Empirical evidence for declines in muskrat populations across the United States

Abstract

ABSTRACTMuskrats (Ondatra zibethicus) are native to North America and widely distributed across the continent. Recent evidence and anecdotal reports suggest that muskrat populations may be declining; however, this assumption has not been rigorously evaluated. We used 42 years of muskrat harvest data (1970–2012) from 37 states to examine trends in muskrat populations across the United States. Annual harvest data are highly correlated with annual pelt prices, which must be controlled for prior to analysis. After adjusting harvest data for the effects of current‐year and 1‐year‐lagged pelt prices, we found strong support that muskrat populations have declined during this period. The slope of decline appeared stronger in the southeastern states and less pronounced in the midwestern states. Our results suggest that wildlife managers should consider active management programs for muskrat populations in regions where declines are observed. Along with recording annual muskrat harvest data, managers should also use rigorous surveys to identify changes in muskrat population abundances. Additionally, our study highlights the need for future research directed at revealing mechanistic explanations for synchronous muskrat declines across this large spatiotemporal scale. © 2017 The Wildlife Society.