Effects of Subterranean Limestone Sinks and Agricultural Development on Benthic Macroinvertebrate Communities of Canyon Creek (Wyoming)

Abstract

This study documented and assessed benthic macroinvertebrate communities on a section of Canyon Creek through Tensleep Preserve in Washakie County, Wyoming, USA. Data for these communities are compared with previous samples collected downstream on agricultural land, as well as upstream and downstream from two subterranean, limestone sinks on the preserve. A shift from Plecoptera, Coleoptera, and Ephemeroptera to mainly Ephemeroptera to mainly Trichoptera was observed from the uppermost to the lowermost sites; Chironomidae and Diptera dominated the previously sampled section. High proportions of scrapers in sampled communities on the preserve beginning downstream of the upstream sink system suggested a prevalence of autochthonous detritus over allochthonous detritus at these sites. Macroinvertebrate community compositions and calculated metrics indicated high water quality for sites on the preserve and lower water quality for the agriculturally impacted sites. Ten taxa recorded from samples between the subterranean sinks were not recorded elsewhere. The mayfly Ameletus validus was abundant at the exit of the upper sink system at which the substrate was lined with irregular limestone slabs, and this taxon may be limited to the interior of this sink. Neothremma is identified as a feasible indicator taxon for climate change.