Habitat Relationships of Red-Backed Salamanders (Plethodon Cinereus) in Appalachian Grazing Systems

Abstract

Woodland salamanders (Plethodon spp.) are important contributors to biodiversity and trophic processes within Appalachian forests. However, altered microclimates and vegetation structure after timber harvest, such as increased soil temperatures and reduced ground cover, can result in long-term population declines of some Appalachian salamanders. If changes in forest structure following harvest alter salamander habitat quality, conversion of forests to pastures or meadows presumably would cause even more severe and permanent impacts. However, woodland salamander responses to Appalachian grazing systems are virtually unknown. Herein, I present results of research measuring responses of red-backed salamanders (Plethodon cinereus) to silvopasture and meadow conversion treatments in southern West Virginia. Artificial coverboards searches within northern red oak (Quercus rubra) silvopasture (6.7 m2/ ha basal area), hay meadow (>5 years after forest conversion), forest edge, and reference forest plots yielded 2,675 salamanders between May 2004 and November 2005. Because abundance differed significantly between years, I conducted analyses of the relationships between salamander presence and abundance and habitat characteristics separately for 2004 and 2005. Models that contained percent herbaceous vegetation and treatment type best predicted salamander presence and abundance in both 2004 and 2005. Salamander presence and abundance was positively associated with percent herbaceous vegetation and negatively associated with increasingly disturbed treatment types, such as grazed meadows and silvopastures. Ungrazed meadows had the highest average percent cover of herbaceous vegetation, followed by woodland edges. Dense herbaceous vegetation may mitigate the loss of canopy cover in habitats that are not regularly grazed by livestock, such as silvopastures and grazed meadows. I found that salamander physiological condition and adult sex ratios did not differ significantly among treatment types, whereas hay meadows had significantly more adults than other treatments. My results indicate that red-backed salamanders may be more resilient to changes in forest cover and structure than previously thought, however populations within meadow habitats may not represent healthy populations in their age structure. My Mark-recapture results indicate that salamanders in both meadows and silvopastures were dispersers from woodland habitats, rather than resident populations. Area-constrained searches showed that silvopasture and meadow habitats were unsuitable for residence of red-backed salamanders, but that salamanders may be able to use these habitats in the presence of artificial cover objects.