The ecology of eelgrass meadows in the Pacific Northwest: A ...

More documents

Recommendations

Info

Because eelgrass is a rooted plant, it performs a vital function of stabiliziny coastal sediment, thus preventing erosion. Studies done in England (wilson 19491, Denmark (Rasmussen 1977), the Chesapeake Bay (Orth 1977a), and in Puget Sound, Washington hilli ips 1972) have documented the ability of eelgrass to stabilize bottom sediments (Figure 2). The eelgrass meadow provides direct and indirect food sources for marine food chains; it also provides habitat and protection and acts as a nursery for many marine species. Following the die-off of 90% to 100% of the eelgrass in the North Atlantic in 1931-33, mny animls associated with eelgrass disappeared. Impacts to the humn economy were severe. Scallops, fish, clams, and crabs declined or disappearedr and the brant geese changed their migration patterns and went inland to feed. In Europe, brant geese numbers declined severely (Einarsen 1965) following the "wasting disease." In the Netherlands the overwintering population of brant declined from more than 10,000 birds to at most 100 by 1953. The Pacific Northwest region extends from southern British Colmbia, Canada, to Humboldt Bay in northwestern California (Figure 3), a distance of about 900 km (560 mi) (Proctor et al. 1980a). In Figure 2. Effect of wave shock on rhizome mat of eelgrass, 22 February 1964. West side of Wdbey Island, Washington (shows persistence of eelgrass).
Pacific Northwest Coastal Region Oraya Cape Harbor Nehalem River 4 /0>rA '.- ----+ Netartr Bay Nestucca Rlver siletz River '7 Yaquine Bay 4 C Alaea Bay contrast to southern California, the coastline of this region is sparsely populated. It has not been without modification, however. In southern British Columbia, Moody (1978) reported that the sdnd and mud flats of the Fraser River foreshore, which supports extensive meadows of eelgrass, were threatened by an increasing number of residential, industrial, and recreational developnents. The largest meadows of eelgrass in the Pacific Northwest occur in protected estuarine areas away from the open coast; i.e., Padilla and Willapa Bays in Washington State, and Humboldt Bay in northern California. The largest stand in northern Oregon occurs in Netarts Bay, while small stands are confined to several narrow river valleys (Figure 3). This report also includes Z. japonica Aschers. & Graebn., since thespecies is heavily used as food by black brant geese. CO~UIII~ RIV.~ --yf r( Six08 Rlver Chetco Rlvet OR Humboldt Bay 4 Cape Mendoclno Figure 3. Map of the Pacific Northwest coastline showing the locations of the estuaries and river systems containing eelgrass (after Proctor et al. 1980b). N xii
Page 2 and 3: ~~~/0~-84/24 September 1984 THE ECO
Page 4 and 5: PREFACE Nearly half the population
Page 6 and 7: CONTENTS PREFACE ..................
Page 8 and 9: FIGURES Number 1 2 ................
Page 10 and 11: ACKNOWLEDGMENTS I wish to acknowled
Page 14 and 15: CHAPTER 1 THE PHYSIOGRAPHIC SETTING
Page 16 and 17: Table 1. Precipitation, temperature
Page 18 and 19: Table 2. Distribution and extent of
Page 20 and 21: Table 2. (Concluded) Extent of mat
Page 22 and 23: CHAPTER 2 THE BIOLOGY OF EELGRASS 2
Page 24 and 25: Table 4. Field observations on eelg
Page 26 and 27: leaves overtopped them and created
Page 28 and 29: 1.0- influence the redox potential
Page 30 and 31: Oxygen There are Little data to ind
Page 32 and 33: enough, increased erosion of bottom
Page 34 and 35: The terms used to describe biomass
Page 36 and 37: estimates are reported on work done
Page 38 and 39: Figure 10. Eelgrass at Blakely Isla
Page 40 and 41: increase in p~), and the sediments
Page 42 and 43: particulate matter and DOM were hig
Page 44 and 45: Table 9. Nutrient content of eelgra
Page 46 and 47: ecause it is dominated by a single
Page 48 and 49: epibenthos, and other components al
Page 50 and 51: shorebirds). From a recent thorough
Page 52 and 53: pink shrimp, and bottom fish (Proct
Page 54 and 55: Table 13 a. (Continued) Phyltnn, cl
Page 56 and 57: Phylum, class, and Resident or Livi
Page 58 and 59: Table 13b. (concluded) Resident or
Page 60 and 61: Table 13c. (Concluded) Living Feedi
Page 62 and 63:
eelgrass) , while 29 species were f
Page 64 and 65:
(239,d9~,9(ii9 kg) (outram and Huln
Page 66 and 67:
Washington State Game Dept., pers.
Page 68 and 69:
Table 15. Energy in various ccmpart
Page 70 and 71:
Export of whole by waterfowl Figure
Page 72 and 73:
storms erode and dislodge some eelg
Page 74 and 75:
CHAPTER 6 HUMAN IMPACTS-MANAGEMENT
Page 76 and 77:
apparent darnazje. IUllzomes and ro
Page 78 and 79:
great annual range of water tempera
Page 80 and 81:
1978, for all assumptions, formulat
Page 82 and 83:
Table 16. ( CDncluded) Spec ies yea
Page 84 and 85:
REFERENCES Rdarns, S.M. 197va. The
Page 86 and 87:
seagrass community. Pages 153-162 i
Page 88 and 89:
on current flow. Estuarine Coastal
Page 90 and 91:
Inst. Agric. Res., Tohoku Univ.: 13
Page 92 and 93:
In flvt. seayrasses, l'halassia McR
Page 94 and 95:
eelgrass (~ostera marina L. ) Phill
Page 96 and 97:
along the Strait of Juan de Fuca. N
Page 98 and 99:
diatom assemblages in Netarts Bay,
show all

The ecology of eelgrass meadows in the Pacific Northwest: A ...

Create successful ePaper yourself

Delete template?

Save as template?