Aquatic Insects of the West River and Salt Marshes ... - Yale University

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PUPEDIS 169The greatest changes will come with the replacement of Phragmitesaustralis and terrestrial vegetation with salt marsh vegetation. Bartenand Kenny (this volume) indicate that the rate and extent of tidalflooding can be controlled in West River Memorial Park. Theimpact on insect communities will depend greatly on the degreeto which tidal flooding is limited and how plant communities willrespond to salinity changes.If the central island in the park is not inundated during periodsof high tide, insect shoreline communities will shift inland as new,salt marsh vegetation is established. Existing species will probablycontinue to persist in a boundary between a completely terrestrialenvironment and the leading edge of the high marsh (Ranwell1972). However, if the central island is completely inundated, thenthe existing insect community will be exterminated and an entirelynew community will be established. New species will be either facultativeor obligate salt marsh species. The existing shoreline communitiesmay disappear entirely.As salt marsh grasses (i.e., Spartina spp. and Distichlis spicata)and shrubs, such as high-tide bush (Iva frutescens), establish themselvesand spread, they will in turn be colonized by insects immigratingfrom outside salt marshes. These colonizers will undoubtedlycome from salt marshes located on the West River below the tidegates and from salt marshes associated with rivers emptying intoNew Haven Harbor. The community of salt marsh insects thatexists at Spring Street Marsh will provide the initial colonizers forthe new marsh.Trignotylus pulcher (redrawnfrom Froeschner 1949)RECOMMENDATIONSA number of salt marshes have already been restored successfullyin Connecticut (see reviews in Dryer & Niering 1995). Insect samplesfrom the restored Pine Creek Marsh indicate that salt marsh insectsare fully capable of colonizing restored salt marsh habitats withouthuman intervention. With the establishment of salt marsh vegetationand the presence of a nearby source of insect colonizers, WestRiver Memorial Park will eventually come to resemble a typical saltmarsh insect community. Natural processes of migration and colonizationwill adequately populate the habitat.A program of consistent monitoring of selected insect groups isstrongly recommended. Insects can and have served as excellentbiological indicators for the health of an ecosystem. In addition todetecting community changes, entomological monitoring of therestoration represents an excellent opportunity to observe the dynamicsof shifting community structure, colonization capability,YALE F&ES BULLETIN
170 INTERDISCIPLINARY RESTORATIONand colonization rate of insects associated with salt marshes. Theseobservations, coupled with baseline data, can predict or assess thesuccess of other, local restoration attempts. They will serve to measurethe effectiveness of salt marsh mitigation projects, the conditionof marshes, and marsh productivity (Peck et al. 1994).If the decision is taken to change the tidal regime of the WestRiver, insect collections must be taken to monitor changing distributionand species composition of shoreline communities on thebanks of the West River. This will provide quick assessment of theimmediate impact of changes in salinity and hydrology of the WestRiver. Biotic community change can be quantified with variouscommunity and diversity indices. The collecting techniques describedherein will be sufficient for monitoring purposes. A pictorial checklistcan facilitate a quick assessment, although a curated samplingmust be collected for verification of species identity. The specieschecklist in Appendix 2 can serve as a baseline for determiningchange in species composition.During restoration, the newly forming marsh must also bemonitored for introduction of exotic species. The international,commercial shipping traffic in New Haven Harbor and the incidenceof major storms moving from the south can be sources ofexotic insects that can more readily gain a foothold in a developingcommunity where niches may be temporarily available. The currentpresence of the exotic true bug Chilacis typhae is such an example.Although most introduced species are innocuous, the possible establishmentof economic pests is always a concern.A recommended, longer-term project will be to monitor theappearance of insect species colonizing new Spartina grass communities.The checklist for the three salt marshes and published accountsof Connecticut salt marsh insects can be used to indicatewhether a typical salt marsh insect community is being established.At present, detailed checklists of Connecticut salt marsh insects arelacking, and a separate initiative will be necessary to produce these lists.Because Diptera have a high profile as potential pests, bloodfeedingspecies must be monitored. Common pest species includedeerflies (Tabanidae), such as the common saltmarsh greenheadTabanus nigrovittatus (Macquart); “no-see-ums” or biting midges(Ceratopogonidae) of the genera Culicoides and Leptoconeps; and thesalt marsh mosquito, Aedes sollicitans (Walker)(Culicidae). If controlmeasures are not implemented in a timely manner, all threegroups can pose significant discomfort and possible health risks torecreationists and residents adjacent to the marsh. The present studyHeterocerus sp. (redrawn fromGreene 1968)BULLETIN 100
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Aquatic Insects of the West River and Salt Marshes ... - Yale University

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