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Abstract: We investigated the effect of decomposing duck carcasses on aquatic invertebrate numbers, biomass, and taxonomic composition in a seasonally flooded, impounded wetland in the Sacramento Valley, California during August-November 1988 and 1989. Major invertebrate taxa were copepods (Cyclopoida, occurred in 8.3% of samples), water fleas (Daphnidae, 8.9%), water boatmen (Corisella, 10.4%), and midge larvae (Goeldichironomus, 9.3%; Chironomus, 11.5%; Tanypus, 17.2%). We found no treatment (carcass present or no carcass) by sampling day interaction for these taxa. We found a significant difference between sample plots with carcasses and those without carcasses only for Daphnidae counts and Corisella wet weights. We found significant differences among sampling days for these taxa that were probably statistical artifacts. We were unable to detect any effect of duck carcasses on aquatic invertebrate community structure and the potential availability of invertebrates as waterfowl food.

Key Words: aquatic invertebrates, avian botulism, California, Chironomidae, midges, wetlands

Table of Contents

• Introduction
• Study Area and Methods
• Results
• Discussion
• Management Implications
• Acknowledgements
• Literature Cited
• Appendix

Tables

• Table 1 -- Treatment by sampling day interaction for counts and wet weights for six major aquatic invertebrate taxa.
• Table 2 -- Treatment effect for counts and wet weights for six major aquatic invertebrate taxa.
• Table 3 -- Day effect for counts and wet weights for six major aquatic invertebrate taxa.

aqinecol.zip ( 31K) -- Aquatic Invertebrate Ecology During a Simulated Botulism Epizootic in a Sacramento Valley Wetland