Enigmatic Extinction in a Boreal Toad Population in Northwestern Montana

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The amphibian chytrid fungus Batrachochytrium dendrobatidis has been implicated in boreal toad declines, although its overall effect on population dynamics is complicated by interactions with changing habitat conditions, population isolation, and other environmental stressors.

USGS researchers conducted mark-recapture studies of boreal toads from 2003 through 2018 at the Lost Trail National Wildlife Refuge in northwestern Montana to examine dynamics of this toad metapopulation. Estimates of male and female abundance decreased dramatically over the 16 years. Researchers found no evidence that disease affected male toad survival but detected striking decreases in recruitment of new males to the population, leading to a near-extinction event. Restoration of historical hydrology within the refuge likely adversely affected amphibian breeding habitat, and researchers hypothesized that these changes interacted with disease, life history, and other factors to restrict recruitment of new individuals to the breeding population over time. Results point to challenges in understanding and predicting drivers of amphibian population change. 

McCaffery, R.M., Russell, R.E., Hossack, B.R., 2021, Enigmatic near-extirpation in a boreal toad metapopulation in northwestern Montana: Journal of Wildlife Management, online, https://doi.org/10.1002/jwmg.22054.

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Date published: November 27, 2017
Status: Active

Wildlife Ecology and Conservation Biology Team (FRESC)

Wildlife respond to changes in their environment, some of which are dramatic and others subtle. To fully understand the factors that drive changes in populations and communities, we need better information on wildlife ecology in natural and human-altered landscapes. We conduct research and provide technical assistance to address applied questions about the ecology and conservation of wildlife...

Contacts: David S Pilliod
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Date published: November 19, 2020

Mark-recapture data for a boreal toad metapopulation at the Lost Trail National Wildlife Refuge, Montana (2003-2018)

From 2003-2018, USGS researchers and collaborators conducted mark-recapture studies of the boreal toad at the Lost Trail National Wildlife Refuge in northwestern Montana, USA. The datasets included here contain information on individual toad capture history, body size, and disease status. These data were collected annually over the 16-year period at up to 11 breeding sites per year on the