Population Assessment of the Scott Riffle Beetle, a Kansas Endemic Species

The Scott Riffle Beetle (Optioservus phaeus) is listed as an Endangered species in Kansas and is under review for federal listing under the Endangered Species Act.  Wide-scale surveys in the 80’s and 90’s of spring habitats in Kansas, Nebraska, Colorado, Wyoming, and New Mexico indicate that the species is restricted to one small spring system in Scott State Park, Scott County, KS.  The only study on this species was conducted in 1985.  As a result, little is known about its life history and population dynamics.  The objective of this study was to update the status of the Scott Riffle Beetle population and assess current threats to its persistence.  Random benthic sampling, conducted using Surber samplers (0.09 m²), determined that densities for larvae and adult beetles was 64.71 and 3.24 individuals per m², respectively.  Both larvae and adults preferred cobble and gravel substrates.  Bi-monthly sampling will be conducted throughout 2016 to improve our understanding and conservation of this isolated species.