Date of this Version
The Prairie Naturalist 51:68-76; 2019
The plains topminnow (Fundulus sciadicus) is an endemic Great Plains stream fish that has experienced declines in geographic range and local abundance. Due to these declines, the species has been considered for federal protection and designated with conservation status in states throughout its historic range. The reasons for declines are likely similar to hypothesized factors for other endemic stream fish declines in the Great Plains. To investigate potential limiting factors a suite of 17 historic sites with reintroduced plains topminnow populations across Nebraska were evaluated for current populations and if plains topminnow were absent, additional fish were introduced. These sites were sampled for plains topminnow persistence with fall backpack shocking in 2014-2016. A suite of 10 abiotic and biotic variables were selected a priori, based on previous research and guidance from fisheries personnel with working knowledge of the species, to evaluate potential factors that regulate populations of plains topminnow following reintroductions. Variables were combined to develop models based on plains topminnow life history characteristics, trophic interactions, and habitat requirements. Competing models were compared and variables were prioritized using an information theoretic approach. Limited backwater pool habitat and high predator fish abundances have the greatest relative importance in limiting reintroduced plains topminnow populations. Future management efforts to reintroduce plains topminnow should prioritize locations with these available habitats and communities and habitat renovation efforts should focus on these identified parameters.