A review of research on the development of lake indices of biotic integrity

Current methods of ecological health assessment of lakes within the United States are not adequate for meeting the requirements of the 1972 Clean Water Act (CWA) and assessing the condition of aquatic biota. Impairment status of lakes has typically been measured and classified by individual states via eutrophication standards or through the use of total maximum daily load (TMDL) protocols. These measurements often fail to account for effects of anthropogenic disturbances on aquatic biota that are not directly reflected by chemical and physical proxies of environmental condition. The index of biotic integrity (IBI) is a potentially effective ecological health assessment method that is meant to integrate ecological, functional, and structural aspects of aquatic systems. Furthermore, the IBI is meant to meet the requirements of the CWA by directly examining biological components of an ecosystem. The adaptation of the IBI for use in lake monitoring has increased in recent years as managers address the need to directly examine the biota of aquatic systems. This review is meant to examine research related to the development of IBIs in lacustrine environments. Obstacles and shortcomings to index development that are commonly encountered are discussed within the review. Attention is also given to robust methods and lessons learned from inadequate methods. The review will facilitate use of the IBI for lake monitoring efforts with the overall goal of improving water resource management.