Establishing ecologically relevant management boundaries: linking movement ecology with the conservation ofScaphirhynchussturgeon

Abstract

We investigated the environmental life history of widely distributed threatened and endangered sturgeons in large rivers of the central United States that experience different regulatory regimes and management priorities. Using microchemistry techniques, our goal was to assess how to improve species conservation by dampening the incongruity that often occurs between management and species’ ecological requirements, particularly at large spatial scales. Pallid sturgeon (Scaphirhynchus albus), shovelnose sturgeon (Scaphirhynchus platorynchus), and their hybrids were analyzed for88Sr and44Ca and related to a geographically relevant range of Sr:Ca values for the Missouri and Mississippi rivers to quantify large-scale environmental history. We found natal origin of 81% of all wild sturgeon collected was the lower Missouri River. Pallid and hybrid sturgeon used the middle and upper Mississippi rivers more frequently as they aged, whereas shovelnose sturgeon occupied the lower Missouri River more often throughout life. Our results highlight a mismatch between conservation boundaries and sturgeon river use. Managers should consider expanding current protections for pallid sturgeon to include the unprotected sections of the Mississippi River and that research and conservation actions consider the importance of Mississippi River habitats to Scaphirhynchus sturgeon throughout their life history. Our findings have implications for conserving wide-ranging riverine species at large spatial scales using the framework described here.