Forest Preserves of Cook County

Abstract Multi‐species approaches provide valuable insight for conservation planning, yet most studies focus on only one species while generalizing across taxa. Here, we employed 5–14 microsatellite DNA loci to evaluate population genetic patterns and future vulnerability for a freshwater turtle assemblage distributed across north‐eastern Illinois. Focal species (Emydoidea blandingii, Clemmys guttata, Chrysemys picta and Chelydra serpentina) differ in conservation status as well as in ecological and life‐history traits, which modulate gene flow across heterogeneous landscapes. We hypothesized (1) common and more ubiquitous species (C. picta and C. serpentina) would exhibit higher levels of genetic connectivity compared to species more restricted in distributions and with an elevated conservation status (E. blandingii and C. guttata) and (2) endangered species exhibit a greater loss of future genetic diversity. We found that genetic patterns varied considerably among co‐distributed species. Endangered species had lower levels of genetic diversity and gene flow, more pronounced genetic structure and a higher risk of genetic drift compared to common species, thus supporting our hypotheses. The observed patterns are potentially attributable to life‐history and ecological traits and will affect the long‐term viability of the four species within a modified north‐eastern Illinois landscape. Our study is an important first step for understanding how landscape features and species‐specific traits interact to affect gene flow and population genetic structure within altered landscapes. It also underscores how multi‐species approaches can be informative for conservation actions.