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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Wetlands I
INFLUENCE OF HYDROLOGY AND FISH ON MACROINVERTEBRATE COMMUNITIES IN BACKWATER SLOUGHS OF THE CENTRAL PLATTE RIVER, NEBRASKA.
M.R. Whiles1 and B.S. Goldowitz2. 1Department of Zoology, Southern Illinois University, Carbondale, IL 62901-6501, 2Platte River Trust, 6611 W. Whooping Crane Drive, Wood River, NE 68883
We examined macroinvertebrate abundance and diversity in 4 backwater sloughs in the central Platte valley that differed in hydrology and the presence of fish. Annual hydroperiods for each site were 158 (ephemeral), 296 (intermittent without fish), 331 (intermittent with seasonal fish), and 365 (perennial with fish) days yr-1. Sloughs were sampled seasonally when water was present during 1997-1998 using a coring technique that collected both water column and benthic macroinvertebrates. Oligochaeta, Diptera (e.g., Chironomidae, Ceratopogonidae, Culicidae) and crustaceans (e.g., Copepoda, Cladocera, Amphipoda) dominated invertebrate abundance in all sites during all seasons. Average annual macroinvertebrate abundance was highest in the perennial site (213,147 individuals m-2) and lowest in the ephemeral site (35,563 individuals m-2). Seasonal patterns were evident in sites that held water most of the year. Macroinvertebrate abundance peaked during summer in the two sites with fish, but was lowest during summer in the fishless intermittent site. The intermittent site without fish had highest taxa richness (49), followed by the intermittent site with seasonal fish (46). The perennial (30) and ephemeral (10) sites had substantially lower richness. Results indicate invertebrate abundance and diversity vary substantially with hydrology and the presence of fish in these wetlands, and that diversity is highest in intermittent sites.
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