A multimetric index of biotic integrity based on macroinvertebrates to assess biotic condition of streams in the Chipiriri Basin, Cochabamba - Bolivia

In order to develop a multimetric biotic integrity index, we collected data on the macroinvertebrate communities and local environmental habitat descriptors in 38 reference and 29 disturbed sites, uniformly distribute within the Chipiriri watershed (Bolivia). Using the reference data set, stepwise multiple linear regression procedures were first applied to develop the simplest possible response model that adequately explained the observed patterns of 12 different biological variables, reflecting macroinvertebrate community structure. In a second step, we selected the most effective variables that discriminate between reference and disturbed sites. Finally, adding the values of the biological variables selected, we obtained a final index score that described biotic integrity of the reference and disturbed sites as excellent, good, fair, poor, or very poor. Our final index achieved good distinction between natural and human-induced variation in biological condition. Including additional parameters, this approach could be used in the near future to develop a nation biotic integrity index.