Biodiversity of Minnesota Caddisflies

INTRODUCTION

Biodiversity has become an important scientific topic over the last 10-15 years, largely due to a perceived decline in worldwide organismal biodiversity and concern over the potential ecological implications of this decline. Biodiversity studies, those which document the distribution and ecological affinities of organisms within a particular region, are important both for conservation efforts and for a greater understanding of the organisms and region of interest.

Pollution of lakes and streams is one of the largest environmental problems currently facing both Minnesota and much of the United States. Quantifying the composition of aquatic invertebrate assemblages is a powerful technique for evaluating aquatic pollution because it directly measures ecosystem functioning. A weakness of this technique is the current lack of taxonomic, distribution, and ecological data for aquatic organisms. Without these data, prediction of the characteristic organisms of specific ecosystems is difficult and only general water quality appraisals can be made.

The caddisflies (Insecta: Trichoptera) are an important water quality indicator taxon due to their high species richness, ecological diversity, importance to virtually all freshwater environments, and varying susceptibilities to pollution and other environmental disturbances. Unfortunately, only a handful of North American studies (Betten 1934, Ross 1944, Denning 1956, Unzicker et al. 1982, Moulton and Stewart 1996) have thoroughly assessed the caddisflies of a region. There have been no comprehensive taxonomic studies of the caddisflies of Minnesota, or of any of its adjacent states and Canadian provinces. There has been no significant effort to document the statewide distribution of the known Minnesota species or to correlate regional distributions with watershed conditions. Etnier's (1965) checklist of 208 species remains the most thorough published treatment of the statewide fauna. Since his study, the known number has increased to 285 species, including many recent discoveries.

Minnesota is an ecologically diverse state, situated at the intersection of the three largest biotic provinces of North America: Prairie, Deciduous Forest, and Coniferous Forest. This ecological diversity suggests a diverse fauna with strong affinities to faunas of neighboring states and provinces. Assessment of the Minnesota caddisflies may, therefore, have important regional utility.

OBJECTIVES

I began the first comprehensive study of Minnesota caddisfly biodiversity in 1997. The objectives of my research are to:

Ultimately, these data will allow for identification of the Minnesota fauna, assess the conservation status of rare species, and predict occurrences of caddisfly populations in various ecosystems. This will increase caddisfly utility in regional water quality assessment as well as evaluate their biodiversity and conservation needs.

CURRENT STATUS

I have had three field seasons and have been entering my specimens into the University of Minnesota Insect Collection (UMSP) Biota database (Colwell 1996). The database currently contains 125,108 specimens representing 285 species. These records come from 1,519 collections during the last 120 years from 591 Minnesota localities. Additionally, I have approximately 200 records from the literature and about 150 specimen records from the Illinois Natural History Survey. Future objectives include sampling in areas under-represented by past collecting, with a completion of fieldwork by the end of 2001.

© 2000-2008 by ADCS and the Regents of the University of Minnesota.