Document Type

Thesis

Date of Degree Completion

Winter 2017

Degree Name

Master of Science (MS)

Department

Biology

Committee Chair

Daniel Beck

Second Committee Member

Robert Hickey

Third Committee Member

John Rohrer

Abstract

Fire is a dominant force in the Pacific Northwest that shapes ecosystems and influences wildlife, yet little is known of its effects on local predators. Northern Pacific rattlesnakes (Crotalus oreganus) comprise an excellent model to investigate how fire may influence wildlife because they are important predators that contribute to controlling prey populations, but are also unable to readily escape from wildfires. We developed a novel technique to assess growth rates of rattlesnakes by using digital photography to analyze differences in widths of their rattle segments laid down over time. We compared growth rates of rattlesnakes in habitats that were affected by recent fires with those inhabiting areas unaffected by recent fires. The snakes from the Methow Valley region, in dens affected by the Carlton Complex wildfire of 2014, showed no difference in growth rates before as compared to after the fire, which may be because those snakes have not had sufficient time to respond to potential changes in their prey populations brought about by fire. Methow snake populations from dens affected by fire, however, showed a size structure that was significantly skewed toward smaller individuals than those in dens outside the wildfire area. Snakes that were tracked using radio telemetry in different burned areas did not show any avoidance of burned habitat during the tracking period.

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