Ellipse (Venustaconcha ellipsiformis) and Spike (Eurynia dilatata) Status and Recommendations for the Chicago Wilderness Area

The goal of this project was to use Bayesian modeling techniques in a Bayesian Decision Network to estimate the best method of reintroduction of Ellipse (Venustaconcha ellipsiformis) and Spike (Eurynia dilatata) to watersheds within the Chicago Wilderness Area (CWA), and assess current population status of each species within the region. A combination of long-term timed search data, targeted mussel density sampling in 2018, cost assessments, and survey data gathered from experts was used to populate models and determine optimal reintroduction strategies for each species in two rivers, the West Branch DuPage River and South Branch Kishwaukee River. An effort was also made to determine the importance of density vs presence data collection when building Bayesian Decision Networks, to inform future sampling needs. Additionally, models were evaluated for sensitivity to input and the impact of expert opinion bias was assessed. Recommendations are presented for each species in our two target watersheds, and future steps needed to facilitate restoration are discussed.