Boreal toad habitat selection and response to grazing

In recent decades, many amphibian populations have declined worldwide. Human-induced habitat disturbance and alteration have been cited as a dominate causes, which can interact with other stressors such as climate change and disease. In the majority of cases, however, mechanisms underlying declines are considered enigmatic; therefore, developing a better understanding of the individual and interactive factors threatening amphibians will be critical to prevent further population declines and species extinctions.

To investigate the possible effects of multiple stressors on amphibians, we will assess how livestock grazing individually and in conjunction with disease may affect boreal toad (Anaxyrus boreas) movement, habitat selection, and survival in the Bridger-Teton National Forest in western Wyoming.

In 2015, we used radio-telemetry to study the summer movements and habitat use of 61 adult boreal toads (40 male and 21 female) across sites varying in grazing intensity. Additionally, we swabbed individuals for disease and inserted passive integrated transponder (PIT) tags into 302 adult toads. We will analyze habitat selection at the micro- and macro-scales by comparing sites used by radio-tracked toads with paired and randomly selected sites. In 2016 and 2017, we will conduct recapture surveys to evaluate toad survival rates. We will also test swab samples for Batrachochytrium dendrobatidis (Bd) to evaluate disease status of boreal toads across several drainages.

Findings from this study will provide valuable information to several agencies working to improve management of toad populations in Wyoming. More broadly, by assessing how multiple stressors may interact to influence amphibian behavior, ecology, and habitat quality, our study design may provide a framework for future research evaluating causative factors in amphibian declines.



Gabe Barrile, M.S. candidate
Wyoming Cooperative Fish and Wildlife Research Unit
Department of Zoology and Physiology
University of Wyoming
Dept. 3166, 1000 E. University Avenue
Laramie, WY 82070
[email protected]

Project Lead

Gabe graduated from Bloomsburg University, PA in 2013, majoring in Biology. His undergraduate research focused on life-history trait evolution in Fowler’s toads (Anaxyrus fowleri ) on several Atlantic Coast barrier islands. Additionally, Gabe compared time-budgeting behavior between captive and free-ranging black-handed spider monkeys (Ateles geoffroyi ). After graduation, he taught marine ecology to middle school and high school students at the Chincoteague Bay Field Station near Wallops Island, VA.

Funding & Partners

Wyoming Game and Fish Department