Date of Award

5-2014

Level of Access

Campus-Only Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Wildlife Ecology and Wildlife Conservation

Advisor

Aram J.K. Calhoun

Second Committee Member

Daniel J. Harrison

Third Committee Member

Malcolm L. Hunter, Jr.

Abstract

Amphibians are declining worldwide more rapidly than any other vertebrate group, including birds and mammals. In the Northeast, habitat loss and degradation are two of the most important factors leading to their endangerment. The Eastern Spadefoot (Scaphiopus holbrookii) and pure-diploid Blue-spotted Salamander (Ambystoma laterale) are two of the rarest and most poorly-understood amphibians in the region. From 2008 through 2011,I investigated the movements and habitat use of both species using a combination of pitfall trapping, radio-telemetry, and PIT tag technology coupled with logistic regression modelling and information theory. I recorded habitat data at 10 m and 1 m diameter circular plots centered on animal locations.

I monitored Eastern Spadefoot burrow emergence with the aid of continuously-running, stationary (but portable) PIT tag readers. On average, Eastern Spadefoots emerged on 43% of nights they were monitored. Emergence nights were warmer and more humid than nonemergence nights. Animals were also much more likely to emerge on a given night if they had emerged the night before. Eastern Spadefoot presence was positively correlated with percent cover of bare soil at the 10 m and 1 m scales, positively correlated with percent cover of gravel at the 10 m scale, and negatively correlated with percent cover of grass at both scales. Spadefoot burrow locations also had warmer soil than random locations.

To detect PIT-tag implanted Blue-spotted Salamanders in situ, on 34 separate occasions I used PIT telemetry via a modified PIT tag reader and scanned systematically within a 13.37 ha area surrounding a salamander breeding pool (~119 hours of survey time) and recorded 42 salamander detections. Salamanders used upland forest and wet meadow more often than their availability would predict. At the 10 m scale, salamander presence was positively correlated with percent cover of slash and negatively correlated with percent cover of grass, total basal area of trees, and relative humidity. At the 1 m scale, salamander locations had deeper leaf litter and moister soil than random locations. My results have improved the understanding of the ecology of these species and can be used to inform conservation and management strategies for them.

Share