Land-use effects on white sucker (Catostomus commersoni) life history and diet in portions of North Dakota and Minnesota

Background/Question/Methods

We relate land use patterns to life history characteristics and diets of white sucker (Catostomus commersoni) in North Dakota and Minnesota watersheds.  In the Midwest, extensive landscape modifications of prairie habitat, due to agricultural practices, has altered the hydrology of most river basins; yet, identifying the proximate mechanisms by which these landscape changes are passed to the species inhabiting these river basins remains elusive. Changes to the aquatic environment may affect fishes both directly (e.g., as temperature increases, metabolism increases) and indirectly (e.g., as light levels decrease, zooplankton productivity may decrease, which reduces food resources for fish).
Results/Conclusions

We found that suckers under 100mm consumed 47% chironomid larvae across tributaries. Those individuals between 100mm and 200mm also preferred chironomid larvae at 55%. Finally, those individuals great than 200mm consumed 40% chironomid larvae and 20% mollusks (present in < 2% of the smaller size classes). We placed our findings within the context of land use by using a Geographic Information System (GIS).  GIS data for land use allowed classification of 13 tributaries (Missouri River and Red River drainages) by percent area occupied by the following land use types: agricultural, urban, range land, forest, and grassland. Our goal was to examine land use effects on white sucker life history characteristics and on aquatic invertebrate communities and fish diet.