POTENTIAL EFFECTS OF FISH PREDATION ON WETLAND INVERTEBRATES - A COMPARISON OF WETLANDS WITH AND WITHOUT FATHEAD MINNOWS

We evaluated potential effects of fathead minnows (Pimephales promelas ) on wetland invertebrates by comparing activity trap catches from sem ipermanent wetlands with and without fathead minnows during 1991 and 1 992. Indices of aquatic invertebrate abundance, biomass, and taxon ric hness were all lower in wetlands containing fathead minnows. Reduction s in abundance and biomass of insects and crustaceans in wetlands with fathead minnows were pronounced during both years. Our results indica te that at high densities, fathead minnows may severely depress abunda nce, biomass, and taxon richness of aquatic invertebrates in semiperma nent prairie wetlands, thereby reducing the suitability of these habit ats as seasonal foraging areas for waterfowl.