Relationships among varying sampling distance and the IBI in warmwater, headwater streams of the Eastern Corn Belt Plain.

摘要: Single-pass electrofishing was used to define the most efficient sampling distance assess stream condition using index of biotic integrity (IBI) methodology in headwater (<36 km2 drainage area), warmwater streams Eastern Corn Belt Plain ecoregion. Based on wetted widths (1–3.3 m) sampled reaches, we defined effort based increased area (range 50–555 m2). Sampled necessary capture a representative fish assemblage until 167-m2 distance, which is equivalent minimum one habitat cycle. No significant difference metric actual observed value response found with increasing Increased required smaller (≤1 achieve recommended sample area. The effect rare IBI tested modified Walford method. A decrease score when 10 % data were removed. presence did not influence individual metrics or scores for either reduced calibrations greater than 3 removed number species, 15 removal minnow and 5 catch per unit (CPUE). affect any score, while influenced darter, madtom, sculpin species but score.