A habitat risk assessment and breeding site projection for Slackwater Darter (Etheostoma boschungi) in Limestone Creek

Abstract

Catalysts for species decline are difficult to identify and are rarely single. The use of predictive models that incorporate multiple factors have proven useful in recognizing major drivers of species declines in multiple systems. In this study, a geographic information systems model was used to evaluate factors contributing to the decline of the Slackwater Darter throughout its distributional range. The species has suffered a precipitous decline, and it is essential to understand conservation threats and to prioritize habitat for restoration and protection. Variables incorporated into the habitat model included land use/land cover, soil and geographic descriptions, hydrologic variables, and others. Habitat where the species has become extirpated or undetectable by conventional sampling was compared to extant populations to identify factors contributing to population loss. Land cover and farm pond density were identified as potential drivers of extirpation. Finally, a model of suitable habitat was used to predict spawning areas in Limestone Creek, where the species was recently discovered. This model identified eight new spawning sites for Slackwater Darter in the system where breeding sites were unknown, and was 44% accurate in its predictive capabilities; however, positive detections were noticeably clustered and indicate the likely influence of some untested variable. With the information provided by this analysis, a framework for habitat protection can be created to assist with restoration of this species.