Movement and Surrounding Community of the Understudied and Endangered Ligumia Recta (mollusca , Unionidae)

Native freshwater mussels (unionids) are indicators of water quality, with unique behaviors and movement patterns. Many of these species are endangered, yet basic movement and co-occurring community data are lacking for successful unionid conservation. In this study, movement, community, and habitat use among Ligumia recta, an endangered unionid in Michigan, were analyzed across four rivers in central Michigan. The effects of sex, community, substrate use, and other abiotic factors on the movement and occurrence of L. recta were quantified. 24 L. recta individuals were found with variable male:female ratios and were monitored bi-weekly. Over the recapture period, L. recta moved an average minimum convex polygon of 1.43 m2 per day but was variable among rivers. 19 unionid species were found occurring with L. recta; ~13 species in the same river reach as L. recta and ~5 species in closer proximity to L. recta. The tribe Lampsilini most often occurred in close proximity to L. recta. This study identified basic movement and occurrence patterns of L. recta and provides a better understanding of the status of L. recta in Michigan. Our study highlights useful methods in understanding imperiled unionids, expanding the knowledge of their movement, behavior, community assemblages, and habitat use.