| A primary objective of this study was to relate and rank the environmental variables of boreal and prairie ponds that influence dytiscid diversity. This objective was accomplished by measuring various environmental variables for each pond including pH, conductivity, chlorophyll a density, pond permanence, pond area, macrophyte density, emergent vegetation density, and presence of fish and tiger salamanders.; An additional objective was to examine the extent that predatory guilds, including odonate larvae, fish, and grey tiger salamanders (Ambystoma tigrinum diaboli Dunn), contributed to the community structure of predacious diving beetles.; The final purpose of this study was to compare and contrast the species of dytiscids in boreal and prairie ponds.; Species found in 25 or more of the 30 ponds included Hygrotus sayi Balfour-Browne, Laccophilus maculosus Say, Liodessus obscurellus LeConte, Ilybius fraterculus LeConte, Coptotomus longulus LeConte, Rhantus sericans Sharp, and Graphoderus perplexus Sharp. Boreal ponds had a higher frequency of ecological specialists, including Desmopachria convexa Aube, Hygrotus farctus LeConte, Graphoderus liberus Say, and Uvarus granarius Aube. Prairie ponds contained more species in greater abundance than boreal ponds. (Abstract shortened by UMI.)... |
