Factors influencing invertebrate communities in prairie wetlands: a multivariate approach

We examined the relationships between invertebrate community structure and a number of biotic and abiotic variables in 19 semipermanent prairie wetlan ds. We tested whether aquatic invertebrate communities differed (i) between wetlands with and without fathead minnows (Pimephales promelas) and (ii) a ccording to drainage history of wetlands (restored versus natural, nondrain ed). We also evaluated influences of other environmental variables on inver tebrate community structure, including abundance of aquatic macrophytes and amphibians and wetland depth and surface area. Invertebrate communities di ffered significantly between wetlands with and without fathead minnows, lar gely due to lower relative abundance of 19 invertebrate taxa (of 32 taxa an alyzed) in wetlands with fathead minnows. In contrast, we found no differen ces in these taxa between natural and restored wetlands. Canonical correspo ndence analysis indicated that invertebrate community structure was affecte d by abundance of fathead minnows, abundance of aquatic macrophytes, and we tland depth, with fathead minnows the most influential variable measured. M any studies have documented the effects of fish predation on zooplankton co mmunities, but our results show that fathead minnows in prairie wetlands af fect a large number of diverse invertebrate taxa. The presence of these fis h results in an invertebrate community distinctly different from that found in fishless wetlands.