Possible climate-induced shift of stoneflies in a southern Appalachian catchment

Abstract

I collected stoneflies (Plecoptera∶Perlidae) across gradients of elevation and stream size within a 274-km2 catchment in Great Smoky Mountains National Park in 1977–1978. I repeated collections of 2 focal species in 2006. Regional climate warmed ∼0.72°C during the interval. Models of stonefly responses to temperature change predicted uphill shifts of 100 to 140 m. One abundant species, Acroneuria abnormis, shifted uphill 60 to 250 m depending on the measure of range shift. Uphill shift was strongly supported by logistic regression and information criteria. The less common Eccoptura xanthenes shifted −61 to +105 m based on several metrics, and no regression model was supported. Data for E. xanthenes, confounded by landscape change and detectability issues, were inadequate to support any conclusion about range shift. Stream acidity has shifted downslope in recent years, counter to the observed uphill shift by A. abnormis, a pattern that supports increasing temperature as the determinant of range limits for this species. Rate of uphill shift by A. abnormis (median elevation, +24 m/decade) was similar to changes by plants and animals in other places.