI IFigure 12.nity type.Bald cypress/bl ack gum commu-

able physiognonies in this species mightbe considered analogous to the heightforins of smooth cordgrass whi ch del ineatezones in salt narshes.Where zonation, as an organizationalexpression of species distributions, actuallyexists in the tidal freshwater marshhabitat, it is probably controlled by acombination of physical variables and eco-1ogi cal processes. Prel irninary evidencesugyests that there may be a certain degreeof consistency in the zonation foundin tidal freshwater oarshes. However, theextent of this patterning with respect tovarious community types, as we1 1 as itsregularity frorn location to location, isunknown.species within a general structural frameworkfor tidal freshwater wetlands. As afirst approximation to community structurewithin this habitat, most of the comnon1.yoccurring vegetation fa1 1 s into one of thefol lowing categories: (1) submerged orfloating-leaved plants, ( ) emergentplants with basal leaves and/or leaflessstems, (3) emergent or damp soil herbswith stems bearing alternate or opposite1 eaves ,. (4) grass1 ike or rush1 i ke ol ants,and (5) broad-1 eaved shrubs and trees(Magee 1381). By recognizing the aporoximatemodal distributions of common plantspecies or communi ty-type indicatorspecies within these structural subgroups,a typical marsh profile can be visual izedand described.The Marsh ProfileThe marsh profile de~icted in Fiqure13 is most characteristic of mid-AtlanticExcept for the most obvious community tidal marshes. Seds of submerqed, rootedtypes, it is difficult to place a given aquatic plants (see Section 2.6) make upBALD CYPRESS - BLACK GUMWAX-MYRTLEWILD RICEGlA NT CUTGRASS4 CATTAILSEDGES - RUSHESBIG CORDGRASSIIIIIROSE-MALLOWJEWELWEED3 BURMA RlGOL DTEARTHUMBSMARTWEED1ARROW-ARUMPICKERELWEEDI IIIIII I I I IHIGH MARSHWOODED SWAMP1FORESTED UPLANDFigure 13.Characteristic profile of mid-At1 antic tidal freshwater marsh.25

an invisible, suspended mat of vegetationat the foot of the marsh where inundationis constant. Verging with this subtidal1 ayer and extending variable distances uponto the muck surface of the marsh are ahost of fleshy-leaved, emergent macrophytes:spatterdock, arrow-arum, pickerelweed,and arrowhead. These species, pluswild rice, big cordgrass, and numeroussedges and rushes, comprise the bulk of1 ow marsh vegetation. The transition fromlow to high marsh is generally marked byan increase in species number, presumahlydue to reduced periods of inundation. Thepredominant components of the high marshzone include low swards of tangled grass(rice cutgrass), erect or sprawl ing herbaceousthickets (burmarigold, tearthumb,jewelweed, smartweed), tall grasses orgrass1 ike plants (giant cutgrass, wildrice, cattail, sweetflag), and shrub1 ikethickets (rose-ma1 low, swamp rose, loosestrife). The most 1 andward extent of themarsh usually coincides with the mean highwater mark and is indicated structurallyby a dense wall of shrubbery (wax-myrtle)and associated overstory (bald cypress,black gum, red maple) and understory (jewelweed,Asiatic spiderwort) species.Variations on this scheme are numerous,and are often associated with thephysiographic characteristics of the marshprof i 1 e. One physiographic feature consistentlyfound in the tidal freshwaterhabitat is an elevated levee forming thecrest of the channel bank. This featurecreates a niche for facultative hydrophytesor less water-tolerant specieswithin the low marsh zone. Plant speciescommonly taking advantage of the leveenichein Virginia are water-hemp, commonthreesquare, squarestem spi ke-rus h, rosemallow,giant ragweed, and other highmarsh herbs. Simi 1 arly, subsidence areaswithin the high marsh zone can create aniche for obl igate hydrophytes. Thisphenomenon can usually be attributed togeologic maturation of riverine and estuarinewetlands (see Section 1.6).Metzler and Rosza (1982) describe amarsh profi le for northeastern At1 anticcoast tidal freshwater wet1 ands. For comparison,it is presented in Figure 14.The definition and extent of zones isquite similar to that described for mid-At1 antic marshes, a1 though there aresignificant differences in species composition.fMHWI I I1 I II I 1I I 1 C__IIIID I EIZONE DESCRIPTION SPECIES CHARACTERISTICSA SUBTIDAL PONDWEEDS, WATERWEED, HORNWORTB LOWER INTERTIDAL ARROWHEADS, SEEDBOX, BULRUSHESC MID-TIDAL MARSH BULRUSHES, WATER HEMP, WATER PARSNIP,BORDERSNEEZEWEED, SMOOTH BURMARIGOLD, WILDRICE, PICKERELWEED, ARROWHEADSD HIGH MARSH SWEETFLAG, CATTAIL, SWAMP ROSE, REEDBENTGRASSE UPLAND RED MAPLE, WATER WILLOW, ARROW-WOODFigure 14. Northeastern marsh profile. Modified from bletzl er and Rosza (1982).

2.4 FACTORS CONT3OLLIVG PLANT DEMOGRAPHYThe distribution of plant speciespopulations in any natural situation reflectsthe response of individual speciesto soeci f ic environmental parameters. Inwetl and habitats these parameters areespecially varied, primarily due to thei nf 1 uence of water on habi tat gradients.Siologically-mediated interactions betweenplant species further coqplicate the perceptionof physical gradients. Much ofthe information concerning the causes forobserved spatial distributions of vascularflora in these marshes is anecdotal, althoughenough exists to warrant a generaldiscussion.InundationThere seems to be a general consensusamong researchers investigating plant demographyin the tidal freshwater habitatthat the frequency and duration of floodingis the primary factor governing speciesdistributions (Kiviat 1978a; Ooumleleand Silberhorn 1978; Ferren et al. 1981;McCormick and Somes 1932). Despite thefact that the vast majority of plantsoccurring in these marshes must experienceflooding on a daily basis, speciesvary greatly in their ability to withstandinundation. For some species, extensiveflooding seems to be a physiological requirement for subsistence, whereas forothers, it can be a detriment to normalgrowth and development. Scul thorpe (1967)notes that nicmerous terres tri a1 pl ants areable to survive long periods eithercompletelyor partially submerged. It isconceivable that facultative hydrophyteshave evolved in order to avoid competitionor to exploit open niches in habitats suchas these.stunted progeny in deep-wa ter experimentalplots (Yamisaki and Tange 1981). Manyother researchers working in sal t marsh,mangrove swamp, and freshwater lake environmentshave concl uded that inundationeffectively contributes to segregation ofpl ant species ~opul a ti ons a1 ong an el evationalgradient (Filandossian and Mc Intosch1950; Aifains 1963; Scul thorpe 1957; Kerwinand Pedigo 1971; Odum 1971). As yet, thisphenomenon has not been quantitativelydetermined for tidal freshwater marshes.However, evidence from other wetl and si tuationssuggests that tidal freshwaterplant communi ties segregate a1 ong inundationgradients as well.SubstrateThe soil in tidal freshwater marshescan be described as a waterlogged organicmuck with varying amounts of sand, silt,and clay (see Section 1.7). Differencesin soil stability, soil moisture retention,and soil nutrient availabil i t,y areall related to the physical characteristicsof a given substrate and may influencespecies distributions directly. Thespatial heterogeneity of substrate characteristicsis not sufficient to explaindistributions or species performance(1Jhigharn and Simpson 1975; Wetzel andPowers 1978). Wetzel and Powers (1978)concluded that substrate characteristicsaffect plant demography only in local izedzones within the marsh, and then, thesesubtl e differences are largely obscured bymajor environmental gradients acting toproduce species distributions (e.g., elevationand tidal inundation). In ouropinion, this is an area which needsconsiderably more research.Current FlowIn the progression from open water Low-gradi ent river courses of thechannels to the tnarsh-upland boundary, the Atlantic Coastal Plain tend to flow ratherspecies composition of vascular flora sluggishly except during extreme storm orchanges noticedbly, even over almost im- flood events. Aside from channel disperceptablevariation in marsh surface charge, however, the daily ebb and floodelevations (Hoover 1983). It is known of tidal water onto and off the marsh surthatcommon and narrow-leaved cattails face can produce significant currentwill segregate along a gradient of water velocities. Much of this water becomesdepth in nontidal habitats, the latter channel ized into dendri tical ly-shapedspecies found in deeper water (Grace and creeks within the marsh. These creeksGetzel 1951). Common reed and wild rice deliver ground water from high marsh toa1 SO respond to varying inundation, each low marsh to channel long after the tidespecies producing fewer and somewhat has ebbed (Hoover 1983). Concentrated27

water movement may (1) impair the abil i t yof seeds, seedlings, or adult plants togrow and develop and (2) may confine thedispersion of particular seeds to portionsof the marsh wqth little or no water flow.Several studies provide evidence tosupport these ideas. Whigham et al.(1979) noted that arrow-arum seed1 ings,which develop uni formly throughout mostsections of the marsh, were absent fromstreambafik areas. Higher rates of watermovetilent a1 ong the s treambank apparentlyprevented seeds from establ ishing themselves,since seeds collected from thesesariie areas were found to be physiologicallycapable of germination. In contrast,pickerelweed is known to prefer streambank1 oca tions, taklng advantage of greatersoil surface temperatures on the exposedmud as we1 1 as reduced competitive pressuresin this area (Garbisch and Coleman1978).Sal i nitvThe variahil ity and complexity ofwetland plant communities increases withdecreasing salinity. Anderson et a1 .(1968), studying a 25-mJle stretch of thePatuxent River estuary in Maryland, il lustratedthis fact by quantifying plant species'diversity at sltes with differentsalinfty regimes (Table 5). Ry definition,the tidal freshwater habitat shouldnot encounter average water sal ini tiesgreater than 0.5 opt. However, thisboundary between tidal fresh and 01 i goha-1 ine waters has been seen to mi grate considerabledistances over the course of ayear in responseperiods. Marshesto drought and floodwhich intermittentlycome into contact with elevated watersalinities may harbor slightly lessdiverse plant co~notun.! ties dominated byfacultative halophytes (see Section 2.2).Freshwater species which appear to dropout of the plant communities in theseareas include spatterdock, sweetfl ap,blueflag, various sedges, and giant cutgrass,Physiological Capabil i tylAnaerobic ToxinsPreliminary evidence suggests thattidal freshwater marsh soils are not asreduced as some salt marsh substrates, atleast in the surface horizon (see Section1.7). Presumably, the extent of oxygendeficiency is not homogeneous over theentire marsh profile, being 1 ess intensein those areas which drain regularly witheach tidal cycle. Nevertheless, soi 1s andassociated microbial populations shifttheir predominant metabol ic pathways underanoxic conditions, affecting both inorganicand organic soil constituents --- thiscan have important consequences for wetlandplant life.The bioavailabil i ty of most nutrientsand toxins responds to the oxidationreductionconditions of wetland soils(Gambrel 1 and Patrick 1978). Increasedlevels of soluble iron and managanese insome reduced soils are reported to be toxicto plants (Armstrong 1975), and furthermore,may facil i tate the formation ofinorganic-oxide 1 ayers around roots whichpotentially impedes the transport of nutrientsfrorn soil to plant (Armstrong andBoatman 1967; Howel er 1973). Extremelyreduced soil s with appreciable organiccarbon mity develop toxic sulfide compounds.Many wetland plants have adapted tothese extreme conditions , devel oping meansof metabol izing anaerobical ly and excludingtoxins froin roots. The provision ofair-space or aerenchy~iiatous tissue is onemechanism enabling plants to transportat~nospheric gas to anoxic rhizospheres.The functioning of this pressurized, flowthroughsystem has been documented indetail for spatterdock (Dacey 1980), aspecies which typically thirves in themost waterlogged portions of the marsh.Other emergent macrophytes which possessaerenchynatous tissue include arrow-arum,pickerelweed, and even certain grasses andsedges. Most of these species will befound in tile lower intertidal zones intidal freshwater marshes.CompetitionFrom an ecological point of view, thediverse flora indigenous to tidal freshwaterwetlands would seem to have a highpotential for speci es-speci es i nteractions.A conspicuous feature of manyplant communities that is often consideredevidence of competitive displacement isthe segregation of species along a habitatgradient. A1 though species segregations

Table 5. Species composition of five marshes along the Patuxent River in Maryland.The marshes have been designated by their respective sal ini ty regimes.This table is modified from Anderson et al. (1968).Speci esSal ini ty regimes10-17 ppt 6-10 ppt 3-7 ppt 0.5 ppt. 0.2 p ~ tAster tenui fol iusDistichlis spicataFi inbri s ty1 i s cas tl aneaJuncus gerardiLythrilm 1 ineareAtriplex patul a- Iva frutescensSci rpus robus tus(continued)29*****

Table 5.Concluded.SpeciesSalinity reqimes10-17 ppt 6-10 ppt 3-7 ppt 0.5 ppt 0.2 ppt--Acer rubrum--Carex a1 ataCarex a1 bolutescens- Carex annectens--Carex colnosa- Ca rex 1 u put i naGal ium obtusum- Geum canadenseJuncus effususLactuca canadens isLythrum sal icariaI~lyosotis &Rorippa palustri scorus cat amus- Aster cal amusBidens frondosa--BidenslaevisCyperus s triposusCyperus re ractusIrl s versicolorLudwigi a a1 ternifl oraLycopus virgini cusOrontium aquaticumS t u r n v eZi zani ops i s mi 1 i acea- ie-Spec'i es Total s

of sorne form (e.g . , major community t-ypes)are apparent in most tidal freshwaterhabitats, ascribing such a phenomenon tocompetition per se is difficult.The mechanisms involved in competitiveplant interactions are varied. Onlya few studies have experimental 1 v detnonstratedthe importance of competitive displacementin maintaining wet1 and y1 antdistributions. Grace and idetzel (1981)showed that populations of common andnarrow-leaved cattail s segregate accordingto water depth, the former competitivelysuperior in shallow water due to itsgreater 1 eaf surface area. However,narrow-1 eaved cattail has the potenti a1 togrow in deeper water than comqon cattail,a capacity facil i tated by phenotypictraits such as taller, narrower leaves andgreater rhizome storage. Cahoon (1982)also noted phenotypic responses in twotidal freshwater species with over1 appingdistributions. Pose-ma1 1 ow was found torespond to the presence of narrow-leavedcattail by increasing its leaf size. However,the consequence of such a strategywas a concomitant reduction in reproductiveoutput. Buttery and La~nbert (1965)found that manna-grass dominated a particularportion of a habitat gradientstrictly through its ability to opoortunistical ly outcompete another speci es , thecommon reed. Without further studies, itis difficult to accurately ascertain theimportance of competition on species distributionpatterns. The evidence avail -able thus far, however, suggests that competiti ve pressures act in con junction withpi~ysical factors to produce speciesniches.rnents with leaf and petiole extracts, aswell as soil extracts, showed that thesespecies vary in their abil ity to affectthe germination of bioassay species, suggestingthat similar interactions may occurbetween marshland species.2.5 SEASONAL SUCCESS1 ONA unique aspect of tidal freshwatermarshes is the continually changingappearance of the vegetation over thecourse of the growing season (Figure 15)A1 lelopathyChemicals derived from one plantwhich have inhibitory effects on thegrowth and development of another plantare termed a1 lelochewics. The concentrationin the soil of alleleochemics from adominant plant [nay exclude many otherpl ant species from the community (Whittaker1975). Mcriaughton (1968) suggestedthat cattails have a1 lelopathic effects onother aquatic sgecies. Bonasera et al.(1979) cornpared the a1 lelopaihic potential Figure 15. Winter and early summer scenesof four species common to tidal freshwater at the same location on tidal freshwaterhabitats --- giant ragweed, arrow-arum, Poto~nac River. Photographs by !lj chaelburinari gold, and comnlon cattai 1. Experi- Dunn.

(Shima et al. 1976; Whigham et al. 1976;McCormick and Somes 1982; Silberhorn1982). In the mid-Atlantic region, thefirst real evidence of renewed plant lifein tidal freshwater marshes is the emergencyof spatterdock in the low intertidalzone. Shortly thereafter, as temperaturesbegin to rise, the spike-like projectionsof arrow-arum and pickerelweed pokethrough the muck surface from undergroundrhizomes. Interspersed among these emergingperennials are large numbers of annualseedlings, largely comprised of wild rice,burmarigolds, tearthumbs, and smartweeds.By early May, arrow-arum, pickerelweed,and spatterdock completely dominate theintertidal zone, forming a dense low canopyover the other species; in places, thiscanopy is overtopped by the tall,sword-1 i ke leaves of ca ttai 1 and sweetflag.Many other species will have germinatedby early summer, but renain largelyobscured by the vegetation canopy. However,it is not long before grasses suchas wild rice and giant cutgrass begin toovertop the 1 ayer of fl esh-leaved perennials,reaching heights in excess of 3meters (10 ft) by mid-July. As otherspecies followburmarigolds,suit (e.g.,tearthumbs,rose-mallow,water-hemp,jewelweed), the diversity of the marshbecomes noteworthy, often as many as 30 to50 species appearing in a single qarshlocation.wild rice, andlweed , somewhatcoming fall: deep reddish hues appear inthe leaves and stems of tearthumb; wildrice stands topple under the force ofstrong winds and rain; the dense clumps ofarrow-arum become reduced to stubby, mudcoveredsprigs. The killing frosts ofNovember eliminate any remaining greenery.All that is left by winter is a mat oftangled, dead stems which gradual ly breakup and disperse under tidal influenceleaving a largely barren rmdfl at untilspringtime.2.6 OTHER AQUATIC VEGETATIONLargely igondred in the existingfloristic studies of tidal freshwatermarshes are (1) species of aquatic vascu-1 ar plants characteristically growingbeneath the water surface, (2) phytopl anktonwithin the water column, and (3) benthicor soil algae residing on muddy substratesor epiphytic on emergent plantparts. Each of these taxonomic groups isinherently less visible than emergentmarsh macropl-lytes, yet their importance tothe overall ecology of the tidal marshhabitat must not be overlooked.Aquatic Vascul ar PlantsSubmerged vascular flora general lygrow in a zone extending approximatelyfrom the level of mean low water to depthsup to several meters depending upon theclarity of the water (see Figure 13).This zone typical ly 1 ies adjacent toemergent low marsh, and in the case ofsmall shallow creeks, can encompass theentire channel. Most of these aquaticplants establish roots in soft benthicmuds, perennially giving rise to herbaceousoutgrowths. The density and extentof stands are extremely variable, and manyspecies are subject to drastic fluctuationsin their populations from year toyear, or in some cases, within a givenseason (Southwick and Pine 1975; Bayleyet a1 . 1978).At the genus level, waterweeds, pondweeds,and watermil foils (Figure 16) aresome of the more prevalent components ofti dal freshwater wet1 ands of theAtlantic coast (Wilson 1962; Tiner 1977;!-IcComick and Somes 1982; bletzler andRosza 1982). In Virginia, some fresh subtidalaquatic beds are composed of various

naiads, wild celery, and dwarf arrowhead,the 1 atter species situated approximatelyat the level of mean low water on gentlysloping channel banks (Hoover 1983). TheConnecticut River has been described specificallyas having a rooted aquatic zonecodomi na ted by waterweeds, pondweeds, andwild celery, with less common species suchas hornwort, pyglnyweed, and mud-pl antainin association (Metzler and Rosza 1982).Of ten, macroscopic algae are found growingamidst these vascular aquatic plants includingspecies of the genera Ni tel la,Spi rogyra and Chara (Lippson et a1 . 1979;FlcCormick and SX 1982).Ecological ly, aquatic vascular plantsare important in several respects. Densestands of aquatic plants can represent asignificant fraction of the overall autotrophicproductivity in tidal freshwatermarshes. Many species are primary foodstufffor migrating and nesting waterfowl(see Chapter 7), and may also serve ashabitat for various fishes and aquaticinvertebrates (Chapter 4). It is possiblethat these plants act to bind substrateswith their dense root networks and mayeven encourage sediment deposition by bafflingwater movement. However, theseeffects are not yet quantified.As with emergent vegetation, the diversity of rooted vascular aquaticsincreases as water salinities decrease.Stewart (196?), working in estuaries ofthe Chesapeake Bay region, showed thedramatic increase in species tomposi tionbehieen brackish and fresh salinityregimes (Table 6). However, in certaininstances, the natural historical distributionof these types of aquatic plantshas been a1 tered by the mu1 tiple impactsof human population growth and activitywithin the estuarine watershed. Haramisand Carter (1983), in an extensive surveyof submersed aquatic macrophytes in thedweedPotomac River, found that the tidal freshwaterportions of the river were essentially devoid of plants. Apparently,long-term enrichment of the river waterhas cailsed massive and persistent algalblooms which have a1 tered the competitiveFigure 16. Common submerged aquatic balance between phytoplankton and macroplantsfound in Atlantic coast tidal phytes, resulting in the decline of thefreshwater marshes.latter.

Table 6. Salinity tolerances of various submerged aquatic plants common toestuaries of the mid-Atlantic coast. Modified from Stewart (1962).SpeciesSal ini ty RegimesPol v- Meso- 01 iuo- TidalMarine ha1:ne haline haline Fresh- - ---Brown aluae- Ul va 1 actucaEnteromorpha spp.Zos tera marinaRed a1 qae~uppia-mari timaZannichellia palustrisPotarnogeton ectinatusPotamoyeton --i- perfo iatusPlyriophyl lux spicatumElodea canadensi sPotamo eton jramineusd m pinnatumMyriophyllum tenellumNajas gracill imaZos terel 1 a dubi aSpeci es Total sPhytopl anktonPhytoplankton are an extraordinarilydiversified group of organisms floatingfreely in the water column as single cellsor as small mu1 ticel 1 ul ar colonies . Seasonaland spatial population dynamics ofthis taxonomic group result from a largeand constantly changi ng array of envi ronmentalparameters interacting with physiologicalcharacteristics of the organisms.Salinity is a major factor influencing thegeographical distribution of phytopl ankton,creating a distinct community intidal fresh water which is comprised, forthe most part, of riverine taxa (Lippsonet al. 1979). Light, temperature, andwater turbidity exert considerable influenceon photosynthesis and other metabolicprocesses such as reproduction. Thesefactors interact with cycling nutrients,especial ly nitrogen and phosphorus, to

govern the seasonal blooms and successionsof phytoplankton populations. In undisturbedtidal freshwater locales this successionalperiodicity is fairly constantfroin year to year; however, biotic transitionsmay be muted in southern Atlanticcoastal regions where cl iniatic changes areless drastic (Sandifer et al. 1980).General izations concerni ng seasonalabundances and periodi cities of phytoplanktersin fresh water are difficult tonake, especial ly if unnatural nutrientloading occurs in the estuary (Wetzel1975). Dne of the feu existing quantitativeassessments of tidal freshwater phytoplanktoncommunities was coinpiled forthe Potomac River in Virginia and rlaryland(Lippson et al. 1979). These algal populationswere largely characterized by (1)species of green a1 gae (Chlorophytes)which are moderate to high in abundanceyear around, (2) diatoms (8acill ariophytes), which are extremely prevalent inall seasons except nidsuminer and earlyfall, and (3) moderate numbers of bluegreenphytoplankters (Cyanophytes) predortiinatingin the summer and fa1 1 vonths.Chlorophyta account for as much asone-third of the total tidal freshwaterphytoplankton communi ty in the Potomac.Over 100 species have been recorded fromthis area with no single species dorninating.J. Fourqurean and D. Childers(Depa rtnient of Environmental Sciences3niversi ty of Virginia, Cliarlottesville;pers. comm.) found that deslnids and filainentousChlorophytes comprised over 50percent of a Virginia tidal freshwaterpiiytopl ankton community in late fa1 1.Species conimonlv found in both of thesestudies inclu-de ilicractinius spp.,Pedl astrum spp., Scenedesmus spp., Spi rogyraspp., and Microspora spp.The rnost ubiquitous and abundant ofa1 1 phytopl ankters are the Saci11 ariop!iytes.Many of these species are actiiallyepibenthic algae which becomeentrained in the water coluinn via tidalcurrents. Peak diatom biomass oftenexceeds one mill ion cells per literjiippson et al. 1979); however, no informationis available concerning the generamost consistently encountered in tidalfresh waters.The remaining phytopl anktonic componentsinclude various Cyanophytes, euglenoids,and di nof 1 age1 1 ates. Freshwaterspecies of bl ue-green a1 gae are stronglyinhibited by salinities greater than a fewparts per thousand and generally do notexceed densities over one-hundred thousandcells per liter. Conmon aenera"includeAnabaena, Anacys ti s and Osci 11 i toria.Populations of eual enoids are transient.and occur only d;ring midsuminer in thePotomac. nensities do not exceed 10,000cells per liter. Durins late suminer themost ?revalent genera are Euglena and z-chelmonas. The dinoflagellate, Peridini-- urn, was found to be an abundant consti tuentof phytoplankton communities in theJames River in Virginia (Fourqurean andChilders, pers. coam.).Benthic/Mud A1 qaeEpibenthic alqae grow wholly or Dartiallysubmerged on a variety of surfaces.They occur as microscopic unicells orlarger colonial forms, with many speciesresiding only temporarily on the benthos.Planktonic forms commonly settle onto Senthicor marsh surface substrates to completethe reproductive or resting stagesof their life cycles. The benthic algalcommunities of tidal freshwater marshesare not well studied, and like phytoplankton,are sub.ject to complex blooms andsuccessions which make it difficult togive general demographic descriptions.The limi ted information available suqgeststhat Cyanophytes, Bacil lari ophytes, . andChl orophytes dominate epibenthic algalcommunities' tidal freshwater habitats.Many of these communi ties are comprised ofriverine species which are intolerant ofsal ine conditions.Summer communities in tidal freshwaterportions of the Potomac River aretypified by the bl ue-green a1 gaeShizothri x spp. and Chromul ina paschreiand by green algae such as Cosmarium sop.and Clostreium spp. (Lippson et al. 1979).In contrast, 1 ate fa1 1 benthic algalcounts in a tidal freshwater tributary ofthe James River showed centric (Cycl otell asp., Ste hanodiscus sp., Coscinodiscus---I- pennatesp.) andNavicul a1 es sp. ) diatomsto be the dominant community constituents(Fourqurean and Childers, pers. comm.).

In a year long study of soil algae ina New Jersey tidal freshwater marsh, atotal of 84 species, exclusive of diatoms,were cataloged (Whigham et al. 1980).Algal diversity peaked prior to the beginningof the growing season. It peakedagain in September after commencement ofthe macrophyte di eback. Chlorophytesstrongly dominated this marsh surface community,followed by Cyanophytes and thenXanthophytes .Whigham et al, (1980) maintain thatsummer growth of emergent macrophytes reducesthe algal density on muddy marshsubstrates. Whigham and Simpson (1975)assessed the productivity of mud algae invarious rnacrophyte communi ty types. Soi 1type appeared to influence productivitymost significantly; the si 1 ty-sand soi 1 sand low organic content of low marshspatterdockzones provided the best substratefor algal growth. In contrast,sil ty-clay soils and high organic contentsfound in mixed-herbaceous high marsh areasand cattai 1 communities produced 1 oweralgal productivities. Presumably, edaphiccharacteristics act in conjunction with1 ight, temperature, and nutrient concentrationsto produce these differences instanding crop. As with phytoplankton,nutritive sewage effluent is known to signif icantly increase a1 gal standing cropsin tidal marshes (Whigham and Simpson1975).Mud algae can often be seen forming adark-greenish band on exposed channelbanks of tidal areas. Peak biomass forthis taxa is estimated to be two to threeorders of magnitude less than peak biomassfor vascular plants (Wetzel and Westlake1969). Mud algae remain as functioningproducers throughout the enti re year,however, and may contribute more to totalannual production than might be expected.

CHAPTER 3. ECOSYSTEM PROCESSES3.1 PRIMARY PRODUCTIVITYIntroductionThe primary productivity of an ecologicalsysteln, community, or any part ofsuch a system, is defined as the rate atwhich various organisms, chiefly greenpl ants, assimilate and synthesize gaseousand dissolved inorganic substances intoorganic inatter. The total amount oforganic matter produced by green plantsduring a particular time interval istermed gross primary production. The rateof storage of organic matter in planttissues in excess of the respi raioryutilization by plants during the period ofmeasurenlent is known as net pri!naryproduction.The organic satter produced by vascularplants, phytoplankton, and benthicalgae in the tidal freshwater habitatserves as an energy source for variousheterotrophic organi s-as. Much 1 ive materialcan be consumed in situ by variousherbivores. Microbial populations decomposeand utilize a large fraction of thedead plant material on the marsh surface.Detritivores further fragment decomposingplant remains. A1 though a significantportion of this organic matter is utilizedand stored within the marsh habitat, alarge fraction may be exported out of thesystem. Tidal currents and wind encouragethe entrainment and transport of organiccarbon to downstream estuarine locations.Migrating consumers may feed within thehabitat and then move on. It is estimatedthat salt marshes export about one-ha1 f ofthe net pritnary production to adjacenttidal waters (Teal 1962, Odum and Skjei1974) ; however, a comparable figure is notavail able for tidal freshwater marshes.Production EstimatesThe biomass and primary production oftidal freshwater wetlands have beenreported to be very high (Odum 1978).Numerous estimates of standing crop andannual aboveground net production existfor the dominant species of vascularplants occurring within this habitat(Table 7); however, there are only a fewestimates of total net communi ty production(Whigham et al. 1976, Dournlele 1981).The existing data on biomass and productionshow a great deal of variability bothwithin and between vegetation types, yetit appears that the total net communityproduction of these marshes generallyranges from 1,000 to over 3,500 g/m2/yr(Odum 1978). Productivity measuresreported for saline wetlands fall withinthe saoie range as those for tidal freshwatermarshes, within a given latitudinalzone (e.g., mid-At1 antic) ; the biomassproduction of fresh tidal wetlands may begreater than higher sal ini ty communities(Whigham et al. 1976).Obtaining accurate estimates of netproduction in tidal marshes, either on aper-species or community basis, is difficultbecause of (1) seasonal patterns ofbiomass allocation, (2) the heterogeneityin plant community composition, (3) seasonalbiomass turnover due to leaf mortality,decomposition, and herbivory, and (4)the inherent problems in measuring theproduction of belowground plant parts(Whigham et a1 . 1978). Traditionally,investigators have compared the productivityof tidal wetland vegetation by measuringpeak aerial standing crops. However,there is no objective way of pinpointingthe exact moment at which the peak cropexists; therefore, the potential for errorwith single harvest methods is high(McCormick and Somes 1982). By restrict-

Table 7. Peak standing crop and annual production estimates for common tidal freshwatervegetation types. Data are largely generated from mid-Atlantic tidal freshwatermarshes. Values are in grams per m2 dry weight. Average values are not necessarily afunction of table entries, but represent best estimates from selected 1 i teraturevalues. This table is an extension of those produced by Whigham et a1 . (1978) andMcCormick and Somes (1982).Peak standing cropAnnualVegetation type Tops Roots Dead production State SourceSpatterdock 514*245743*5166 05529*-1175Average 627Arrow-arum/ 459pickerelweed 648*98812865 94*587*-667553Average 671Wild rice 2091*1178"5 6013901600866*134611 17Average 1218* 1578Giant cutgrass 1039 518 - 2048 G A 1Smartweedricecutgrass

Table 7. Continued.Peak standing cropAnnualVegetation type Tops Roots Oe ad production State SourceAverage 1141 869Cattail 2338 - 167 - MD 71190* - 300 - MD 496 G - - 1868 MD 8987 - - - NJ 11850 1800 - - NJ 51007" 1371 - - NJ 6- - - 95 6 NJ 131297* - - 1320 IVJ 161199 - - 1534 NJ 10804 5053 - - NJ 141310* - - - PA 9Average 12 15 1420aur~nari gold 1025 910 NJ 161109 1771 NJ 10900 - - - PA 9Average 1017 1340Sweetfl ag 117 4* - - - MD 12605 - - - NJ 1181 9* - - - NJ 15623 - - 1071 NJ 10Average 85 7Avera ye 432Water- hemp 1112 - - 1547 NJ 10678 560 - - NJ 5Average 960Giant RagweedAverage 1205(continued)

Table 7.ConcludedPeak standing cropAnnualVeyetati on type Tops Roots Dead production State SourceCormnon reedAverage 1850 ,I872Big cordgrass 3543* - - - MD 1295 1 - 241 - MD 41207 - - 1572 MD 8Average 2311Spiked- 2 104 - - 2100 NJ 16loosestri fe 1373 - - - PA 9Average 1616Swanp rose 699** - - - MD 12Red map1 elash 522** - -Bald cypress 344** - - - MD 12rvlud a1 gae 4* - - - NJ 16*Value generated from more than one estimate**Leaves of woody pl ants; no wood is includedList of Sources :1-Birch and Cooley 1982 8-Johnson 1970 15-Wass and Wright2-Cahoon 1962 9-McConnick 1970 19693-Doumlele 1381 10-McCormick 1977 16-Whigham and4-Flemer et a1 . 1978 11-McCormick and Ashbaugh 1972 Simpson 19755-Good and Good 1976 12-McCormick and Somes 19826-Good et a1 . 1975 13-Stevenson et al. 19767-Heinle et al. 1974 14-Walker and Good 1976

ing the sampling effort to just one pointduring the growing season, those planttissues which develop after sampling andthose that senesce or are consumed byi nsects before sampl ing are missed. Giventhe dramatic seasonal successional changesthat are known to occur in almost alltidal freshwater vegetation communities,estimates of total community productionare likely to he inaccurate and underestimatedunless mu1 tip1 e harvests are made.Dens i ty of vegetation and speci escolnposi tion a1 so yreatly i ~ fuence l productionestimates. Doumlele (1981) notedthat peak biomass values for arrow-arumfrom a number of di5ferent studies rangedfrom 57 to 1,286 g/m . These drastic differenceswere attributed to the degree ofspacing between individuals at variouslocations and to the relative pureness ofthe predominant vegetation type within agiven stand. Pure stands of any givenspecies are uncommon in tidal freshwatermarshes, especially at higher elevations.Total biomass production estimates ofmixed tidal freshwater marsh communitiesare strongly dependent on species composition.A diversified cornillunity can containa variable proportion of pro1 i fic producers(e.g., comlnon reed or wild rice) orspecies with inherently lower biomass production(e.g., arrow-arum or spatterdock)(Whigham et al. 1978; Joumlele 1981).Inspection of the peak standing cropand annual net production estimates compiledin Table 7 clearly reveals the highvari abi 1 i ty between species. Marshesdominated by tall reeds and grasses suchas ldild rice, comison reed, giant cutgrass,big cordgrass, or cattail produce thegreatest quantities of biomass, generallyin the range of 1,500 to 2,000 g/m2/yr.Considering the potential heights and densitiesattained by these species, such extraordinaryproduction rates are not sur-?rising. Early in the growing season,many marshes are doini nated extens i vely byfl es hy-1 eaved macrophytes (arrow-arum,pickerelweed, spatterdock) and would seeminglyshow high rates or biomass accumul a-tion. However, all these species showmaxiinum peak standing crops of less than700 g/m2/yr. In reality, all of theseemergent perreni a1 s produce aeri a1 leavesand stems composed primarily of water andair-filled aerenchynatous tissue.Other vegetation producing significantquantities of biomass on an annualbasis include burmarigold (1,340 g/m2),water-hemp, giant ragweed, rose-ma1 low(069 g/m2), and sweetflag. In addition,shrubs and hydrophytic trees may supply300 to 700 g/m2 of leaf material onto themarsh surface.No satisfactory method exists forquantifying belowground production in wet-1 and habitats. Belowground productionmeasurements, however, are essential totke accurate assessment of per-species orcomriiuni ty productivity. Whighain et a1 .(1978) suggested that be1 owground productioncan be quite high for some soecies.Data for cattail, spatterdock, and arrowarumshow impressive underground productioncapability (see Table 7), but as perrenials,these values do not representbiomass accumulation from a single grovi ngseason. In order to account for changesin belowground biomass on a yearly basisfor either annual or perrenial species,production rates need to be calculatedover short, repeated intervals. 41 thoughlargely unquantifi ed, the rates of belowgroundproduction in these soecies arethought to be high.Unfortunately, the peak standing cropproduction information in Table 7, fromstudies spanning a number of years andlocations, is not conducive to makingbetween-mars h comparisons of producti vi t.~.If seasonal changes in cornrnuni ty bi ornassper marsh unit were quantified (e.g.,Doumlele 1981), our understanding oP thefactors influencing marsh productivi tvwould be greatly enhanced.Biomass PartitioningThe partitioning of net primary productionbetween aboveground and belougroundstructures of tidal freshwatermacrophytes can provide insight into the1 ife history strategies of species populations.Whigham and Simpson (1978) notedthat yearly production in annual speciesincluding grasses (wild rice) and herbs(burmarigold, jewelweed, smartweed,water-hemp) was largely a1 located toaboveground shoot production except duringearly stages of growth. At peak standingcrop, the ratio of belowground (roots) to

aboveground (sterns) bi omass (R: S) averagedless than 0.5 for all annual speciesmeasured. Perennials exhibited more vari -ation in patterns of biomass allocation,but generally partitioned greater amountsof biomass to be1 owground plant parts.Arrow-arum provides the most extrerneexample of this trend, allocating up to90% of its total biomass to roots andrhizomes (R:S much greater than 1.3).Differences in biomass parti ti oni ngare most likely related to reproductivestrategies, survival strategies, or physi-01 ogical adjustments associated withexploitation of stressful portions of ahabitat gradient (Whigham and Simpson1976; Ferren and Schuyler 1980). Annualseed1 ings a1 locate more biomass to rootingstructures during establ ishment phases,then convert to a rapid phase of shootgrowth. Anaerobic conditions prevail ing inlow marsh substrates demand physiologicadaptations for survival. The deep undergroundtubers produced by arrow-arum areadapted to cope with such stresses, butthe energy expenditure required to maintainsuch structures is great.Table 8. Two groups of tidal freshwatervascular plants based on rates of decompositionunder similar conditions arearranged in approximate order of rate ofdecay with the most rapid at the top.Other plants in the marsh lie betweenthese two groups. Decay rates are ofaboveground aateri a1 on1 y.SpeciesRAPID DECOMPOSERSSpatterdock, Nu har luteurnArrow-arum. P&ra virqinicaBurnlarigold, aidens laevisPickerelweed, Pontedaria cordataArrowhead, Sa m t mHibiscus (1hb-cheutosMild rice, Zizania aquaticaReferenceVan Dyke (1979)Odum and Heywood ( 1978)Sickels et al. (1977)Our unpubl ished dataOur unpublished dataCahoon (1902)Our unpubl ished dataSLOW DECOMPOSERSSednes. Carex soo. Qowden (pers. corn% )~roid-ieafttail, T ha latifolia Rrinson et al. (1981Narrow-leaf cattail. an usti olia Brinson et al. il%l!Comnon reed. Phra mites -iP7i austra is 8ur unpublished dataHlbiscus ( s t e h c u s rnoscheutos Cahoon (1982)o-----oSpartina cynosuroides3.2 OECOMPOSITION AND LITTER PRODUCTIONDecompos i ti on of marsh pl ant materi a1(reviewed by Brinson et al. 1981) variesgreatly in response to a variety of factom.These include ambient tempera tures,moisture, periodici ty of flooding, nutrientavai 1 abi 1 i ty from external sources,presence or absence of oxygen, consumeractivity, and a range of plant substratecharacteristics including nitrogen andcrude fiber content. In spite of thisvariabi 1 i ty, there are several generaltrends associated with tidal freshwaterplant material which we have identified.I 1 . 10 5 10 20 30 40 50OAYS ELAPSEDTidal freshwater vascular plants can Figure 17. Typical decomposition curvesbe placed into two general groups based on for high marsh plants (e.g., S artinathe rate at which they decompose (Table cynosuroides) and low marsh p l a n t h8). One group, generally found in the low Zizania aquatica) subject to similar enviandmid sections of the marsh, decompose ronmental conditions. From Turner (1975).m and Heywood 1978)se ~lants have relaresistantcompounds, cellulose, 1 ignin) rates of oxygen consumption (BOD) duringly high amounts of nitrogen decomposition (Van Dyke 1978). During thetotal dry weight according to warm summer months, these plants may loseso have the highest 30% to 40% of their dry weight in one week42

and completely decompose in 4 to 5 weeks(Van Dyke 1979, Turner 1978).The second ground of tidal freshwaterplants (Table 9) are found in the highersections of the marsh and have nwch slowerrates of deco~nposition (Figure 17). Ingeneral, they contain high concentrationsof resistant co!npounds and lower concentrationsof nitrogen than the first groupof plants (3unn 1975). Consumption ofthis type of plant material bv detritivoresis significantly lower than from thefirst group (see Section 3.5).Plants that decompose rapidlydominate the low marsh in tidal freshwaterTable 9. Typical zooplankton to be expectedin mid-Atlantic tidal freshwater.ilata from Lippson et al. (1979) for thePotomac River, and from Van ingel andJoseph (1968) for the York River.Jellyfishwinter jellyfish, Cyanea capillataCopepodsEu rytemora affi ni sNesocycl ops edaxAcartia tonsa(see Chapter 2). The low marsh has amodest litter layer during the summermonths and very 1 ittle litter during thewinter and spring. This contributes tothe high erodibility of the low marsh(Section 1.6) and the tendency to releasenutrients into tidal waters during thewinter and spring (Section 3.3). The highmarsh with its slower decomposing plantsretains a significant litter layerthroughout the year (personal observation).In some northern marshes, such asthe North River garsh in Massachusettswhich is dominated b,y species of Calamaro s t s Carex, and Typha, and wheredecomposition rates are qeneral 1 y sl ower,much of the marsh retains a significant1 itter layer during all seasons (Bowden1982). The same situation exists insoutheastern marshes dominated by giantcutgrass which has an extensive rhizomesystem and produces a thick peat layer.Not only do the rapidly decomposingplants have a high nitrogent content, hutduring the early stages of decompositionthe nitrogen and phosphorous content nayincrease (Odum and Heywood 1975; Turner1978) (see Figure 18). Sickels et al.(1977) and Whigham et al. (1980) showedthat tidal freshwater rnarsh 1 i tter is capable of concentrating both phosphorus andnitrogen from selvage effluent releasedonto the marsh surface. This nutrientconcentration has imp1 i cations for understandingnutrient flux (Section 3.3).Neomysis ameri canaIt appears that the low marsh, withAllphi podsits seasonal litter layer, may serve as aCorophidm lacustrenutrient sink only during the suminer andMonocul odes edwards ifall months while the high narsh may haveGammarus S~P. a greater year-long nutrient uptakecapacity.Cl adoceransDaphnia In summary, the low atid high marshSida crystal 1 ina plants of the tidal freshwater marshLeptodora kindiidecoinpose at dramatical ly different rates.Bosmina longi rostrisThis leads to differences in the thicknessand duration of the litter layer, erosionRoti fersrates, and nutrient retention capacity inKeratella cochlearis different sections of the marsh. As aBrachionus cal ci florusresult, depending upon the relative proportionsof high and low marsh vegetation,Benthic invertebrate larvaethese :narshes may vary in their capacityRhi thropanopeus harissi i (mud crab) to absorb excess loads of nutrients (i.e.,sewage ef f 1 uent) .43

-6.0 -0.55PERCENTNITROGEN(AFDW)5.0 -/4.0 - //0.40PERCENTPHOSPHORUS(AFDW)3.0 -2.0NITROGEN* - - - - -0 TOTALPHOSPHORUSDAYS ELAPSEDFigure 18. Changes in total nitrogen and phosphorus content of decaying wild rice,Zizani a aquatica, expressed as percent of the remaining ash-free dry weight. Plottedm a r e mean + 1 S. E. From Turner (1978).3.3 NUTRIENT CYCLING (OTHER THAN CARBON)The general model of nutrient cyclinqin estuarine lnarshes is based on a numberof studies (e.g., 9xelrad et al. 1976;Valiela and Teal 1979; Nixon 1980). Thismodel appears to apply in principle totidal freshwater marshes. Certaindetails, however, may be different.The general estuarine model ( Figure19) indicates that coastal marshes actprimarily as transformers of nutrients,particularly nitrogen and phosphorus; inaddition they may function as either sinksor sources of nutrients depending upon avariety of conditions. As transformersthey import dissolved oxidized inorganicforms (nitrite, nitrate, phosphate) andexport dissolved and particulate reducedforms (ammonium, forms of organic nitrogenand phosphorous compounds). There is atendency for coastal wetlands to have anet import of nutrients at the beginningand during the growing season and to havea net export in the autumn and winter.Whether a specific marsh is a net importeror exporter of nutrients depends on a numberof factors including: (1) successionalage of the marsh, (2) salinity andredox characteristics, (3) presence orabsence of upland sources of nutrients,(4) presence or absence of human inputs ofnutrients, (5) tidal energy input, and (6)magnitude and stabil ity of nutrient fluxin the estuary to which the marsh iscoupled (Stevenson et al. 1977).Tidal freshwater marshes apparentlyfunction in a similar fashion (Heinle andFlemer 1976; Stevenson et a1 . 1977; Adams1978; Siinpson et al. 1978; Simpson et al.

SOURCES(LARGELY INORGANIC, OXIDIZED N AND P COMPOUNDS)PRECIPITATIONGROUNDWATER SEEPAGETIDAL FLOODING OR RIVER INFLOWNITROGEN FIXATIONANIMALS (BIRDS, MAMMALS, FISH, ETC.)*MARSH COMMUNITY(LARGELY MICROBIAL ACTIIVITY)NITROGENPLANT UPTAKE AND RELEASEDETRITAL UPTAKE AND RELEASEAMMONlFlCATlON(ORGANIC -AMMONIUM)DISSIMULATORY NITRATE REDUCTION(NITRATE AND NITRITE -AMMONIUM)PHOSPHORUSORTHOPHOSPHATE ADSORPTIONPLANT UPTAKE AND RELEASEOUTPUTS(LARGELY ORGANIC P, AND REDUCED AND ORGANIC N)TIDAL FLUSHINGATMOSPHERIC RELEASE OF AMMONIADENlTRlFlCATlONFigure 19. A general model of nitrogen and phosphorus nutrient cycling in coastalmarshes. Based on Valiela and Teal (1979) and Nixon (1980).1981; Bowden 1952). One possible difference,however, is that the characteristicseasonal nutrient exchange tendencies aremore pronounced in tidal freshwatermarshes, probably due to a lack of winterplant and litter cover. In these marshesthere appears to be a clear pattern ofnitrite, nitrate, and phosphate importfrom river water to the marshes at thebeginning of the growing season. This ismetabol ized by bacteria i nto forms moreuseful to plants (e., ammonium) andstored during the summer months in bothplant tissues and the litter layer on thesurface of the marsh. Whigham et al.(1980) demonstrated the importance of thelitter layer in holding both nitrogen andphosphorus temporarily during the summerand early autumn. Later in the autumnthere is considerable export of reducednitrogen and phosphorus due to the rapiddisappearance of dead and dying plantmaterial from the lower sections of themarsh. During the winter nutrients con-

tinue to be exported, but at a slowerrate.The preceding discussion remainshypothetical. There is a lack of studieson processes involved in the cycling ofnitrogen and phosphorus in tidal freshwatermarshes. Whether the spring andauturnn peaks of nutrient flux are morepronounced than in sa1 t marshes remains tobe demonstrated conclusively.The importance of ni trogen fixationin tidal freshwater wetlands is not certain.Excessive shading by the Sroadleavedplants (arrow-arum, pickerelweed,spatterdock) may limit the activity ofblue-green algae to creek banks during theearly spring and late autumn.Bowden (1982) has emphasized the importanceof ammonium in tidal freshwatermarshes. In a mass balance study of theNorth River, Massachusetts, he found thegross ammonium production by microbes tobe 53.5 g ~/m'/yr. This production ratewas sufficient to supply all of the nitrogenrequired to support pl a ~ productiont(estimated to be 22.3 g N/m /yr), microbialassimi lation (measured as 17.9g ti/m2/yr) , and ni tri fication (measured as11.6 g f4/m2/ yr) . The ammonium productionrate was supported by efficient internalrecycl ing of ni trogen in 1 i tter, by microbialimmobilization of ammonium and nitrate,and by sedimentation of allochthonousoryanic matter frorn the adjacentriver. This marsh imported inorganicni trogen during the plant growing season.Unl ike many southern marshes, an extensivelitter layer persists all year and mayretard nitrogen export even during thewinter.Most other studies (e.g., Axelrad etal. 1976; Heinle and Flexer 1976; Stevensonet al. 1977; Adams 1978; Simpson eta1 . 1981) have concluded that tidal freshwatermarshes are net exporters of bothnitrogen and phosphorus on an annualbasis. This may reflect the fact that allof these studies were done in eutrophic orhypereutrophic locations. Under theseconditions, the marsh sediment-plant complex can become saturated wi th both nitrogenand phosphorus, at least in the lowmarsh. Without a permanent litter layeror significant amounts of peat, there maybe no mechanism for excessive nutrientstorage and the marsh functions as a netsource of nutrients. This suggests thatmany tidal freshwater wetlands probably donot have a great assimilative capacity foreither sewage effluent or heavy metals(discussed in Chapter 9).In summary, the overall pattern ofnutrient cycl ing in tidal freshwatermarshes appears to be similar to the patternhypothesized for estuarine marshes.Simply stated, oxidized nitrogen and phosphorouscompounds are processed within themarsh and reduced co~npounds are releasedback into the river. In tidal freshwatermarshes the spring influx of oxidized compoundsand the auturnn release of reducedcompounds may be more pronounced than inestuarine marshes. In addition, mosttidal freshwater marshes which have beenstudied appear to be net exporters of bothni troyen and phosphorus.3.4 CARBON FLUXAs in the case with most wetland ecosystems,knowledge of carbon flux in tidalfreshwater marshes is incolnplete. Yeveralstudies have addressed this topic (e.g.,Axelrad et al. 1976; Iieinle and Flemer1976; Adams 1978), but no tnore than hypothesescan be presented at this time.Sources (or inputs) of organic carbonfor the marsh include: (1) primary productionwithin the marsh, (2) dissolvedand particulate carbon flowing into thernarsh on the rising tide, (3) dissolvedcarbon in rainwater, and (4) dissolvedcarbon in groundwater. Outputs frorn the(narsh include: (1) export of dissolvedand particulate carbon on the outgoingtide, (2) permanent burial of carbon inthe marsh sediments, and (3) release ofmethane and carbon dioxide to the atmosphere.The most significant inouts aremost likely primary production in themarsh and carbon imported on the floodingtide. The latter probably includes considerable amounts of terrestrial carbonbrought from upstream in the river water(Biggs and Flemer 1972). Significant outputsare probably tidal export and burial.Regardless of the net carbon flux (netimport or net expo'rt) from an individualmarsh, it is important to note that there

is an approximate 100% turnover of t)?eaboveground biomass on an annual basis.Individual tidal freshwater marshesfunction as net importers or exporters oforganic carbon in response to the samefactors which control this process inestuarine marshes (discussed by Odum etal. 1978 and Nixon 1980). These factorsinclude, but are not limited to, tidalrange, basic geomorphol ogy, re1 ati veamount of marsh versus open water, andamount of freshwater input to the system.Studies by Axelrad et al. (1976) and Adams(1978) found significant ex~ort of carbonfrom tidal freshwater marshes on the Yorkand James Rivers in Virginia. In bothcases the bulk of export appeared to he inthe form of dissolved carbon compoundsrather than particulate vatter. ButHeinle and Flemer (1976), on the otherhand, found neither export nor import inpoorly flooded 01 i gohal ine marshes on thePatuxent River in Maryland.CJith only a handful of studies compl?ted,it is difficult to conclude muchbeyond the foll o\vi ng hypotheses. Tidalfreshwat2r narshes that (1) are relativelyyoung (see Section 1.7), (2) do not havean outer berm or natural dike, (3) havesignificant icesheari ny of the vegetationduring the winter, and (4) have a significanttidal range, probably export significantquantities of both particulate anddissolved carbon. Older marshes that arernore developed both geological ly and ecologically(i.e., have a large area of highmarsh) probably do not export significantquantities of particulate carbon (Heinleand Flemer 197G); they may, however,export quantities of dissolved organiccarbon. This last point is far from resolved.Nethanogenesis is one aspect of carbonflux which deserves close study intidal freshwater marshes. As pointed outby Swain (1973), there is a gradient ofmethane loss in progressing fron freshwaterto rnarine wetlands. ilnder freshwaterconditions, methanogenesis is animportant pathway of anaerobic decompos i-tion; under marine conditions it is relativelyminor because sul fate reductionreg1 aces methanogenesi s. Since SO, i s nottypically abundant in freshwater, thismeans that methane release from freshwaterenvironments should be wch higher thanfrom sealvater environments. There isconsiderable evidence to support thishypothesis (Robert Harriss, NASA, Hampton,Virginia; pers. comm.), although King andWiebe (1973) reported relatively .highmethane release rates froin Georgia coastalsalt marshes.Following current theories, tidalfreshwater marshes should release significantamounts of methane. This can occurthrough (1) direct release to the atnospilerefrom the lnarsh surface, (2) releasefrom plants such as cattails (Sebacher andHarriss, in press), or (3) release fromdissolved methane in creek water (Harrisset al. 1982). Lipschul tz (1981) measuredthe release of methane from a tidal freshwatermarsh dominated by Hibiscusmoscheutos. He estimated an annual lossof 10.7 g c~,/m~/yr, a value more similarto freshwater conditions than marine. Onthe other hand, this loss was less than 1%of annual net primary production in thismarsh and, therefore, appears unimportant.Robert tlarriss (pers. comm.) suggested,based on prel iminary measurements, thatrates of methane release from tidal freshwatermay be much higher than indicated byLipschul tz's (1981) estimate. More workis needed in this area.3.5 ENERGY FLOWAny attempt to describe energy flowin tidal freshwater marshes will be speculativesince no complete study exists forthis habitat. We can, however, present ahypothetical model based on a few partialstudies and our experience in the field.Our hypothetical model (Figure 20) isbased on functional groups. In some casesthese represent a single group (i.e.,juvenilefishes) while others, such as Senthicfauna, may include many taxa. Sevora1prel iminary but important observationscan be derived fron this model.(1) There appear to be three principalsources of energy to support food wehs--marsh macrophytes, terrestri a1 organicmaterial, and phytoplankton. Benthicmicroflora within the marsh may be of someimportance, but there is presently noinformation to confirm this. The relative

MAFISH VEGETATION TERRESTRIAL CARBON PHYTOPLANKTONINSECT! -. . . ..- OMNIVOROUS(-1 trophic--1LARGER FISHES(at least two levelsof carnivores)Figure 20. Hypothetical pathways of energy flow in a tidal freshwater marsh ecosystem.Not all possible pathways have been drawn. For example, benthic microflora in themarsh may provide carbon for consumers; however, evidence is lacking at this time.importance of the three major sources of dissolved versus articulate detritus isenergy is unknown. We suspect that marsh totally unknown at this time. Waterplant detritus and associated micro- draining tidal freshwater rnarshes typicalorganismsare most important in well- ly contains 5 to 10 tirlles as much disflushedmarsh systems, that terrestrialmaterial is of importance where largeriver systems bring quantities of organiccarbon from upstream sources, and thatphytoplankton plays a key role in certainsi tuations (see number 3 be1 ow). "1 tI(2) In general, we suspect that tidalfreshwater wetlands are primarilydetri tus-based ecosyste~ns, a1 though thisis unproven. Dunn (1978) shored that a w-number of benthic invertebrates \ti11readily consume vascular plant detritus 9 - afrom tidal freshwater marshes (Figure 21).Large quantities of particulate and dis-zsolved carbon are flushed out of theseoac5 f$ dmarshes and also from upstream sources PLANT(see Section 3.4). At certain times ofthe year (late summer, autulnn, winter), Figure 21. Percent leaf disc consumedlarge quantities of particulate detritusare present on the marsh surface and on(ODW) by amphipods, Gamarus fasciatus,during 96-hr feeding tests. Plotted valthebottom of the marsh creeks (personalobservations). The re1 ative importance ofues represent the mean of three samples 21 S.E. From Dunn (1978).48-4

solved carbon as particulate carbon.There are, however, significant quantitiesof particulate material available for thebenthos. Associated with this particulatemat2rial are large numbers of bacteria andfungi (Marsh and Odum 1979), suggestingthat it has an enhanced food value.(3) The food chain consisting of phytoplankton/detri tus-zoopl ankton-1 arval andjuvenile fishes is of considerableinterest and importance to man because ofthe co~n~nercial fisheries involved. Thedatd of Van Engel and Joseph (1968) in theYork and Pamunkey Rivers documented thekey role of zooplankton as a dietary componentfor a wide variety of larval, postlarval,and juvenile fishes, many of comlnercialimportance. They found that themost common zooplankters in fish stomachswere the nlysid, Yeomysis americana; thecopepods, Acartia tonsa and Eur ternoraaffinis; f o m i v e species of 7%-c a ocerans;and several s~ecies of am~hi~ods.~hese zooplankters, ' in turn, ha've ' beenshown to ingest both phytoplankton andorganic detritus (Heinle et al. 1977).(4) Within the marsh system (marsh surface,small marsh creeks), terrestrial andaquatic insects along with the benthicfauna appear to be important in the dietsof onnivorous fishes. Van Enqel andJoseph (1968) found the crab ~hithropanopeusharissii and the sllri~nps Crangonseptemspinosa and Pal aemonetes pugio to beimportant components of the diets of avariety of fishes. Dias et al. (1978)emphasized the importance of the aquaticlarvae of terrestrial insects as a foodsource for tidal freshwater fishes, whileDiaz and Boesch (1977) mentioned the significantcontribution of benthic fauna(01 i gochaetes, chi ronomid 1 arvae, theAsiatic clam) in the diets of benthicfeeding fishes such as catfish, stripedbass, carp, perch, eel, and cyprinodontminnows (see Chapter 5 for more on thissubject).5) Direct usage of marsh plant material[ 1 eaves , seeds) appears considerablyimportant in tidal freshwater marsh systems,in fact, probably niore importantthan in salt marshes. Muskrats, beaver(during the summer), and nutria consumequantities of fresh plant material (seeChapter 8) ; other mammals including whitetaildeer ingest smaller quantities (personalobservation). Birds util ize theseed production of tidal freshwatermarshes extensively in the late summer,fall, and early winter (see Chapter 7).Insects graze certain marshpi ants heavily(i.e., Hibiscus) while other plants suchas Phragmites are scarcely touched.In sumnary, our knowledge of energyflow in tidal freshwater wetlands isalmost total ly speculative. We hypothesizethat foodwebs are generallydetri tus-based with a variety of ornnivorousbenthic fauna serving as the intermediary1 ink to fishes. Zooplankton apparentlyplay a key role in supporting1 arval and juvenile fishes. Directgrazing and seed consumption by mammals,birds, and insects are probably mpre significantthan in higher salinity estuarinemarshes farther downstream.

CHAPTER 4. COMMUNITY COMPONENTS: INVERTEBRATES4.1 ZOOPLANKTON that the amount of particulate detritusavailable in the early spring controlsThe zooplankton community of tidal zooplankton production and that this, infreshwater is dominated by a combination turn, may influence year class strength inof freshwater rotifers and cladocerans fishes such as white perch and stripeda1 ong with estuarine copepods. Typicalexarnpl es of the different phyla are shownbass (Joseph Mi hursky, Chesapeake Bi ol ogicalLaboratory, Solomons, Yaryl and; Ders.in Table 9. Although the numbers of comm.).species represented are far less thanfurther downstream, there is some evidenceBased on 1 imited data of our own, itthat total numbers (density) of zooplank- appears that the mysid, Neomysis ameritonin tidal freshwater are significantly =, and several species of amphipodsgreater than in contiguous nontidal fresh- provide the greatest biomass of food forwater or estuarine water (Van Engel and larval and juvenile fishes in tidal fresh-Joseph 1968). water. The two species of copepods, theAt any particular location the plankc1adocerans, and the roti fers apparentlyare the most important food sources forton may be dominated by rotifers, cladocerans,or copepods depending upon therecently hatched larvae and postlarvae (EdHoude, Chesapeake Biological Laboratory,season. Lippson et a1 , (1979) reported Solomons, Mary1 and; pers. comm.).typical concentrations of zooplankton fromthe tidal freshwater section of thePotomac River as: (a) rotifers (80 4.2 BENTHIC INVERTEBRATESspecies), 5,000 to 20,000/m3 with a peakin sgring and summer; (b) cladocerans Comprehensive documentation of the(approxi~nately 8 species), 5,000 to benthos in tidal freshwater is scarce. An100,000/m3 with peaks in spring and fa1 1 ; early study of the Hudson River, New Yorkand (c) copepods (approximately 9 (Townes 1937), characterized the benthosspecies), 1,000 to over 100,000/m3 with a of tidal freshwater as composed of freshcharacteristic1 ate summer peak. In the water snails, 01 i gochaetes (Limnodri lusYork River, Van Engel and Joseph (1968) spp.), chironomids, and the amphipod,found the dominant zooplankton in terms of Gammarus fasciatus. This amphi pod seemse to be the mysid, Neomysis ameri- to be characteristic of many tidal freshhecopepods, Eurytemora affinis and water locations. Dunn (1978) found it totonsa, several species of amphi- be abundant in plant and algal rnats in, a r a number of species of Virginia while Calder et al. (1977) mentionit as common in South Carolina freshwatertidal marshes.on in tidal freshwaternt food source for theStudies of southern tidal freshwaterae of anadrornous fishesshad. There isbenthos(19771,are re1 ati vely rare. Dorjesquoted in Sandifer et a1. (1980)~pods derive a found the dominant macrobenthi c inverteirdiet from brates in the tidal freshwater areas of(Heinle and the Ogeechee estuary, Georgia, to 5e then hypothesized amphi pod, Lea idactyl us dytiscus , and t$e

polychaete, Scolecol epides viridus. In of chironomids, approximately 1 g of nema-South Carol ina, Calder et a1 .mj foundthese two species to compose 60% by numbertodes (the major component of the microbenthos),and 1 g to 2 g of the Asiaticof the rnacrobenthos from tidal freshwater clam.stretches of the South Edisto River.The Asiatic clam, introduced earlierin the century, is well establishedOne of the most complete studies ofthroughout tidal freshwater environmentstidal freshwater benthos is that of Diazin the Southeastern States (Sandifer et(Diaz and Boesch 1974; 9iaz 1977; Diaz etal. 1980). It entered the southern tribual.1978). His studies concentrated ontaries of Chesapeake Bay about 1968 (Diazthe tidal Jalnes River, a typical, although1977) and has since spread northward athighly eutrophic, tidal freshwater riverleast as far as the Potomac River where itin Virginia. The marsh macrobenthos was was established by 1975 and now reachesdominated qual i tati vely and quantitatively dens! ties as great as 665/m? (Dresl er andby tubif icid 01 igocliaetes and larval Cory 1980). Diaz and Boesch (1977) havechirono~nid insects. 01 i gochaetes were noted that the ease with which the Asiaticmost abundant and chi ronomids were mostclam has populated tidal freshwater may bediverse. Dominant species included a a clue to the extent to which benthic comchironomid, Chi ronoms tanypus , and an munities are structured by physical rather01 i gochaete, m n i s spp. A1 so highly than biological processes in this environabundantwas the introduced Asiatic cl am. ment. Presumably, if interspecific compe-Corbicul a fl umi nea (formerly C. mani 1 en- tition and competitive exclusion were in--whichis discussed be1 ow.tense, the spread and proliferation of theThese studies also showed that theAsiatic clamdramatic.would not have been asnumber of benthic macrofauna s~ecies intidal freshwater is considerably 'lower (69according to Koss et al. 1974; 49 accord-Penaeid shrimp do not appear to occurin tidal freshwater habitats in high deningto Diaz 1977) than further upstream in sities, although they are very common atnontidal freshwater (between 150 and 200 sl ightly higher sal ini ties (personalspecies according to Kirk 1974). This observation). However, the carideanrelatively sirnple community structure in shrimp, particularly Palaemonetes pugio,tidal freshwater was attributed to a lack has been reported commonly in tidal freshofdiverse habitats; the most available water from Georgia (Sandifer et a1 . 1980)habitat was a silty mud bottom (Diaz and to Virginia (personal observation). InBoesch 1977). Diaz (1977) likened tidal SouthCarolinaandGeorgia, thefreshwaterfreshwater benthic communities to those shrimp, Yacrobrachium ohione and l. scanfoundin large lakes, such as the Great thurus are common in tidal freshxrLakes, or the profundal zone of smaller -(5iFKfer et al. 1980).1 akes, pol luted harbors, or the vicinityof river mouths. Furthermore, he con- A general and preliminary list ofcluded that there is no species of benthic representative benthic macrofauna fromanimal which is special ized for exclusive tidal freshwater marsh systems is shown inexistence in tidal freshwater. Most Table 10. It is probable that certainspecies which are present appear to be groups such as crayfish and amphipods areeurytopic (wide range of tolerance) with even more important than indicated butfew species exhibiting qual i tative have been poorly sampled in past studies.prefermce for a particular substrate In addition, more mobile estuarine organtype.isms are known to stray in fair numbers(personal observations) into tidal fresh-Diaz et al. (1978) found the macro- water (e.g., the blue crab, Callinectesbenthic diversity (HI) in the Janes tidal sapidus, the mud crab, Rhithropanopeusfreshwater marshes to be relatively low, harissi i , the caridean shrimp, Pal aemonerangingfrom 2.0 to 2.2. Mean densities tes pugio, and, in the southern part ofwere 1800-4000/m2; 85% to 97% 1 ived in the its range, the brackish water fiddlertop 10 an of marsh sediment. Annual pro- crab, - Uca minax). Except for the work ofddction was estimated (in dry g/m2/yr) as Diaz, our knowledge of the tidal fresh-4 g to 7 g of oligochaetes, less than 1 g water macrobenthos is very preliminary.5 1

Table 10. Representative benthic macrofaunafrom mid-Atlantic tidal freshwaterenvironments. Data from Lippson et al.(1979) for the Potomac River, Grant andPartick (1970) for the Delaware River, andDiaz (1977) and Diaz and Boesch (1977) forthe James River.A sALm SEASONAL7 1 I RANGE I rB MARSH FAUNASpongesHydraSpongi 1 la 1 acus tri s and other speciesHydra americanaProtohydra spp.0 50SEAWARD CHANGE -+100 KmMOUTHLeechesBarentsia racilusLoph*podel~ ,Pectinatel a magni ticaFanil ies Glossiphoni idae, Piscicol idae01 i gochaetesInsectsFamilies Tubificidae, NaididaeDipteran larvae (especially family Chironomidae)Larvae of Epheineroptera, Odonata, Trichoptera,and ColeopteraAmphipodsFallela aztecaamnarus m t u sm y l u s dytKcus (southeastern States)CrustaceansCrayfishFigure 22. Seaward change in (a) salinity,(b) species composition, and (c) totalnumbers of microfauna of the marshesalong the Rappahannock Estuary, Virginia.From El 1 i son and Nichols (1976).strictus, Difflugia constricta, and D.pyriformis. Density of ten reaches2,000120 m1 of sediment. Just downstream,in the oligohaline zone of the estuary;Blue crab. Call inectes sapidus the thecamoebinids disappear and areCaridean shrimp, Palae~nonetes paladosusreplaced by the Arnnioastuta fauna. This islo^ IUS~S a qroup - . of foraminifera dominated byFingernail clam, Pisidium spp.Ammoas tuta salsa and including AS tramminaAsiatic clam. ~o-lurninea(formerly C. mamlensis) rara and Mi 1 iammina earl andi . DifferentBracki stuater clam. b n q i a t a -Pulmonate snails (at least six families)groups of forams predominate at 1 ocationsfurther do\~nstrearn in the estuary athigher salinities (Ellison and Nichols1976).The microbenthos in tidal freshwateris more thoroughly documented than themacrobenthos thanks to the work of RobertEllison and Maynard Nichols (summarized inEllison and Nichols 1976). They havedescribed a sharp demarcation in the distributionof the microbenthos which occursat the border between tidal freshwater andestuarine conditions (Figure 22). In thetidal freshwater marshes the dominantgroup is the thecamoebinids (a group ofamoeba with theca or tests); the foraminifera,common in estuarine sat inities, areabsent. Dominant species of thecamoebinidsare Centropyxis arenata, C, con-The demarcation between thecamoebinidsand forams provides a convenientgeological and ecological indicator of theextent of tidal freshwater wetlands in therecent geological record. Using theoccurrence of these organisms in marshcores, Ellison and Nichols (1976) concludedthat the tidal freshwater environmentmoved downstream in the James Riverbasin during the most recent period ofrelative sea level stability (past 6000years) perhaps due to sediment depositionand marsh building throughout the estuary.

4.3 MARSH PLANT INSECT COMMUVITYPub1 ished information deal ing withthe insect community associated with vascularplants of tidal freshwater is veryinadequate. One exception is the study ofSimpson et al. (1979) that describes theinsects associated with three plants:burmari go1 d, arrow-arum, and jewelweed.In general,they found both low densitiesof insects and low species diversity.Insects from 32 farnil ies and 6 orders werecollected; only 11 families were found onall three species of plants. The Coccine11 idae (ladybird beetl es) were themost ubiquitous. Other common familieswere the Curcul ionidae (snout beetl es) ,the Lampyridae (fi ref1 ies) , the Lagnuridae(1 izard beetl es) , the dipteran familyDo1 i chopodi dae (long-1 egged flies) , theOti tidae (picture-winged flies) , theSyrphidae (flower flies), the Tachinidae(deer and horse flies) , the hemipteranAnthocoridae (minute pi rate bugs), and theho~nopterans Aphidae (plant1 ice) and Cicadelli dae (1 eaf hoppers). Additionalfainil ies were found only on specificplants.Simpson et al. (1979) found littleevidence of herbivorous insects or ofherbivory in general and concluded thattidal freshwater marshes, 1 i ke coastalSpartina marshes, are only 1 ightly grazed.Cahoon (1982), on the other hand, foundgrazing rates on Hibiscus to be as high as20% to 30% in certain locations inMary1 and tidal freshwater marshes. Wehave recorded grazing rates on a mixtureof tidal freshwater marsh plants as highas 12% to 15% in discrete patches ofmarsh, but less than 10% for the marsh asa whole (unpublished data). At this time,with little data in hand, we must agreewith Simpson et al. (1979) that grazingrates by insects on most plants in tidalfreshwater are low, Hibiscus excepted.A1 though direct grazing rates may below, it should be emphasized that insectsapparently pl ay an important role inenergy flow in the tidal freshwater marshsystem (see Section 3.5). In particular,the aquatic larvae of terrestrial insectsappear to be an important food source forthe postlarvae and juvenile fishes whichutilize this habitat as a nursery area(see Chapter 5).

CHAPTER 5. COMMUNITY COMPONENTS: FISHES5.1 INTRODUCTION 5.2 THE FAUNA: AFFINITIES AND NATURALHISTORY OF IMPORTANT SPEC1 ESThe tidal freshwater portion ofAtlanticcoastestuaries isa transitional Freshwater Fisheszone between a typically freshwater fishfauna found above tidal influence and In tidal freshwaters, fish of freshfaunacharacteristic of the 01 igohal ine water affinity are particularly common.portion of the estuary. No fish species In fact, up to a salinity of approximatelyis known to be restricted to the tidal 3.5 ppt, freshwater fish often outnumberfreshwater habitat. Instead, the fish estuarine, anadromous, and marine speciescommuni ty of tidal freshwater (summarized combined (Keup and Ray1 iss 1954). Soeciesin Appendix B) is a complex and seasonally of freshwater fish found in tidal freshvariable mixture of freshwater forms waters general ly occupy 1 entic (slowtolerantof low salinity conditions, typi- flowing) habitats, such as lakes, ponds,cal estuarine residents, anadromous fishes and river backwaters, in nontidal freshonspawning runs and their juveniles, waters. In tidal freshwaters, freshwaterjuvenile marine fish using the area as a forms are more often associated with shalnurseryground, and adult marine fish best lows and vegetation than with deeperconsidered seasonal transients (Figure channels. Freshwater species characteri s-23). tic of lotic habitats with fast flowingwater and gravel substracts rarely extendBecause the unconsol idated sediments their range into tidal f reshwatersand dense vegetation make sampling within (~ippson et al. 1979).the marsh difficult, most of our infomationon fishes of the tidal freshwater The three families with the mostreaches of the estuary comes from trawl species and individuals in tidal freshsurveysin the main channels and beach water are the cyprinids (minnows, shiners,seining in unvegetated shallows. As a carps), centrarchids (sunfishes, crappies,result, much of the following discussion bass), and ictalurids (catfishes). Whileconcerns the fishes of tidal freshwaters a relatively large proportion of the catingeneral and is not restricted to those fish and sunfish populations in a givenfishes that use the marsh directly. Where geographic area extends into tidal freshdirectuse has been observed, this dis- water habitats, this is not the case fortinction is made. the minnows. As a group, minnows are muchmore common above the Fall Line in nontidalhabitats.RIVERS ESTUARIES OCEANSMinnows are small , often school inqspecies, most abundant in the shore zone.Of this group, the spottail shiner, silveryminnow, satinfin shiner, and goldenshiner are the tnost common. Many of theother smaller members of this group listedfigure 23. Distributions of different in Appendix !3 are best considered straystypes of fishes by salinity zones. Modi- in tidal freshwaters because their occurfiedfrom Lippson et al. (1979). rence there is sporadic. As a group the54

minnows occupy midwater and benthic habi -tats. The carp and goldfish have beenintroduced widely from Asia and may belocal ly common in tidal freshwaters. Sothspecies have broad niches; they are omnivorousin feeding habits and have wideto1 erances for variations in dissolvedoxygen, turbidi ty, and sal ini ty.4s a group the sunfishes are mostcommon in shallow, still waters containingsome cover. The smaller menbers of thefamily in the genera Enneacanthus andEl assoma are invari aSly associated withvegetation and are most abundant in tidaland nontidal swamps (Wang and Kernehan1979, Lee et a1 . 1930). The bl uegi 11 andlargemouth bass are common in tidal freshwatersthroughout the mid- and southeastAtlantic regions. The pumpkinseed is morecolnnon in the mid-Atlantic, while the redbreastand redear sunfishes, warmouth, andblack crappie reach peak abundance intidal freshwaters in the southeast.Juveniles of all these species are mostabundant in the shallows, and largerfishes are found in deeper water. All hutthe smallest sunfishes are important tosports fishermen. As a result of theirrecreational value, many species have beenintroduced to areas outside their nativerange (see Appendix B).Catfishes are bottom oriented andwell adapted to feeding in turbid waterswhich often occur in tidal freshwaterhabitats. Here they locate their preyprimarily by nonvisual means (ie., bytactile and olfactory stimul i). They alsotolerate conditions of low dissolved oxygen.3f the larger members of the genusIctalurus, the white catfish, channel catfi sh, brown bull head, and ye1 low bull headare common. The smaller members of thegenus Noturus are known as madtoms and arenore abundant in nontidal freshwaters.Only the tadpole madtom is common in tidalfreshwaters.A number of other species of freshwaterfish are resident in tidal freshwatersand are important there eitherbecause of their numerical abundance ortheir role as predators. Of the saallerspecies, the mosquitofish is particularlyabundant a1 ong creek edges, in backwaters,and on the marsh surface. One or inore ofthe darters and suckers are often common,The darters reside in the shallows, thesuckers in slightly deeper water. Thepirate perch is locally common in theupper tidal freshwater habitat, particularlywhere the rnarsh and swamp are inclose proximity. Gars, pickerels, andbowfin are resident predators whose abundanceand activities probably affect thepopulation structure of the smaller fishspecies using the tidal freshwaterhabitat.Estuarine FishesThe estuarine component of the tidalfreshwater fish assemblage is cotnposed ofresident soecies that compl ete theirentire life cycle in the estuary, Thesespecies are general ly most abundant inlower, more sal ine portions of the estuary,but several extend their ranges intotidal freshwaters.The cyprinodontids or killifishes arevery abundant in tidal freshwater marsheswhere they occur in schools in the shallowsand on the marsh surface at hightide. At low tide these small fishes congregatealong marsh edges and also on themarsh surface in rivulets and tide oools.The two most common species in tidalfreshwaters are the banded klllifish andthe mummichog (Raney and Massrnann 1953;Hastings and Good 1977; Virginia Instituteof Marine Science 1978; Lipnson et al.1979). These two species feed o~portunistically,taking food items in proportionto their relative abundance in the environment( Baker-Di ttus 1978; Vit-gi niaInstitute of Marine Science 1978). Theirdiets are very similar and the.v sometimeseven feed in mixed schools (Raker-Dittus1978). While their niches appear broadlyoverlapping, the two species may reachpeak abundance in different hahi tatpatches. Hastings and Good (1977) suggestedthat the mumrnichog shows a preferencefor muddy substrate and the handedkillifish for sandy areas. Killifishesare often used as bait hv sports fishermenand are important forage fishes for numerouslarger fishes which are of commercialor sport importance. Kill ifishes are alsoan important food item for most species ofwading birds (see Chapter 7).The bay anchovy and tidewater silverside,small pelagic school i ng fishes, are

important forage species for larger fishesof recreational or connnerci a1 interest.The tidewater sil verside is most abundantspring through fall and is often moreabundant in tidal freshwaters where it maybreed than in salt water (Raney andklassmann 1953; Virginia Institute ofMarine Science 1978; Lippson et a1 . 1979).Bay anchovy juveniles and adults entertidal freshwater in spring to feed. Inlate spring adults return downstream tospawn in areas of >10 ppt salinity, f4ewl.yhatched larvae move irpstream to oligoha-1 ine and tidal freshwater nursery areas insummer (Dovel 1971, 1981). Most anchoviesreturn to the lower estuary to overwinter(Lippson et a1 . 1979; Dovel 1981).Hogchokers and naked gobies arebottom-oriented estuarine residents whoseyoung use tidal freshwater and oligohal inenursery grounds. Spawned in mesohal ineportions of the estuary in midsummer,young of both species are transportedupstream in the sa1 t wedge to the upperestuary where they are common in the shallowsthrough autumn. The species differin their use of this habitat in coldweather. Hogchoker adul ts and juveni 1 esnay overwinter here, while naked gobiesreturn downstream to adult habitat in themiddle and lower estuary (Van Engel andJoseph 1968; Dovel et al. 1969; Lippsonet al. 1979).Anadromous FishesAnadromous fishes are those whichascend from an oceanic habitat to freshwaterto spawn. Like the anadromousfishes, semianadrornous forms ascend tofreshwaters to spawn, but spend most orall of their lives within the estuaryrather than the ocean. Many of thesefishes are of considerable commercialirnportance in At1 antic coast estuaries.Characteristics of these fishes are summarizedin Table 11.Of the anadromous fishes, theclupeids (herrings and shad) are of majorcommercial importance. These fishes arecaptured on the upstream spawning runs ingill nets operated in tidal fresh andbrackish waters. Except for hickory shad,the peak abundance of young of thesespecies is in tidal freshwaters. In thisnursery area, the juveniles feed heavilyon small invertebrates before rni grati ng tothe lower estuary or out to sea by latefall or early winter. While in the nurseryarea, these juveniles are importantforage fishes for striped bass, whiteperch, catfishes, and others. Considerableresearch on the biology of the anadromousclupeids has been conducted by thevarious state agencies responsible forf i sheri es management and is summarized intheir progress reports ( Adams 1970; Shol ar1975; Loesch and Kriete 1976; Hawkins1980; Curtis 1981; Loesch et al.,undated).The two species of sturgeons, onceimportant commercially in east coast estuaries,were badly overfished and theirnumbers decimated by the turn of the century(Reiger 1977). In addition todecl ines due to overexpl oi tati on, smallsturgeons of no economic value were purposelydestroyed when they becameentangled in and damaged the gill nets ofherring and shad fishermen (Ryder 1890;Brundage and Meadows 1982). The shortnosesturgeon, probably never common, is nowdesignated an endangered speci es , and theAtlantic sturgeon is relatively rare(Ryder 1890; Bigelow and Schroeder 1953;Reiger 1977). Because sturgeons are rare,relatively little is known of theirspecific habitat preferences for s~awningand nursery areas. Both species of sturgeonsspawn in nontidal and tidal freshwatersand the juveniles [nay remain infreshwater for several years (Vladykov andGreeley 1963; Brundage and leadows 1952).Small commercial fisheries still exist forthe Atlantic sturgeon in New York and theCarol inas (Reiger 1977).Of all the fishes occupying tidalfreshwaters at some tiae in their 1 ives,probably none has received greater attentionthan the striped bass, a species ofmajor com~nerci a1 and sport importance(Figure 24). Though mesent along theentire Atlantic coast of the UnitedStates, spawning is 1 argely restricted tothree estuaries. Major tributaries ofChesapeake Bay account for approximately90% of the striped bass spawned on theeast coast, while the Hudson River, NewYork, and the Roanoke River, North Carolina,account for the remainder (Berggrenand Lieberman 1977). In the mid-Atlantic,adult striped bass overwinter in the lower

Tab1 e 11.Characteristics of anadromous and semianadro~nous fishes of the At1 antic coast.FishSpawning areaSpawningResidence timetemperatureof juveniles in" C Nursery ground tidal freshwater Commercial use ReferenceAnadromousAlewife Small nontidal freshwater 12-22.5streams, also tidal fresh;primarily tributaries, onbottomBlueback In mid-Atlantic; tidal 15-24herring fresh & low brackish (to2 ppt) tributary streams.In Southeast; river floodplains& backwaters, abandonedricefields, mainstream & tributariesAmerican Nontidal & tidal freshwater 12-20shad in main stream; on shallowflats with relativelyswift currentsTidal freshwater Until late fall Fertil izer Uang &, Kernehan 1979;& 31 igohal ine Lippson et al. 1973areasWithin 5 nautical IJntil late fall Fertil izer; &darns 1970; Christiemiles of spawning live-bait fishery R Walker 1952; Uanqareas 4 Kernehan 1379Same general areaas spawning area,or slightly downstream!Inti1 late fall Food fish; eqrrs 'lassnlann et al.,for caviar 1952; Sholar 1977;Llawkins 19WHickory Mid-Atlantic; tidal fresh- 13-21shad water mainstream & lowerportion of some tributarieson shoals. Southeast Atlantic;tributary streams,lakes & river floodplainsSea Nontidal freshwater streams 11-24lamprey in rapidly flowing water; 14-15.6will use tidal freshwater (peak)if passage blockedAtlantic Nontidal & tidal freshwaters, 14-18sturgeon a1 so 01 igohal ine watersShortnose Nontidal & tidal freshwaters 8-19sturgeonBrackish & marinewatersNatal freshwaterstreamsFreshwaterUpper estuaryLittle; ,juveniles Food fish Adams 1Q7Q; Wana Linove to sounds RKernehan lq79;offshore waters Hawkins 1980soon after hatching3-4 years' asa~nmocoetelarvaeUp to R yearsUp to 4 years"one; a pest Wang t Kernehanspecies 1979Food fish; egqs \/ladykov R creelevfor caviar 1953Once used as food Heidt R Gilhert 1981;fish; endanqered, Srundage 4 Yeadowscannot he leqal 1 y 1982harvested(continued)

SpawningResidence timeFish Spawning areatemperatureOC Nursery groundof juveniles intidal freshwater Commercial use ReferenceRainbow Nontidal freshwater streams, 8.9-18.3 Brackish & marine Little; juveniles Food fish Scott & Crossmansmel t brooks; tidal freshwater if waters move rapidly to 1973; Yirchels %progress blocked; main sea Stanley 1951stream & tributariesTomcod Nontidal & tidal Freshwater 0-3.9 Oligohaline areas Little; mainly Food fish, rec- 5cott K Crossqanstreams use brackish reational use 1973waterson1 vStriped Tidal fresh ti oligohaline 10-23 Same as spawning area, Until late summer Gfajor food fish Hang t Kerneban 1974;bass (to 2 ppt) in mainstream; 15-18 also associated Li onson et a1 . 1979waters 2 in depth (peak) tributariesAtlantic Nontidal freshwater 0ct.-Dec. Nontidal freshwater None; juveniles Food fish; rec- 'cott R Crossqan 1971salmon in Mew only migrate reationalEnglandthrough tidal& Canadafreshwater4%6 Threespine nontidal & tidal freshwater, lo-? Tidal fresh & Throughout summer ?loneScott ,t Crnssman 1973;stickleback 01 igohal ine watersoligohal ineWang Q+ Kernehan 1379Semi - anadromousWhite Tidal fresh & 01 igohaline 10-20 Shallows downstrPaa Sl igh t downs t rearn Food fishperch (to 2 ppt), tributaries & 14-18 of spawning areas; ~novement in summer,main stream; shallows; also (peak) mouths of tributary but may re~nai n 8.nontidal freshwater creeks & min stream, overwinter in deepertidal freshwater channelsYellow Mainly tidal fresh & 01 igo- 6.8-12.5 Downstream of spawning Probably through Food fishperch haline (to 2 ppt); less in area; lawer portions & fallnontidal fresh; tributaries mouths of tributaries &main streamUang R Kerneqan 1979;Lip~son et al. 197sWang Li ooson 4 Yernehan et a1 . 1979;Gizzard Main1 y tidal freshwater, 10-25 Tidal fresh 8 01igo- Probably through Little; considered Waw a Kernehan 1979;shad main stream & tributaries; 15-25 haline, in shallows fall a trash fish Lippson et a1 . 1979a1 so nontidal freshwater (peak)

Figure 24. Striped bass, the most importantsport and commercial fish utilizingtidal freshwater envi ron~nents. Photographby Dennis Allen, Relle W. Baruch Institutefor Marine Science and Coastal Studies,University of South Carolina, Georgetown.estuary and open ocean, returning to theirnatal streams in s?ring to spawn (Lippsonet al. 1979). In Georgia, striped bassare etiti rely riverine, never enteringcoastal waters (Hornsby 1980). We havechosen to classify striped bass as anadromousbecause in the mid-Atlantic, thearea of peak abundance, some proportion oftile spawning population overwinters in theocean.Spawning occurs in tidal fresh andoligohal ine waters in the nain watercoursewhen temperatures exceed 10°C (50°F) earlyApril at the latitude of Chesapeake Say.Most adul ts return to estuarine watersafter spawning. Juvenile striped basspreferentially inhabit nearshore zoneswithin the tidal freshwater and oligohalinenursery area where food is denserthan in channels and deeper waters(Boynton et a1 . 1981). Juveniles movegradually downstream as they grow.Detailed studies on survival of .iuvenilestriped bass and variation in yearclass strength have demonstrat2d that thecritical period is the larval stage. Itis hypothesized that variation in fooddensities, pri,~iarily rotifers and copepodnauplii within the tidal freshwater and01 i gohal ine nursery zone, may be the cri t-ical factor in determining year-classstrength (Atlantic States Marine FisheriesCommission 1981). Apparently, strong yearclasses are correlated with cold wintersand high spring runoff. It is thoughtthat high runoff contributes nutrient anddetrital influxes vdhich favor high zooplanktondensities, and thus high larvalThe only catadrornous fish species inestuaries in this geographic area is theAmerican eel. Eels spend nearly a1 1 theirlives in fresh or brackish water, returningto the ocean in the region of theSargasso Sea off Bermuda to spawn. Youngesls return to the coast and enterestuaries, some ascending into nontidalfreshwaters. Eels are ubiquitous throughoutthe estuary and are very common in thetidal freshwater reaches. They readilventer tidal marsh creeks and may move ontothe marsh itself (Virqinia Institute ofMarine Science 1975, ~iviat YS; Livpsonet al. 1979).Marine FishesMarine fishes soawn at sea and spendmost of their lives in the marine habitat.They use estuaries either as nurseryareas, in which case they are estuarinedependent, or as seasonal feedi nq groundsas adults. Many more marine fishes usethe lower estuary than tidal freshwaters.Atlantic menhaden, spot, croaker, silverperch, weakfish, spotted seatrout, blackdrum, and the summer flounder are marinespecies whose young occupy nursery areasextending into tidal freshwater reachesduring the warmer months (Massmann et al.1952; Dove1 1971; Thomas and Smith 1973;Markle 1976; Virginia Institute of MarineScience 1978). In Georgia and Florida,snook and tarpon are dependent upon tidalfreshwater and 01 igohal ine nursery "areas(Rickards 1968). General 1 y, these vounqof-the-year,and adults of marine speciesas we1 1, leave the estuary as telnperaturedeclines in the fall.CJe have attempted to summarize thesediverse patterns of habitat use in Table12. The more common species for whichadequate 1 ife history information isavail abl e are arranged by affinity groupon the basis of their use of tidal freshwaters.5.3 COMMUNITY STRUCTURERe1 a ti ve AbundanceThe relative abundance of fishspecies in tidal freshwaters is best

Table 12. Patterns of use of tidal freshwaterhabitat by fishes.Pattern ofAff i ni ty group habitat use Exarnpl esI. Freshwater Resident Pumpki nseedTessellated darterRedfln pickerelLongnose garLargernou th bassSpawn elsewhereSome catfishMost suckers11. Estuarine Resident Mumni chogTidewater si lversideNursery areaHogchokerNaked goby111. Anadrornous Nursery area American shadA1 ewifeStriped bassMigratory onlyIV. Marine Nursery area SpotFeeding groundfor adultsHickory shadRainbow me1 tMu1 l etassessed from comparable data coll ected ata series of sites. In Table 13 the mostcommon fishes from ten studies arearranged by rank abundance. The eightspecies lsited for each study account forbetween 80% and 99% of a1 1 fishes capturedin these investigations. While differencesexist in sampl i ng method01 ogy andproportion of the annual cycle covered,some general i zations are possi b1 e. Overa, freshwater species outnumber a1 1others. Estuarine and migratory forms(anadromous and semi anadromous) are aboutequally abundant. Marine fishes are tlieleast comlnon group in tidal f reshwaters.The coverage in this table on a latitudinalbasis is relatively completeexcept for North Carolina. Only the CapeFear, New, and White Oak Rivers in thesouthern portion of this state have tidalfreshwater marshes comparable to those ofthe other states. ~nfortunatefy, thesurvey data from the tidal freshwater portionof these three river systelns areinadequate to include in this table.Biogeographic observations from Table 13are discussed in Section 5.7.Di vers i tySeasonal diversity in tidal freshwatersin the mid-At1 antic general ly peaksin late summer and early fall when theyoung of freshwater, estuarine, anadronous,and marine forms are still on thenursery ground (Merriner et al. 1976,Lipton and Travelstead 1978). In thesoutheast, the diversity peak appears tobe later - in fall or winter (D. Holder,Department of Natural Resources, GeorgiaGame and Fish, Waycross, pers. comm.;Hornsby 1982). Few data sets exist fromwhich to compare diversity of fishes alonga salinity gradient. The data of Merrineret a1 . (1976) from birnonthly trawl sa~npl esin the Pinakatank qiver, Vi rqinia, showedmore species at the sal ine end of the gradient (20 species, mean salinity 16.3)than at the 01 i gohal i ne-seaonal ly freshend (11 s~ecies, mean salinity 4.3).Similarly, Dahlberg (1972) found a decreasein fish species richness from themouth of the Newport River, Georgia, ashis sampl ing extended into freshwater. Noreadily discernable differences existed inthe diversities of collections of fishesmade at two times by beach seine in mesohaline(H' = 1.80, 1.62) and tidal freshwaterreaches (ti1 = 2.20, 0.94) of theJames River, Virginia (Lipton and Travelstead1973). In surnmary, it aopears thatthe tidal freshwater fishes are lessdiverse than in more saline oortions ofthe estuary.5.4 FUNCTION OF TIDAL FRESi-IWATEq MARSHFOR FISHESSpawning LocationThe tidal freshwater marsh itself isa spawning ground for several species offishes (Table 14). The shallow watermarsh edges, channel s, and tidal impoundmentsare spawning areas for a large numberof other species. The only obligatemarsh spawners are the two killifishes,the banded ki 11 if i shy and mumi chog (Tab1 e14). These two species also breed inhigher salinity marshes. The use of thenarsh as a spawning site is a facultativeuse by the remaining marsh spawners; theyalso breed in the shallows in both tidal

Table 13.Numerically dominant fishes in tidal freshwaters, New York to Georgia.Hudson R. Woodbury Delaware R. Potomac R. Rappahannock Pamunkey James River Winyah Bay Savannah R. Savannah R. Altamaha 9. Altamaha 9.Rank NY Ck., NJ tributaries VA River,VA R., VA V4 drainage, SC nxhow, creek qainstrearn oxhow mainstrearn-1 blueback mummichog white perch white perch Atlantic hlueback spottail largemouth strioed striped hlack channelherring menhaden herring shiner bass mullet mullet crappie catfish2 white banded rmm~nichog Atlantic blueback satinfin spot pirate redbreast redhreast 5lueqill hoachokerperch killifish menhaden herring shiner perch sunfish sunfish3 tesselated silvery banded gizzard rmmmichog spottail white perch warmouth spotted qizzard redbreast redhreastdarter minnow killifish shad shiner sucker shad sunfish sunfish4 banded alewife tidewater threadfin tidewater tesse- threadfin banded redear sootted warmouth Flathea6 9.killifish silverside shad silverside lated shad killifish sunfish sucker mall catdarterfish5 spottail blueback hogchoker brown white perch knerican tidewater yellow bluegill bowfin oi rate brownshiner herring bull head shad silverside bullhead oerch hull head6 yoldfish pumpkin- bay anchovy alewife satinfin banded mumnichog bowfin gizzard larqemouth tadoole carp~~jckerseed shiner kill i- shad hass inadtom soeciesfish7 pumpkin- brown pumpkinseed spot striped alewife gizzard strioed howfin kerican F1 orida whiteseed bull head bass shad mullet shad gar catfish8 American white bluegillshad perchbanded tide- striped brown largemouth hlueqill oizzard hl~~eqillkillifish water bass bull head bass shadsilversidesam- 9,260 12,143 41,025 4,546 1,500 6,000 6,319 46n unknown unknown 4,140 11,611~1.esizesam- Sum Sum, Fa1 1 Spr-Fall Spr-Fall Sum-Fa1 1, Summers, seasonally Zor-Sum seasonally seasonally 11-31-79 10-4-QnPI e 1969-1970 1976 1951 1949-1951 1976-1951 1982periodplace shore shore shore zone channel shore zone shore shore zone entire width shore zone s'lore zonP ~ntire ontirezone zone zone & marsh creeks, oxhow riverinterior ditches width, 4.3hasam- seine seine seine gill net, seine seine seine,fykegillnet, electro- electro- rotenone rotenonePI emethodfyke net,D-trapsnet, minnow lankt tontraps net,shock shockrotenonenumber 18 + 17 43speciessource Perl- Hastinqs Smith 1971 Powell 1977 Massman et Massqann VIMS 1978 N. Roark Hornshv Hornq'lv n. Hnlrl~r ~lnlnc-Pal. 1952 et a11952pers. corn. 1982 1982 pers. corn. 1987- - . " -. " ,. .*N. Roark, S.C. Wildlife and Marine Resources Department. Charleston, SC.

Table 14. Fishes reported to spawn in tidal freshwater. (Compiled from I-ippson et al.1979; Wang and Kernehan 1979; Christie and Walker 1982; Curtis 1982; Anonymous.)Channels or shoals Tidalkrsh Shall ows away from shore impoundmentsBanded kill ifishMummichogMosqui tof i shEastern mudininnowBluegillPumpkinseedCarpRedfin pickerelChain pickerelGo1 den shiner American shad Largemouth bassSatinfin shiner BluebackherringC NorthernpikeSpottail shiner A1 e~.ii fe Slueback herringSilvery minnow Hickory shadC 20 othersTessellated darter Striped bassTidewater silverside Gizzard shadYellow perchWhi te perchHickory shadBl ueback herringAtlantic needlefishaa~eported to spawn in this habitat in Potonac River, Virginia.,,freshwater spawning unknown.in the southeast regionCin inid-Atlantic regionGenerality of tidaiand nontidal freshwaters. Those speciesusing the shallows may spawn just off theedge of the marsh, often in associationwi th submerged vegetati on. The presenceof marshes is probably of 1 ittle consequencefor the breeding activities of thechannel spawners. The re1 ati ve importanceof tidal impoundments as soawninq locationsis poorly known. These habitats arerather common from the Cape Fear Siver,North Carol ina, south through Georgia.Since Curtis (1982) reported the findin?of the eggs of 20 species in an abandonedricefield on the Cooper River, SouthCarol ina, it is 1 ikely that these habitatswi 11 be important spawning locations.Primary Habitat for Resident SpeciesThe tidal freshwater marsh and associatedshall ows and waters provide year-roundfood and shel ter for adults and juvenilesof resident species. Resident fishes areprimarily freshwater species and may ormay not spawn in tidal freshwaters. Thisgroup includes the fol 1 owi ng commonfishes: longnose gar, American eel, redfinand chain pickerels, carp, goldfish,silvery minnow, golden shiner, satinfinshiner, spottail shiner, white and creekchubsuckem, white and channel catfish,brown bull head, banded ki 11 if i sh , mummichog,mosqui tofish, redbreast sunfish,pumpkinseed, bluegill, largeniouth bass,bl ack crappie, and tessellated darter.Nursery Zone and Juvenile HabitatThe role as a nursery zone for theyoung of nonresident adults (Table 15) isa particularly important function of tidalfreshwater marshes and associated shallows.The broad zone at the tip of thesalt wedge (i.e., the freshwater-sal twaterinterface) is often the region of maximumprimary and secondary productivity withinthe estuary (Dovel et al. 1969; Cronin andNansueti 1971). The hydraulics of thesalt wedge can act to concentrate the larvalstages within the upper portion of theestuary near the tidal freshwater zone.In addition, it is in this same riverreach that tidal freshwater and 01 igohalinemarshes occur. The often extensivevegetated zone of these marshes providesshel ter to small fishes and an additionalfeeding ground rich in benthic invert@-brates, algae, and detritus.Dovel (1971, 1981), in studying the

- Table 15. Fishes using tidal freshwaters OCEANas nursery grounds.ESTUARY-RIVERAffinity groupSpeci es Anad- Ma- Esturomousrine arineA1 ewi fe tArneri can shad tFRESHWATERAt1 antic menhaden tAt1 antic sturgeon tBay anchovytBl ueback herring tGizzard shad tHogchokertNaked gobytShortnose sturgeon tSouthern flounder tSpottStriped bass t Figure 25. Concept of rnovement ofTidewater sil verside + es tuarine-dependent fish larvae throughWhite perch tYe1 low perch +the low-sal ini ty critical zone and towardthe ocean as the fish grow. The movementsof individual fish (*) show a graduallychanging relationship to the salt front,which results in a downstream shift ofichthyopl ankton of the Patuxent Piverynursery zones for succeedingdevel *went (from Dovel , 1981).stages ofMaryland, and the Hudson River, New York,formulated the concept of the criticalzone of the estuary, an area encompassingthat portion of the estuary with salini- in the creeks (Curtis 1982)-ties betw2en 0 and 1Q ppt (Figure 25).Dove1 considered this region critical Estuaries are believed to he imnorsinceit is within this area that the tant nursery grounds because they are (1)survival and strength of each year classof most species of anadromous fishes isrich in food and (2) low in oredators.The second portion of this explanation isdetermined. Dovel further pointed out llOt entirely accurate for tidid freshthatthis critical zone is variable in Waters. While tidal freshwaters lacklocation and extent since it is affected large marine predators, freshwater oredabyboth freshwater runoff and tidal tor's are abundant (see Section 5.5 below).changes.Tidal freshwaters may act as an importantnursery ground because juveniles are foundThe tidal freshwater marsh and asso- in the extreme shall ows and larger nredaciatedshallows are also important habitat tory fishes in deeper waters, as suggestedfor the juveniles of resident freshwater the South Carolina data above*species listed in the previous section.The south Carol ins Wild1 ife and parineJuveniles may also select habitats withhigh stem densities (marsh surface and/orResources Depart~nent compared three sets vegetated shallows) where the foragingof abandoned ricefields and adjacent tidal efficiency of fish predators is reducedcreeks during two summers. On an areal (Vince etalo 1976, CrOwder andbasis, over 80% of all fish collected were 1979)-taken in ricefields. Ninety-two percentof O- to 4-inch gamefish (largemouth hass, 5.5 TROPHIC ASSOCIATIONSredbreast sunfish, warinouth, pumpkinseed)were captured in ricefields. Larger fish, The diets of fishes recorded fromsix inches and greater, were more numerous tidal freshwater marshes are given in63

Appendix B. Wherever possible, published ate steps in the food chain, specificallyinformation was sought from studies under- through the small crustacea and immaturetaken in this habitat. The dietary infor- insects.mation appears in as much detail as wasgiven in the orginal citation, and dietaryThe most abundant fishes which preyitems are listed in order of decreasing on small fishes in tidal freshwaterimportance for a species. marshes include largemouth bass, longnosegar, American eel, redfin pickerel, chainA number of general izations are pos- pickerel, bowfin, warmouth, black crappie,sible from these data. First, most fish and striped bass. Wading birds, kingfishpassthrough several ontogenetic feeding ers, certain ducks, terns, and gulls takestages. The striped bass is a good small fishes in the shallows. Ospreysexample. The postlarvae are nlanktivor- feed both on the marsh at high tide and inous. Juveniles begin to take larger food less turbid waters next to the marsh whereincluding a range of benthic inverte- they take larger fishes from coves, tidalbrates. Adults continue to take some creeks and the mainstream (see Chapter 7invertebrates, but are main1 y piscivorous and Appendix D) .(see Appendix B). Such changes are afunction of both growth and maturation of It appears from these observationsthe feeding apparatus and capabilities as that the abundant primary production ofwell as changes in habitat. Secondly, the marsh system is channeled through amany fish are opportunistic, without host of small invertebrate consumers ofstrict food preferences. Instead, they plant detritus and algae to numerous smalltend to feed on locally and seasonally and medium-sized fishes and then to aabundant food resources within an appro- smaller number of top predators, includingpriate size range, switching to other predaceous fishes, birds (Chapter 7), anditems as food avail abil i ties change. mama1 s (Chapter 8).The tidal freshwater marsh has anabundance of srnal 1 crustaceans, iqrnature 5.6 SEASONALITYinsects, and annelid worms (see Chapter4). Crustaceans (including a~nphi pods,The trophic patterns described aboveostracods, cl adocerans , mysids, and cope- are seasonal in nature. The anadromouspods) and insect nymphs and larvae are and semianadro~nous fishes are among theimportant foods for nearly all the smaller earliest spawners, Their young begin tofishes and many of the larger ones that use the tidal freshwater nursery area earusethis habitat. Annelid worms (oligo- ly in the spring, often before the freshchaetes)are apparently not a major die- water fishes spawn. Other early arrivalstary item in this habitat, possibly are the juveniles of winter spawning mabecausethey tend to be infaunal rather rine fishes including the croaker andthan epibenthic, A1 ternatively, they may spot. As the waters warm, the freshvraterbe more important than they appear to be species begin their reproductive seasondue to a lack of hard chitinous parts and more juveniles are found in the shalwhichwould appear in gut contents. They lows. The resident killifishes spawn inmay be thus underestimated in food habit midsummer. Thus, there are sequential ar-studies.rivals of juveniles in this nsrsery area.Invariably, the greatest number of indi-Depsite the abundance of algae and viduals and of species are observed inplant detritus in this habitat, few summer and fall in the mid-Atlantic (~erspeciesof fish feed directly on these riner et al. 1976; Lipton and Travelsteadresources. Those whose guts do contain 1978).appreciable quantities of these itemsinclude gizzard shad, striped mullet, sil- As temperatures decline in the latevery minnow, golden shiner, blacknose fall in this region, fish populations dedace,mamh killifish, and hogchoker cl ine. The juveniles of the anadromous,(Appendix B). More generally, these abun- marine, and estuarine species (except fordant resources of detritus and algae aremade available to fish through intermedi-64the killifishes) move downstream to overwinterin the lower estuary or to return

to the ocean. The freshwater residentstend to move to deeper waters where thetemperatures are slightly higher and lessvariable. Some resident kill fishes mayburrow in silty sediments within the marsh(Kiviat MS) or move to deeper waters(Fritz et al. 1975). In the mid-Atlanticthe shallows are largely deserted in thewinter, and ice may cover the marsh. Despitespecies-speci fic variations in there1 ative abundance, communi ty-wide popul a-tion levels are less variable seasonallyin the southern portion of our geographiccoverage (Figure 26).5.7 B IOGEOGRAPHYThe geographic area covered by thisconmuni ty profile is large, and there areevident differences in the fish communitiesin the northern and southern portions.Marine biogeographers have longrecognized that on the Atlantic coast CapeCod, t4assachusetts, and Cape i-latteras,North Carolina, are boundary areas separatingcoastal regions with distinguishablewater masses, floras, and faunas(Marshall 1951; Pielou 1979; Whitlatch19'32). Similarly, North Carol ina seems tobe a transition area in the distributionpatterns of freshwater fishes, with a numberof species terminating either northernor southern ranges at this latitude(Jenkins et a1. 1971; Lee et al. 1380).Exainination of Table 13 suggests real differencesin the fish communities of themid-Atlantic (Hudson River to James ~i ver)and the Southeast (South Carol ina andGeorgia). Based on Appendix B, Table 11,and Table 13, the following general izationsregarding 1 ati tudinal differences infish conmuni ties in tidal freshwaters canbe made:1. Some species, 1 argely restrictedto nontidal freshwaters in themid-Atlantic, arc! cozrion in tidalfresiwaters in the So~theast(bowfin, warmouth, pirate perch,banded sunfish).2. Some species present in bothareas use different spawninghabitats in the two regions(hickory shad, blweback herring).3. Juveni 1 e sci aenids (drums) extendinto tidal freshwaters inthe mid-At1 antic, hut apparentlynot in the Southeast.x-x - 7x/x/ \/ \1 \X_/ \\\ //&SAVANNAH. W//--/--- --x-// /' 'L- X---- x / \ PIANKATANK. VA\/ \\XISPRING SUMMER FALL WINTERSEASON-x-x + ALTAMAHA, GAFigure 25. Comparison of seasonal variationin total fish numbers in three riversystems. (Relative abundance in arbitraryunits because of di fference in sampl ingmethods. Data from Holder, pers. comm.;Hornsby 1982; Merriner et a1 . 1976).4. There is a greater tendency forsome marine species to penetratefreshwater in the Southeast(striped mu1 let, southern fl'ounder ) .5. There is less pronounced seasonalchanye in fish density in theSoutheast.6. As a result of human nodificationof the environment, thereexists in the Southeast a ratherunique habitat (the abandonedricefield, analogous to a tidalimpoundment) which appears to heintensively used as spawning andjuvenile habitat.

CHAPTER 6, COMMUNFY COMPONENTS: AMPHIBIANS AND REPTILESMuch literature exists concerning the river cooter, Florida cooter) are by sightamphibians and reptiles of freshwater the most conspicuous members of the1 akes , ponds, rivers, streams, swamps, and herpetofauna of tidal freshwater wetl ands .marshes. This literature, however, rarely These turtles are abundant in almost allmentions tidal freshwater wet1 ands as a river drainages in the Southeastern Unitedhabitat for these two groups of organisms. States. The turtles reported from mid-For example, Behler and King (1979) list a Atlantic tidal freshwater wetlands are atotal of 283 species of amphibians and diverse group. ranging from very rarereptiles for North herica. Only one of species such as the fa1 se man turtle,these is listed as inhabiting tidal fresh- introduced at the Tinicum marshes nearwater marshes. We feel that this repre- Philadelphia, to the ubiquitous snappingsents the fact that many biologists fail turtle. The wood turtle is a northernto recognize tidal freshwater wetlands as species, occasionally found in the higha distinct community type, and not the marsh. Arndt (1977) stated that in thefact that there is an absence of fauna in wet sedge meadows he surveyed along thethis community.Delaware Bay the bog turtle was the mostIncluded in our compilation are 102common reptile found. Once considered anendangered species, the hog turtle is nowspecies: 22 salamanders, 28 frogs and recognized as being secretive rather thantoads, 18 turtles, 6 lizards, and 28 rare (Arndt 1977). Eastern box turtlessnakes (Appendix C). Two reasons account are usually considered to be terrestrial.for this large number of species: (1) the We have found a surprising number of reflargegeographic region covered and (2) erences which record box turtles as beinqthe many reptiles and amphibians using found occasionally to commonly in tidalnontidal freshwater habitats that can also freshwater wetlands (rlcCormick 1970; Arndtuse tidal freshwater habitats. Many 1977; Mckenzie and Barcl ay 1980).species of amphibians, especially thosewhich 1 ive in the terrestrial envi ronment Diamondback terrapins are brackishas adults, must breed in permanent water and salt water turtles. They often enterand also spend their larval stages there. the tidal freshwater reaches of estuaries.These species have not been included in Once hunted extensively for food, the pop-Appendix C because the literature did not ulations of these turtles were rapidlyspecifically identify them from tidal decimated (McCauley 1945). Between 1880freshwater habi tats. and 1900 approximately 23,900 kg (50,0001 b) of meat were harvested annually from6.1 SPECIES COMPOSITION Maryland alone. By 1920 the harvest was373 kg (823 lb). With legal protectionSalamanders are generally rare or from indiscriminate harvesting, the takeuncommon in tidal freshwater wetlands.Mudpuppies, sirens, and amphiumas areincreased to 2,600 kg (5,800 1 b) by 1935(McCauley 1945). A major factor in theuncommon in northern marshes, becoming continued increase in this species hasmore common to the south. Frogs and toads been the loss of a market due to changingare much more common in tidal freshwater public tastes (McCauley 1945). Currentlywet1 ands than sal amanders . terrapin is considered a high-priced del i-cacy in many parts of Maryland; however,River turtles (e.g., painted turtle, overall public demand is still low.66

Lizards and 1 izard-1 ike reptiles arethe least common group of reptiles in thetidal freshwater wetl ands. Those specieslisted in Appendix C are most often foundin tidal swamps, shrub marshes, and highmarsh where vegetation is high enough forthem to escape inundation. The Americana1 1 igator was once abundant throughoutcoastal plain rivers and marshes in theSoutheast. Their populations declineddrastical ly due to over exploitation.Fol lowing protection, a1 1 igator popul a-tions have increased rapidly, but thespecies remains on the list of threatenedspecies (Federal Register 1980). A1 ligatorsare found in tidal freshwater marshesand swanips from North Carolina to Florida.They are more comlnon in the southern portionof this range. Although alligatorsuse tidal freshwater wetlands, they arefound in a variety of other wetland habitats.Three species of watersnakes, Nerodia(formerly Natrix), appear to he the mostabundant snakes in tidal freshwater wetlands.These snakes (pl ain-be1 1 ied, northern,and banded watersnakes) make use ofthe low marsh, high marsh, and tidalswamps. They also use a wide variety ofother wetl and habitats. Cottonmouth moccasinsare fo~lnd from the south shore ofthe James River southward. The manyreports of this species from other portionsof the Chesapeake Bay are proabablysightings of Nerodia which are mistakenfor the cottonmouth(lMc~au1 ey 1945).There are no species of amphibians orrepti 1 es included here which are confinedsolely to tidal freshwater wetlands. A1 1are capable of using a wide variety ofwetl and and terrestri a1 habitats.5.2 LATITUDINAL DISTRIBUTIONChesapeake Bay is a region where manyspecies reach their distributional 1 imi tsand can be used as a dividing line fordistinguishing a northern and southernherpetofauna. Southern species (e.g.,cottonmouth moccasin) are at the northernedge of their range, and northern species(e.g., bog turtle) are at the southernedge of their range. Musick (1972a) lists41 species which reach their northerndistributional 1 imit around the ChesapeakeBay and another nine species ~hich reachtheir southern 1 imi t.Reasons for this separation are basedon the change in winter climate betweennorthern and southern areas. Tidal freshwaterwetlands in New England, DelawareBay, and Chesapeake Bay are subjected tomuch more severe winters than tidal freshwaterwetl ands from North Carol ina southward.The northern marshes are oftenfrozen and covered by snow for prolongedperiods. Freezing temperatures are infrequentand of short duration along thesouthern At1 antic coast. Re~til es andamphibians, being both ectothermic (coldblooded)and incapable of long distancemigration, are the vertebrate group mostaffected by this latitudinal change inclimate. As a result we see that thespecies diversity of this group is greatlyreduced in northern regions in comparisonto southern regions. Of the species1 isted, 25 are reported from tidal freshwaterwetlands in Vew England and 83 aregiven for the wetlands of Georgia.6.3 DAILY AND SEASONAL VARIABILITYThe temporal variabil i ty exhibited byamphibians and repti1 es is probablygreater than that shown by birds and mammals.This temporal variation is manifestedas daily and seasonal activitycycles. Most amphibians and reptileshibernate during the wi nter months, oftenseeking a hibernaculum which may belocated some distance from the nearestwetland (Cagle 1942, 1950; Gibbons 1970;Ernst 1971, 1976). Kiviat (1978b) catalogedthe following species of tidalfreshwater reptiles which commonly usemuskrat lodges or burrows for their winterquarters: snapping turtle, musk turtle,mud turtle, spotted turtle, bog turtle,wood turtle, false nap turtle, pondsl ider, painted turtle, and northern watersnake. In southeastern Pennsylvania,Ernst (1971, 1976) found that most turtlesusing wet, nontidal sedge meadorvs alongthe Susquehanna River are active only fromApril to September. Daily activity cyclesare a1 so well developed and are dependenton air and water temperature (Cagle 1942,1953; Ernst 1971, 1976; Arndt 1977).Turtles, especially those in the generaChryseinys and Clemmys are rarely active

until the ainbient temperature reaches10" C or higher. If the temperature goesabove 34" C, many of these same turtleswill become inactive, seeking cool areas.Similar patterns of winter and dailyactivity are noted for frogs, toads, andsnakes (Noble 1954; Orr 1971). Salamandersof the family Plethodontidae areadapted to cold waters with high oxygenlevels and hence might be more active inthe winter than the other species ofreptiles and amphibians listed inAppendix C.5.4 ECOLOGICAL RELAT IONSllIPSMost tidal freshwater amphibians andreptiles are primary or secondary carnivores.They feed on a wide variety ofanimal matter from tiny insects tomedium-sized mama1 s and birds (AppendixC). One important exception to thisgeneralization are the turtles in thegenus Chrysemys. While young, these turtlesare carnivorous. As they mature,they switch to a diet which is almostcompletely vegetable matter (Ernst andBarbour 1972). This change in diet maycause the total biomass of these species'populations to reach very high values, onthe order of 200 to 500 kg/ha (Table 16).Only fish and the tiger salamander havepopulation biomass densities which exceedthose of herbivorous turtles (Iverson1982). Most carnivorous mamals and birdshave population standing stock biomasseswhich are 10 to 100 times less than thatof these turtles (Table 17). A1 thouqhthese estimates are based on studies doneTable 16. Population densities (numbers/ha) and standing stock biomass (kg/ha) of selectedspecies of turtles and various other vertebrate groups. Data are modified fromIverson (1982), Tables 1 and 2. 0 = Ominivorous, C = Carnivorous, H = Herbivorous.Species or groupFoodPopulationHabitat habits Density biomassSnapping turtle marsh C 1.2 9.1Snapping turtl e pond C 59 181Mud turtle creek 0 81+ 2 0Musk turtle pond 0 80 8.4:dusk turtle lake 0 150 10.2Painted turtle lake 0 4 9 11.2Painted turtle pond 0 571-591 28-102Spotted turtle pond 0 40-80 3.2-8.7Bog turtle bog 0 123 10.9Bog turtle swamp 0 140 12.9Chicken turtle pond 0 40 8.2River cooter spring H 170 384Florida cooter spring H 154 31 1River cooter pond H 5.2 4.0Pond sl ider pond 0 58- 36 1 27-283Pond slider river 0 190 40Softshell river C 42 19Large mammals - H - 280Small mannals - H - 100Large mammals - C - 1Small marrenal s - C - 1Bi rds - 0 ,C - 1Snakes - C - 5Frog s - C - 2 7Sal amanders - C - 2 1Fish - C - 47758

Tab1 e 17. Efficiency of secondary productionby various species of aniqals. Dataadapted from Pough (1930), Table 3.Efficiency (%)Species Gross NetWarm-bloodedCottontai 1 rabbitDeer :nouseMeadow voleSavannah sparrowLong-bil 1 ed marsh wren--Cold-bloodedRed-backed sal amanderSouthern toadNorthern watersnakeCorn snakein ponds, streams, and nontidal freshwatermarshes, they are probably comparable tothe value in tidal freshwater wet1 ands.High population biomass does notnecessarily inply that the energy flowthrough the population is also large. Aresult of ectothermy is that high biomasscan be supported with a low level ofenergy flow if the organisms are efficientat util izi ng what they consume (Pough1980). It has been shown that the grossand net efficiency of secondary production(i.e., the efficiency of an organisn inconverting what it eats into body mass) ofainphibians and reptiles is 10 to 100 timesgreater than that of birds and mammals(Table 17). Hence the biomass of herbivorousturtles may become large and besupported by a low level of energy flowthrough the entire population. A nanagementconsequence of this point is that itmay take a long time for the populationsto reach high levels. If the populationsare exterminated frorn an area, it willtake many years for them to recover(Iverson 1982). The effect of amphibianand reptile populations on the structure,function, and energy flow within wetlandsis poorly understood and should be studiedmore in the future.

CHAPTER 7. COMMUNITY COMPONENTS: BIRDS7.1 INTRODUCTION and snamps from the lower Chesapeake Bay.He did not, however, refer directly toTidal freshwater wetl ands provide a tidal freshwater marshes. Domenic Cicconevaried habitat for birds. Of the dif- (Refuge Manager, Mason Neck National Wildferenttypes of coastal wetl ands, tidal 1 i fe Refuge, Lorton, Virginia; pers.freshwater wetlands are among the most comm.) cited 76 bird species from thestructural ly diverse. Structural diversi- tidal freshwater marshes at Mason Neck onty is provided by the broad-leaved plants the upper Potomac River. ,4n additionalcharacteristic of the low marsh, tall three species were listed as uplandgrasses of the high marsh, the intermedi- species which frequently entered theate canopy provided by the shrub zone, and marsh. Mass and W i l kins (1978) found 129the high canopy found in tidal freshwater species using a tidal freshwater marshswamps.which had been built by the Army Coros ofEngineers on dredgespoil in the JamesTidal freshwater wetl ands harbor a River. Harold 01 son (Refuge Manager,higher diversity of bird1 ife than strut- Presquile National Wildl ife Refuge, Hopeturallysimpler wetland types such as salt well, Virginia; oers. comm.) stated thator brackish water marshes. Low marsh and 83 species of birds are comqonly seen inadjacent exposed mdfl ats are used by the tidal freshwater marshes at Presquil e.shorebirds and rails. The grasses and P. E. Young (Outdoor Recreation Planner,sedges characteristic of higher elevations Georgia Coastal National Wildl ife Refugein the marsh are similar to grassland or Complex, Savannah, Georgia; pers. comm.)savanna habitats and support an abundance provided an exhaustive list of 215 speciesof seed-eating species. Tidal channels which are known to util ize tidal freshandpools provide habitat for wading water wetlands in Georgia. Of thesebirds. Waterfowl use the open water areas species, 63 are mostly limited to tidalin addition to the marsh surface itself, marshes; the remaininq 151 species use theShrubs and trees found in the high marsh tidal swamps and upland forests whichand along the upland-marsh ecotone provide border the tidal marsh. Sandifer et al.habitat for a large nulnber of arboreal (1980) listed 76 birds which inhabit thebirds. These arboreal birds can often be palustrine, nonforested wetlands of thefound feeding in or over the marsh proper. South Carolina and Georgia coasts. Theyalso listed 122 species from forestedThe few surveys which have been con- palustrine wetlands.ducted in tidal freshwater wetlands reveala diverse assemblage of birds. Kiviat Based on information obtained from(1978a) observed 142 species of birds the 1 iterature and limited field surveyswhich used the tidal freshwater marshes conducted by T. J. Smith, we have compiledalong the Hudson River. The Hamilton a 1 ist (Appendix D) of 280 species ofmarshes on the Delaware River in New birds which use tidal freshwater wetlandsJersey supported 64 species of birds dur- for feeding, breeding, roosting, or othering the summer (Hawkins and Leek 1977). activities. Me have included rare andMcCormick (1970) reported 246 species from abundant species- The most commonthe region of tile Tinicum marshes near species, or those which are nOSt deoendentPhiladelphia. Mass (1972) listed 109 on tidal freshwater wetlands, are disspeciesas being found in the freshwaters cussed here.71

The birds of tidal freshwater wetlandshave been divided into seven groupsfor the purposes of this volume, The distinctionas to group membership vras madeon the basis of trophodynamics or on themethod employed by a particular species inprocuring its food (hawki nq, di vinq, probing).The seven groups are: floating anddiving waterbirds, wadinq birds, rai 1 s ands horebi rds, bi rds of prey, gull s andterns, arboreal birds, and ground- ands hrub-dwel 1 i ng hi rds. These groups arenot meant to represent guilds in an ecologicalsense, rather they are intended toshow very general affinities betweengroups and provide for ease of discussion.7.2 FLOATING AND DIVING WATERBIRDSThis group of 44 species is comprisedprimarily of members of the waterfowlfamily (Anatidae) plus gal 1 inules, coot,pel icans, grebes, doubl e-crested cormorant,and anhinga. Because of their economicand recreational importance, waterfowlare tile most studied and best understoodof the wetland avifauna, but characterizationof their utilization of wetlandhabitats remains difficult. Shaw andFredine (1956) inventoried the wetl ands ofthe United States and rated them accordingto their value to this group. Many areasrated as having high waterfowl use at thattime no longer support even srnall populations.An example is the greatly reduceduse of the Susquehanna Flats region of theupper Chesapeake Bay during the past 20years. This can be related to a drar~iaticdecrease in the amount of submerged aquaticve etdtion (Bayley et al. 1978). Lynch(19683 stated ". . . cases of consistentlyheavy exploitation of these coastal wet-lands (referring to all types of wetlands)by waterfowl are almost overshadowed byinstances of their partial or i nterni ttentuse or even casual abandonment."As an example of the vari able natureof waterfowl use of differing wetlandtypes and of different wetlands of thesame type, we present three years of annualmid-winter waterfo~rll survey data forVirginia (Table 18). This survey is conductedin early January, across the entirecountry to provide baseline data on trendsin waterfowl populations and on changes inhabitat use. Virginia is divided into 19survey units which we have arranged alonga gradient of sal ine to freshwater. Patternsof use between years, between differingsalinities, and among units of thesame salinity are striking (Table 18).The Paniunkey, Mattaponi , and ChickahominyRivers all have large acreages of tidalfreshwater marshes and swamps. Only thePamunkey is used substantially by geese,often having more than 10,000 individuals,while the Chickahominy has less than 100.The greatest use by dabbling ducks of tidalfreshwater marshes also occurs alongthe Pamunkey but is highly variable. Overa three-year period, January populationsin the Pamunkey fluctuated by a factor offour. The Nattaponi River marshes, whichare less than five kilometers from thePamunkey, receive little use by dabblingducks. Tidal freshwater marshes alongthese two rivers appear, visually, to beidentical (T. J. Smith, personal observation).Causes for disparities in usageare unknown but may be related to subtlehabitat differences, historical factors,microcl imatol ogical differences betweensites, disturbance, or some other causes.These data also indicate other importantpoints in the use of wetlands bywaterfowl. Dabbling ducks and geese(especially Canada geese) appear to bemost closely tied to tidal freshwater wetlands(Figure 27). Diving ducks andmergansers are found in tidal freshwaterhabitats but are rmch more common in01 igohal ine and brackish wetl ands. Seaducks are almost never found in tidalfreshwaters, being most abundant in Srackish and saline environments. In morenortherly areas where tidal freshwaterwetlands are in closer proximity to brackishand salt marshes, the diving and seaducks occur more regularly in the freshwaterareas.Of the various types of coastal marshand wetland habitats, Shaw and Fredine(1956) rated shall ow, tidal freshwatermarshes as the most important habitat forducks, geese, and swans. Stewart (1962)provided one of the most comprehensivediscussions of wintering habitat use bywaterfowl. In the upper Chesapeake Bayregion, thirteen wetland habitats weredelineated, two of which were tidal freshwatermarsh systems. These two habitattypes (estuarine river marshes and fresh

The seasonal pattern of waterfowl usein tidal freshwater marshes is most 1 ikelydetermined h.y a combination of food availability,food qual i ty, and weather conditions.The vegetation of tidal freshwatermarshes provides an abundant source ofhigh energy foods when waterfowl need themmost, i.e., immediately following theirsouthward migration when energy stores aredepleted and prior to the northward flightwhen energy reserves must be built up.During the winter months when a bird'smaintenance requi rements ;nust be met,lower qual i ty foods avai 1 able in brackishand sal ine environments are sui tab1 e.Additionally, at northern locations tidalfreshwater wetlands freeze over in thewinter and food plants are not available;the waterfowl are forced to move to morebrackish wetlands or to migrate to areasfurther south.Figure 27. Late autumn mixed assemblagesof Canada geese and ducks in tidal freshwatermarshes of the Pamunkey Ri veryVirginia. This photograph was taken froman aircraft approximately 200 feet in theair.estuarine bay marshes) comprised only4.82hf the entire study area. Dabblingducks were obviously selecting tidalfreshwater marshes in place of otheravai 1 ah1 e wet1 and habitats (Tab1 e 19),especially early in the autumn. Greenwingedteal were the most selective; insone inonths one quarter of these birdswere found in tidal marshes comorisinqonly one-twentieth of the total wetlandarea. Ma1 lards, American black ducks, andAmerican ~i geon were a1 so selective, butnot to the- extent of green-winged teal(Table 19).Diving ducks such as canvasback, redhead,scaup, buff1 ehead, common go1 deneye,and ruddy ducks were highly selective forfreshwater and 01 igohal ine estuarine hayhabitats (Stewart 1962). These species doutil ize tidal freshwater marshes but werenot as common there as in the open-waterbays (Stewart 1962).The seeds and rhizomes of annual andperenni a1 sedyes, rushes, grasses, andbroad-leaved herbs appear to be favoredfoods of most waterfowl. Those speciesmost co~ninonly eaten include threesquare,softstem bulrush, saltrnarsh bulrush, ricecutgrass, knuckl egrass, ha1 berdl eaf tearthumb,dotted smartweed, Walter's mil let,dwarf spi kerush, squares tem spikerush,fragrant u~nbrelasedge, and wildrice. Itappears that these ;niddle to upper intertidalmarsh species are more importantfood items than are the seeds and rhizomesof the broad-leaved species of the lowmarsh (Stewart 1962; Conrad 1965; Kerwinand Webb 1971; Perry and Uhler 1981).However, exceptions to the above general i-zation do occur. Perry and Uhler (1981)reported thdt approximately one third ofthe food by volume of the wood ducks fromthe James River in Virginia was arrowarum.They a1 so stated that Canada geesseoccasional ly fed on pickerelweed. Stewart(1962) 1 i sted arrow-arun as important inthe diets of Canada geese, mallards, blackducks, and wood ducks from the upperChesapeake region. Ye1 low water1 ily is anirnportant food of rin -necked ducks in theupper Chesapeake Bay 9 Stewart 1962).The great diversity of foods availableto and eaten by waterfowl in tidalfreshwater wetlands indicates the value ofthis habitat type to them (Perry and Uhler1931). A notable feature of the foodhabits of waterfowl is the opportunistic

Table 18. Distribution of waterfowl in various regions of Virginia during early January1978-1980. Regions are arranged on a gradient of salinities, from tidal sal ine totidal freshwater. Data provided by Fairfax H. Settle, District Biologist, VirginiaCommission of Game & Inland Fisheries. TR = Trace.- Sal ineRrackisllMobjack Chi nco- Yi rginia Lower Lbper Poquoson Halnpton Lower Yorkteague barrier eastern eastern Roads Jaqes Pi verislands shore, shore, Riverbayside baysideWhistl ing swanCanada geese, snow geese, and SrantDabbling ducksDiving ducksSea ducksTable 19. Percentage of total species population present in the upperChesapeake Bay, observed in tidal freshwater habitats, estuarine rivermarshes, and fresh estuarine bay marshes. (Tabulated from data in Stewart1962.) NR = Not reported.Species Oct. hlov. Dec. Jan. Feh. MarchWhist1 ing swan 0 3 TR 0 NR 1Dabbl i ng ducksMa1 1 ard 13 17 14 12 NR 9Slack duck 16 9 4 4 NR 6Green-winged teal 52 30 24 16 NR 36k~ierican wi yeon 4 15 TR 0 NR T R74

FreshwaterLower Reedville Back Hog upper Presquile Chicka- Pamunkey Mattaponi llpperRappa- Bay Island James hminy River River hooahannockRiver River hannockRiverQi vprfeeding and consequently the wide diversityof items eaten. Perry and Uhler (1981)examined 115 gizzards from eight speciesof waterfowl and found 136 different fooditems. Ten American black ducks ate 51types of food while five American wigeonconsumed 21 di fferent foods (Table 20).Other examples of rnarsh onnivores are theAmerican coot, common gallinule, and Durplegallinule which feed on the leaves andseeds of sedges, rushes, spi kerushes,wildrice, and pondweeds. They also take a1 arge number of aquatic insects, tadpoles,snails, frogs, and small fish.Perry and Uhler (1981) reported thattwo hooded mergansers taken from the upperJames River, Virginia, fed exclusively onalewives. Johnny darters and Americaneels are eaten by the hooded merganser inthe upper Chesapeake Bay (Stewart 1962).Common mergansers were reported to feed onpumpki nseed sunfish and ye1 1 ow perch a1 ongthe tidal freshwater wetlands of the PotomacRiver, Virginia (Stewart 1962).Loons, pel icans, cormorants, and anhinqasare also fish eaters. Gallinules andgrebes consume a broad range of aquaticinvertebrates and vertebrates. During thefall, grebes and gallinules will eat theseeds of numerous marsh plants such aswi ldri ce, sedges, and rushes (Terres1981).Few waterfowl breed in tidal freshwaterwetlands of the mid- and southAtlantic coasts. 9nly wood ducks, and toa lesser extent American black ducks andma1 1 ards, commonly use these wet1 ands forbreeding habi tat. Stotts and Davi s (1960)found that 65% of the nests of Americanblack ducks were located in upland areasoften hundreds of yards from the nearestwater. Only 17% of the nests were in themarsh and these were located on elevatedsites above the high-tide line. Once the

Table 29. Breadth of diet of selected species of waterfowl from tidalfreshwater wetlands. Calculated from data presented in Stewart (1962) andPerry and Uhler (1981).Spe ci esNumber of Number of FoodNum be r animal pl ant i terns/examined foods foods bi rdCanada gooseWood duckArneri can wi geonGreen-wi nged tealNall arda1 ack duckPintailNorthern shovelerilooded rllergansereggs have hatched, the brood moves to the 1962; Perry and Uhler 1981). The remainnearestwetland. Although brood rearing ing species are most abundant in tidalway occur in a n~lnber of habitats, it freshwater when it lies in the vicinity ofseerns that sedge, cattail, and bulrush large areas of brackish or salt marsh.~ndrshes are favored (Be11rose 1975). Pi ed-bill ed grebes, gallinules, and cootsAvailabili ty of cover is the most impor- occasionally nest in the marsh, choosingtant criterion for brood-reading areas high marsh sites with plentiful sedges andsince duck1 i nys feed on aquatic insects, reeds for constructing their floatingnot vegetation. Wood ducks are tree- nests.cavity nesters and their breeding activityis restricted to freshwater swamps (tidaland nontidal ) and wooded uplands. They 7.3 WADING BIRDSwill often nest over one mile from thenearest water. Favored species dhich pro- Fifteen species of herons, egrets,vids suitable cavities include cypress, ibises, and bitterns make up this familiarsyca~nore, sweet gun, willow, and red group of marsh birds. These species aremaple. Once the eggs have hatched, the commonly seen during the summer throughoutbrood is immediately lead to the nearest the Atlantic coastal region. Only themarsh. The tidal freshwater wetlands limpkin and wood stork are restricted inalong the rdestern shore of the Chesapeake range, being found soutCl of YoutCl Carn-Bay, such as along the Pamunkey and 1 i na. The great blue heron ( Figur~ 28) f sNattaponi givers in Virginia, are used the only species found during winter Inextensively for brood rearing by this tile northern parts of the Atlantic coast.species (Smith, personal observation), as The other snecies ,xigrate southward in theare similar areas througiiout the inid- and winter. Along the southern portions ofsouth Atlantic (anonymous reviewer). the coast, waders are present year-round.These birds make heavy use of the tidalLoons, grebes, pel icans, gannet, channels, creeks, and ponds found throughmergansers,cormorant, anhinga, and gall i- out the low and high marshes. They arenules compri se the remainder of the float- a1 so found commonly along the banks ofing and diving waterbird group. Of these, watercourses in tidal swamps and saltonly the common and hooded mergansers, marshes.pied-billed grebe, gallinules, coot, andanhinga are found with regularity in tidal Fish, from small minnows and silverfreshrtatermarshes and swamps (Stewart sides to catfish, are preferred prey.76

7.4 RAILS AND SHOREBIRDSFigure 28. The great blue heron feeds intidal freshwater rnarshes throughout theyear.Other food i tems include: crayfish,snails, frogs, 1 izards, and snakes. Occasi onal ly herons and hi tterns consume somewarm-blooded prey i tems such as mice andshrews or even young birds. Limpkins havehave a highly specialized diet consistingalmost entirely of snails.Green herons and bitterns nest intidal freshwater marshes. Green heronsbuild nests of sticks in vegetation low tothe ground. Bitterns use sedges andgrasses to construct nests low over thewdter. Breeding colonies of herons use alride variety of trees and shrubs to supporttheir nests, and sometimes nest onthe ground in dense vegetation. Theactual location of the nest site is notcritical to these birds as they will fly1 onq di stances betwezn heronry and feedinggrounds (Kushlan 1977; Maxv~ell and Kale1977). During the summer when thesewaders are raising young, their fish preyis most abundant within the rnarsfi (seeChapter 5). The food which the wadersgather from tidal freshwater marshes isundoubtedly iinportant to the tnai ntenanceof ddul ts and to the growth and survivalof thei r young.At least 35 species of shorebirds andrails tnake extensive seasonal gse of thehigh marsh, low rnarsh, and especially ofthe associated tidal flats. Hawkins andLeck (1977) observed killdeer, spottedsandpiper, sora rail, and American \'roodcockin tidal freshwater rnarshes in NewJersey during the sumr?er. The woodcockwas confirried as nesting in the wildricefarrow-arum zone of this wetland. The otherthree species were believed to havenested but nests were never found.?lcCormick and Somes (1982) observed a numberof species of sandpiners and rails atOld!nans Marsh, also in Yew Jersey.Greater ye1 1 o ~l egs were observed yearround,coinrnon snipes and dun1 ins duringwinter and in nigration, kinq rails in thesumrner, and large nu~ribers of least sandpipers,nectoral sandpipers, and Virginiarai 1 s during surnlner and rni qra ti ons. Lesseryellowlegs were seen only dtlrinqmigration. Fifty percent or more of thetotal sightings of these ~iqht soecies,sumlrled over all habitats surveys, weremade in tidal freshwater marshes(McCorlnick and Sornes 1982). Yi rly railsare one of the few species of birds to beactive during winter months in the tidalfreshwater wetlands of the upper ChesapeakeBay (?leanley 1975). King railsremain active despite snow and ica coveringthe rnarsh surface. Peak abundance ofsoras occurs during fall migration attidal freshwater wetlands along the enti reAt1 antic coast (ldebster 1964, i'leanley1965).Primary foods of these sneciesinclude freshwater worrns, crayfish,snails, and mollusks. In fact, they willeat almost any invertebrate organismsfound in the upner few centimeters of tbesediment surface (Baker and Baker 1973;Schneider 1978). Ourinq t'.reir fa1 1 migrations,surprising nu~nbers of shorebirdsqake extensive use of the seeds of marshplants suc9 as wi ldrice, three-square,ha1 berdl eaf tearthumb, dotted smartweed,redroot sedge, rice cutgrass, and rnanvother marsh plants. Yany sl~orehirds arepresent only during the fall migrationwhen the seed supply is maxi~um. Aninteresting note is the utilization ofwildrice by rails. Ourin? autcmti rdqrationlarge numbers of soras (and possibly

other rails) gather to feed on the seedsof this abundant marsh plant (Uebster1964; Mean1 ey 1965). We have observedflocks of several hundred soras feeding onwildrict? seeds in tidal freshdater marshesalong the Chickahominy River (Snli thy personalobservation). Ouring the month-longperiod in the fall bvhen wildrice seeds areripening, they may comprise 90% of thesora's diet (Uebster 1964).7.5 BIRDS OF PREYHawks, falcons, eagles, osprey, owls,vultures, and the loggerhead shrike formthis group of 23 predatory or carrion-eating birds.These species are at thetop of the wetlands' food pyramid and sowere never abundant. Recently, somespecies of birds of prey have sufferedra?id and drastic declines in populationsize because of pollution, habitat loss,and, inost importantly, chlorinated hydrocarbonpesticides (Yenny et al. 1974). Ofthis group the southern bald eagle andperegrine falcon are officially 1 isted asendangered ( Federal Register 1980).Swallow-tailed kites and Cooper's hawksare groposed for inclusion on SouthCarol i na ' s endangered and threatenedspecies 1 ists, respectively (Gauthreaux etal. 1979, quoted in Sandifer et al. 1980).Additional ly, the barn owl , great-hornedowl, merl in, Mississippi kite, and logger-head shrike are ?reposed for specialconcernstatus by South Carolina. All ofthese species Rave suffered large declinesin population size in the South Carolinacoastal zone in recent years.prefer the ecotone between forested andnorlforested habitats. They are most oftenfound in the region where the tidal freshwatermarsh grades into upland forest ortidal swamp.Popul ations of osprey are recoveringfrom their pesticide-caused decl ines ofthe 1960's. Ospreys are common along manystretches of the At1 antic coast. Breedi nqospreys use tidal freshwater wet1 andsaround the Delaware Bay (Hawkins and Leek1977), Chesapeake Bay (Henny et a1 . 1974),and along the Georgia Bight (Sandifer etal. 1980). Henny et al. (1974) reportedthe observation that nesting ospreys useman-made structures (e.g., navigationbuoys, towers) almost as much as naturalstructures. This habit appears to be qoreprevalent in the Maryland portions on thebay. In Virginia, ospreys are more proneto use trees such as cypress to hold theirnests (Henny et a1 . 1974).Ospreys and bald eagles are highlydependent on tidal marshes for the productionof fish, their primary prey. Marshhawks are also very dependent on tidalwetlands. 411 three of these raptors canuse wetlands along the entire estuarinesalinity gradient, and so are notrestricted to tidal freshwaters. r3f theother birds of prey in this group none arecompletely dependent on tidal freshwatermarshes since they all can exploit a varietyof other habitats, both wetland andup1 and.7.6 GULLS, TERNS, KINGFISHERS, AND CROWSSouthern bald eagle populations Included in this group of 20 speciesappear to have stabilized in the past are gulls, terns, crows, and kingfishers.decade. Breeding eagles are found along Gulls are present during winter and duringtidal freshwater stretches of the Potomac migration. Common and Fors ter' s terns areRiver (Lippson et al. 1979). In South present in the summer and during ~nigra-Carolina, areas of impounded marsh, many tion. Fish and American crows, laughingof which are tidal freshwater habitats, gulls, ring-billed gulls, and the beltedare apparently very important for nesting kingfisher can be found year-round. Hereagles(Sandifer et al. 1980). ring gulls and great black-backed gullsare common winter residents of coastalNorthern harriers (marsh hawks) and saltwater areas which often range up theAmerican kestrels are comtilon in tidal estuary to tidal freshwater regions.freshwater iaarshes, especially in winter. Glaucous and Iceland gull s are reportedgeed-shouldered and red-tailed hawks are from the vicinity of the Tinicum !4arshcommon permanent residents. Cooper's near Phi 1 adel phi a, Pennsyl vani a.hawks are more likely to be found in river McComick (1970) reported that these gullsswamps. knerican swal 1 ow-tai Ted kites are attracted by garbage dumps which are78

close to these marshes. This may notreflect true use of the tidal freshwaterwetlands by these species.Tidal creeks, channels, and pools inthe marsh are used for hunting fish. Thebe1 ted kingfisher, American crow, and fishcrow breed in tidal freshwater wetlands.7.7 ARBOREAL BIRDSThis is the largest group, comprising90 species. Flycatchers and swallows arethe most iinportant species in this group.Stewart and Robbins (1958) reported thatflocks of swallows numbering into the tensof thousands could be seen over tidalfreshwater marshes in the upper ChesapeakeBay during fall and spring migrations,evidently feeding on the abundant insectfauna of the marsh. Sandifer et al.(1980) noted that swal lows were importantto tidal freshwater wetlands in SouthCarol ina and Georgia for similar reasons.We have commonly observed flycatchersfeeding over tidal freshwater wetlands inVirginia (Hoover and Smith, personal observations).Species such as easternki ngbi rds and great-crested flycatcherswill perch in trzes or shrubs along theupland border of the marsh in search ofprey. When an insect is spotted flyingover the marsh, the bird darts out tocapture it. Both swallows and flycatchersare important insectivores in the marsh.Many of the other species 1 isted in thisgroup are birds of the ecotonal communitybetween the marsh and upland. The woodwarblers have mostly been reported fromtidal freshwater marshes and swamps duringmigration. While these warblers are intransit between summer and winter quarters,these wet1 ands may provide importanttemporary habitat. The arboreal birds asa group are the least dependent on tidalfreshwater marshes for their survival.7.8 GROUND AND SHRUB BIRDSFifty-three species of birds areincluded in this group which is composedof the emberizids and fringil ids (sparrows,juncos, finches, blackbirds, wrens,and several other species). The seeds ofthe high marsh plants which are importantto other groups are also the staple dietof these species.ed as breedingTen species are recordintidal freshwatermarshes, including ring-necked pheasant,red-winged blackbird, herican go1 dfinch,rufous-sided towhee, savannah sparrow,grasshopper sparrow, tree sparrow, chippingsparrow, field sparrow, swamp sparrow,and song sparrow (Meanley and Webb1963; Hawkins and Leck 1977). Largeflocks of red-winged blackbirds, dickcissels,and bobolinks create a spectacularsight in wildrice marshes when they congregateduring early autumn. Flocks numberinginto the tens of thousands are common.The timing of the arrival of theselarge flocks coincides witb seed set bythe wildrice. It takes only a few daysfor these birds to consume vost of thecrop and then move to another marsh.Bobolinks were referred to as ricebirds inthe last century by plantation owers inGeorgia and South Carolina. These birdswith their voracious appetites inflictedheavy losses on the rice crops.Of the birds in this group, marsh(I ong-bill ed) wrens and sedqe (shortbilledmarsh) wrens are most dependent ontidal freshwater marshes. Short-bil ledniarsh wrens are most abund3nt in brackishand saline environments, though they arecommon in tidal freshwater marshes.Short-bil led marsh wrens are considered aregional ly endangered species in NewJersey (Hientzleman 1971).7.9 ENERGY FLOW AND AVIAN CO?4MUNITYDYNAMICSWiens (1973) suqqested three possibleroles for birds in ecosystems: (1) theymay directly effect the ecosystem byinfluencing the flow of nutrients and/orenergy, (2) by acting as controlling factors,they flay help naintain stability inthe ecosystem without playing a major rolein nutrient and/or energy flows, and (3)they may simply be frills living off theexcess production of the ecosystem andhaving no influence on it whatsoever.There have been few studies on the role ofbirds on energy and nutrient flows in ecosystemsof any type to test Wien's ideas.The role of hi rds in nutrient cycl inqhas not been studied in tidal freshwaterwetlands. Bedard et al. (1980) examined

the effects of seabirds on nutrient con- al. (1973) examined the energy flow of thecentrations within the St. Lawrence River entire salt marsh/ shallow bay region ofestuary. The effect of ifitporting nutri- Barataria Bay i n Louisiana. These authorsents to the estuary from outside sources reported an average yearly standing cropby seabirds was negligible compared to the of 0.044 g dry wt/m2 for the avian compoamountof nutrients already present in the nent of the system. This value is slightsystem.nanny et al. (1975), McColl and ly higher than what Hawkins and LeckBurger (1976), and Onuf et al. (1977) Dre- reported for only the common breedingsented data to show that on a localized birds in a tidal freshwater marsh. Whenscale birds may be qui te important. In the nonbreedi ng birds, uncomrnon breedi ngthese three studies, birds (Canada geese, birds, and the juvenile birds which areFranklin's gulls, and herons, resnective- produced are included in the calculations,ly) were shown to be important by import- the annual biomass of birds in tidaliny nitrogen, phosphorus, potassium, and freshwater lnarshes will probably be hiqherorganic carbon to wetland systems. Nanny than in salt or brackish marshes. Day etet al. (1975) and Onuf et al. (1977) were al. (1973) reported that total consumptionabl2 to show that the imported nutrients by the birds amounted to 7.33 g dry wt/rl121 ed to increased levels of primary produc- for the year. A portion of the bird'stion. Onuf et al. (1977) presented addi- consumption is returned to the marsh surtionalevidence to show elevated secondary face as feces. This amounted to 2.20 qproduction in regions receiving nutrient dry wt/m2/yr. Respiration accounted forinputs by herons. The input of nutrients 5.11 g dry wt/m2/yr, and the rernaininqled to increased nitrogen content of t+e 0.022 g dry wt/m2/yr was production by theplants (mangroves in this instance) which birds. Day et al. (1973) state that cermadethem more pal atable to herbivores. tain groups of birds, esoecially the dah-On a local scale then, birds can be an bling ducks, may be ten times more abunifiiportdntvector in nutrient flow. dant in nearby freshwater marshes. Energyflow through the avifauna of tidal fresh-In tidal freshwatermarshestnigratory water marshes may be somewhat higher thanwaterfowl and shorebirds and the large in brackish and salt marshes.flocks of blackbirds and rails could possiblyact as nutrient exporters since theyAlthough the flow of energy throughfeed in the wetlands and then leave. If the avian component of tidal freshwatercolonially nesting species were to develop wetlands represents only a small portiona colony in or ne3r a marsh, this could of the overall energy flow, birds cancertainly provide for an input of nutri- exert other influences on the system.ents.Reed (1978) studied the effect of grazinqby snow geese on tidal freshwater marshesThe role of birds in the energy flow along the St. Lawrence River in Canada.of lnarhes has 1 ikewise received 1 ittle He found that increasing grazing pressureattention. Hawki ns and Leck (1977) resulted in greater primary production byexamined the breeding bird fauna in three three-square, the dominant plant. Hencetidal freshwater marsh habitats in New grazing faci 1 i tated energy flow throughJersey. These included a cattail marsh, the entire system. Along the mid-Atlantichigh marsh, and low marsh. Breeding bird coast, hoviever, snow geese are much morebiomass in these marsh habitats was esti- common in salt marshes. The.y can drasticmatedto be 0.012-0.017, 0.006, and 0.007 ally reduce primary production and causeg dry wt/m2, respectively. The energy changes in species composition of theflow through the breeding bird component marsh vegetation (Lynch et al. 1947; Snithof this system was estimated using and Odum 1981; Smith 1983). Canada qeesemeasured weights of birds present in the have been reported to cause temporary,mdrsh and converting to energy using local loss of vegetation from tidal freshstandardmetabolic equations. Energy flow mter wetlands through overgrazing (Smith,was reported as 0,037-0.050, 0.015, and personal observation). Thus, organisms0.021 kcal/:n2/day in each of the wetland which account for only small fractions oftypes studied, respectively. Over the the total energy flow may '7ave more impor-SO-day breeding season this represented tant impacts on the system than energy2.82-3.00, 0.30, and 1.26 kcal/n2. Day et flow alone would suggest.80

CHAPTER 8. COMMUNITY COMPONENTS: MAMMALS8.1 SPECIES OCCURRENCEThe 45 species of mammals that wehave found to be reported from tidalfreshwater marshes (Appendix E) range fromabundant, almost ubiquitous species suchas the Virginia opossum, to relativelyrare or local ized species such as thenine-banded armadillo. In this section wehave chosen to focus only on the common orecological ly important species. Due tothe lack of published studies restrictedto tidal freshwater marshes, regionaloccurrences listed in Appendix E shouldnot be construed as comprehensive.A variety of rnammals utilize thetidal freshwater marsh as year-round residents(Table 21a). A1 1 of these specieshave the fol lowing characteristics: (1)they are capable of obtaining a1 1 of theirnutritional needs from within the tidalfreshwater habitat (note that thesespecies are either herbivorous or omnivorous),. (2) . . they have a fur coat ~hich isrelatively impervious to water, and(3) they have the ability to nest (andhibernate in more northern areas) withinthe marsh either in a submerged lodge or anest elevated on vegetation. A variety ofother species are unable to exist in thetidal freshwater narsh habitat on a permanentbasis, but make periodic feedingforays into the marsh (Table 21b).Of the species listed in Appendix Eand Tables 21a and 21b, those which appearto be most dependent upon the tidal freshwatermarsh habitat include the riverotter, muskrat, nutria, mink, easternraccoon, marsh rabbit, and marsh rice rat.This does not imply, of course, that thesespecies do not use a1 ternate habitat suchas swamps, river bottom flood~lains, andfreshwater streams .Tab1 e 21a. Examples of mammals commonlyfound in tidal freshwater rnarshes as yearroundresidents.Star-nosed moleMarsh rabbitBea ve rMarsh rice ratMuskratMeadow voleYutriaEastern raccoonRiver otterMinkTable 21b. Examples of rnamlnals which makeforays into tidal freshwater marshes forfeeding purposes, but which are not consideredpermanent residents.Virginia opossumLeast and short-tai ledshrewsBig brown batHouse mouseNorway ratRed and gray foxStriped skunkBobcatWhi te-tailed deerCompari sons of :gamma1 species diversitybetween tidal freshwater marshes onone hand and saline marshes, nontidalfreshwater marshes and swamps on theother, have generally not been made. Wesuspect that species diversity is significantlyhigher in tidal freshwater marshesthan in saline marshes; however, data forcompari son wi thontidal freshwater andup1 and habitats are general ly lacking forthe east coast.8.2 ROLES IN MARSH ECOLOGYUnfortunately, not much is knownabout the ecological interactions between

the various soecies of mammals in tidalfreshwater marshes. Most informationwhich is available comes from research inthe wetlands of Louisiana or the 01 igohalinestretches of east coast marshes.Neither hahi tat is di rectly coinparable totidal 'resiiwater narshes. For this reasonmuch of the information which follokvs inthis section should be regarded as eitherextrapolations or guesswork !lased oninformation from better studied habitats.In revi evri ng the fo11 owing inaterialtwo points should be remembered. (1) Theprocess of herbi vary is probably importantboth directly as an impact on the structureof the tidal freshwater plant communityand indirectly through its effect onsubstrate rnorphol ogy and integrity. (2)The hiqher troahic levels (predators) areprobabiy not a; important to' the structureand functioning of the tidal freshwater Figure 29. White-tailed deer feeding in amarsh cornmuni ty. Virginia tidal freshwater marsh. Photo-- Herbi vo resgraph by Michael Dunn.Weller (1978) states that theacti vi ty of herbivoroils animal s is thernos t i,nportant factor, after fluctuationsin b~ater 1 evel, in structuring plant cornmunities in nontidal freshwater wetlands.In tidal freshwater wetlands this is alsoprobably true with only tidal action itselfbeing inore important. A large numberof the mammals which are found in tidalfreshwater wetlands are herbivorous(Appendix E). Small mammals such as micein the genus Peromyscus fall into thistrophic category. The white-tailed deeralso feeds on the leaves and stems of wildrice, cattails, and other wetland plants(Fi yure 29). However, herbivorous muskrats,nutria, and beavers influence wetlandvegetation to the greatest extent.?!uskrats are fwnd in a variety ofmarsh types; from nontidal freshwaterrnarshes of the Midwest to tidal saltmarshesof the Atlantic and Gulf coasts.Tidal freshwater marshes dominated bysweetflay, arrow-arum, and wild rice areconsidered favored habitat for muskratsalong the Atlantic coast (McCorrnick andSomes 19821. Threesquare and cattailmarshes along the eastern seaboard area1 so considered prime muskrat habitat(McCormick and Somes 1952). Wass andWilkins (1978) reported high muskratdensities (2.25 active houses/ hectare) ina tidal freshwater marsh dominated byburmarigold on the Janies River. InLouisiana muskrats appear to be most abundantin brackish and 01 igohal ine marshesin which threesquare rushes (Sci rpusamericanus and 2. olne i ) are the dominant-1misano&Surprisingly, the inuskrat is notfound in the coastal marshes of Georgiaand most of South Carolina, although itoccurs in the piedmont regions of bothstates. The more southern distributedmuskrat, the round-tailed muskrat(~eofiber a1 leni), occurs in1 and in southGeoraia (as close to the coast as the~keeieenokee Basin). It would not be surprisingto find this muskrat eventuallyextending its range into the tidal freshwaterhabitat along the Georgia coast.kskrats feed extensively on theshoots, roots, and rhizomes of threesquares,cattail, sweetfl ag, arrow-arum,and other marsh plants. These plants mayrepresent almost 80% (by weight) of themuskrat diet. The young shoots, which arehigh in nutrients, especial ly nitrogen,and older stems are favored in the springand summer, respectively (We1 ler 1991).

Leaves of marsh plants are seldom, ifever, consumed. During the winter monthsroots and rhizomes comprise almost 100% ofthe muskrat diet (Stearns and Goodwi n1941). The activity of muskrats in diggingup roots and rhizomes can havedeleterious effects on marsh soils. Rootsand rhizomes of marsh plants are thefibers which bind the marsh substrate.When muskrats remove these plant orgarls,the substrate lacks cohesiveness and iseasily resuspended and may be washed awayby storms and even normal tidal action(Lynch et a1 . 1947). Muskrats harvest alarger mass of above-ground plant parts(leaves and stems) than Selow-ground plantparts. Above-ground portions of the vegetationare used in construction of theirhouses and feeding pl atforms. Muskrathouses may be 2-3 m (5-10 ft) wide at thebase and 2 m (6 ft) tall. Often mud andsticks are worked into the house tostrengthen it. It is common to see uplandvegetation sprouting from the tops ofthose muskrat houses which are not inundatedby tides.The mskrats' practices of digging uproots and rhizomes for food and of clearinglarge areas of above ground vegetationfor houses could potentially cause denudingand disruption of large areas of marsh(Lay and O'Neil 1942; Lynch et al. 1947;Weller 1981). The practices of snow geesehave similar effects on salt marshes(Smith and Odurn 1981, Smith 1983). Areasof the marsh which are heavily grazed anddisrupted by muskrats (or geese) arereferred to as eat-outs by marsh managers.Eat-outs may range up to several squarekilometers in area (Lynch et al. 1947).Generally, the influence of muskrats onthe vegetation is not this severe.Initially a small clearing is createdimmediately around the house. If thereare many muskrat families present in agiven marsh, this will result in manysmall openings in the vegetation.Numerous small open areas actually benefi ta variety of other wetland species includingwaterfowl, grebes, and herons (Wellerand Spatcher 1965, We1 ler and Fredrickson1974). Continued muskrat activity mayenlarge and deepen these initial excavations.Arrowheads, arrow-arum, and spatterdockmay become established in thesmall ponds which open around muskrat1 odges (Mean1 ey 1975). When the muskratpopulation grows to high densities, thesesmall openings are enlarged and may bejoined to other openings nearby. It isestimated that if the muskrat populationreaches densities greater than 75 individualsper hectare (33/acre), losses ofvegetation and accompanying populationcrashes are 1 ikely (Dozier et a1 . 1948,Errington 1963, Wilson 1968, Weller 1981).Eat-outs are usual ly revegetated withinseveral years dependi ng on cl imatic condi -tions and the severity of the eat-out(Lynch et al. 1947). In cases where 1 ittlevegetation remains or storms havewashed away the marsh soil s, revegetationmay not occur for 10-15 years. Lynchet al. (1947) and Weller (1981) presentedexcel 1 ent di scussions of the various successionalpathways which nay be followedafter marshes have been grazed by muskrats(or geese). Unfortunately, their workdeals with brackish marshes and nontidalfreshwater marshes, respectively. In ageneral manner their resul ts probably ho1 dfor tidal freshwater marshes as well.Along the Atlantic coast, nutria arecommon in Maryland arld North Carolina(Evans 1970), especially in Dorchester andSomerset Counties, Mary1 and. The distributionof nutria in Virginia is not wellknown. Evans (1970) presents distributionmaps showing that tidal freshwater reachesof the James, Chickahominy, Pamunkey,Mattaponi, and Rappahannock Rivers areinhabited by nutria. Mass (1972) statedthat nutria are abundant in the 01 igohalinemarshes around Back gay, Virginia,but did not mention their occurrence inany of Virginia's tidal river marshes.These marshes abound with muskrats andwould seem to be ideal nutria habitatalso. Lippson et a1 . (1979) stated thatnutria are present in moderate numbersalong the Potomac River.Nutria are ecological ly similar tomuskrats. A small difference is that nutriafeed more heavily on leaves of marshplants than do muskrats. Leaves may makeup 20% of their diet at certain times ofthe year (Wil lner et al. 1979). Duringmost of the year, roots and rhizomes comprisethe bulk (70%) of the nutria's diet(Willner et a1 . 1979). Because theirhabitats and feeding habits are similar,nutria and muskrats may 5e competitors.Interactions between these two species

h?ve not been directly studied. Studies inLouisiana indicate that nutria have agreater preference for freshwater marshesthan do muskrats (Wilson 1968, Palmisano1972). Along the Atlantic coast nutriaand muskrats appear to be found in thesame types of marshes, ranging from oligoha1ine threesquare marshes to tidal freshwaterwetlands at the heads of estuaries(Evans 1970, Lippson et al. 1979).Direct field experiments will berequired to fully understand the ecologicalrelationships between nutria and muskrats.Nutria are not tolerant of cold temperaturesand are often killed by hardfreezes. (Willner et al. fs79). Duringthe winter of 1975-1977 substantial nutriamortality was noted by Willner and coworkersin the marshes of OorchesterCounty, Mary1 and. They reported it commonto find dead nutrid with extensive frostbitedamage to feet and tails. It is notlikely that nutria will expand their rangenorthward. However, they could easilymove into tidal wetlands in South Carolinaand Georgia.Beavers are becoming more common,especial ly in the tidal freshwater marshesat the headwaters of the tributaries toChesapeake Bay. Often beavers will damthe upper reaches of a tidal freshwaterstream, cutting off the influence of thetide (Figure 30). We have observed theactivities of beavers on a tributary ofthe Chickahominy River in Virginia. Wildrice was growing on both sides of the dam.The only noticeable difference was that onthe upstream side the wild rice was muchmore open and generally less dense than onthe downstream side. The influence ofbeavers in other habitats is well knownand they obviously can have an impact ontidal freshwater marshes. The nature ofthe effect of beavers needs to be studiedin detail.CarnivoresFrom an economic standpoint, the mostimportant carnivorous mammals in tidalfreshdater marshes are the raccoon, mink,and river otter. These species are veryimportant to the fur trade in the UnitedStates (Chabreck 1979). Raccoons preyheavily on juvenile muskrats and may playa role in controlling the size of muskratpopulations. Predation by raccoons maykeep muskrat populations be1 ow the 1 eve1 swhere they will damage marsh vegetationand/or where it is feasiSle to harvestthem (Wilson 1953). Mink and river otteroccasionally prey on muskrats (~ilson1954). For the mink, however, mice,voles , and srnal 1 birds are more importantfood items. River otter feed primarily onfish, taking only small amounts of otherfoods (Wif son 1954).Except for the relation between raccoonsand their muskrat prey, the relationshipsbetween mammal ian predators andtheir prey in wetlands are poorly under-Figure 30.Virginia.Beaver dama tidal freshwatermarsh stream near the Potomac River,84

stood. We do not know if any carnivoresare acting as keystone predators, keepingtheir prey populations in check. The roleof carnivores on nutrient and energy flowswithin wet1 ands is not understood.8.3 ECONOMIC VALUEWhile it is clear that a number ofmammals of the tidal freshwater marsh havevaluable pelts (e.g., otter, mink, n~uskrat,nutria, and raccoon) and that peltsfrom this habitat enter the commercialmarket, the magnitude of this fur productionis not known. This is becausedetailed harvest records are not available;the origin of muskrat pelts fromtidal freshwater, oligohaline, and estuarinehabitats is not differentiated bymost of the State and Federal agencieswhich keep fur production records.Louisiana is one exception and recordsfrom this state offer some insight intothe relative importance of tidal freshwatermarshes as fur producers.Data gathered by Palmisano (1972) andChabreck (1979) are summarized in Table22. As shown by this table, freshwatermarshes are most important for nutria;01 i gohal ine marshes for muskrats; andswamps for mink, raccoon, and river otter.The harvest of muskrats is greater infreshwater marshes than in swamps and isat least comparable to that of brackishand oligohaline marshes. Harvest of allother species is greatest in the freshwaterwetlands (marshes and swamps) thanin the other categories. In terms of dollars,the freshwater marshes are second invalue to swamps. Swamps gain their valuebased on the large catch of river otter,valued at close to 650 per skin.Of course, this data cannot beextrapolated directly to east coast tidalmarshes. Louisiana fresh marshes areoften nontidal or affected only by irregular,wind-driven tides; as a result, thevegetation is considerably different fromeast coast tidal freshwater marshes.Nevertheless, the Louisiana data suggestthat muskrat harvest from tidal freshwatermarshes on the east coast must be substantialand that harvest of beaver, mink,otter, and nutria is probably greater fromtidal freshwater than that from areas ofhigher sal inti es. Our personal observationsfrom Virginia and Maryland tend tosupport this speculative hypothesis.Table 22. Mean number of aquatic furbearers harvested per 400 hectares988 (1000 acres) according to marsh type. Data originally from Palmisano(1972) and Chabreck (1979).Speci esMarsh typeBrackish 01 igohal ine Fresh Swampilu sk. ratNutri aMinkRiver otter 3 I 6 98Raccoon 1 1 1 2Total Value $1124 $2752 $4564 $5040($1400 ha)

CHAPTER 9- VALUES, ALTERATIONS, AND MANAGEMENT PRACTICES9.1 VALUE TO MAN Table 23a. Commercial fish harvest fromthe tidal freshwater portion of the PotomacRiver. Values are in pounds/yearIn reviewing the material presented averaged for the period 1964-1971. Fromin the first eight chapters, it becomescl ear that tidal freshwater wet1 and eco-Lippson et al. 1979.sys terns have a considerable inherent valueto man. Both direct and indirect valuesare involved. Unfortunately, both categoriesof values tend to defy conventional1. Catfish (brown bullhead,white and channel catfish)138,872economic analysis, and it is very diffi- 2* Strip* bass 34,211cul t to place an economic value on these 3- American eel 28,028wet1 ands. After examining the following 4* American shad 18,2031 is t i ng , we have concluded that tidal 5. White perch 5,449freshwater wetlands are best regarded as 6* hr~ 5,064"priceless". 7.8.Alewife and blueback herringYellow perch1,121754Fi sheries 9.10.CrappiesHickory shad18722A number of species of freshwater,estuarine, marine, and anadromous fishesuse tidal freshwater at some stage inTotal 231,911their life histories (see Chapter 5).This results in extensive sport and commercialfisheries in most tidal freshwaterrivers. As an example, the Potomac River Table 23b. Commercial fish harvest fromsupports a commercial fishery worth severa1million dollars. A relatively smallthe entire tidal Potomac Xiver. Valuesare in poundslyear averaged for the periodportion of the Potonac catch actuallycomes from tidal freshwater (Table 23a).1964-1971. From Lippson et al. 1979.Iiowever, close examination of the totalriver catch (Table 23b) reveals that theleadingeightspeciesspendpartofthejr 1. Alewifeandblueback 7,044,637life cycle in tidal freshwater even thoughherringthey may be captured further downstream. 2. At1 antic menhaden 3,952,136There are also fish not represented in 3* Striped bass 1,117,248Table 23a, that utilize tidal freshwater 4* 422,691as a nursery area, invade or pass through 5- American shad 366,495as juveniles Or adults, and may be eventu- 6. American eel 340,738ally caught at a distant location. The '* White perch 191,327~tlantic menhaden and striped bass are 8- Catfish (same as Table a) l61,o88exampl es . 9. Flounders 47,30910. Bluefish 44,356Sport fisheries' catches from tidalfreshwater are not well documented but are Total 13,688,025apparently high (personal observation).86

Important sport fishes include stripedbass, largemouth bass, white perch, severalspecies of catfish and sunfish, crappie,pickerel, and yellow perch. Thequa1 i ty of sportfishing can be excellent.For example, the Chickahominy Riverprovides some of the most consistent andproductive fishing in the state ofVirginia.TrappingAs discussed in Chapter 8, tidalfreshwater marshes provide excel 1 ent habi -tat for a variety of mammals includingvaluable fur bearers such as beaver,nutria, muskrat, raccoon, and otter. Asiqnificant, but undocumented portion ofthe fur production of Virginia, Delaware,Maryland, and New Jersey comes from thesemars hes .Bi rdsWe have attempted to emphasize thediversity of birds found in tidal freshwatermarshes in Chapter 7. This habitatprovides an important location for breeding,feeding, and stopovers during migratorymovement. Resident and visitingbi rds include those of considerable recreationalimportance (ducks and geese) aswell as birds of interest to birdwatchers.EndangeredSpeciesWe have been unable to identify anyendangered animal species which is solelydependent upon tidal freshwater. Thereare several endangered and threatenedanirnal s, however, which use these areasextensively. These include the peregri nfalcon, the Anerican bald eagle, theAmerican a1 1 igator (south of Vi rginia),and the short nose sturgeon.Ferren and Schulyler (1980) mentionedthat a number of rare plant species occurin tidal freshwater wetlands. Furthermore,they have documented the extirpation(local eradication) of six plant speciesfrom tidal freshwater sections of theDelaware River, seven from the Schuyl killRiver and, possibly, five or more speciesfrom the Raritan River. Factors consideredresponsible for the extirpationsinclude dumping of dredge spoi 1, 1 andfill,and refuse as we1 1 as bul kheading, dammingof tributaries,Aesthetic Valueand diking of wetlands.Considerations of aesthetic value arecomplicated by extreme subjectivity andlack of easily quantifiable variables. Inspite of this, tidal freshwater wetlandsappear to have a broad appeal to manytypes of people. The combination of (1)diverse plant communities, (2) plentifulwi ldl ife, (3) diversity of landscape types(forest, marsh, waterways) in close juxtaposition,(4) broad expanses of open land,(5) numerous flowering plants, and (6) adiversity of plant types ranging frombroadleaf to grasses and ferns produces anarea with a great deal of appeal for artists,sportsmen, naturalists, scientists,and others. Further amp1 ifying this highaesthetic appeal is the occurrence of manytidal freshwater wet1 ands in close oroximity to major urban areas, such as Boston,New York City, Philadelphia, andWashington, D.C.Value as a BufferAs pointed out by Simpson et al.(1983) tidal freshwater marshes lie in anintermediate position between coastalwaters and marshes on one side and uplandland and streams on the other. Pollutants(heavy metal s, nutrients) and suspendedsediments from upstream sources can be atleast partial ly intercepted and processedin the tidal freshwater system. Sedimentsare trapped by reduced flows on top of themarsh surface with the result that downstreamloadings on the estuary arereduced. 4s s3own b.y Grant and Patrick(1970), eutrophic river water is processedin the tidal freshwater marsh by a combinationof sediments, bacteria, algae, andvascular plants. The result is thatreductions rnay occur in nutrient concentrations,SOD (biological oxygen demand),COD (chemical oxygen demand), and sedimentloads. Tn certain cases marsh plants mayraise the dissolved oxygen concentrationof the river water flowing through themarsh on the rising tide. The net resultis that the tidal freshwater narsh can actas a partial filter to improve the waterquality of freshwater flowing into thehead of the estuary. The magnitude ofthis cleansing action is not well documented.Certainly, it must vary from one

estuary to the rlext dependinq upon rela- regions. Local inputs of sewage and othertive inputs of river and tidal water, the wastes have exacerbated the problem. Thedegree of eutrophication of inflowing results are manifold: (1) rapid sedimentwater, the extent of tidal freshwater wet- deposition rates on the wetland surfacesland, and the time of year. (Chapter I), (2) hypereutrophication atmany sites (Chapter 3), and (3) alterationof plant and animal community composition.9.2 CONNECTIONS WITH ADJACENT ECOSYSTEMSIn colonial times in the NortheastIn any consideration of the manage- and mid-Atlantic States, mill ponds werement of tidal freshwater wetland ecosys- constructed across the upper ends of manytelns, it is important to recognize that tidal freshwater sites. In most cases,these are extremely open ecosysteqs and these unused ponds remain, partiallyare coupled with a variety of nearby s.vs- filled with sediment, and covering sitestems. By "open" we mean that significant of former tidal freshwater marshes.flows of nutrients, including carbon, movebetween tidal freshwater wetl ands and Ricef iel d Conversionsnearby systems such as terrestri a1 up1 andforests, tidal swamp forests, nontidal and In the Southeast during the 18th andtidal freshwater rivers, and downstream first half of the 19th centuries, slaveoligohaline marshes. For example, as we labor converted thousands of hectares ofdiscussed in Chapter 3, inputs of nitrogen freshwater tidal marsh and swamp to dikedand phosphorus to tidal freshwater marshes ricefields (Figure 31). Some of thesecan co~ne from the adjacent river water as diked areas, particularly in Southwell as from upland terrestrial sources. Carolina, are now managed for waterfowl,This means that attempts to aanage tidal trapping, and even aquaculture (Sandi ferfreshwater wetlands must also include et al. 1980). Many other former riceconsiderationsof human activities in fields still exist. These ricefields arenearby associated sys tems. There are many in disrepair and have perforated dikessituations similar to the Tinicum Harsh on which allow the tide to rise and fa1 1 northeDelaware River (Grant and Patrick mally. These areas are covered with a1970). The marsh itself thas been pre- typical freshwater marsh plant communityserved wi th no di rect a1 terations. How- dominated by giant cutgrass. Managementever, it has been badly degraded by activ- options for these old ricefields rangeities (sewage and waste dumping) further from continued control for waterfowl proupstream.duction to complete abandonment and areturn to tidal freshwater aarsh. Correctmanagement decisions for individual loca-9.3 ALTERATIONS BY MAN tions are usually difficult to , reach.Often, the answer is determined by site-Historical Aspectsspecific characteristics such as the numoerof waterfowl supported in the managedSince the arrival of the first colo- marsh versus the aaount of juvenile fishesnists at Jarnestown, Virginia, tidal fresh- supported by the natural marsh.water wetl ands have undergone a continui ngprogression of a1 terations and changes, Twentieth Century Problemsresul ting from human activities. Almostall of this habitat on the Atlantic coast The pattern of alterations begun inis in the 13 original colonies; much of it colonial times continues unabated in thelies adjacent to major cities. Most tidal late twentieth century. High sedimentafreshwaterwetlands are connected to tion rates in tidal freshwater marshesrivers wi~ose watersheds have been dramat- still occur because of poor land use pracicallya1 tered over the past three cen- tices upstream. Interruption of freshturies.Poor farming practices combined water input from upstream sources iswith extensive forest clearing and land caused by diversions for irrigation anddevelopment have produced heavy loads of navigation purposes and is widespread.sediments and dissolved nutrients in the Two recent large diversions in the Southfreshwatersflowing i nto tidal freshwater east, the Santee-Cooper diversion in South88

Figure 31. Abandoned ricefields. Photograph by Dennis A1 len.Carolina for facilitating hydroelectricpower generation and the partial diversionof the Savannah River between South Carolina and Georgia for navigation concerns,have caused upstream sal i ni ty increasesand conversion of tidal freshwater wetlandsto 01 igohaline wetlands.Diking, dredging, and filling oftidal freshwater wet1 ands have occurredthroughout the Northeast and mid-At1 anticStates. Some of the most damaging episodeshave occurred on the Connecticut,Hudson, Delaware, and Poto~nac Rivers(personal observation). A characteristicsiqn of this t.yype of alteration is theprofusion of monotypic stands of the comrnonreed (Phragmites austral is) on many ofthese sites.As ~entioned in Chapter 3, eutrophicationof tidal freshwater is a widespreadand persistent problem at inany 1 ocations.On many of the tidal freshwater stretchesof the Potomac and Delaware Rivers,eutrophication, in combination with significantheavy metal inputs, has led todrastical ly lowered di ssol ved oxygen concentrationsand to sirnpl if ied animal communities (fewer species).Pesticide contamination of tidal freshwaterwetlands does not appear to begeneral ly we1 1 documented. However, themost serious kepone contamination from theAllied Chemical spill occurred in thetidal freshwater zone of the James River,Virginia (Drifmeyer et al. 1980). Eventoday, many years after the event, manyfisheries remain closed in the tidalfreshwater James Ri ver because of continuingcontamination.A1 teration of tidal freshwater wetlandecosystems is a problem which beganin colonial times and has become evenworse in the twentieth century. The closeproximity of this habitat to large ui-banareas, shippi ng channels, and industri a1sites has produced a rml ti tude of problemsranging from direct impacts such as dikingto more subtle changes resulting froineutrophication.9.4 POTENTIAL FOR SEWAGE ASSIMILATIONGrant and Patrick (1970), in one ofthe earliest holistic studies of a tidalfreshwater marsh, concluded that considerablepotential existed to assimilate andprocess nutrients contained in raw or partially treated sewage. Uhigharn andSimpson (1978) confi rmed that thesemarshes could take up nutrients, a4 leaston a seasonal basis (see discussion in

Section 3.3). Simpson et al. (1981) furtherdemonstrated a capacity to removemetals from river water flowing across themarsh.Recently, however, Whigham et a1 .(1980) directly tested the ability oftidal freshwater marshes to accumulatenutrients from secondary treated sewage.They concluded that the marsh can assimilatenutrients fran sewage during thespring and summer growing season, but thatthere is a tendency to release nutrientsin the fall and winter. Evidently, thelack of a permanent 1 itter layer orextensive peat deposits, along with certainother sediment chemistry characteristics(e.g. , pY), 1 imits the capacity ofthis type of marsh to process and assimilatelarge quantities of partially treatedsewage.In sumqary, it appears that tidalfreshwater marshes may be useful inirnprovi ng the water qua1 i ty of Iiyoereu trophicrivers such as the James, Potolnac,and Delaware, at least on a seasonalbasis. On the other hand, their use asdirect receivers of treated sewage seemsunfeasi bl e.9.5 REST MANAGE!4rlEFIT PRACTICESC1 ea r1 y, tidal freshwater marsheshave great value to man. The wisestmanagement plan appears to be protectionand preservation. Controlled hunting,trapping, and fishing are compatible withthis plan. Dumping of pollutants andsewage is destructive. Diking or impoundingthese marshes is not advisable. Partof their unique character and their highproductivity can be traced to the dailytidal pulse (Odum et al. 1983). Mostevidence suggests that insects (mosqui toesand biting flies) are a miniqal problem intidal freshwater that is flooded daily(Dai ber et a1 . 1976) ; therefore, mosquitoditching or diking is not necessary orcost effective.While preservation of tidal freshwatermarshes is desirable, constructionor building of new marshes with expensiveplant propagation programs does not seemto be necessary. Lunz et al. (1978) concludedthat the vegetation of tidal freshwatermarshes can become es tab1 i shed veryrapidly on new sites (e.g., spoil disposali sl ands) without much he1 p from humans.Although much of the tidal freshwateracreage on the east coast does not lie inpreserved tracts, virtually a1 1 Statesprotect this habitat with the same lawswhich protect other tidal wetlands. Inaddition, there are significant areas oftidal freshwater marsh which are locatedin Federal and State refuges and wild1 ifemanagement areas. Private organizationshave also played a role in preservingthese wetlands. For example, the NatureConservancy recently acqui red Chapmant sPond, the largest tract of tidal freshwatermarsh on the Connecticut River(Nature Conservancy 1982).

CHAPTER 10. COMPARtSON OFTIDAL FRESHWATER MARSHES AND SALT MARSHES10.1 A GENERAL COMPARISONIn Chapter 1 (Figure 1) we show thatestuaries consist of a gradient of conditionsfrom tidal freshwater at the head ofthe estuary to near marine conditions atthe mouth. Throughout this profile wehave mentioned apparent differencesbetween tidal freshwater wet1 ands and theSpart ina-dominated sal t marshes closer tothe ocean. To facil i tate this comparison,we have prepared a table of physical andbiological characteristics of the twotypes of ecosystems (Table 24). Thistable is based upon earlier attempts tocontrast the two wetland types (Odum 1975,Odum et a1 . 1978). In considering thesecharacteristics, two points should beremembered. (1) The estuary is a gradientfrom freshwater to marine conditions. (2)Characteristics at any given location mayfluctuate daily, seasonally, or from yearto year.10.2 PHYSICAL COMPARISONSAll of the physical characteristicspresented in Table 24 are also discussedin Chapter 1. Essentially, there are twosignificant differences in the two typesof ecosystems. First, the sediments intidal freshwater are high in clay, silt,and organic matter, but generally low inpeat (see exceptions in Section 1.6) andin total plant root biomass. This resultsdirectly in a higher susceptibility toerosion, low profile stream banks, andtidal creeks with low sinuosity (Garofalo1980) compared to higher salinity estuarinemarshes which general ly havegreater percentages of sand, peat, andplant root material. These differences insubstrate can be traced to sedimentsources and the types of plants growing inthe two environments. Tidal freshwatersediments are derived primarily from upstreamriver sources (clays, silt, fineorganic matter); in addition, much of theorganic content probably comes fromautochthonous plant production. Theplants in tidal freshwater marshes generallyhave a relatively low root/shootratio (see Section 3.1) leading to lessroot and peat material in the sediments.Salt marsh sediments are derived from avariety of sources including some sandfrom downstream (marine) sources. Inaddition, the salt niarsh plants tend tohave a higher root/shoot ratio.The second great difference in thephysical characteristics of the two environmentsconcerns water chemistry. Sal tmarshes are flooded by water containingsignificant quantities of seawater; waterflooding tidal freshwater marshes islargely river water. As a result saltmarsh water is not orlly saltier but differsconsiderably in its elemental makeup.For example, seawater has approximatelythree orders of rnagni tude more dissolvedsulfur than freshwater. For this reason,the process of sulfur reduction is importantin sa1 t marshes under marine conditionsbut probabl'y is of less significancein freshwaters. See Morris et al. (1978)for a discussion of the chemical differencesin marine and freshwater and thezone of transition between the two.10.3 BIOLOGICAL COMPARISONSCharacteristics of the vascular plantcommunity are discussed at length inChapter 2. The significant differences indiversity, zonation, seasonal succession,and root/shoot ratios are summarized inTable 24. Benthic algal productionappears to be relatively low in tidalfreshwater wetlands (less than 1% of total91

Tab1 e 24. Hypothetical comparisons of ecosystem characteri stics between tidal freshwatermarshes and higher salinity, Spartina-dominated salt marshes (based on Odum 1978,Odun et a1 . 1978).Characteristics Tidal freshwater marsh Salt marshPhysicalLocationHead of estuary (above01 igohal ine zone)!lid and lower estuarySalinity Average be1 ow 0.5 ppt Average above 8.0 potand below 35 ppt(approxtlydrol ogy2i veri ne i nf 1 uence andtidal influenceLargely tidal influenceSedimentsSediment redoxpotenti a1Sediment erodabi 1 i tyS treambank morphologyStream channelmorphologyDi ssol ved oxygen(water column)Dissolved sul fur8iol ogicalSil t-cl ay, high organiccontent, low root andpeat contentIiloderate-strongly reducing(redox pai rs unkown)High erodabi 1 i ty(particularly in the lowmarsh)Low gradient, littleundercuttingLow senuos i tyVery 1 ow (summer)Trace (1 ppn)More sand, lowerorganic content, higherpeat and root contentStrongly reducing,(due to sulfur reduction)General 1 y 1 owererodahil i tySteeper gradient,more undercutti ngModerate to highsinuosityLow ( summer)Very high (2500 ppm)!.lac rophytes Freshwater species Marine and estuarinespecies;!acrophyte diversity High species diversity Low species diversityMacrophyte zonation Present, but not always PronounceddistinctSeasonal sequence of Pronounced Absent or minordominant ~nacrophytesPiacrophyte root/shoot Low (general ly be1 ow 2.0) High (general 1 y above5.0)(continued)02

Table 24.Continued.Characteristics Tidal freshwater marsh Salt marshBiologicalAbove-ground annualprimary product ionBenthic algalproductionPhytoplanktonDecomposition rate ofintertidal vascularAnaerobicdecompositionNutrient cyclesSewage assimilativecapacityPrimary consumersDi rect grazingOetri tus qua1 i tyInvertebrates(other than insects)Comparable (?)Very low (less than 1% ofNet community primaryproduction)Comparable (?)Low marsh plants =extremely rapid, highmarsh plants = moderateto slowMethanogenesi s andfermentation probablypredominatePronounced spring uptakeof NO, NO, PO largeautumn re1 ease of reducedcompoundsLowLarval and adult insects,01 i gochaetes, amphi podsVariable (5-15%), higheron HibiscusHigh (low C/N ratio lowcrude fiber)Low species diversity,freshwater speciesFloderate (may be asHigh as 30% of netcommuni ty primaryproduction)Moderate to slow fora1 1 plantsSulfur reductionpredominatesMore even orocessingand re1 ease (conversionfrom oxidized toreduced forms throughoutthe year)ModerateAdult insects, crustaceans,polychaetes,mollusksLow (5%)Low to moderate (higherC/N ratio, high crudefiber)Floderate speciesdiversity, estuarineand marine speciesInsectsFi shesBoth aquatic 1 arval insects i40stly adult terresandterrestri a1 speci es tri a1 speciesFreshwater and 01 igohal ine Marine and estuarinespecies, and larvae,speciesjuveni 1 es, and spawningadults of anadromous species(continued)

Table 24.Concluded.Characteristics Tidal freshwater marsh Salt marshBiologicalReptiles andamphibi ansHigh species diversity Low species diversityWaterfowlFu rbearersHigh species diversity,high but spotty densitiesHigh species diversity,moderate densitiesLow to moderate speciesdiversity , moderatedensitiesLow to moderate speciesdiversity, moderatedensitiesnet community prirnary production accordingto Whigham and Simpson 1976). The data ofGallagher and Oaiber (1974), on the otherhand, show that benthic algal productioncan contribute as inuch as 39% of the netcomrnuni ty primary production in some saltmarshes. The lower contribution fromtidal freshwater may ref1 ect the extensiveshadi ng from broad-1 caved tidal freshwaterplants. Phytoplankton production may besimilar in the tidal creeks of the twoecosystems. Good comparat i ve data aregenerally lacking, but Axel rad et a1 .(1976) found similar rates of primary production(5 to 15 mg c/m3/hr in the twoenvironinents. Conversely, in the NorthRiver, Massachusetts, higher chlorophyllconcentrations were found in tidal freshwaterand 01 igohal ine locations than downstreamin the estuary proper (J. Hobbieand 3. Peterson, Ecosystems Center, WoodsHole, Massachusetts; pers. comm.).In Chapter 3 we discussed differencesin decompsoi tion, decomposition rates,detritus, nutrient cycling, and consumers.Invertebrates are discussed in Chapter 4,fishes in Chapter 5, waterfowl in Chapter6, amphibians and reptiles in Chapter 7,and furbearers in Chapter 8. Sewageassimilative capacity and fisheries arecovered in Chapter 9. The significantdifferences in these aspects of the twowetland types are sammarized in Table 24.In addition to the differences discussedin Chapters 3 through 8 and thosenoted in Table 24, several additionalpoints should be made. Ilnlike the vascularplant community, most components ofthe tidal freshwater marsh animal communityare much less diverse than in saltmarshes. For example, Diaz et al. (1978)found that the benthic macrofauna in thetidal freshwater portion of the JamesRiver was less diverse than further downstreamin the high salinity zone.same river, Ellison and NicholsIn the(1976)reported a lower diversity of benthicmicrofauna in tidal freshwater. Siinilarly,the fish co~nmuni ty in the James Riverhad its lowest diversity in th,e tidalfreshwater section (Dias et al. 1978). Inthe case of rnacrofauna and fishes, thenumber of species increased downstreamtoward the estuary mouth and upstream innontidal freshwater. We suspect that thesame pattern also holds for zooplankton(personal observation).Not all anirnal species, however,appear to follow this pattern of reducedspecies diversity in tidal freshwater.Mammals, waterfowl, and insects are probaSlymore diverse in tidal freshwatermarshes than in salt marshes, presumablybecause of the higher diversity and foodvalue found in freshwater plant species.

10.4 COMPARISON WITH NOWTIDAL FRESGfWATERMARSHESFew researchers have directly comparedtidal and nontidal freshwater marshecosystems which lie in close proximity.There are intriguing questions associatedwith such a comparison since in one casetidal energy is present and in the otherit is absent. One could hypothesize thatthe presence of tidal energy might encouragehigher primary production in tidalfreshwater marshes than in nontidal fresh-water marshes (Odum 1971). Mum et al.(1983) compared the annual net productionof giant cutgrass, Zizani opsi s mil iacea,in the two environments separated by adike and found 38% greater production intidal freshwater. As with all comparisons,variability in factors other thantidal amp1 i tude (e.g., substrate type,nutrient supply) creates difficulties. Itseeins, however, that carefully control ledcomparisons of tidal freshwater and nontidalfreshwater may reveal a great dealabout the ecological importance of tidalenergy.

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Whi ttaker, R.H. 1980. Communi ties andecosystems. 2nd ed. MacMillan Publ.Co., Inc., N.Y. 385 pp.Wiens, J.A. 1973. Pattern and process ingrassland bi rd communities. Ecol.Monogr. 43:237-270.W i l kes, R.L. 1976. Tidal marsh and swampextent in Georgia. U.S. Rep-. Agric.Soil Conserv. Serv. Hinesville, Ga.(unpubl ished) .Willner, R., J.A. Chapman, and J.R.Goldsmith. 1975. A study and review ofmuskrat food habits with specialreference to Maryland. Yd. Wildl.Admin. Publ. Wildl. Ecol. 1:l-25.W i l lner, G.R., J.A. Chapman, and D.Pursl ey. 1979. Reproduction, physiologicalresponses, food habits, andabundance of nutria in Mary1 and marshes.Mildl. Monogr. 65. 43 pp.Wilson, K.A. 1953. Raccoon predation onmuskrats near Curri tuck, North Carolina.J. Wildl. Manage. 17: 113-119.Wilson, K.A. 1954. The role of mink andotter as muskrat predators innortheastern North Carol ina. J. Wildl.Manage. 18: 199-207.Wilson, K.A. 1962. North Carolinawetlands, their distribution and management.Federal aid in wildliferestoration project W-6-R. N.C.Wildlife Resources Commission, Raleigh.169 pp.Wilson, K.A. 1968. Fur production insoutheastern coastal marshes. Pages149-162 in J.D. Newsom, ed.proceedings? marsh and estuarymanagement symposium. Loui siana StateUni versi ty Press, Baton Rouge.Yamasaki, S., and I. Tange. 1981. Growth-+responses of Zi zani a 1 ati fol i a,Phra mites austral is and Miscanthussaccharif orus to varying inundation.Aquat. Bot. 10:229-239.

APPENDIX APlants of the Tidal Freshwater MarshFamily and species list of characteristic plants occurring in tidalfreshwater marshes of the Atlantic coastal region. Scientificnomenclature conforms with the National List of Scientific Plant Names(Soil Conservation Service 1982). Ccmmon names conform with Gray'sManual of Botany (Fernald 1971).OsmundaceaensmundauPol y podiaceaew b i l i sUelv~teroidesSalviniaceaeBzolla-Pinaceae. .distichwTy phaceae--lu2k.B-_TvDha anaustifolia2YRbB_LaucamnensisSparganiaceaeSDaraaniwneurvcaraunGreatPotomogetonaceaePotamomZannichnellia galustrisNa jadaceaeNaiasa2LAlismataceaeA1 i ma subcorda tynSanittariasubulataittaria falcataHydrochari taceaeElodeam ..EllodeanuttallllGramineaeP=ginicusaustral isRoyal FernSensitive FernMarsh FernWater FernBald CypressCommon CattailNarraw-leaved CattailBlue CattailSouthern CattailBurreedBranching BurreedPondueedsHorned PondweedNaiadsMud-plantainbarf ArrowheadBul tongueDuck-potatoWa terweedsNuttall WaterweedTapegrassFrogbi tColr~non ReedWild Rye Grass

Gramineae continued:-arostF;r canadensisCinna grundinaceaSDartina cvnosuroideaSpart- a1 ternifloraaartina gectinataPhal ari s arundinaceaLeersia yirainicaLeersia orvzoides2izanio~si.s mil iac-Zizania jwuaticaPanicum viraatumEchinochloa crusaall iEchino- ya1 terj,ArundodonaxCyperaceaeQmrus SegCv~erus sfrinosusQoerus esculentusEleocharis obtusaEJeocharis ~alustrbEleocharis a uadranaul a taDichromena colora taFimbristvlis autunnal isScirDusamericanusScir~us robustusScir~usmithiiScirDusvalidusScir~us cvmri_nus. .ScirDus fluviatlllsBhvnchosmra macrostachraiaEii!m .iamaicenseCarexuCarexluridaCarex crinitaCarexy ul ~i noi deaCarexi5ki&aCarexalataCarexsauarrosaAraceaePel tm YirninicamuatismAcoruscalamusLemnaceaeLemna~ge,Comnel inaceaeC o m virainica ~Murdannia keis&Reed-BentgrassWood-ReedgrassBig CordgrassSmooth CordgrassFreshwater CordgrassReed-CanarygrassWhitegrassRice CutgrassGiant CutgrassWild RiceSwitchgrassBarnyard GrassWal ter8 s MilletGiant ReedUmbrella-sedgesStrawcolor Unbrella-sedgeYellow NutgrassBlunt Spike-rushCreeping Spike-rushSquarestem Spike-rushStar RushAutumn SedgeComnon ThreesquareStout BulrushSmith' s BulrushSoft-stem BulrushWoolgrassRiver BulrushHorned RushSaw-grassSedgesSallow SedgeFringed SedgeFoxtail SedgeErect SedgeBroadwing SedgeSpreading SedgeAr row-ArumGo1 dencl ubSweetflagDuckweedsDay flowerAsian Spiderwort

PontederiaceaePontederia cordataZosterella-J uncaceae+luncuss~p~JuncusacuninatusJuncus-JuncuseffususPickerelweedWaterstargrassRushesSharpfruit RushToad RushSoft RushSaururaceae2edumGicernuusSal icaceaeSalixgpp,SallixcarolinianaMy r icaceaeliw!SceriferaBetul aceaeCarPinuscarolinianawserrulalteUrticaceaePileaouDilaBoetmeriacvlindricaPol y gonaceaeAuneixverticillatusPolvnonunvirninianunfolvaonun-YolvaonumDensvlvanicunPolvnonun-PolvnonunhvdroPiPerPolvRonunDersicariaPolvPranwnaunctatunPalvaonun.hvdroDiDeroidesPdvnonunsanittatunPalvaon\anarffoliLanAmaranthaceaeAmaranthus--Dhilcxeroides A1 1Blue FlagSouthern Blue FlagYellow IrisLizard's TailWillowsSwamp WillowWax-MyrtleAmerican HornbeamTag AlderC1 earweedFalse NettleWater DockJunpseedSouthern SmartweedPinkweed%amp SmartweedCommon SmartweedLady's ThunbWater SmartweedMild Water-pepperSagittate TearthumbHalberd-leaved TearthumbWater-Hanpiga torweed

Cera tophyllaceaeCerato~hvll~ demersunNymphaeaceaeNu~har luteun rnacro&yLlmNuPhar luteun varieaatwnNym~haea odorataBraseru schreberiRanunculaceaeClematis crisDaRosaceaeRasa palustrbJiQs3multifloraLegminosaeGledi tisa aauaticaCassia fasciculataAmorDha f ruticosaaDiosamericanaStroPhostvlesFAeschvnomene WnicaAceraceaeAcerrubrunBal saminaceaeImoatiens ca~ensis-Ma1 v aceaeKostelet&s virnini caHibiscus moscheutoQ palustrigcusHibiscus laevis (militaris)GuttiferaeHvDericun-ElatinaceaeEl&im mericanaLy thraceaeDecodon verticillatuaLvthrw lineareLvthrun wcariaCornaceaeNvssa aauaticaNvssa svlvaticaSpat terdoc kBullhead LilyWhite Water LilyWater-Shiel dBlue JasmineSwamp RoseMu1 tif lora RoseWater LocustPartridge PeaIndigo-BushG roundnutPink Wild BeanSensitive-joint VetchRed MapleJewelweedSeashore-MallowSwamp RoseMallow RoseHal berd-leaved RoseSt.WaterwortJohn's WortSwamp LoosetsrifeLinear LoosestrfeSpiked LoosestrifeCotton GunBlack Gun

Ona graceaeJossiaeare~en~LudwuriaDalustrisHalorrhagidaceae.!mauhamUmbelliferaeEwn~iun iicruatic~Cicuta maculataSiun suavePtil imniun w a c e wC1 ethraceaeClethra-OleaceaeFraxinuspennsvlvanicaAscl epiadaceaeAscle~iag incaraataConvolvul aceaeI(;onv_olvulusarvensis!2!uma@sePiLmi2J.E&mc;omr>irct.allxmQscDccinewLabiataceaeLvcoDusvirainicusLYCOPUS-BignoniaceaeCanDslsradicansScrophul ar iaceaeCratiolavfrninfana--Linderina lu2i3Lenti bul ar iaceaeUtr icul ariaRubi aceae!&&iM?!mButtonbushCaprifol iaceaeVlburnun re-Viburnum dentatmCanpanulaceae.Lobelia-Creeping Primrose-W illowWater-pursl aneWater-Mil foilsMarsh EryngoWater HemlockWater ParsnipMock Bishop1 s WeedSweet PepperbushRed AshSwamp MilkweedField BindweedHedge BindweedSwanp DodderMorning GloryW ater-HorehoundEuropean HorehoundTrunpet FlowerHedge- hyssopFalse PimpernelBladderwortsStiff BedstrawArrawwoodSouthern ArrowwoodCardinal Flower

Composi taeVernoni a noveboracensisEuvatoriun ~erfol iatunEupatoriadel phus f istulosusMikania scandensAsterAster subulatusBaccharis halimifouPluchea purDurascens- Iva frutescensAmbrosia trifidaBidensBidens JaevisBidens connataBidens cclmosaBidens frondosaBidens coronauCosmos bi~inna tusHeleniun autunnalc:Senecio-IronweedBonesetJoe-Pye-WeedClimbing HempweedAstersAnnual Marsh AsterGroundsel TreeMarsh FleabaneMarsh ElderGiant RapeedBurmar igol dsSmooth Burmarigol dSwamp BeggarticksLeafLbract BeggarticksBlack BeggarticksTickseed SunflwerSpanish NeedlesSneezeweedRagworts

APPENDIX BFISH OF TIDAL FRESHWATERSIntroductionThe geographic region on which we have concentrated in our account is the Hudson River, NY through southern Georgia. We makeoccasional references to areas north or south of these boundaries where isformation is available on given species, even though surveysof the entire community were unavailable. The species included in this tabulation are limited to documented observations from tidalfreshwaters. The sources of information include published accounts, master's theses, government reports, and personal ~0innI~nicationfrom fisheries workers with varicus state agencies. These sources are numbered in the Appendix with a key given at the end.Nomenclature follo~s Robins et al. (1980). We have neither included hybrids nor subspecies in this list.Relatlve abundance refers to the abundance in tidal freshwaters only. This assessment does not apply over the whole geographic range,nor over all habitats occupied by the species.Explanation of categories and abbrevlatlonsCompass directions expressed in lower case (n,s,e,w).State and province abbreviations are capitalized andare standard postal ones given in Carlander (1969) andLee et el. (1980). Unless otherwise noted Gulf coastrefers to the Gulf of Mexico.rl8 US STATES Alabama AL Ohio OHCalifornia C A Okl ahosa 0 KConnecticut CT Pennsylvania PADel aware DE South Carolina SCFlorida FL Texas TXGeorgia G A Virginia Y RIll in01 s IL CANADALouisiana LA British Colombia BCMaine ME New Brunswick NKMaryland HD Newfoundland N FMassachusetts HA Nova Scotia NSMississippi HS Labrador LBMissouri NO Ontario ONNew Hampshire NH OTHERNew Jersey NJ Great Lakes G LNew York NY Mexico HEXNorth Carolina NC Atlantic ATLPacificPACR - rare. Seldom seen, likely a stray from an adjacent habitat.END - endangered. Threatened with extinction.U uncommon. Infrequently encounterec.O - occasional. Seen frequently enough to beconsidered a reeular member of the community.C - common. Encountered on nearly every saepling trip duri~gthe appropriate season.LC - locally common. Present in appreciable numbers, butrestricted to particular habitats or localized areas.A - abundant. Conspicuous by its presence. Encountered iaappreciable numbers on every sampling trip durirg theappropriate season.LINK - unknown. Insufficient data to assess abunoance in tidalf reshuaters.fu : < 0.5 ppt.brackish = > 0.5 PPt.Food items listed in decreasing order of frequencyof wcurrence.Information is provided on affinity group, rangeof habitats, preferred habitat, seasonality Of use,differences in juvenile and adult use of habitat.

APPENDIX B.Fishes of tidal freshwaters of the mid and south Atlantic coast.NamePetromyzontidae -lampreysGeographic Salinity Re1 ativerange range abundancePPtLamnetra c3,3a.vDter2 upper OH fw - 1.5least brook lamprey drainage, ATLcoast-PA to NCh~sira ~ERSD!Uupper OHAmerican brook lamprey drainage, ATLcoast-NH toRoanoke River, NCktrpmyzo~ mrjusea lampreyAcipenseridae -sturgeonsATL coast-LBto FL, alsoG LfwFood habitsCommentsSourceU f il ter-f eelers; adults non- Restricted to small 33 , 35parasitic streams. Burrows insediment.R f ilter-feeders; adults non- As previous species. 33,35parasiticC Young to four years nonparasi- Anadromous; ascends fw 33,35tic, feeding on minute orga- streams in spring to spawn.nisms. Adults parasitic, feeding Young stay 3-4 years inon the blood of otherfreshwaters.fishes.p c i ~ e n ~ brevirostyy@ rNK to St. fw - 35 R, END A bottom feeder. Anadron~ous; small popula- 5,6,46,shortnose sturgeon John's River, FL Young: algae, protozoa, crus- tions exist in Canada, 52taceans, small insectsMaine, the Hudson, DelawareAci~sps9r QZYL~YLC$_~S LB to ne FLAtlantic sturgeonLepisosteidae -garsLneisea&as essus much of e ha1 f fw - 33longnose earof USThiMUFlorida garplatv-FL & CAExtirpatedor threatened throughoutmuch of its range.Adults: benthic organisms, small & Altamaha Rivers.plantsR A bottom feeder. Anadromous; young remain 6,33,46Young in fw; aquatic insects, in fw a year, inampt~ipods, oligochaetes,estuary up to 4 years.~~LYIII clams.In marine environments; gastropods,shrimp, amphlpods,other benthic invertebrates,small fish (launce).C Young to 50 mm; small of fw affinity, but very 6.33crustaceans, insect larvae tolerant of higher salin-Adults; almost entirely fish ities.taken in the water column.fw LC mostly fish, alsocrustaceans, insectsRecorded from Altamaha & 26,27Savannah Rivers, CA

Amiidae -bowfins&Labrvf inElopidae -tarponsName Geographic Salinity Relativerange range abundancePPts?lr_aMS, OHGulf & GLdrainages,ATL coast-CTto FLKeualo~~ &l=L&_o_s ATL coast- SC fw - 35 Rtarponto BrazilAnguillidae -h) freshwater eelsh)Anauilh EsxLCg_taAmerican eelOphichthidae -snake eelsflrrQ~hia EliasMfusspeckled worm eelClupeidae -herricgsU a a wfiraLisblueback herringfwATLcoast-Gulfof St. Lawrencefw-35 Ato West IndiesFood habits Comments SourceNocturnal feeders on fish, Inhabitant of sluggish, 26,33,crayfish, insects, molluscs, clear often vegetated low- 46,50,earthworss, frogs, leeches. land waters. More corn- 5 1mon in tidal fw's in s.portion of its range.Juv; fish, copepods, ostracods, Spawns offshore. Young in- 26,27,shrinp, insects habit headwaters of brack- 33Adul t s; almost exclusively ish & f'w streams. Adultsfish. marine. Recorded from Altamaha,GA, St. John's,FLIn fw: Largely nocturnal feeders 9,64,67Young; benthic macroinverte- & highly opportuttistic.brates (insect nymphs & larvae, Burrow in mud in winter.oligochaetes, cladocerans)Eave been captured onOlder fish; crayfish, tadpoles, fw tidal marsh surface;f ish. fewer invertebrates.eatadromous.In brackish water: soft bluecrabs, bivalves, polychaetes.ATL coast-NC 18 - 35 R In brackish water; polychaete A stray from the lower 3,11,57to Brazil worms, sand crabs estuary. Recorded onlyinfrequently from tidalfw's.ATL coast- fw - 35 C- A Juv; feed at surface on Anadromous; spawn it- fast 15,16.NS to St. cladocerans (primarily flowing water over hard 33937John's River, bosmids), copepods, crus- substrate. Juveniles useFL tacean eggs, chironomid tidal fw & low salinitylarvae (as drift)nursery areas untilautumn.

NameGeographicrangeSalinityrangePPtRelativeabundanceFood habitsCommentsSource&Is= Wiarrtshickory shadus2 pseudo&r_eggmalewifeATL coast-ME to FLGL, NF tosc&aa &a~ldi&L_m_a G U I ~ of st.American shadLawrence toFL, peakabundance CTto NC; introducedon USwest coastRrevoo~tJ_a JyrannusAtlantic menhadenQQrsaQm upasfiznMngizzard shadNS to FLHA to MEX,MS basin bGLfw - 35 0 chiefly small fishCJuv in tidal fw; cladocerans,copepods, crus-tacean eggs, insects(various dipterans)fw - 35 C-A Juv; feed somewhat opportunisticallyboth at thesurface & beneath the surfaceon cladocerans (primarilydaphnids), chironoaidlarvae (as drift), waterboatmen, terrestrial insects(flles, gnats, ants),fish larvaefw - 33 C-A f il ter-feeders:smallcrustaceans, especiallycopepods, annelid worms, rotifers,unicellularplantsfw - 29 C-A Juv; protozoa, copepods,ostraeodsAdults; microscopic plants,phytoplankton, algae,detritusAnadromous; least common 1,22,65species of this genus,Peak abundance ChesapeakeBay & NC. Juveniles spendlittle time io tidal fwnursery.Anadromous; spawn ic slower 15,37,65moving water than bluebackherring. Juveniles use fwtidal L low sal ir1t.y nurseryareas until autumn.Anadromous; spawn primarily 15,16,65in main channels oversand skoals In areasof perceptible currents.Juv. use fw tiaal h lowsalinity nursery areasuntil mid to lrteautumn.Spawn at sea. Juveniles 24,35,46are estuarine dependent.Spawns in fw. Young inha- 45,46bit fw 6 low brackishnursery sreas.Prefers quiet waters oflakes large rivers, estuarie,s.Young are in,portantforage for severalspecies of game fish.Q-3 &fgg&se native to lower fw - 17 0-C principally plankton, alsothreadfin shad MS & Gulf dipteran larvee (wcoast draicages;$PrY9, chironomids)widely introducedelsewhereEngraulidae -anchovies&nc_hea &frhWbay anchovy#A to MEXSpawns ir fw, juver;iles 6,35,46eater estuarine waters.fw - 35 C-A Feeds pelagically on Important forage species 33,46zooplankton; copepods, insect for larger species oflarvae, mysids, shrimps, larval commercizl importance. Mostfishes, gastropod larvae, crab abundant at salinitieszoeae. Feeds on benthic organlsms less than 20 ppt.when zooplankton are scarce.

Geographic Salinity Relativerange range abundancepptFood habitsSourceNSaLD9 Sa.31Atlantic salmonOsmeridae -smelts!Amsrus rrrs-xrainbow smeltUmbridae -mudminnowskbra urnaa?eastern mudminnowEsocidae -pikesUsX msriGzlPusredf in pi ckerelma his*northern plkeWntgPrchain plckere3Hudson Strait fW - 35 UNK Juv; may flies, chironomids, Anadromous; spawn ir non- 55to CT River; caddisflies, stoneflies, Cla- tidal fw in Oct-Dec. FryArctic Circle docerans, dipterans, molluscs, inhabit riffles, spendingto Portugal, fish fry (suckers) 2-3 years in nontidal fw.s GreenlandAdults & young migratethrough tidal fwls. Hajorcommercial & sport importance.CL, LB to NJ fw - 35 U Young: copepods, cladoceracs, Anadromous; spawn in non- 6,30,32Adults ir! fw lake: insecttidal fw at night. Juvelarvae,copepods, amphipods, niles move rapjdly to sea.small molluscs, fish (shiners)ATL coast- fw - 4 U In fw stream: copepods,Long Islandcaddisfly larvaeto FLATL coastsME toFL. AlsoLake Champlaindrainagen Europe, AsiahNAms t o eNY, also n MSbasinATL coast - fw - 22 0- CNS toFL, MSdrainagefw - 8.7 0 Fry; planktonJuv;cladocerans, amphipods,immature insectsAdults; fieh. crayfish.dragonfly nymphsfw - 1.6 UNK A aiurnal feeder.fry; microcrustaceans, fishlarvae65mm; priaarily fish. alsosalamanders, crayfish, mayfliesYoung; invertebrates includingamphipods, chironomids,daphnidsAdults; fish (minnows,sunfish) , frogs, crayfishInhabits small, sluggish 6,46muddy stream & weedbeds. Burrows ir, soft.silty substrates.Ichabi ts sluggish streams, 6,46,50weed bees, swamps.Inhabits weedy lakes, 6,33ponds, rivers. Breeds icChapman's Pond, a tidallake on the ConnecticutRiver. Important gamespecies.Adults feed nocturally in 6,19,44shallows, rest in deeperwater by day.

NameCyprinidae -minnows, carpsClprin~3 carDiocommon carpH~bo~nathus repiuseastern silveryminnowlissmds r a wbull chubNotemin~n_u_s EUBQ=kcaseolden shinerNokPEis mPO1111Scomely shf nermou rn~l~~rG3sati nf in shinerNs_troDLs kiflml&ubridle shinerGeographicrangeintroduced fromAsia; presentthroughout USintroduced fromAsia; widelydistributed inATL coastdrainagesSalinityrangePPtRelativeabundanceSt. Lawrence fw - 14 0- C& ONdrainages;ATL coast sto Altahama,C AJames, Chowan, fw RRoanoke, Neuse& Tar Rivers,VA & NCNY s through fw RCape Fear River,NCHudson River fw - 2 LC& Lake ONdrainages sto Peedee River,SCHA to Neuse fw - 11.8 URiver, NCfw - 17 LC Omnivorous with preferencefor phytoplankton.Young feed more onzooplankton & insectlarvae.fw - 17.6 C An omnivorous bottomfeedertaking vegetation,insects, worms.waters.Food habits Comments SourceFeeds in large schoolsnear bottom on dietoms,desmids, filamentousa1 gae.benthic insects, crayfish,snails, fish, filamentousalgaeOmnivorous; algae,macrophy tes, amphipods,molluscs, detritus, insectsIn fw stream; insectlarvae (mayflies, caddisflies,stoneflies)small invertebrates,algae, macrophy tesPrimarily inhabits still 33,46often oxygen deficientwaters with thickvegetation.Inhabits streams, rivers, 33.46ponds, impoundments;both clear & turbidOften considered a pestdue to habit of stirringup bottom sediments duringfeeding.More abundant in channel 46.50than in coves.New species described 33,64in 1971. Morecommon above fall line.Prefers quiet vegetated 19,33,46water with accessto extensive vegetatedshallows.Typically found in nontidal 33,50freshwaters in channels.A schooling mid-water form.Preferentially inhabits 19,33,46ueedless streams, strayinginto tidal fw's.Inhabits sluggish streams 33,46over areas of mud,silt, detritus in slackwaterareas with mcderateto abundantvegetation.

NameCatostomidae -suckersGeographicrangeSalinityrangeRelativea bundanceP P ~Food habitsComments~ ~ s c ~ ~ r l St. n u Lawrence sfw - 10.7 R A benthic feeder on Inhabits turbid riversquillback River; DE insect larvae & other and clear lakes.drainage toorganisms found in bottomA1 tamaha, CA ;sediments.MS basin &Gulf coastMgg-yg commersoni Arctic Circle fw - LC Insects, molluscs, worms, cope- Inhabits larger streams, 19,33white sucker s to New brackish pods, cladocerans, ostracods, ascends small creeks inMexico & GA microscopic plants spring to spawn.- E U - z e p obl ongusME to fw C Largely crustaceans (clado- Inhabits quiet waters with 33,46,64creek chubsucker A1 tamaha, GA; cerans, ostracods, copepods), thick growths of subwGulf coast also chironomid larvae, mergent vegetation.& MS basinnematodes, molluscs, diatomsE.L.hlXluaQC! sll!S..e2&3 s VA to Lake fw U Young; copepods, cladolakechubsucker Okeechobee, FL; cerans, chironomidsGulf & MS-L drainagesh)-4 ii~€s&nli~fi~ oiaricans MS, OH fw - R-U bottom faunanorthern hog sucker & GL brackishbasins; upperATL coastdrainages sto n GASourceOccupies ponds, oxbows, 6,26,33,sloughs, impoundments. 4 1Prefers clear water &aquatic vegetation.More abundant above fall 6,32,33,line. 46,54w r m melanou ~Cape Fear River fw - LC A benthic feeder on insect Inhabits larger streams, 6,26,27,spotted sucker to 3 GA; brackish larvae (particularly chirono- oxbows, impoundments. 33,68MS 6 Gulf mids), crustaceans (cladoce- Intolerant of turbiddrainages rans, copepods), oligochaete waters.worms.WQSLQ~~ DMSQLSR~Z Hudson River, fw - 5 0-c molluscs, microcrustaceans, Inhabits large rivers & 33,35,50,&.L~lll NY to Santee immature insects small tributaries. Readily 54shorthead redhorse River, SC; enters brackish waters.MS & St.Lawrence basins,GL, Hudson BaydrainageIctaluridae -cat€ ishesIctal urug brunneua 'NC to n FLsnail bull headLCOmnivorous benthic feeder;molluscs, insect larvae,small fish. filamentousalgae.More abundant in nontidalfw 's. Recordedfrom Altahama, GA

NameGeographicrangeSalinityrangePPtRelativeabundanceFood habits Comments SourcedIUdliww a!u3white catfishblue catfishIctalurus melasblack bullheadmi?l~r!rusNY to FL;widelyintroducednative to MSbasinstoHEXnative to MSdrainage && n MEXfw - 14.5 C-A 4-57 cm; an opportunisticfeeder; amphipods, isopods,decapods, copepods, cladocerans,my sids, cumaceans,chironomid larvae, polychaeteworms, small clams,larval & adult insects, fishfw - 7Al&aS native to e fwyellow bullheadk c US&talus&a nebulosu_s native to e fw - 8brown bullheadhalf of US& s CanadaL&l+l!US wX= NC to s GAGs?blHflat bullheadrnlurus punctatuschannel catfishl k a e~rig~i3 ~ ~ ~tadpole madtomnative toGulf & MSdrainages;introducedel sew hereATL, Gulf& MS drainagesYoung; zooplanktonAdults; insect larvae, crayfish,fish, detritusYoung; isopods, small crustaceans,insect larvaeAdults ; insects, smallcrustaceans, plant debris,fish, frogsIn stream; decapod crustaceans(palaemonid shrimp,crayfish), mayfly nymphs,annelid worms, beetlesinsect larvae (dipterans,mayflies, caddi sflies,dragonflies), molluscs,algae, fish (spottail shiner,elvers), polychaete worms,zooplanktonJuv; insectsAdults; fish, insects, annelids,molluscs, bryozoansinsect larvae (chironomids,dipterans), terrestrial insects,spiders, crustaceans (cladocerans,harpacticoid copepods,ostracods), plant material(berries, grasses, SagLtseeds),molluscs, fish& fish eggsIn lake; cladocerans, ostracods,isopods, chironomiask detritusMinor. sport importance. 23.33.46,Most tributaries, main- 63stream.Introduced Into James 6,33846& Rappahannock Rivers, Va.Characteristic of deeprivers & swift currents.Recorded from a tr ibu- 6,33,49,tary of Potomac River 51Va. & Winyah Baydrainage, SC. Inhabitsponds, pools, swamps.Inhabits swamps, ditches, 19,33,46,sluggish streams. 5 1Inhabits sluggish oxbows, 33,39,46backwaters, impoundments.Mi nor sport importance .Juveniles inhabit small 26v33.51clear streams. Adultsinhabit slow movingwaters of large rivers.Inhabits mainstream. 46,64Rests in deep water byday, moves to shallowsat night to feed.Inhabits quiet waters with 6,11,26,extensive vegetation. Best 33,35,46considered a stray in tidalfwls, except in Altahamawhere it is relativelycommon.

Name GeographicrangeSalinityrangeRelativeabundancePPtFood habits Comments Sourcekwi!mQ iEsianis NY to CAmargined madtomm m ; ! e e t a c ~ ~ SC ~ to LAspeckled madtomf u 0 In stream; insect larvae More abundant above fall 19,33,46(dipterans, stoneflies) , fish1 ine.Occupies areas of mode- 33rate current.P~lodictus ow native to MS fw R 100 mm; insect larvae (may- Inhabits large rivers. Re- 6,33,50flathead catfish basin & into fly & caddisfly nymphs) corded from Winyah BayAphredoderidae -pirate perches#EX; sparingly 100-200 mm; insect larvae, fish. drainage, SC.introducedcrayfishAs&s_b&nruspirate perch alms NY to TX; fw LC an opportunistic feeder; Inhabits quiet ponds, ox- 11,20,26,Gulf coast & Juv; mostly crustaceans bows, swamps, sluggish low- 33,51,65MS basin (ostracods, amphipods, cl ado- land streams. Usuallycerans)associated with dense vege-Adults; mostly insect larvae tation. More common in tid-(dragonflies, damselflies, may- al fwls in the SE.flies, dipterans, hemipterans)Cadidae -codf ishesAreS wGulf of St. fw - 31.4 UNK shrimp, amphipods, worms,Anadromous; spawns in fw 18,32,46* r n t o m c o d Lawrencetosnails, immature fishin winter. Larvae move to 55V Alow salinity waters duringfirst year. Does not spawnin Chesapeake system. Minorsport importance.Belonidae -needlef ishesS~TPDS~YLB wrLtil)r7Atlantic needlefishME toBrazilfw - 35 LC In low brackish estuary; A marine form which 13133,351small fishes, insects, shrimp, readily enters fw. Best 36.46small amounts of vascularconsidered a summer tranplantmaterial & algae sient. May breed in tidalfwls in Potomac, Va.fw- 32.8 R In higher salinities;detritus, filamentousalgae, nematodes, smallcrustaceansfw - 24.4 U larval & adult mosquitoes,shrimp, copepods, annelids,plant materialMore common in higher 33,35,40,salinity areas. Inhabits 46,47shallows. Winters in channelsor low salinity pondsburied in mud.Inhabits bayous, mangrove 11.33swamps, tidal streams, fwrivers and streams.

GeographicrangeSalinityrangePPtRelativeabundanceFood habits Comments SourceEundulusbandedkillifishPunduluslinedtopminow--rainwater killifishPoeciliidae -livebearers5alnh&larfinismosquitoflshs VA toDade Co., FLCape Cod toMEXNJ to FL;s MS basin-formosa CapeFear River, fw- 30least killifishNC to LALC-Asmall crustaceans, insects,molluscs, annelid worms,detritusIn tidal fw; crustaceans(ostracods, cyclopoidcopepods), insects (dipterans.homopterans), fish eggs. grassseeds (- sp.) , gastropods,spidersIn brackish waters; smallcrustaceans, detritus, polychaeteworms, insects, smallbivalves, eggs. small crabsepiphytes, vascular plantscopepods, mosquito larvaeFeeds primarily near surface.In fw stream; insects(hemipterans, dipterans)In brackish waters; amphipods,chironomid larvae, mitescopepods, snails, ants, adultinsects, polychaete worms, ostracods,mosquito pupae. algaeMore likely to occur in fw 33,36,46than most others of genus.Common in bays. rivers,coves in low salinity areas,extending into freshwater.Inhabits muddy marshes. 11,26,33,grassf lats, channels, pools 40.46,64in marsh inter.ior in summer.May burrow in siltin winter.Found in clear streams. 26,33backwaters. ponds.Recorded from Altahama, GAInhabits tidal creeks, 35,48,65sandy flats, grass beds.More common in lowerestuary.In heavily vegetated ponds 10,33& streams in areas oflittle or no current. Toleratesvery low dissolvedoxygen content.Inhabits weed beds, muddy 33.35coves. More common athigher salinities.Inhabits tidal pools, 11,19,33.coves & backwaters. Readily 42.46,47,follows flood tide onto 50marsh surface. May remainin marsh pools during lowtide.R- U In brackish waters;insect larvae. small crusta-Inhabits weedy pond andstream margins.11,33,47ceans, filamentous algae,diatoms

NameGeographicrangeSalinity Relativerange abundancePetFood habitsCommentsSource4W4sailf in mollyAtherinidae -silversidesbrook silverside. .Erlembrasmartlnlcarough silversidetidewater silversideMenidiemenidiaAtlantic silversideGasterosteidae -sticklebacksSC to MEXSC to sFL; GL,MS & Gulfdrainages;widelyintroducedNY to MEXMA to MexAoeltesavadracus Gulf of St. fw - 26fourspine stickleback Lawrence toto Trent River,NCGaeterosteus aculeatus n Europe & fw - 35threespine stickleback N AM; HudsonBay to VA;also PACcoast of NAMfw - 34 U algae, vascular plants.detritus, mosquito larvaefw R A specialized feeder nearsurface on cladocerans,terrestrial insects. Chaaboillslarvae3 - 24 U In brackish waters; zooplanktoncrustaceans, juvenileand larval fishes,insects, detritus, small snailsfw - 31 C copepods, mysids, isopods,amphipods, insectsfw - 31 U crustaceans, annelid worms,molluscs, fish eggs. plants,insectsULCsmall crustaceans. mainlyamphipods. In fw; chironomid& mayfly larvae,cladoceransAn opportunistic feeder;aquatic & terrestrial insects,worms. fish eggs &fry, algaeRecorded from low salinity 11.33creeks in GAInhabits clear vegetated 26,33and unvegetated warmwaters.An estuarine species. 46,48,64,Young occasionally enter 65low salinity reaches ofestuary.Estuarine resident; readily 46,48,50.enters fw. May spawn 58in tidal fw. Inhabitstidal creeks & grassflatsin summer, channels inwinter.Collected well above 33,40,46,brackish water in James. 50Rappahannock, Pamunkeyrivers in VA. but morecommon in lower estuary.Estuarine resident. Occu- 32,33,40,piesshallowsinsummer. 46channel & channel edgesin winter.Anadromous; 6,33,46.in Chesapeake Bay area 55inhabits small tributariesduring breeding season.rare or absent rest ofyear.

Name GeographicrangeSalinity Relativerange abundancePPtCentropomidae -snooksGsauuuuandenilMJ&snookPercichthyidae -temperate bassesMoroneamericanawhite perchUQLQmaaxatilisstriped bassFL to Brazil fw - 35 UNK Juv. in brackish waters;caridean shrimp, small killifishes,gobies, mojarrasSt. Lawrence fw - 35 C-Ato St. John'sRiver, FL.Gulf of MEX;introduced intoOregon, CAFood habits Comments SourceJuv; copepods, cladocerans,rotifers, amphipods,insect larvae (ceratopogonids& dipterans), smallmolluscs, mysidsAdults; larger crustaceans%-?Aharrisll),small fish (eels,spottail shiners, FYndulusSPP. 1Postlarvae; zooplanktonJuv. 25-100mm; flexiblenonselective feeders on insects(dipteran larvae &pupae, mayfly larvae), am--phipods, shrimp,other decapods, mysids, fish& fish larvae U.-9, l@-t~PPiGMenidia SPP.) rpolychaetesAdults in tidal fw; 84%of diet clupied fish(~revoortlatuanniu, Al~saaestivalis, & -,PPrnmma ixpedkurn) , 4%spiny-rayed fish, 3% invertebrates(amphipods, mayfly rdipteran larvae, blue crabs,palaemonid shrimp)Young inhabit oligohaline 33834r47& tidal freshwater nurseryareas. Strays north toCape Fear River during warmperiods. Very sensitive tolow temperatures.Semianadromous; juveniles 21,33,35,inhabit shallows. moving to 46,49,58,deeper water in winter. 6 4Minor sport b commercialimportance- Peak abundanceHudson River to ChesapeakeBay.Anadromous; peak spawning 2,4,35,in tidal freshwaters. 38,64~dults move downstreamafter spawning, juvenilesmove downstream as theygrow. Inhabit deeper waterby day, move into shallowsat night to feed.Overwinter in deeperchannels. Major sport& commercial importance.

Centrarchidae -sunfishesName Geographic Salinity Relativerange range abundancePPtBcantharchus wmotismud sunfishrock bassentrarchus-WflierElasaoma everaladeiEverglades pygmy sunifish&uaa!aWzonatumbanded pyqmy sunfishcoastal plainse NY to nFLraDestris native toMS basin;introduced intoATL coastdrainagesVAtoFL;MS basin nto s ILCape Fear River,NC to s FL;Gulf coast toMobile Bay. ALNC to c FL;Gulf drainagesMS basin nto ILEnneacanthus chaetodon coastal plainblackbanded sunfish NJ to c FL;also w FLEnneacanthus ~~Q&Eu& se NY to FLbluespotted sunfishEnneacanthusobesusbanded sun£ ishFood habits Comments SourceYoung; copepods, insects.crustaceans, chironomids, amphipodsAdults; fish, crayfish.molluscs. wormscladocerans, insects (chironomidlarvae, water boatmen)copepods. cladoceranssmall crustaceans. chironomidpupaeaquatic insects, gammaridamphipods, filamentous algae.plant leavesIn fw stream; 55% diet crustaceans(copepods, crayfish,amphipods, cladocerans) . Alsoinsect larvae (dipterans,hemipterans, dragonflies)Inhabits sluggish. heavily 29,33.64vegetated swamplike waters.Very secretive.More abundant above fall 7,32133line. Best considered astray into tidal reaches.Inhabits sluggish lowland 7,11,29,areas with clear. heavily 26,33,46,vegetated waters. May be 51more common in woodedswamps than in marshes.Prefers quiet vegetated 11,33waters below the fallline.Inhabits swamps, weedy 7,26,29,ponds. sluggish streams 33below fall line.Most abundant in heavily 7,20,33.vegetated swamplike waters 46,65of low pH, 6 in cypresslowlands.Associated with submerged 19,42,46,weedbeds in tidal fw. A 50common inhabitant of sluggishstreams, acid ponds,swamps. More abundant incoves than in mainstream.similar to E, gla&uua. Most common in sluggish 7,29,33,streams. swamps of low pH 46,50,656 ditches over mud substrates.Often associatedwith bluespotted sunfish,but less abundant.

edear sunfishLeDomisDunctatusspotted sun£ ishGeographic Salinity Relativerange range abundancePPtNC to FL,w to TX &fw - 12.3 CS MO &OH; introducedinto OK.CA. VA- PA.ILNC to s FL: fw - 11.8 0s MS & Gulfdrainagesdolomieui NF to VA;smallmouth bass MS basin;fw - 7.4 Rintroduced intoATL coastdrainages40 salmoides native to MS fw - 12.9 LC-AUI largemouth bass drainage & ATLcoast drainagen to SC;widely introducedelsewhere.including ATLcoast drainagesPomoxisannulariswhite crappienative to MSdrainage;fw - 1.5 Uintroducedelsewhereincludingmost ATLcoast drainagesNY toFL~UZU n.hik native to fw - 1.5 0-ClIlAd&Ublack crappieMS. Gulf6 ATL coastdrainages nto VA; introducedelsewhere,includingmost ATLcoast drainagesFood habits Comments Sourcesnails, insect larvae (chi- Most common in large warm 7,10,26,ronomPds, mayflies) , clado- rivers, bayous & lakes. 33,51cerans, isopods. Seldom Often associated with vegefeedson surface.tation, submerged stumps orlogs.In brackish water: variety Occupies swamps, sloughs, 7,11,26,of crustaceans (amphipods, floodplain lakes. 33,51,69mysids, xanthid crabs), . . .sponge (Eohvdatia -1,insects (chironomid larvae,ants)Young; copepods, cladoce- More abundant above the 7,32,46,rans, rotifers, chironomid fall line. Prefers clear 64larvae, mayfly nymphs, larval fast flowing waters.fishAdults; crayfish, fish(alewives, centrarchids),tadpolesIn fw: young; microcrus- Inhabits sluggish streams, 7,11,27,taceans, insects, cladocerans, weed beds; prefers creeks 33,35,46,amphipods, decapods, small 6 coves to river proper. 50fishSpawns in fw tidal portionAdults; large insects, fish of Potomac River. Va.(small centrarchids, gizzard Kajor sport importance.shad) . crayfish. frogsIn brackish water; blue crabs,shrimp. fish. insectsYoung; zooplankton during Quite intolerant of turbi- 7,33,46first year, later amphipods, dity & siltation. Moreinsect larvae (chironomids. k common in nontidal fw's.Q~SILU~ mayflies)Adults; fish (cyprinids,threadfin shad, darters. centrarchids,catfish)Young; cladocerans, copepods, Associated with abundant 7,26,32,chironomid larvae. Ch&mcu aquatic vegetation- Does 33,46r56larvae. ostracods, oscillatorial not readily enter brackalgae,insects, forage fish ish water.Adults; cladocerans, terrestrialinsects, fish (shiners. threadfin& gizzard shad, largemouthbass, striped bass, whitecatfish. channel catfish.centrarchids)

Percidae -perchesEtheostomafusiformeswamp darterGeographic Salinity Relativerange range abundancePPtPood habits Comments Sourcefw - 1.3 R insect larvae (chironomids, Inhabits swamps, back- 20.26,33,mayflies), crustaceans (amphi- waters of sluggish 46,65phipods, copepods, cladocerans, streams, ponds. Often assoostracods)ciated with dense vegetation,mud or organic substrate.Etheostoma olmstedi St. Lawrence fw - 13 0-C microscopic crustaceans.tessellated darter to Altahama, GA small insects, detritusInhabits shallows & low 32.33,46.gradient rivers. Spawns in 66nontidal fw streams, swampruns.l?sSaflavescens native NS fw - 13 C-A Young; zooplankton, later Spend most of year in 33,35,46,yellow perch to Santee small insects low salinity portions of 48,50,66River, SC & Adults; insects, crayfish. estuary. Adults migrate upupperMS small fish stream to spawning areas inbasin; widelyintroducedearly spring. Very adaptablespecies. Most abundantin clear open water withmoderate vegetation.niorofasciata Edisto River, SC fw R diurnal visual subsurface feeder Most common over gravel or 26.33blackbanded darter to c FL; also on immature insects (dipterans, sand in nontidal fw's.Gulf drainagesmayflies, caddisflies)Carangidae -jacksCaranxlLiiuWicrevalle jackGerreidae -mojarrasNS toUruguayfw - 35 R mainly fish Marine species. but juve- 26,33niles occasionally enter fwin s. portion of range. Recordedfrom Altamaha River.G AEucinoatomus araenteus NJ to Brazil fw - 35 R In estuarine waters; ostra- Recorded from fw's only in 27,33spotfin mojarra cods, copepods. polychaetes. s. portion of range, Ga,bivalves, insect larvaeFL & LA

I),Haemulidae -gruntsNameQrthoDrisrisLcXapigfishGeographic Salinity Relativerange range abundancePetCape Cod toMEX; morecommon s ofCape Batteras.NCSciaenidae -drums. .Balrdlellachrvsoura MAtOTXsilver perch0 nebulosus Cape Cod tos e a t r o u t MEXQU2X&UlweakfishLeiostomus ~UWUUUspotMA to GAMA to TXFood habits Comments Sourcefw - 35 R In brackish water; shrimp, Reported from Altahama Ri- 26,33polychaetes, molluscsr amphi- ver. GA; autumn only, Morepodscommon in lower estuary.fw - 35 U Larvae; copepods, larvalfish (tidewater silversides)Juv; largely mysids. alsoshrimp, fish (bay anchovy),mysids, grass shrimpfw - 35 R In brackish water; 50 mm;copepods, planktoniccrustaces50-274 mm; wide variety offish.fw - 35 U In low salinity nursery ground;20-40 mm; largely mysids,also penaeid shrimp, fish(bay anchovies, naked gobies.clupeids, spot, pig£ ish) . Adultsprimarily piscivorous.fw - 35 LC A benthic feeder: juveniles inlow brackish water; harpacticoidcopepods, amphipods, polychaeteworms, nematodes, mysids,ostracods, isopods. chaetognaths,bivalves, snailsMarine form, spawned at 8,33,46,sea. Juveniles present in 47,63estuary into tidal fw insummer, fall. More abundantin lower estuary. A pparently less likely to entertidal fwls in SC & GAPresentintidal fwlsin 8,33,40,spring, summer, fall, but 47,60more common in lower estuary.Winters in deep channelsin estuary or in inshoremarine waters. Notrecorded from tidal fw'sin SC or GAA marine form- spawned at 8,28,43sea. Juveniles present inestuary in spring, summer,fall. Some enter tidal fwreaches.A marine form. spawned at 8,57,63,sea. Juveniles arrive in 64Chesapeake Bay in April,use estuary as a nurseryarea, leave in Dec. Fw tidalreach is upper portion ofnursery area-

Name Geographic Salinity Relativerange range abundancePPtFood habits Comments SourceWL-M ~ c ~ O D O K O ~ ~ ~ S&&USAtlantic croakerE e e w Up%Sblack drumMugilidae -mullets-La ~ ~ cephas i 1QI - striped mulletGobiidae -gobiesMA toArgentinafw - 35 LC Juveniles feed in water column, A marine form, spawned at 8,28,35,adults feed on bottom. In low sea, juveniles present 57brackish water juveniles feed spring through fall. Inhaprincipallyon mysids & gammarid bit channels in fw tidalamphipods, also on copepods & areas, though more common inpolychaete worms.lower portion of estuary.Suffer high mortality insevere winters. Peak abundances. of Cape Hatteras.MA to Argen- fw - 35 U A bottom feeder. 180 mm juv- Adults enter DE Bay 13,46961,tlna h Gulf eniles in low salinity waters; mid-late April on spawn- 63of MEX small bivalves (&&$&& latera- lng runs, leave early June.U) & polychaete worms, also Young-of-the-year collectedmysids, amphipods, blue crabs. in June in 0-6 ppt tidalmarsh creeks. Young leavebay in October.NS to Brazil ; fw - 35 0-C plant material, detritus & Often enters fw's, particu- 11,27,33,most common associated fauna, plankton larly in s. portion of its 47,51Chesapeakerange.Bay south;circumtropicalGobionellus .&+g&sM NC to Brazil fw - 29 R- Usharptail gobyGobionellgs shuf eldtifreshwater gobyNewport River,NC to c FL;Gulf coast toTXGnPinssma MA to MEXnaked gobyFrom oligohal ine waters;copepods, ostracods, nematodes,chironomid larvae, foramsLarvae; zooplanktonAdults; mainly small crustaceansincluding gammarideanamphipods. Also annelid wormsfishes, fish eggs, dyingoysters.A marine form occasionally 3,56taken in freshwater. Mostcommon at 20-24 pptsalinity.Prefers low salinity marsh- 11,33,52es and upper estuarles.Estuarine resident, spawns 11,12,17,in moderate salinity areas, 33,46,63pelagic larvae move upstreamto low salinity nurseryareas. Adults occupy oysterbar community, only youngextend into tidal fw's.

NameBothidae -lefteye floundersGeographicrangeSalinityrangeRelativeabundancePPtU r i c h t h v s NJ to Brazil fw - 35&gJsbay whiffFood habits Commen ts SourceU mysid shrimp, crabs, cope- Juveniles regularly enter 11,33,48,pods, amphipods, fish, anne- fw's in central America. 62lidsRecorded from tidal fw's inNE Cape Fear River, NC &Newport River, GAParalic&hys dentatus ME to FLsummer fl ounder--i&&m .lethe- VA to n fw - 35stigmasouthern flounder-L$ Soleidae -solesFL; GulfcoastTrinecte? maculatus MA to Panama fw - 32hogchoker& Gulf ofHEXR In brackish water; fish, Rarely recorded from 40,46shrimps, crabs, mysids, small tidal fwls. More commonmolluscs, sand dollars, anne- in lower estuary.1 ids, amphi podsU mainly fish, also crabs, my- A marine form with a 11.14,33,sids, molluscs, penaeid shrimp, tendency to enter tidal 64amphi podsfw's in s. portion of itsrange.C A benthic feeder on smallcrustaceans including amphipodsEstuarine resident inhabit- 11,13,17,ing channel edges, mud 46,47,64& mysids, also annelids, iso- bottoms. Nursery zone expods,detritus, insect larvae tends into tidal fWts.(chironomids), algae, forams

Reference Numbers Key1. Adams 19702. Atl. St. Mar. Fish. Comm. 19813. Bailey et al. 19524. Boynton et al. 19815. Brundage and Meadows 19826. Carlander 19697. Carl ander 19778. Chao and Musick 19779. Compton 196810. Curtis 198211. Dahlberg 197212. Dahlberg and Conyers 197313. Darnell 195814. Darnel1 196115. Davis and Cheek 196616. Domermuth and Reed 198017. Dove1 19714 18. Est. Study Group 197719. Flemer and Woolcott 19660 20. Fox 198221. Hastings and Good 197722. Hawkins 1980Heard 1975Hi1 debrand 1963Holder 1982Holder, pers. comm.Hornsby 1982Joseph 1972Keup and Bayllss 1964Kircheis and Stanley 1981Kiviat 1978aKiviat manuscriptLee et al. 1980Roy Lewis 111, pers. comm.Lippson et al. 1979Loesch and Kriete 1976Loesch and Lund 1977Markle and Grant 1970Massengfll 1973Massmann 1954McCormick 1970McIvor, unpub. detaMerriner 1975Meyers and Muncy 1962Miller 1960Musick 1972bOdum 1971Peterson and Peterson 1979Powell 1977Raney and Massmann 1953D.N. Roark, pers. comm.L. Rosas and S. Vitamvas, pers. comm.Rulifson et al. 1982Schwartz 1962Scott and Crossman 1973Spitsbergen and Wolff 1974Springer and Woodburn 1960Smith 1971Smith 1979Tabb 1966Thomas and Smith 1973US Army Corps of Engineers 1979Van Engle and Joseph 1968VIMS 1978Wang and Kernehan 1979Werner 1980Wenner and Musick 1975Coomer et al. 1977Desselle et al. 1978Roy Lewis 111, Mangrove Systems, Inc., Tampa, FL** L. Rosas, Dept. of Envfronmental Sciences, Univ. of Va., Charlottesville, VAS. Vitamvas, Dept. of Biological Sciences, Univ. of North Carolina-Wilmington, Wilmington, NC

THE VERTEBRATE FAUNA (except fish) OF TIDAL FRESHWATER WETLANDSIntroduction to Appendices C, D, and E.The geographic region covered in our literature search was centered on the mid-Atlantic coast, but references toestuaries from Maine to northern Florida have been included. References to vertebrate species (except fish, see Appendix B)from this region had to satisfy one of three criteria before that species was included in Appendices C, Dl or E: 1) directreference to the use of "tidal freshwater marshesI1, "tidal riversIt, I1freshwater tidal estuariest1, or similar wording, 2)reference to the species occurence in a specific geographical locale (e. g. Pamunkey River marshes, Gunpowder River) which weknow, from other sources, to be tidal freshwater habitats, or 3) reference to the use of permanent bodies of fresh water suchas I1swampsn, I9narshes1l, Ithead-waters of estuariesIt, llriverine marshesl1, which do not explicitly state tidal freshwater, butimply that tidal freshwater habitats could be used. Application of these criteria has led to the production of ratherextensive species lists since we have included rare as well as abundant species. Nomenclature follows AOU (1982) for bi rd sJones et al. (1979) for mammals, and Collins et al. (1978) for amphibians and reptiles.A key to the abbreviations used is given below. The heading Region refers to the areas (State or bay) along the Atlanticcoast from which the species has been reported. Our estimate of regional occurrence should not be construed as beingcomprehensive at this time. Under Status we give an estimate of the relative abundance of each species. This estimate is forthat species abundance in tidal freshwater wetlands only. It does not apply over a species entire geographical range or forall of the various habitats it may use. Thus, for example, the eastern box turtle is listed as rare to uncommon in tidalfreshwaters. It is a common species in pine woods habitat. Where possible our estimate of status is based on reports fromthe primary literature. When these sources were not available we used the gray literature and species lists provided to us byvarious National Wildlife Refuges in the region. Under Habitat we list in a general way the types of tidal freshwaterwetlands which are used. An estimate of the time of year during which a species is present is given under Season. Theselatter two categories apply only to Appendix D: Birds.REG IONAppendices C-ENE - New England, particularly the Hudson and Connecticut A - Abundant. A species which is very conspicuous, beingestuaries. seen on almost all visits during the appropriate season.JPDEL Delaware River and Bay, including its tributaries. C - Common. Species seen in good numbers during appropriateJ CH - Major tributaries of the Chesapeake Bay including the seasons but not on every visit.Susquehanna, Patuxent, Potomac, Rappahannock, Mattaponi, FC - Fairly Common. Seen in moderate numbers at thePamunkey, Chickahominy, and James Rivers on the westernproper season, and/or on 1/2 to 2/3 of the visits.shore and the Nanticoke and Pocomoke Rivers on the UC - Uncommon. A species which is observed infrequentlyeastern shore.(on 1/3 to 1/2 of the visits) or in low numbers.STATUSNC - North Carolina, particularly the Cape Fear River OC - Occasional. A species seen on 1/4 to 1/3 of theand estuary.visits or in small numbers during the proper season.SC - South Carolina, with special reference to the Waccamaw R - Rare. A species seen very infrequentlylower Pee Dee, Combahee, South Edisto, Santee,and Savannah Rivers.(

l m L o .Arl- >4J 3o m uc, mEU mmm .-4J O -s 3 c ) mu)m mm G -4C C C O m 'Am* m ~ m01 4Jk r soo o m mm.- m . c)clu o m o 4vlm ww23 30LU LLo m o h0 -4m mc Er l mrl 00E - s mm m m Q,- w d ZZm w w 'r morco . mas cmm m m x4C .A dm r-4.A e B 3 m.A .A 4 E-s Jf 4 mm a a oE..$0 Im- sm u .om s mS C ex m 4o m m m .A e0 3 b .Awr: Jfd*A='Am m 4 m a.+ .A .n 0 L EOL 'rE o m- --- UU -Wrn Ua - lAma"-4o4JPrn\h4EL.

Family / Species Region Food habits ReferencesPlethodontidae - lungless salamandersSouthern dusky salamander(Desmoanathus auriculW)Northern dusky salamander(L fysw)Two-1 ined salamander(Eucvcea bislineata)Three-1 ined salamander(EL lQngFEawKWineihta)Dwarf salamander(I ~dridlaitab)Four-toed salamander(HesouacLulicam s-)Red-backed salamander(Plathodon ainer_ews)Slimy salamander(E Wtinosus)Many-1 ined salamander(Sterearhilus IlmxiBLus)Mud salamander(LssuPneriton montanus)Bufonidae - toadsAmerican toad(&fo americanus)Woodhouse's toad(L kiQQdhousel)Oak toad(BL QlLeUu)Southern toad(BI f;errestris)Hylidae - treefrogsNorthern cricket frog(Acris rrenitans)Southern cricket frog(A& ullm)CH, NC, SC,GADEL, CHNE,DEL,CH,SC, CACH, NC, SC,GANC,SC,GA,FLDEL, CHNE,DEL,CH,NCSC,GANE,DEL,CHDEL, CHCH, NC, SC, CASC,GADEL,CH,NC,SCNC, SC,GAUC-CR-UCUC-CR-UCUC-CRRU CRU COC-CCUC-CCinsect larvae, sowbugs, wormsworms, insect larvaesmall invertebratessmall invertebratessmall invertebratessmall invertebratesearthworms, ants, bugsants, bugs, earthwormsaquatic insectsaquatic invertebrates, small insectssmall insectssmall insectssmall insectssmall insectssmall insectssmall insects

Family / SpeciesRegionStatusFood habitsReferencesGreen treef roe(HYl3 !2ufxsa)C-Asmall insectsSpring peeper(HA crucifer)arthropods, small insectsCope's gray treef rog(8, .cdxu.wneLis)insects, spidersCommon treefrog(L ~SicDlor)small invertebratesPine-woods treef rog(HA moralis)insectsSquirrel treefrog(L sovlrella)CH, NC, SC,GA,FLinsectsBarking treefrog(Ha axiLipsa)insects-LPPBird-voicedtreef roe(HA aui-1Little grass frog(Limnaoerlus Qwlaria)C-SavannahRiver drainageonlyUC-Csmall insectsinsectsBrimley Is chorus frog(Pseudacris brimlevi)insectsStriped chorus frogce, LL.LSW)insectsSouthern chorus frog(EL niarita)insectsOrnate chorus frog(EL arn&)Microhylidae- narrow-mouthed toadsNC, SC, GAinsectsEastern narrowmouthtoad(.Gas- caroliamb)CH,NC,SC,GAants and other small insectsRanidae - true frogsBullfrog(Bans &asbeiana)C-Acrayfish, aquatic insects, smallvertebratesC-Asmall vertebrates, insects,crayfish

-LFamily / Species Region StatusGreen frog(5, . c l a w )Carpenter frog(EL YLC&3.wEs)River frog(EI heckscheri)Wood frog(R, ulu-)Pickerel frog(EL rnustris)Southern leopard frog(B, gphsmcePhala)Chelydridae - snapping turtlesSnapping Turtle(Ghelrdra serDentina)Kinosternidae - mud turtlesP StinkpotU\ (Kims&nmn subrubrum)Eastern musk turtle(Stenotherus ssiQE&22)Emydidae - pond turtlesPainted turtle(GhErsemvs nLEi=i)Slider(CL aKiR&)Cooter(GI flnridana)River cooter(L mrinna)Redbelly turtle(St Jxt2riYnm)Chicken turtle(Peirochalvs reticularia)Spotted turtle(Clemmvs suttata)NC, SC,GA,FLNE,DEL,CH,NC, SCCH, NC. SC,CA,FLNE,DEL,CH,NC, SC,GAC-AUC-CC-LCUC-CUC-CUC-CFood habitsarthropods, snails, freshwater01 igochaetesarthropods, snails, spiders,crustaceanssnails, insects, crustaceansinsects, crustaceans, spidersinsects, spiders, other artropodssmall insectsaquatic invertebrates, fish, reptiles,carrion, aquatic plants, birdsinsects, mollusks, carrioninsects, snails, carrionyoung-tadpoles, amphibians, mollusksadul ts-aquatic plantsyoung-aquatic insects, mollusks,carrion, adults-aquatic plantsalgae, aquatic plantsalgae, aquatic plantssnails, crayfish, tadpoles,aquatic plantscrayfish, fish, snails, carrionaquatic plants, small invertebrates,carrionReferences

- fIn-f W--7.40 -> 0171- Lw m mUtu N-4 bO rlEdl rl-- U-- m-1-WV)aU-1ah 42 -UO U

Family / SpeciEastern ribbon snake{Thamndohissaurfris)Common garter snake(L iwrd&)Worm snake(hLPh9PhlS amaenus)Rlneneck snake(Rudn~his ounctatvs)Eastern earth snake(Yirniniaualeriae)Crotalidae - pit vipersCopperhead(tc&imam contorfa)Cottonmouth(k sudxQua)Pygmy rattlesnake(Sistrurusmiliarlus)Eastern diamondbackrattlesnakeRegion Status Food habitsOC-CR-UCR-UCR-UCUCOC-AR-UCRfrogs, salamanders, smallfishtoads, frogs, salamanders,earthwormsworms, soft-bodied insectssalamanders, earthworms, frogs, smallsnakesworms, slugs, snails, f rogsmice, voles, frogs, caterpillarsfish, amphibians, small mammals,sometimes waterbirdsmice, lizards, frogs, small snakessmall mammals, f rogs, othersnakesReferencesTimber rattlesnake(Canebrake)(L hPrtidl43)CH, NC, SC,GA,FLrodents, rabbits, small birdsREFERENCES1) Husick 1972a2) Hardy 19723) Klimkiewicz 1972a4) Klimkiewicz 1972b5) Ciccone, pers. comm.6) Arndt 19777) HcCormick and Somes 19828) Young 19829) Kiviat 1978a10) McCormick 197011) Richmond and Coin 193812) Carr and Coin 195513) Martof 195614) Sandifer et al. 1980Conant 1975Gibbons 1978Harrison 1978Jobson 1940Neill 1947Neill 1952Chamberlain 1937Richmond 1940Huheey 1959USACE 1979Behler and KingLefor and TinerHushinsky et al.

APPENDIX D:Avifauna of tidal freshwater wetlandsFLOATING AND DIVING WATERBIRDSFamily / Species Region Season Status HabitatsFood Habits ReferencesCaviidae - loonsCommon loon(G.iuh Lmmnr)UC-AL MFish, crabs, mollusks, frogsRed-throated loon(L stell&)NE,DEL,CHUCL MMolluscs, fish, crabs, frogs,Podicipedidae - grebesdHorned grebe(Ldis~,~ auritus)NE,DEL,CH,NC, SC,GA. FLRed-necked grebe NE, DEL, CH,(L e ri~sia) NC,SC,GAPied-billed grebe(fs.aua2~ JmiAaS)$ Pelecanidae - pelicansAmerican white pelican(PelecanusWruhucha)Brown pelican(E aadslentalis)Sulidae - boobies and gannetsNorthern gannet~~ Passw)Phalacrocoracidae - cormorantsDouble-crestedcormorant(Ehalacrocm auritus)Anhingidae - anhingasAnhinga(Anbinn;a .a.Qhi.tle~)NE,DEL,CH,NC, SC,GA,FLSC,CA,FLSC,GA,FLNE,DEL,CH,NC,SC,GA,FLCH,NC,SC,GA, FLSU, T-northP-southW,T-northP-southLC-CA-UCAR-UCUCUC-CLM, HML MLM, HML Haquatic insects, fish, molluskscrustaceansFish, mollusks, aquatic insectscrayfish, aquatic insects,mollusks, fishfishfishfishfishSU-north R-north LM, HM,TS fluill LeDomis, frogs,P-south C-south aquatic insects, crustaceans

Region Season Status Habitats Food Habits ReferencesAnatidae - swans, geese,and ducksMute swan(CvPnus plpy)R-UCLM, HMWhistling swan(It columbianlbg)NE,DEL,CH,NC, SC,GAA-northR-southLM, H ICanada goose(Brpnta raoabensis)NE,DEL,CH,NC, SCUC-LALM, HHBrant(& hernicla)NE, DELSnow geese(Ansz cc.asul9scens)roots and rhizomes of 5-8,SParfina, !&?.ew, -r 10,12,Eleocharis 14,17Fulvous whist1 ingduck(- bicolor)CH, NC, SC,GA.FLLH, HM, TSNE, DEL,CH,NC, SC,GA,FLLH, HH,TSMottled duck(& fuluinula)CA, FLLM, HMeanicum, Polvaonum, !a.BxJu,-, aquatic insectsAmerica black duck(& l3wARm)NE,DEL,CH,NC, SC,GA,FLLH. HM,TSCadwall(& imxacca)UC-CLM, HH, TSNorthern pintail(& arYta)UC-ALH, HH, TSGreen-winged teal(& crecca)CLH, HM, TSBlue-winged teal(& discors)C- ALH, HM, TSAmerican wigeon(& amerirana)NE, DEL, CH,NC, SC,GA,UC-CLH, HM

Hooded merganser(LoDbodvtes-)Common merganser(kkmwi N-)Red-breasted merganser(JL wW)RegionNE,DEL, CH,NC,SC,GA,FLNE,DEL,CH,NC,SC,GANE,DEL,CH,NC,SC,GA,FLRallidae - gallinules, coots, and railsPurple gallinule(PorDhvrula martini=)Common moor hen(Common gallinule)(Gallinula-)CH,NC,SC,GA,FLNE, DEL, CH,NC, SC,CA,FLAmerican coot NE, DEL , CH ,(EUlka i3D.!$ricana)NC, SC,GA,FLSeasonW, TSU-TPStatus Habitats Food HabitsUC-FC LM, HM, TS Fundulus, Xctalu~~, An&iaLlLa,Etheostoma, ALQ5aFC-C-north LM fishUC-southUC-FC LM, HM, TS fishR-northUC-southUC-AReferencesLM, HM lizaaia, SL~LDU, Eleocharis, 5,6,9,12,aquatic insects, snails, frogs 16-1 8LM, HMLM, HMZizania, GYRelllas, Scirous,grasshoppers, aquatic insects&~.uw, -a9 ~~~erus, 1,4-10,-, ~ m a e t o n , small 12,14-17fish, tadpoles, snails

WADINGBIRDSFamily / Species Region Season Status Habitats Food HabitsArdeidae - herons and bitternsReferencesAmerican bittern(8otaurus-)NE,DEL,CH,NC, SC,GA,FLSU,T-north C LM, HM, TSP-southfish, aquatic insects,frogs, mice. shrews5-7,12-17Least bittern(Ixobrrchus exilis)NE,DEL,CH,NC, SC,GA,FLSU, F-north F C LM, HMP-southfish, aquatic insects,amphibians, crustaceansBlack-crowned nighther'on(Nvctiaoraxnvcticorax)NE, DEL, CH,NC.SC.GA.FLSU,T-north A LM, HM, TSP-Southcrayfish, fish, crabs, mice,frogsYellow-crowned nightheron(L ULeLaau)DEL, CH, NC,SC,GA,FLSU, T-north C LM, HM, TSP-southsnails, aquatic insects, fish,crayfish, crabsGreen-backed heron(Butorides striatus)NE,DEL,CH,NC, SC,GA,FLSU,T-north C LM, HM, TSP-southsmall fish, crayfish, aquaticinsectsdU1OCattle eeret(BubulcusU)Little blue heron(L caerulea)NE,DEL,CH,NC, SC,GA,FLSU, T-north R-north LM, HMP-south A-southSU, T-north C LM, HM, TSP-Southgrasshoppers, crickets,spidersfish, crayfish, Orthoptera,amphibiansTricolored heron(Louisiana heron)(G tricolor)SU, T-north UC-north LM, HM, TSP-south C-Southfish, snails, lizards, frogsSnowy egret(L W)S,SU-north C LM, HMP-southfish. crayfish, crabs,aquatic insectsGreat egret NE, DEL, CH ,(- zd.Lui) NC,SC,GA,FLS, SU-north C LM, HM, TSP-southaquatic insects, fish, crayfish,crabs, snailsGreat blue heron(Brdea herodias)NE,DEL,CH,NC,SC,GA,FLmice, amphibians, fish,crayfishCiconiidae - storksWood stork(Mucteriaamericana)SC,GA.FLFC-summerUC-winterLM, HMsnails, aquatic insects, fish

FamilySpeciThreskiornithidae - ibisesRegion Season Status Habitats Food HabitsGlossy ibis NE,DEL,CH, S. SU-north R-north LM. HM, TS snails, crayfish, fish,(Plenadis falcinellud) NC, SC,CA, P-south C-south aquatic insects, crabsFLReferencesWhite ibis DEL,CH,NC, SU,T-north R-north LM,HH,TS crabs, aquatic insects, crayfish 5,6112,(Eodocimus il.lbLu) SC,GA, FL P-south A-south 14,16-18Aramidae - limpkinsLimpkin GA,FL SU R LM,HM,TS snails(8ramus e~l;a-1

RAILS AND SHOREBIRDSFamily / Species Region Season Status HabitatsFood Habits ReferencesRallidae - rails and gallinulesKing rail NE,DEL,CH, P(EaudS eleaans)NC, SC,GA,FLVirginia rail(& UmicrLa)NE,DEL,CH,NC, SC,GA,FLSU, T-northW,T-southSora NE, DEL,CH, SU, T-north(l3ILU.M carolina) NC,SC,GA, W,T-southFLYellow rail DEL,CH,NC, SU,T-north(CoturnicoDs SC,GA,FL W,T-southnoveboracena)Black rail DEL,CH,NC. SU, T(Laterallus iamaicensis) SC,GA,FLCharadriidae - plovers and turnstonesQ01 Killdeer NE, DEL, CH, SU,T-north(Charadriusuociferus) NC, SC,GA, P-southFLSemipalmated plover NE,DEL,CH, w,T(L smi.s?almahia) NC,SC,GA,FLLesser golden plover NE,DEL,CH, T(Pluvialis domlnlca)NC, SCBlack-bellied plover NE,DEL,CH, w,T(L dauatarola) NC, SC,CA,FLC LM, HM seeds of: Zizania, Polvnonm;Orthoptera, worms, spiders,snails, crayfish, small fishC LM, HM seeds of: Zizania, w,m u m ; worms, slugs,snails, small fishUC (A in LM, HMmigration)R (FC in LM, HMmigration)seeds of: Zizania, Q.~erm,-a; aquatic insects,worms, spiders, snailsseeds of: &!uxS!da, fd&2aun9Lizania,worms, snails, %GlJ=a; spidersworms, snails, spidzrs,a1 so seeds of: Scirous,Zizania, CvDerusC LM, HM Coleopotera, Orthoptera,HymenopteraFC-C LM crustaceans, mollusks, freshwaterworms, seeds of ~~UC-CCLML Mworms, snails, crustaceans,grasshopperscrustaceans, freshwater worms,mollusks, grasshoppers, beetlesScolopacidae - snipe, woodcock, and sandpipersRuddy turnstone NE, DEL, CH, W,T(AESMELS interores) NC,SC,GA,FLcrustaceans, grasshoppersmollusksCommon snipe NE,DEL,CH, SU, T-north(!alluwQ K ~ ~ U U K Q ) NC,SC,GA,FL P-southUC-CLM, HMaquatic Coleoptera, snails, worms,seeds of: ,$sicus, E UmuAmerican woodcock NE,DEL, CH, SU,T-north(ScoloDax mLtlQ11) NC,SC,GA,FL P-southUC-CLM, HMearthworms, larvae of: craneflies,horseflies, snipe flies

Family / SpeciesRegionSeasonStatusHabitatsFood HabitsReferencesUpland sandpiper(Bartramialonaicauda)Spotted sandpiper(ALtLiUs macularia)NE, DEL , CH ,NC,SC,GA,FLTR-UCLM, HMLM, HMfreshwater worms, snails, centipedes, 6,10,11millipedes, aquatic insects,seeds of: w, CeDhalanthusnymphs of: caddisflies, 1,5-7,mayflies, dragonflies; mollusks, 9-1 2 ,worms, grasshoppers, crickets 15-17Solitary sandpiper(Trinaa solftaria)NE, DEL, CH,NC,SC,GA,FLUC-CLM, HMmol lusks, worms, Hymenoptera, 5,699,Orthoptera, small frogs, nymphs of: 11,12,caddisflies, mayflies, dragonflies 15,17Greater yellowlegs(L ~JE&*P)Lesser yellowlegs(L flauiPes)NE, DEL, CHINC, SC,GA,FLNE,DEL, CH,NC,SC,GA,FLC-AUC-CLM, HMLM, HMaquatic insects, worms, mollusks, 5-7,9,10,small fish 12,14,15,17aquatic insects, snails, worms-LWillet(-i=uahms)Short-billed dowitcher(Limnodromus nriseus)cn --a Stilt sandpiper(CalidrisbimantoDus)NE, DEL, CH,NC,SC,GA,FLR-UCUC-CUC-FCLM, HMLM, HMLM, HMaquatic insects, worms, crabs,mollusks, small fish, seeds of:CuDerus, Scirousl eolvacnumfly larvae, worms, snails, 5-7.10-12,seeds of: m, Eelyge(LIUn, 14CvoerusPotamon-,clamworms, mollusks, aquaticinsects, seeds of: w,ScirDus, -worms, mollusks, insects 6,7,9,10Red knot(L .ciUU&s)Least sandpiper(L minutilla)NE, DEL, CH ,NC, SC,GA.FLR-UCLM, HMLM, HMsnails, periwinkles, worms,seeds of: ScirDus, Potamoneton,CvDerusworms, mollusks, aquatic insects, 5-7,9-11,seeds of m, Panicurn 15White-rumped(L-)sandpiperR-UCLM, HMinsects, clamworms, small fish, 5 I 6snails, grasshoppersPectoral sandpiper(L melanotos)NE,DEL,CH,NC, SC,GA,FLUCH Maquatic insects, worms, mollusks, 5-7,9,10,seeds of: w, Panicurn 14Semipalmated sandpiper(L (L)NE,DEL,CH,NC, SC,CA.FLFC-CLM, HMlarvae of: caddisflies, mayflies, 6,719110,dragonflies; clamworms, mollusks, 17seeds of: w, eotamonetonBaird's sandpiper(L bairdii)DEL, CHamphipods, beetles, weevils,mosquitoes, cranef lies

Family / Species Region Season Status HabitatsWestern sandpiperNE,DEL,CH,(4L -1 NC, SC,GA, FLSander1 ing(L ;,IRuff(Philomaahus ~unnax)Buff-breasted sandpiper(Trvnnitessubcllfi9ollis)Red-necked phalarope(Phalaroaus lobatus)DEL , CHDEL, CHDEL, CHWilson's phalaropeDEL, CH, NC,(E tricolor) SC,GARecurvirostridae - avocets and stiltsAmerican avocet4 (Becurvirostraa americana)YBlack-necked stilt(Himantoous nlsxk~)DEL,CH,NC,SC,CASU, T-northT-southFCLM, HMFood Habitsaquatic insects, beetles, mollusks,seeds of: mJFtM, ScirDusU C LM, HH flies and their larvae,mollusks, wormsUC LM, HM aquatic insects, worms, mollusks,fliesU C LM, HM beetles and their larvae,flies, seeds of: m,SoirDusRR-UCR-UCRLM. HMLH, HMLM, HMLH, HMsnails, midges, fly larvaelarvae of: caddisflies, may flies,dragonflies; seeds of: C-3,Scirous, Potamoaetonclamworms, aquatic insects,seeds of: u, Potamoaetonaquatic insects, snails, small fishReferences

Cathartidae - vulturesRegionDIURNAL AND NOCTURNAL BIRDS OF PREYSeason Status Habitats Food HabitsReferences-LTurkey vulture(Cathartes -1Black vulture(!hrXKUS atratus)NE,DEL,CH,NC,SC,GAFLCH,NC, SC,CA,FLAccipitridae - kites, hawks, and eaglesMississippi kite(ZctiniamississiDaiensis)SC,GA,FLP C HM,TS carrionP U C HM, TS carrionSU,T UC-FC HM, TS lizards, frogs, snakes,large insectsAmerican swallow-tailed SC,GA,FL SU, T UC-FC HM, TS snakes, lizards, frogskite(Elanoides W)Cooper's hawk(AcciDiter -ISharp-shinned hawkNC, DEL,CH,NC,SC,CA,FLNE,DEL,CH,(& striatus) NC, SC,CA.FLNorthern harrier(Marsh hawk)(Circus sy.alEus)Red-tailed hawk(8uteo iamaicensis)NE,DEL,CH,NC, SC,GA,FLNE,DEL,CH,NC, SC,CA,FLRed-shouldered hawk NE, DEL, CH,(& l.iWf;U) NC, SC,CA,FLBroad-winged hawkNE,DEL,CH,(& nlatvoterus) NC, SC,GA,FLRough-legged hawk NE,DEL,CH(& lagpnus)Southern bald eagle(Haliaeetusleuc0ce~hal yg)NE,DEL,CH,SC,CA,FLSU, T-northP-southP-northW, T-southSU, T-northP-midW, T-southPU C LM, HM, TS small passerines, mice, volesUC-FC LM. HM,TS mice, voles, small passerinesC LM, HM, TS mice, voles, rats,amphibians, snakes, smallpasserinesC LM, HM, TS mice. shrews, voles, rabbits,muskrats, gallinules, rails,small passerinesUC-C HM, TS rails, small owls, mice,voles, small passerinesSU,T-north UC HM, TS lizards, mice, snakes, frogs,W,T-southvoles, large flying insectsWPT UC HM, TS voles, mice, snakes,frogs, small passerinesR LM, HM, TS fish, waterfowl, rodents,carrion

Family / Species Region Season Status HabitatsOspreyNE,DEL,CH, SU,T-north FC-C LM, HM, TS(Pandion -1NCJSC,CA, P-southFLFalconidae - falconsPeregrine falconDEL,CH,NC,(.blGQ .nerearinus)SC,GA.FLMerlin(EL colwmbarius)American kestrel(L sgihsverius)Tytonidae - barn owlsCommon barn owl(zYl& aua)NE,DEL,CH,NC, SC,CA,FLNE,DEL,CH,NC, SC,GA,FLStrigidae - typical owlsUI(O Eastern screech owl NE, DEL, CHI(Qk4.S asin)NC, SC,GA,FLGreat horned owlNE,DEL,CH,(El&Q 'LirainianusfNC, SC,GA, FLBarred owl(Strix !Lai.a)Short-eared owlNE,DEL,CH,(A&2 flammeus) NC, SC,CA, FLW-TPUC-FCCLM, HM, TSLM, HM, TSfishFood HabitsReferenceswaterfowl, shorebirds, coots, 6,9,12,gallinules, swifts, kingbirds, and 14,17small passerineswaterfowl, passerines, voles, 6,10,12,mice, frogs, snakes 16,17mice, voles, frogs, bats, 1,6,7,9,insects, small passerines, lizards 12,16,17UC-FC LM, HM, TS mice, voles, small passerinesUC-FCCLM, HM, TSLM, HM, TSLM, HM, TSLM, HMmice, voles, frogs, smallpasserines, large insectsshrews, voles, mice, rats, 7,9,10,shorebirds, small passerines, 12,18bitterns, herons, waterfowl, hawks,other owlsmice, voles, small 5,6,9,10,passerines, shorebirds, waterfowl 12,15,17,18mice, esp. WW,voles, small passerines,large flying insectsNorthern saw-whet owl(Aeaoliusacadicus)DEL, CH, NCLM, HM, TSlarge flying insects, alsomice, voles, shrew, smallpasserinesLaniidae - shrikesLoggerhead shrike(LiXlUS -1DEL,CH,NC,SC,GA,FLR-UCLM, HMmice, voles, smallpasserines, large insects

CULLS, TERNS, KINGFISHERS, AND CROWSFamily / Species Region Season Status Habitats Food Habits ReferencesLaridae - gulls and ternsGlaucous gull(Larus hvoerboreus)Iceland gull(LA slaucoides)Great black-backedgull(L marlnus)Herring gull(I.& aPPentatUQ)Ring-billed gull(LA delawarensis)Laughing gull(L akIAaua)Bonapartefs gull(I, -1Black-legged kittiwake(&issa tridactvla)Cull-billed tern(Sterna nilotica)Forsterrs tern(SL forsteri)Common tern(L hirundo)Least tern(SL antillarum)Royal tern(L Inai&nu)Sandwich tern(L sandvicensis)Caspian- tern(L sawla)Black tern(Chilodonias ntner)Black skimmer(Rhunchoos nlu.c)W,TR-UCLM, HMfish, mollusks, ducks,carrionHE, DEL , CH WR-UCLM, HH fish, crustaceans, garbage,carrionNE, DEL,CH LH, HM fish, carrion, garbageHE, DEL , CHNE,DEL,CHNE,DEL,CHNE,DEL,CHNE,DEL,CH,NC,SC,GA,FLDEL, CHW,TPPcAU CW, T UC-FCSU, T-northX, T-southSU,TLH. HMLH, HHLH, HHLM, HMfish, crustaceans, mollusks,some insectsfish, Coleoptera, Orthoptera.mollusks, crustaceans, rodentssmall fish, earthworms, carrion,crustaceans, garbagefish, insects, worms,crustaceans, carrion, garbageW R-UC LM,HH small fish, crustaceans,mollusksT R-UC LH, HM dragonflies, caddisflies, frogs,small fish, earthwormsUCR-UCLH, HHLM, HMLM, HMLM.HMdragonflies, caddisflies, frogs,some small fishpipef ish, menhaden, alewivessmall fish and crutaceansfishSU R-UC LM. HM fishSU,T UC-FC LM, HM small fish, particularlymenhaden, mullet, suckersLH. HML Hcaddisflies, may f lies, dragonflies,moths, caterpillars, small fishsmall fish, crustaceans

Family / SpeciesRegionSeasonStatusHabitatsFood HabitsReferencesAlcedinidae - kingfishersBe1 ted kingfisher(!22lXb &QLQn)NE,DEL,CH,NC, SC,GA.FLPCLM, HM. TSfish, crayfish, crabs, mussels,newts, snails, frogs, toads,turtles, grasshoppers, beetles5-8,22Corvidae - crows and jaysFish crow(Corvus ossifraaus)NE,DEL,CH,NC,SC,CA,FLLM, HM,TSfish, crayfish, carrion,Cornus, Smilax, ZizaniaAmerican crow(LL -)NE,DEL,CH,NC,SC,CA,FLLM, HM, TSfish, grasshoppers, beetl.es, 1,697, 10,amphibians, reptiles, small birds, 22carrion m, Cornus

ARBOREAL BIRDSFamily / Species Region Season Status HabitatsFood Habits ReferencesCuculidae - cuckoosYellow-billed cuckoo(rdxs!Uuamericanus)NE,DEL,CH,NC,SC,CA,FLSU, T UC-C LM, HM, TS hairy caterpillars, crickets,dragonflies, grasshoppersBlack-billed cuckooNE.DEL,CH,(fi. ervthroDthalmus) NC, SC,GA,FLCaprimulgidae - goatsuckersSU,T-north UC-C HM, TST-southgrasshoppers, crickets, dragonflies, 6,7,12,13hairy caterpillarsCommon nighthawk(Chordeilus IlLiUxfNE, DEL, CH,NC, SC,GA,FLLM, HM, TSflying ants, beetles,grasshoppers, mosquitoesChuck-will I s-widowCH, NC,SC,(- carolinensis) GA,FLUC-FCHH, TSmoths, flies, mosquitoes, 9,12,16,18grasshoppers, small passerinesWhip-poor-w ill(L vociferous)SU, T-northW, T-southLM, HM, TSmosquitoes, moths, flies,grasshoppersApodidae - swiftsChimney swift(Chaetura Delaaica)Trochilidae - hummingbirdsRuby-throatedhummingbird(Archilochus colubris)Picidae - woodpeckersPileated woodpecker(l2cU&UU Rih&ddS)Red-bellied woodpecker(-carolinus)Red-headed woodpeckerNE,DEL,CH,NC,SC,GA,FLNE, DEL,CH,NC,SC,GA,FLNE,CH,NC,SC,GA,FLCH,NC,SC,GA.FLNE,DEL,CH,(L ervthroceohalus) NC,SC,GA,FLYellow-bellied sapsucker(SohvraDicus uarius)DEL, CH, NC,SC,GA,FLLM, HMcaddisflies, mosquitoes, mayflies, 1,6,7,9,beetles, wasps, ants 10,12,16SU, T HM. TS Hibiscus, LmDatiens, Ioomoea,TecomaR-UC-northUC-FC-SouthUC-FCUCUC-FCT SHM, TSHM, TSHM, TSants, larvae of woodboring beetles, Toxicodendron,Sassafras, wild grapeseeds of: Ouecus, Fraxinus,Ahus, Mvricabeetles and their larvae,ants. caterpillars, grasshoppers,sedds of: Ouercus. Mvricasap and wood of: Ouercus,AGer

Family / Species Region SeasonHairy woodpecker(Picoides -INE,DEL,CH,NC, SC,GA,FLDowny woodpeckerNE, DEL, CH,(E Dubescens) NC, SC,GA,FLTyrannidae - tyrant flycatchersEastern kingbird(xYlYumaLYrannus)NE, DEL,CH,NC,SC,GA.FLPStatusUCHabitatsT SHM. TSFood Habitsbeetle larvae, ants, spiders,millipedes, ~GQ&&QQ, Cornusbeetle larvae, moths, ants,snails, caterpillars, GQCI~YS,ToxicodendronSU, T C-A LM, HM, TS various Hymenoptera andOrthopteraReferences4Great-crested flycatcher(Hviarchus crinitus)Eastern phoebe(Savornis 3LhQS.b)Acadian flycatcher(EmDidonaxvirescens)O) Willow flycatchera (EL traillii)Eastern wood pewee(Contoous virens)Hirundinidae - swallowsBarn swallow(Hirundo rustica)NE,DEL,CH,NC, SC,GA,FLDEL, CH, NC,SC,GA,FLNE, DEL, CHNC,SC,GACliff swallowHE, DEL, CH,(HA Dvrrhonota) NC, SC,CA,FLNorthern rough-winged DEL,CH,NC,swallow (serrioennis 7 scyGApFLBank swallowNE, DEL,CH,(Rioaria rioaria)NC,SC,CA.FLTree swallowNE,DEL,CH,(Tachvcineta bicolor) NC, SC,CA,FLSU, T-northW,T-SouthSU,T-northT-SouthSU, TSU, T-northP-southSU, TCU CR-UCLM, HM, TSLM, HM, TSLM, HM,TSLM, HM, TSLM, HM, TSLM, HHLH, HHLepidoptera, caterpillars,beetles, dragonfliesgrasshoppers, crickets, dragonflies, 5,6,9,10,wasps, bees 12,13,16,18beetles, bees, waspsbeetles, moths, caterpillars,bees, waspsflies, beetles, treehoppers,grasshoppers, wasps, beesgrasshoppers, crickets, 1,5,6,9,dragonflies, moths, mosquitoes 10,12,14,16,18,22beetles 6,7,9,14,16SU, T LH, HH wasps, bees, dragonflies,beetlesC-ALH. HMLH, HHtermites, ants, damselflies,dragonflies, aphids, beetlesbeetles, flies, wasps, 1,6,7,9,10,bees, seeds of: Mvrica, ScirDus, 12,14-17,eolvnonum. CvDerus 2 2

Family / Species Region Season Status Habitats Food Habits ReferencesPurple martin NE,DEL,CH, SU,T(ikQKU a&iS)MC,SC.CA,FLParidae - Chickadees and titmiceBlack-capped chickadee(Perus atricaoflluJ)HE, DELCarolina chickadeeDEL,CH,NC,(EL w) SC,GA,FLTufted titmousece bicolor)C LU, HH beetles, wasps, bees,dragonflies, damselfliesUC-C HM,TS moths, plant lice, spiders,katydids, roxicDdendronC LM, HU, TS eggs of insects,beetles, caterpillars,nvrica. ToxicodendrDnUC LM. HU. TS caterpillars, wasps, ants,HvricaSittadae -- nuthatchesWhite-breasted nuthatch NE,DEL,CH,(&u&a -INC, SC,GA,FLUC-FCHM, TSbees, wasps, moths,caterpillarsRed-breasted nuthatch(a& Esnadensis)NE,DEL,CH,NC, SC,GAR-UCHH, TStwig and bole insectsBrown-headed nuthatch(S, ourilla)CH, WC,SC,GA, FLUCHM, TSbole and twig insectsCerthiidae - creepersBrown creeperDEL,CH.NC,(Certhiaamericana)SC,CA,FLUimidae - mockingbirds and thrashersNorthern mockingbird NE, DEL, CH, P(&LllU&? NthaQum) NC,SC,CA.FLMuscicapidae - thrushes, gnatcatchers, and kingletsWood thrush DEL,CH,NC, SU, T(BYlocfahla-)SC,GA,FLHermit thrush DEL,CH,NC, T(Catharus l&!&U)SC,GA,FLSwainson's thrush DEL,CH, NC, W, T-north(LL JJ&uhwa) SC,GA,FL T-southGray-cheeked thrush DEL, CH , NC, T(L Ltminimusf SC,GA.FLUC-FC HM, TS spiders, beetles, ants.caterpillars, PanicurnU C LH,HM, TS beetles, ants, wasps,bees, grasshoppers, Smilax,ToxicodenPtQnUC LM,HM,TS beetles, ants, caterpillars,spidersUC-FC HM, TS beetles, ants, caterpillars,~mtlar, ToricodendconU C HH,Y,TS ants, beetles, caterpillars,U C HM,TS caterpillars, beetles, ants,Smilax, Toxicodendron

I.Family / Species Region Season StatusVeerySU, T-north u C(L fuscescens)T-southEastern bluebird(Sialia sialis)Golden-crowned kinglet(Beaulus satraDa)Ruby-crowned kinglet(L calendula)Bombycillidae - waxwingsCedar waxwing(8ombvcilla cedrorum)Vireonidae - vireosWhite-eyed vireo(Yirep ariseus)Yellow-throated vireo(L flavifrons)Solitary vireo(E solitarius)Red-eyed vireo(E olivaceus)Warbling vireo(L nilvus)NE,DEL,CH,NC, SC,GA,FLNE,DEL,CH,NC, SC,CA,FLNE,DEL,CH,NC, SC,CA,FLDEL, CH, NC,SC,GA.FLNE,DEL, CH,NC,SC,GA,FLNE,DEL,CH,NC, SC,GA,FLUC-CCUC-CUC-FCHabitatsHM. TSLM, HMHM, TSHM,TSHM, TSFood Habitsbeetles, ants, wasps, bees,weevils. grasshoppers, crickets,Mvrica, -flies, caddisflies, gnatswasps, flies, beetles,plant liceflies, beetles, ToxicodendmUC-C LM, HM Smilax, Mvrica. Eornus,berriesUC-C HM. TS moths, beetles, ants,waspsUCR- UCFC-AHI(, TSLM,HM,TSLM,HM,TSReferenceseggs and caterpillars of 6,9,12,18moths and butterflies, dragonfliesdragonflies, damselflies,bees, wasps, ,.ric ,etsbeetles, ants,wasps,mothsDEL , CH R-UC HM, TS caterpillars, beetles 6,9

Family / Species Region Season Status Habitats Food Habits ReferencesEmberizidae - wood warblers, blackbirds, tanagers, grosbeaks, buntings, and sparrowsBlack and white warbler DEL, CH,NC, T-north C HM, TS ants, moths, flies,(Mniotilta Y.a%t) SC,GA,FL W, T-south aphids, spidersProthonotary warbler CH,NC, SC, SU,T C-A HM, TS aquatic insects, mayflies,(Protonotaria Gi.U3X) CA,FL caterpillarsBlue-winged warbler NE, DEL, CH, T R-UC HM. TS beetles, ants, spiders(Verrnivora pinras)NC, SC,GA.FLGolden-winged warbler(L _L)Tennessee warbler(L Y*)Nashville warbler(L rufica~iLLa)Orange-crowned warbler(L celata)Bachmanls warblerg) (L bachmanii)a, Northet n parula(Parula americana)American redstart(Setoohaaaruticilla)Yellow warbler(Rmdmha Detechia)Magnolia warbler(L maanolia)Black-throated bluewarbler(L caerulescens)Black-throated greenwarbler(PI virens)Yellow-throated warbler(L dominica)Prairie warbler(L rllscslnr)Cape May warbler(R. tiarina)DEL,CH,NC,SC,GA,FLDEL,CH,NC,SC,CA, FLDEL . CHDEL, CH, NC,SC,GA,FLCH, NC, SC,GA, FLDEL, CH, NC,SC,GA,FLDEL, NC, SC,CA,FLCH,NC,SC,GA, FLT R-UC HM, TS inch worms, spidersT R-UC HM,TS beetles, weevils, scale insects,aphidsTSU, TSU,T-northT-southSU,TSU,TSU, TRUC-FCC-AHM, TSHM, TSTSHM,TSHM, TSleafhoppers, aphids, flies,grasshoppersleafhoppers, aphids, spiderslittle known, probablysimilar to other warblersbeetles, cankerworms, spiderscraneflies, leafhoppers,moths, beetles, m aF C HM, TS mosquitoes, aphids, spiders,cankerworms, weevilsUC HM, TS moths, scale insects, aphids,leafhoppersC HM, TS moths, flies, beetlesC HM, SU,TS beetles, ants, caterpillars,spidersT Sbeetles, moths, aphids, spiders,mosquitoesC HM, TS insects, spidersU C HM,SU,TS bees, wasps, crickets,dragonflies, moths

Family / SpeciesRegionSeasonStatusHabitatsFood HabitsReferencesBlackburnian warblerte, fusca)DELTU CHM, TSbees, caterpillars,cranefliesYellow-rumped warbler(L sX2Ixm-1NE, DEL, CH,NC,SC,GA,FLLM, HM, TSflies, beetles, ants,Toxicodendron. MvricaChestnut-sided warblertL oensvlvanica)HM.TScankerworms, beetles,grasshoppers, caterpillarsPine warblerCLL JliluU)T Sants, wasps, bees, 6,12eanicum, Toxicodendron, CornusBay-breasted warbler(e, castenea)HM, TSflies, moths leafhoppers 6,12Palm war-bler(LL palmarum)DEL,CH, NC,SC,GA, FLHM, TSmosquitoes, beetles, flies,MYrica, R.uhd3Blackpoll warbler(LL striata)HM. TSaphids, scale insects, gnats 6,7,13,16Yellow-breasted chat(Icteria uirens)Hooded warbler(Wilsonianitrina)Wilson's warbler(L Pusilla)Orchard oriole(J.chwu sDurius)Northern oriole(L nalbula)Brown-headed cowbird(Molothrus afsr)Thraupidae - tanagersScarlet tanager(Piranaa olivacea)Summer tanagerce rvnra)DEL, CH, NC,SC,GA,FLDEL,CH, NC,SC,GADEL,CH,NC,NE,DEL, CH,NC,SC,GA.FLCHM, TSants, wasps, beetles 6,9,12,13UC-FCHM, SU,TS caddisflies, moths,aphids, wasps, beesU CHM,TS leafhoppers, scale insects,ants, aphidsSU, T CLM, HM grasshoppers, ants, spiders,beetles6,9,10,12C LM, HM, TS spiders, ants, beetles,caterpillarsC-ALH, HHHM, TSHM, TSbeetles, bees, wasps,caterpillarscaterpillars, wasps, bees, beetles 12,13

Family / Species Region Seasonnorthern cardinal(Cardinaliacardinalls)NE,DEL,CH.NC,SC,GA,FLPStatusCHabitatsLH. AH. TSfood Habitsgrasshoppers, beetlesPolvnonr&as !kQeus, ToricodcndronReferencesRose-breasted grosbeak(PheucticusNE,DEL,CH,NC,SC,GAHH, TSbeetles, ants, wasps,bees,Blue grosbeak(Cuiraca cserulee)Evening grosbeak(CoccothraustesuesDettfous)DEL,CH,IIC,SC,GA.FLDEL , CH , NC,SC,CAHH,TSgrasshoppers, beetles, weevils,Peniclmr. CvoeruJ, ScirnLu,wR-UC HH, TS beetles, caterpillars,roxicodendron, CornusIndigo bunting(Paasetina cvanea)NE,DEL,CH,WC,SC.CA,FLLI, HUcaterpillars, grasshoppers,beetlesPainted bunting(& W)SC,GA.FLUCHU.TS'nprica, Panicrtm, beetles,caterpillars, grasshoppers(bAmerican tree sparrw(SDizsllaarhorca)NE, DELUC-CHI, TSPanicurn, CvDerus, kmaranthus,Leersia, Setaria, beetles,antsFringillidae - finchesPurple finch(Catoodecus-)DEL,CH,NC,SC,GAUC-FCHM, TSHouse finch(L C,) DELR-UCtin, TSPine siskin(Carduelis Riua)DEL,CH, WC,SC'GIUCHH, TScaterpillars, aphidsCommon red pol 1(Brantbis ElemiPea)DELAmerican goldfinchNE,DEL,CH.(L t&u.ku) NC,SC,GA,FLRCHH. TSLH, HH, TSseeds of: u,ealvnonum, Setaria, Lizania,Amaranthus; aphids, caterpillars

em G ian *mo >.Id m e-L Z ar*U 34s r:au suL.3 0300 L Osol o m aI 1 G ICt.-,. A?.3% V)xvlc0d w0mme*0enVJ\X4El..

Family / SpeciesMarsh wren(Long-billed marsh wren)(Cistothorusnalustris)Sedge wren(Short-billed marsh wren)(L olatensis)Mimidae - mockingbirds andGray catbird(Dumatellacarolinensis)Region Season status Habitats Food Habits ReferencesNE,DEL,CH, SU,T-north C LM, HMNC,SC,GA, P-southFLNE, DEL, CH, SU, T-north R-UC LM,HMNC, SC,GA.FL W,T-souththrashersNE,DEL,CH, SU,T-north A LM,HM,TSNC, SC,GA, P-southFLaquatic insects, snails,craneflies, dragonflies,mosquito larvaebeetles, moths, caterpillars,ants, grasshoppersSmilax, Mvrlca, -Brown thrasher DEL, CH, NC, SU,T-north U C HM,TS beetles, ants, grasshoppers,(Toxostoma Edflm) SC,GA,FL P-South Smilax, Toxicodendron, M U~uscicapidae - thrushes, gnatcatchers, and kingletsAmerican robin NE,DEL, CH SU,T-north A LM, HM,TS caterpillars, beetles, worms,(Turdus l&u&uAu) NC,SC,GA. W, T-south SmilaxFLdMotacillidae - pipits' Water pipit DEL,CH,NC, W,T UC-C LM, HM beetles, flies, caterpillars,(8nthus slimld&) SC,GA,FL crickets, PanicurnSturnidae - starlingsStarling NE, DEL, CH, P C-A LM, HM, TS beetles, grasshoppers, millipedes,(Sturnis !u&arAl) NC,SC,GA, Toxicodendron, MvricaFLEmberizidae - wood warblers, blackbirds, tanagers, groabeaks, buntings, and sparrowsWorm-eating warbler DEL , CH , NC, T U C LM, HM, TS grasshoppers, walking sticks,(Hermitheros vermivorus) SC,GA.FL span worms, weevils, spidersSwainson's warbler CH, NC, SC, SU, T-north R-UC LM, HM, TS ants, bees, spiders,(Limnothlvois-) GA, FL T-south small caterpillarsOvenbird NE,DEL,CH, SU,T-north UC LM, HM, TS snails, slugs, worms,(Seiurusaurocaoillus) NC, SC,GA, W, T-south crickets, ants, spidersFLNorthern waterthrush NE,DEL,CH, SU-T UC-C LM, HM, TS water beetles, damselflies,(s. noveboracensis) NC,SC,GA, mothsFL

Family / Species Region Season Status Habitats Food Habits ReferencesLouisiana waterthrush(L lwwiiua)SU,T-north UC-FC LH, HH, TST-Southdragonfly and cranefly 5,6.9-12,larvae, killifishes, mollusks 15-17Common yellowthroat(Geothlvoia trichas)NE, DEL, CH,NC,SC,GA,FLSU,T-north C-A LH, HH. TSP-southgrasshoppers, dragonflies, beetles, 1,5,7-14,damselflies, spl ders 16-18Mourning warbler(QmuuXAl-1Connecticut warbler(a aailis)Kentucky warblerCQ. fprmnsus)Canada wafbler(WflsonieEanadensis)Bobolink(-)Eastern meadowlark., (SeYrnellamagna)-LRed-winged blackbird(Aaelaiusohoenireus)Rusty blackbird(EunbanusEarolinus)DEL T U C HH, TS insects, spiders 6.11DEL,CH, NC.SC.GADEL, CHI NC,SC,GA,FLT R-UC HH, TS spiders, bark insects 6,12SU , T FC-C HH,SU,TS moths, caterpillars, grubs, 5,699-12,aphids 16,17DEL, CH SU,T R-UC HM, TS beetles, mosquitoes, flies, 5,6,9,13mothsNE, DEL, CH,NC,SC,GA.FLNE,DEL,CH,NC, SC,GA,FLNE,DEL,CH,NC, SC,CA,FLSU,T-north UC ( LA LH, HNT-south in migration)Zlzanfa, Panicurn, Polvnonum, 5-9,12,grasshoppers, caterpillars 16'17P C-A LR, HH u. -, cricketsgrasshoppersSU , T-nor th A LH, HK, TSP-Southseeds of: m, 1,5-10,12,lbkullm* IzinkUn1 A~~LQLU, 12,14-18,!aReKu 21,22W s T FC HM, TS Zizania, Panlcum, aquaticinsects, beetlesBrewer l s blackbird(G -1W.T R-UC LH. HW.ants, grasshoppers, spiders 12Boat-tailed grackle(Ouiscalus maipc)NE,DEL,CH,NC, SC,GA,FLSU, T-north C-A LN. HWP-southCommon grackle(a, dulscub)NE,DEL,CH,NC, SC,GA,FLLH, HMbees, grasshoppers, crickets,earthworms, crayfish,Zizania, QuercusPesseridae - sparrowsHouse sparrowuL&iuZ domesticus)LM, HM, TS

drQFamily / SpeciesFringilidae - finchesRufous-sided towhee(PioiloSavannah sparrow(Passerculussandwichensis)Grasshopper sparrow(Ammodramussavannarum)Henslow's sparrow(A. henslowii)Le Contets sparrow(A. leconteii)Sharp-tailed sparrow(A. caudacutus)Vesper sparrow(eooecetesgramineus)Slate-colored junco(Juncohvemalis)Chipping sparrow(Soizella DasserinafField sparrow(S, Dusilla)White-crowned sparrow(ZonotrichiaRe$ionNE, DEL, CHNC,SC,GAFLNE, DEL,CH,NC. SC,GA,NE, DEL, CHNC,SC,GANE, DEL, CHNC, SC,CA,FLDEL, CH, NC,SC,GA,FLWhite-throated sparrow NE,DEL,CH,(L albicollis) NC, SC,GA,FLFox sparrow(Passerella iliaca)Swamp sparrow(Melosoiza-)DEL,CH,NC,SC,GA.FLNE, DEL, CH,NC,SC.GA,FLSeason Status Habitats Food Habits ReferencesUC-FCUC-FCUCU CU CACCC-AHM, TS seeds of: Panicurn, E-, 1,6,7,9,G2UE.uat k k i = 10,12913,16,18LM, HMLM, HMLM, HMLM, HMLM, HMLM, HMLM, HMLM, HMLM. HMLM,HMLM, HMLM, HMLM, HM,TSuochloa, Polvaonum, eanicum, 6-10,12,16-cYJmuseolvaonum, Panicurn,grasshoppers, caterpillarseanicum. Polvaonum,beetles, grasshoppersPanicurn, Polvaonum, grasshoppers,beetlesZizania, -,leaf hoppersPolvaonum, Panicurn,beetles, grasshoppersPolvaonum, Panicurn, GxQ.fXS, 6,12,16ToxicodendrJln, beetles, caterpillarsgrasshoppers, caterpillars,Setaria. eanicum, Amaranthus,i!.QlY-Panicurn, mranthus, Setaria,beet1 es, grasshoppersPanicurn, eolvaonum, S e t a r i a s 6,7,9,10,-, spiders, bees, wasps 12fUY~3a~am. Setaria, Cvoerus, 6-10,12,Panicurn. Amaranthus, ants, bees 13,16Polvaonum, Setaria, 3bxicodendron. 6,9,12,millipedes, beetles 13,16CuDerus, Polvaonum, Panicurn,m, w.beetlescrickets, grasshoppers

Family / SpeciesRegionSeason Status HabitatsFood HabitsReferencesSong sparrowNE,DEL,CH,(L melodial NC,SC,GA,FLLM, HM, TSPolvaonum, Panicurn, CvDerus,Amaranthus, beetles, cricketsSnow bunting(Plectroohenaxnlvalis)DEL, CHW UC LM, HME=t2dra. Setaria, Cvoerus,Panicurn, fly larvae and pupaeREFERENCES1) Hawkins and Leck 19772) Perry and Uhler 19813) Stewart and Manning 19584) Stewart 19625) Wass 19726) McCormick 19707) Kiviat 1978a8) Olson 19829) Stewart and Robbins 195810) Wass and Wilkins 197811) Terres 198012) Young 1982McCormick and Somes 1982Shanhol tzer 1974Ciccone, per s. comm.Sandlfer et al. 1982Forsythe 1978USACE 1979Landers et al. 1976Kerwin and Webb 1971Meanley 1975Lefor and Tiner 1974Conrad 1966

APPENDIX E:Mammals of tidal freshwater wetlands of the Atlantic coastal regionRegion Status Food habits References-LrlPVirginia opossum(melohis Pirniniana)Soricidae - shrewsMasked shrew(Sorex cinereus)Southeastern shrew(3, lonairoatris)Short-tailed shrew(Blarina brevicauda)Southern short-tailedshrew(& wolinensis)Least shrew(!bauui2 J&c!u)Talpidae - molesStar-nosed mole(Condvbra sxiisda)Eastern mole(i%dQRm i%uaLkM)Vespertilionidae - batsSilver-haired bat(Lasionucterisnoctivaaans)Big brown bat(k2&3.km fuscus)Seminole bat(Lasiurus seminolus)Dasypodidae - armadilloesNine-banded armadilloa!aiwuS oouemcinctus)NE,DEL,CH,NC, SC,GADEL. CHDEL, CH , NC,SC,GARE, DEL, CHNC,SC,GAR-UCinsects, fruits and berries,small mammals, birdsinsects, crustaceans, mollusksspiders, slugs, snailsinsects, crustaceans, annelids,molluskscrustaceans, insects, mollusks,annelidsgrasshoppers, moths, beetle larvae,and other insectscaddis fly larvae, midges, leeches,aquatic oligochaetes, small fishterrestrial and aquatic01 igochaetesflying insectsColeoptera, Hymenopteracrickets, large flying insectsbeetle and their larvae,snails, slugs, centipedes

Family / Species Region Status Food habits ReferencesLeporidae - rabbitsHarsh rabbit(.&lUlUU-)Eastern cottontail(SA floridanus)Sciuridae - chipmunks and squirrelsEastern chipmunkaaum striatus)Gray squirrel(Sciurus -1Fox squirrel(S, nu=)Southern flying squirrel(Claucomus !u?lmA)Woodchuck(Marmota ULQnU)4Castoridae - beaversU1Beaver(!aahr canadensis)Cricetidae - mice and ratsHarsh rice rat(Orrzomvs Delustris)CH,NC,SC,CA, FLNE,DEL,CH,NC,SC,GA,FLNE,DEL,CH,NC,SC,GA,FLNC, SC,GANE,DEL,CHHE,DEL,CHEastern harvest mouseCH,NC, SC,(&Jthrodontw humulis) CA,FLYhite-footed mouse(Peromuscus leucolzlbs)Cotton mousece nossvoinlrs)Deer mousece maoiculW)Eastern wood rat(leotoma flaridana)Meadow vole(fi,ussu nennsvlvanicus)NE,DEL,CHNC,SC,GA,FLNESC,CANE, DEL, CHleaves, stems, roots of aquaticemergent plantsgrasses, sedges, twigs ofshrubssmall birds, snakes, mice,slugsnuts, seeds, berriesseeds, berries, nutsberries, nuts, insects, smallbirdsperrenials, grasses, sedgeswoody and aquatic plants - sweet gum,alder, willow, Peltandra, PmM!xia,s,sedges, grassesseeds, esp. lizania, grasses,sedges, insectsmoth larvae, seeds ofgrasses, esp. Setariainsects, grasses, sedges,seeds ofgrasses, sedges, insectsrushes, grasses, sedges, berries,nutsgrasses, sedges, seeds, nutsrushes, sedges, grasses

Family / SpeciesRegionStatusFood habitsReferencesMuskrat(Ondatra zihthku)NE, DEL, CHC-LAroots and rhizomes of: 1-3,7,8,12,-a americanus, Sanaitaria, Iuha, 13,15,16LenrsFa, Zizania, Pontederh,Q,!genu, Eanicum., and many othersSouthern bog lemming(Sunaatomvs cooDeri)grasses, sedges 12,13Hispid cotton rat(5ipmod9n hisDidus)crayfish, insects, grasses,sedgesMuridae - old world miceHouse mouse(&is W)NE, DEL,CH,NC, SC,GA. FLseeds, esp. Setaria, beetleand butterfly larvaeNorway rat(Rattus oorvenicus)DEL,CH,NC, SCseeds, small mammals andbirdsZapodidae - jumping miceMeadow jumping mouse(Zaeus hudsonius)NE,DEL,CH, NCbeetles, cutworms, berries, seeds,esp. ImDatiensCapromyidae - nutriasb,Nutriaflwua&QL cov~u%)DEL, CH, NCUC-LAstems and leaves of: I-,grasses, rushes, sedgesCanidae - foxesRed fox(liuloes xUl!2ea)rabbits, mice. voles, birds,snakesGray fox(WYPn cinereoaraenfeus)NE,NC,SC,GAmice, voles, shrews, rabbitsUrsidae - bearsBlack bear(Ursus americanus)NC, SC,GAomnivorusProcyonidae - raccoonsEastern raccoon(Procvon LetPI1)fish, crayfish, frogs, mussels,birds, reptiles, muskrats

Family / Species Region Status Food habits ReferencesMustelidae - weaselsLong-tailed weasel(nustela frenata)NE,DEL,CH,NC, SC,CAmice, rabbits, rats, shrewsMink(L ?_L)NE,DEL,CH,NC, SC,GA,FLmice, voles, frogs, smallbirds, muskratsStriped skunk( N W meDhitis)mice, beetles, berries, crickets,nuts amphibiansRiver otter(Lutra canadensis)crayfish, frogs, turtles, fishFelidae - catsBobcat(Eells rYfras)UC-LCmarsh rabbits, muskrats, squirrels,miceCervidae - deerWhite-tailed deer(S!dsaileus virainiam)NE,DEL,CH,NC, SC,CA,FLsedges, grasses, esp.U&anU4Delphinidae - dolphinsCommon do1 phi n(DelDhinus delohis)fishREFERENCES1) Sandifer et el. 19802) USACE 19793) Hamilton and Whittaker 19794) Sherman 19355) Sherman 19396) Wilson 19547) Kiviat 1978a8) Wharton 19799) Sanders 197810) Penney 195011) Tomkins 193512) Ciccone, pers. comm.13) Wass 197214) McCormick 197015) McCormick and Somes 198216) Lefor and Tiner 197417) Whittaker 198016) Wilson 1953

50272 -to1 1REPORT DOCUMENTATION2.3. F(cclpient's XCCCSSiOn NO.PAGE4. Title and SubtitleThe Ecology of Tidal Freshwater Marshes of the United StatesEast Coast: A Community Profile~ ~ t h ~ ~ ( ~ ) W i--I l i am t . Udum, Thomas JTtKTIUniversity of VirginiaDepartment of Environmental SciencesCharlottesvil le, VA 22903---- - -J::C--I 6.i ~ T ~ ~ c t / ~ a s k Unit / ~ oNo.r kI , John K. HodveFFand-- '=~organizatl~n ~ept. No.I-- -1 11. Contract(C) or Grant(G) No12. Sponsoring Organization Name and Address 13. Type of Report & Per~od CoveredU.S. Fish and Wildlife ServiceDivision of Biological Services -Department of the Interior 14.Washington, DC 20240-- -IS. Supplcmcntaty Notes1. REPORT NO-FWS/OBS-83/175. Repon DateJanuary 198416. Abstract (Limit: 200 words)Tidal freshwater marshes are a distinctive type of estuarine ecosystem located upstreamfrom tidal sal ine marshes and downstream fron non-tidal freshwater mqrshes. Theyare characterized by freshwater or nearly freshwater conditions most of the time, floraand fauna dominated by freshwater species, and daily lunar tidal flushing. This reportexamines the ecology of this community as it occurs along the Atlantic seaboard fromsouthern New England to northern Florida.This marsh community is heavily influenced by river flow, which maintains freshwaterconditions and deposits sediments high in silt and clay. The plant assemblage in tidalfreshwater marshes is diverse both in numbers of species and structural plant types. Plantconnnunity structure is markedly diverse spatially and seasonally, and reflects thedynamic processing of energy and biomass in the marsh through high productivity, rapiddecomposition and seasonal nutrient cycl ing.The diverse niches in this heterogeneous environment are exploited by a very diverseanimal community of as many as 125 species of fish, 102 species of amphibians and reptiles,280 species of birds, and 46 species of mammals over the community's broad range. AlthoughI fewer species are permanent residents or marsh breeders, use of this community for foodand cover is high. This use, coupled with the marshes' capacity to be natural buffers andI water filters, argue for their high value as natural resources.Ecology, primary biological productivity, decomposition, invertebrates, fishes,amphibia, reptiles, birdsb. Identif~en/Open.Ended TermsI Tidal freshwater marsh, ecological succession, plant demography, nutrient cycling,carbon flux, energy flowc COSATI Fteld/Group__ __ --- - -.--- . .--- ---19. Secur~ty Class (Thss Repon) 21. No. of Pages18. Avallablitty StatementL(See ANSI-239 18)Unlimited. Unclassified --- ix + 176-.---- --- - - -- - - --- -20. Scc~r~ty Class 0h1s Page)Unclassified22. PrtceOPTIONAL FORM 272 (2-771(Formerly NTIErlS)Department of tommrrrr* U.S. GOVERNMENT PRINTING OFFICE 1984-771 -783