Limnological Characteristics of Waterfowl Production Area Wetlands in St. Croix and Polk Counties, Wisconsin;Technical bulletin

摘要

This report represents one part of a larger, long-term, multidisciplinary study designed to evaluate existing and potential habitat management methods intended to increase waterfowl and pheasant production on private and public lands in Wisconsin. This federally funded study was conducted from 1983 to 1992 and separated into six categories, each with a distinct set of objectives. The six categories included (1) a management and evaluation program, (2) monitoring waterfowl and pheasant populations, (3) habitat (upland) assessment, (4) hunter bag checks, (5) development and evaluation of predator indices, and (6) limnological assessment of Waterfowl Production Area (WPA) wetlands. The results of the first five categories are presented in Evrard (2002). In this report, I present the results related to category number 6, summarize the significance of these findings to waterfowl management, and provide specific management recommendations that address increased waterfowl production capabilities. The primary objective of category number 6 was to identify the ecological significance of limnological habitat (as opposed to surrounding upland habitat) in WPA wetlands to waterfowl production. Limnological habitat includes the physical, chemical, and biological attributes of wetland basins. To estimate the relative importance of the various limnological attributes, I compared annual changes in limnological habitat attributes to corresponding annual changes in waterfowl utilization on a selected set of wetland basins located within WPAs. I concentrated on two specific habitat issues that are suspected to be critically important to waterfowl production: fish/invertebrate relationships and aquatic plant/invertebrate relationships since these relationships influence the availability of invertebrate food items to waterfowl.