Date Awarded

2022

Document Type

Thesis

Degree Name

Master of Science (M.Sc.)

Department

Biology

Advisor

Matthias Leu

Committee Member

Randolph Chambers

Committee Member

Robert Isdell

Committee Member

Drew LaMar

Abstract

Frog and toad, or anuran, species are currently declining globally. One of the major causes of this decline is habitat loss due to human development. Regulations in place throughout the United States protect habitat for anurans but typically focus solely on pro-tecting breeding habitat rather than the habitat anurans require throughout their annual migration cycle, or yearly movement between breeding and overwintering habitat. In ad-dition, the annual migration cycle of anurans is currently understudied, and we do not have the information necessary to effectively protect these species’ habitat. In Virginia specifically, riparian buffers, or forest habitat directly adjacent to lakes, rivers, creeks or wetlands, only extend to 30 m at select “Resource Protection Areas” (RPA) determined by state and local governments. RPAs are not necessarily designed with anuran conser-vation in mind. In order to create effective anuran conservation policies, we must learn more about their terrestrial habitat use and compare this habitat use to current policies.My goal was to fill the anuran migration knowledge gap for Virginian anuran species by examining their distribution and terrestrial habitat use. I utilized transect surveys at seven study sites in Southeast Virginia on a weekly basis for one full year to record anuran dis-tributions. Transects at these sites were placed 0 m, 25 m, 50 m, 75 m, and 100 m from the terrestrial ecotone of the breeding habitat. I then compared the locations of these de-tections in relation to the breeding locations and to the locations of ephemeral water sources to determine which species were found closest to water when not at their breed-ing site. Most of the anuran species I detected traveled beyond the 30-m RPA buffer throughout the year. I also found that while some species, such as the American Toad (Anaxyrus americanus americanus), spread out into forest habitat after leaving their breeding habi-tat, more aquatic frogs such as the coastal plains leopard frog (Lithobates sphenocepha-lus utricularius) and green frog (Lithobates clamitans) stayed close to their breeding habi-tat throughout the year. However, even these species were still detected over 100 m from their breeding habitat, indicating that individuals in these species may be making short trips away from their breeding habitat before wintering near the breeding site. When aquatic frog species were detected, they were often found closer to ephemeral water than less aquatic toad species. The proximity of anuran species to ephemeral wa-ter sources along with observations of anuran species 100 m from their breeding location indicates that current RPAs in Virginia should be expanded and include ephemeral water sources in order to preserve terrestrial anuran habitat.

DOI

https://dx.doi.org/10.21220/s2-hdjr-k270

Rights

© The Author

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