A Comparison of Genetic Diversity between Sympatric Populations of the Endangered Winged-Mapleleaf (Quadrula fragosa) and the Pimpleback (Amphinaias pustulosa) in the St. Croix River, U.S.A

Assessing genetic variation in species of conservation concern is critical for developing sound recovery strategies. In this study, we compared sympatric populations of two related species, the endangered Quadrula fragosa (Conrad, 1836) and its common relative Amphinaias pustulosa (Lea, 1831), using standard genetic parameters such as allelic richness, heterozygosity, and effective population size. Our primary aim was to determine if a small population size and isolation from conspecifics had negatively affected the genetic diversity of this population of Q. fragosa. By comparing the endangered species to a related and sympatric, common species we can assess the rare species for genetic effects associated with reduced population size, and in addition, develop management targets for what a recovered Q. fragosa population looks like genetically. Examination of eight microsatellite loci indicated that Quadrula fragosa exhibited reduced genetic variation when compared to A. pustulosa at all measures,...