Endemics and Invasives: a recent history of distributional range shifts in the fish fauna of the lower New River drainage, USA.

Invasive species are often central to conservation efforts, particularly when concerns involve potential impacts on rare, endemic native species. The New River drainage, which represents the upper reaches of the ancient Teays River, is delineated by Kanawha Falls, a well-documented zoogeographic barrier to fish distributions. The New River drainage begins in North Carolina, flows through western Virginia, and ends in southern West Virginia. The lower New River system in West Virginia is naturally depauperate of native fish species and it is nearly saturated with nonnative fish species: 32 natives including at least 8 endemics, and 62 nonnatives. Herein, we conducted time-series data analysis to examine chronological shifts in fish species distributions. Specifically, we documented range contractions of four endemic species in the lower New River system: Kanawha Minnow (Phenacobius teretulus), New River Shiner (Miniellus scabriceps), Appalachia Darter (Percina gymnocephala), and Candy Darter (Etheostoma osburni). We contrasted these findings with five nonnative species that have recently undergone rapid range expansions: Telescope Shiner (Notropis telescopus), Whitetail Shiner (Cyprinella galactura), Rainbow Darter (Etheostoma caeruleum), Roanoke Darter (Percina roanoka), and Variegate Darter (Etheostoma variatum). The endemic species are of conservation concern given limited distribution ranges and documented population declines. Although among-species comparisons of range shifts do not support causal inference, the documentation of changes in distribution ranges of endemic and invasive species are critical to inform conservation efforts.