Fish indicators of anthropogenic stress at Great Lakes coastal margins: Multimetric and multivariate approaches.

摘要

Two commonly applied approaches to assessing the health of an aquatic habitat are the multimetric index of biotic integrity (IBI) and the multivariate approach. Fish community composition and local environmental conditions were measured at 143 sites across the entire U.S. coastline between 2002 and 2003, using overnight-set fyke nets (a large collaborative study to develop environmental indicators at Great Lakes coastal margins (GLEI)). Of these sites, data from 55 wetlands were used in an attempt to develop IBIs for the Northern Great Lakes (NGL) ecoregion and the Erie and Ontario (EOL) ecoregion. Candidate metrics were evaluated with respect to agricultural stress measured at drainage basin and immediate watershed topographical scales. An IBI could be developed only for the NGL ecoregion, based on a criterion requiring inclusion of at least 4 metrics representing attributes of a natural habitat. Fish community metrics in the NGL ecoregion varied more strongly with stress at the larger segment-shed scale.; A further test of the IBI approach was done using independently developed IBIs for Typha and Scirpus aquatic plant zones of Great Lakes coastal wetlands (Uzarski et al. 2005). IBI scores were calculated for 32 wetlands with dominant Typha and Scirpus vegetation using data collected through the GLEI project. The results indicated that both the Typha and Scirpus IBI were selectively responsive to anthropogenic stressors. The Typha IBI varied most significantly as a function of population density-related stress and the Scirpus IBI most strongly reflected agriculture-related stress. (Abstract shortened by UMI.)