The Development and Evaluation of an Index of Biotic Integrity for Small Lakes in Western and Central New York

Abstract

The ecological "health" of aquatic ecosystems is important to scientists, resource managers, and the general public. In order to properly protect or restore the integrity of an aquatic system we must first accurately assess its present condition. The Index of Biotic Integrity (IBI) is a relatively new approach to this problem which utilizes the characteristics of a lake's fish assemblage to assess lake health. My study focused on developing an Index of Biotic Integrity for several small lakes in New York. The objectives of my study were to (1) select metrics applicable to the set of eight small lakes, (2) calculate an Index of Biotic Integrity for these lakes, and (3) to evaluate the ability of the IBI to estimate the condition of the lakes in terms of anthropogenic impact. The results of the 181 assessment were evaluated via comparison with assessments based on two other methods: a standard rating based on water quality and watershed data and a modification of the Trophic State Index (TSI). Results showed that neither the 181 or TSI could accurately assess the level of anthropogenic impact completely. Although the 181 was unable to correctly assess the level of impact on all study lakes, the results were encouraging and several metrics showed promise for uses outside the realm of the IBI. Furthermore, a comprehensive assessment based on the results of all three methods used in this study produced the best overall results.