Standing crops and ecology of aquatic invertebrates in agricultural drainwater ponds in California

The authors examined standing crops and ecology of aquatic invertebrates in agricultural drainwater evaporation ponds in California from Oct 1982 to Mar 1983 and Sep 1983 to Mar 1984. Evaporation ponds supported low diversities but high standing crops of aquatic invertebrates. A water boatman (Trichocorixa reticulata ) and a midge (Tanypus grodhausi ) were the most abundant invertebrates, constituting 44.9% and 51.4% of total macroinvertebrate biomass. Regression models indicated that of 6 environmental variables measured, only electrical conductivity (EC) and Julian date affected biomass and density of water boatmen. EC was the only significant correlate of midge biomass in evaporation ponds.