Semester

Summer

Date of Graduation

2019

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Wildlife and Fisheries Resources

Committee Chair

Donald Brown

Committee Member

Jamie Schuler

Committee Member

Thomas Schuler

Abstract

Amphibians are facing global declines due to climate change, loss and degradation of habitat, invasive species, and disease. The Appalachian region of the eastern USA is a global biodiversity hotspot for salamanders, which are considered keystone species that influence nutrient dynamics in terrestrial and aquatic food webs. There are high rates of salamander endemism in the Appalachian region, with many species restricted to isolated, high elevation areas. The Cow Knob Salamander (Plethodon punctatus) is one such species. It is only found at elevations >675 m (most populations are above 900 m) on Shenandoah Mountain, North Mountain, and Nathaniel Mountain in the Valley and Ridge Province in eastern West Virginia and Virginia. A recent study found that P. punctatus may be one of the most vulnerable species of Appalachian salamander to climate change due to its narrow distribution and poor ability to acclimate to warmer temperatures. However, little research has been conducted on P. punctatus, and information is needed by land managers to guide habitat and species management actions. The purpose of my thesis was to quantify the influence of broad and fine-scale habitat characteristics and assess the influence of climate change and active habitat management using prescribed fire, on the distribution and abundance of P. punctatus.

In chapter 1, I provide background information on the causes of amphibian declines globally and in the Appalachian region, and information on the biology and conservation status of P. punctatus. I also summarize the goals of this research and give a summary of chapter topics.

In chapter 2, I created habitat suitability models to examine the climatic and geological factors contributing to the distribution of P. punctatus. I also projected mid and end-of-century changes in habitat suitability as the climate warms. I found that the distribution of P. punctatus is largely driven by variables that contribute to a cool, moist climate. Elevation, heat load index, slope, hillshade, and mean annual temperature largely explain where this species is found. I projected that the climatic niche for P. punctatus will mostly disappear by mid-century, with a continual decrease through the year 2100. However, I identified areas of climate refugia that may, at least temporarily, allow for the persistence of this species.

In chapter 3, I examined the influence of forest characteristics and habitat management using prescribed fire on terrestrial salamanders on Shenandoah Mountain. I surveyed salamanders in 4 burn units that differed in burn history as well as adjacent control areas, using nighttime visual encounter surveys and cover board surveys. I compared the response of P. punctatus with the more common and widespread Eastern Red-Backed Salamander (Plethodon cinereus). I found that areas that have more talus, are on the west side of Shenandoah Mountain, and have higher canopy cover had a higher abundance of P. punctatus and P. cinereus. Abundance was lower for P. punctatus in burned areas, but I was unable to draw conclusions about burn severity. A high-severity burn was negatively correlated with P. cinereus abundance, but there was not a significant effect for low-severity burns.

My findings in Chapter 2 are consistent with previous studies that project P. punctatus will lose most of its climatic niche by the end of the 21st century. The results of Chapter 3 indicate potential short-term negative impacts of prescribed fire on woodland salamanders in central Appalachia, particularly when burning results in reduced canopy cover. This thesis contributes to the general ecological knowledge for P. punctatus and provides land managers with information that can be used for proactive conservation of the species.

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