N. Wang R.J. Sarver C.F. Rabeni 1999 <div class="col-lg-9 article__content"><div class="article__body show-references "><div class="hlFld-Abstract"><div class="abstractSection abstractInFull"><p>Selection of a representative stream reach is implicitly or explicitly recommended in many biomonitoring protocols using benthic invertebrates. We evaluated the adequacy of sampling a single stream reach selected on the basis of its appearance. We 1st demonstrated the precision of our within-reach sampling. Then we sampled 3 or 4 reaches (each ∼20× mean width) within an 8-16 km segment on each of 8 streams in 3 ecoregions and calculated 4 common metrics: 1) total taxa; 2) Ephemeroptera, Plecoptera, and Trichoptera taxa; 3) biotic index; and 4) Shannon's diversity index. In only 6% of possible cases was the coefficient of variation for any of the metrics reduced &gt;10% by sampling additional reaches. Sampling a 2nd reach on a stream improved the ability to detect impairment by an average of only 9.3%. Sampling a 3rd reach on a stream additionally improved ability to detect impairment by only 4.5%. We concluded that a single well-chosen reach, if adequately sampled, can be representative of an entire stream segment, and sampling additional reaches within a segment may not be cost effective.</p></div></div></div></div> application/pdf 10.2307/1468466 en University of Chicago Press Evaluating adequacy of the representative stream reach used in invertebrate monitoring programs article