Use of the Coefficient of Community Loss (I) to Assess Cultural Stresses on Monongahela River Tributary Fish Communities

ABSTRACT

We utilized a single metric, the coefficient of community loss (I) to assess the health of fish communities inhabiting 27 low-order Monongahela River tributaries in Pennsylvania. All streams were sampled during summers of 2003 and 2004 utilizing two-pass back-pack electrofishing from the mouth extending 200 m upstream. Environmental stressors observed in and on-stream were habitat alteration and non-point source discharges due to urbanization and agriculture along with point-source discharges of raw and treated sewage, net alkaline mine drainage, and acid mine drainage (AMD). Species richness and I-metric scores in streams impacted by major AMD and/or untreated sewage were 0 and α, respectively. While those exhibiting minimal cultural stress had species richness totals and I-metric scores of 24 and 0.24, respectively. Values of I were negatively correlated with index of biotic integrity scores (-0.951), suggesting that I could provide a rapid comprehensive assessment of the relative health of fish communities within a major watershed.