Multitaxon distribution models reveal severe alteration in the regional biodiversity of freshwater invertebrates

AbstractKnowledge of current and historical conditions is needed to guide conservation and restoration policies, but such information is lacking for most taxa. This problem is especially severe for small, inconspicuous taxa, such as the thousands of invertebrate species that inhabit stream and other freshwater ecosystems. We describe a novel application of River Invertebrate Prediction and Classification System (RIVPACS)-type multitaxon distribution models that, when applied to the biological survey data routinely collected in support of water-quality monitoring programs, can quantify the regional biodiversity status of hundreds of taxa. We used models developed for 2 stream data sets (North Carolina and the Mid-Atlantic Highlands, USA) to illustrate the potential of this approach. The models were calibrated with data collected from sites considered to be in reference condition and predict how probabilities of capture for each taxon in a data set vary across natural environmental gradients. When applied t...