Case Study: Upland Ponds Provide On-Site Mitigation for Bat Habitat along American Electric Power’s 765-kV Powerline ROW in the Appalachian Mountains, USA

Abstract

Initially, mitigation for protected species in the United States was project-specific, in-kind, and on-site, benefiting local populations of focal species. Recent mitigation policy uses in-lieu fees and mitigation banks, consolidating mitigation at large off-site locations, targeting regional population. This is true for the Indiana bat (Myotis sodalis), a species that roosts in trees and forages along many types of woodland edges. Drinking water is essential but considered ubiquitous and rarely factored into mitigation. In high-relief areas, runoff is rapid, precipitation is low, and evapotranspiration is high in late summer, limiting drinking pools for lactating females and juveniles. In Virginia’s Ridge and Valley region, our on-site mitigation paired ponds, roost boxes, and edge foraging habitat along a new electric transmission line right-of-way (ROW). During mitigation, white-nose syndrome (a fungal disease) decimated populations of this and four additional species of bats, which we included in analyses. Mitigation metrics were abundance, presence of focal species, species richness, and species diversity. The Indiana bat was known regionally, and an adult male was captured pre-construction along the ROW but not at mitigation sites; the species was recoded acoustically at a mitigation site post-construction. For other focal species, abundance (total and reproductive females), was dramatically greater post-mitigation. Species richness and diversity increased severalfold post-mitigation.