Potential Influence of Competition on Local Occurrence of the Cow Knob Salamander (Plethodon punctatus) and White-Spotted Slimy Salamander (Plethodon cylindraceus)

William D. Flint^1,*, Donald J. Brown^2,3, Amelia M. Hansen¹, and Jena M. Staggs³

¹Department of Biology, James Madison University, MSC 7801, Harrisonburg, VA 22807. ²Pacific Northwest Research Station, USDA Forest Service, Amboy, WA 98601. ³School of Natural Resources, West Virginia University, 1145 Evansdale Drive, 322 Percival Hall, Morgantown, WV 26506. *Corresponding author.

Northeastern Naturalist, Volume 33, Issue 2 (2026): 322–336

First published early online: 26 June 2026

Abstract
The Appalachian Mountains in eastern North America are a global biodiversity hotspot for woodland salamanders (genus Plethodon) and contain many range-restricted species endemic to areas of high elevation. Previous research indicates that interspecific competition could exert a strong influence on geographic distribution boundaries and local occurrence probabilities for high-elevation salamanders, but competition dynamics have not been assessed for most species. We investigated co-occurrence and competition dynamics between 2 large woodland salamanders that occur on Shenandoah Mountain in western Virginia and eastern West Virginia: the range-restricted Plethodon punctatus (Cow Knob Salamander) endemic to high elevations and the widespread P. cylindraceus (White-spotted Slimy Salamander). We performed salamander surveys along elevational transects across the zone of sympatry to estimate the relationship between elevation and relative abundance of each species and to assess if co-occurrence of the 2 species was random. We also performed laboratory experiments to characterize territorial behavior and determine factors that influenced probability of territory defense and invasion success. We found that relative abundance of Cow Knob Salamander and White-spotted Slimy Salamander increased and decreased with elevation, respectively, and the species were less likely to co-occur within the zone of sympatry than expected by chance. Our laboratory experiment indicated that White-spotted Slimy Salamanders were competitively dominant. Climatic changes on Shenandoah Mountain could increase competition pressure between the 2 species if the distribution and density of the White-spotted Slimy Salamander increases at the high elevations where the Cow Knob Salamander is currently most abundant

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