Application and transferability of Great Lakes coastal wetland indices of biotic integrity to high quality inland lakes of Beaver Island in northern Lake Michigan

摘要

Biological indicators or indices of biotic integrity (IBI) have been developed for land management and regulatory agencies to categorize the condition of a given ecosystem. IBIs are more widely used in lotic systems and those that can be used over wide geographic regions or multiple systems are deemed most valuable. Lacustrine wetlands have intrinsic complexity and multidimensionality making them very difficult to classify. This, in turn, greatly affects the transferability of indices created for explicit regions and wetland types. Similarly, due to scarcity, relatively pristine reference conditions are seldom included in IBI calibration and represent a critical end of the disturbance continuum. The robustness and transferability of macroinvertebrate and fish IBIs created for fringing lacustrine and drowned river mouth wetlands of the Great Lakes for use in wetlands occurring in inland-lakes on islands within the Great Lakes were tested. Islands within the Laurentian Great Lakes contain unique and critical habitats that have received little attention, but also require specialized tools for monitoring and management. Inland-lake wetlands of Beaver Island, Lake Michigan, were ranked a priori along a disturbance gradient based on adjacent land use/cover. Transferability of the pre-existing Great Lakes IBIs was determined by correlating the site-specific IBI rank with the site-specific disturbance ranks. Results indicated that the IBIs were not directly transferable and may require substantial modification.