Reconstructing the natural distribution of individual unionid mussel species and species diversity in wadeable streams of Illinois, USA, with reference to stream bioassessment

Abstract

AbstractFreshwater mussels are considered one of the most imperiled aquatic species groups in the USA. One of the challenges in protecting and restoring mussel biodiversity effectively is a lack of understanding of their natural distributions at relevant spatial scales. Without this information, assessing the current status of individual species and overall biodiversity or evaluating restoration success is difficult. We compiled records for 45 mussel species and a range of natural environmental variables describing climate, geology, soil, land cover, and watershed topography in Illinois wadeable streams. We used reaches (segments between 2 neighboring tributaries) as the basic spatial unit of the stream network for modeling species distributions with Maxent. We applied these models statewide to all identified wadeable reaches. Stacking the predictions of individual models yielded an estimate of species richness for each reach. The estimates were compared with observed richness from 2 sets of independent s...