ISSN:
1365-2427
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
SUMMARY. Benthic macroinvertebrate distribution, abundance, and composition were observed in a fluctuating (7.7 m) central Wisconsin, U.S.A., reservoir during 1973–74. Chironomidae and Oligochaeta represented 98% of the total fauna by number. The chironomid, Chironomus plumosus, and an oligochaete, Limnodrilus, each averaged 36% of the total benthic biomass. Annual mean numbers and biomass in areas exposed to air, exposed to ice cover, or remaining inundated were 3025/m2 (1.8g/m2), 4311/m2 (4.5g/m2), and 8558/m2 (16.0 g/m2), respectively. A substantial portion of the benthic fauna was stranded and subsequently decreased rapidly in drying and frozen substrates exposed to air. Total benthic numbers and biomass were greatest immediately below the drawdown limit.Recolonization required 3 months (mid-March to mid-June, 1974) to attain pre-drawdown values for numbers and biomass, and subsequently both were greater after reinundation than before the substrate was exposed. Recolonization of areas exposed to the air was greater in substrates containing large amounts of organic matter than in sandy areas containing little organic matter. Sorting and transportation of sediments redistributed organic materials from the regulated zone to below the drawdown limit, and macrophytes were eliminated from the regulated zone. When compared to other reservoirs and lakes, the density of benthos in the Big Eau Pleine Reservoir is neither high nor low. However, when compared with non-fluctuating reservoirs the number of Ephemeroptera, Plecoptera, Trichoptera, Amphipoda, and Gastropoda was low.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2427.1978.tb01449.x
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