Document Type

Thesis

Date of Degree Completion

Spring 2017

Degree Name

Master of Science (MS)

Department

Biology

Committee Chair

Dr. Daniel Beck

Second Committee Member

Dr. Alison Scoville

Third Committee Member

Dr. Scott McCorquodale

Abstract

Elk (Cervus elaphus) are generalist herbivores, exploiting a variety of environments. I studied habitat selection and sexual segregation of the Colockum elk herd in central Washington. I used a resource selection probability function (RSPF) to evaluate habitat use by males and females during summer and winter seasons. I assisted Washington State Department of Fish and Wildlife (WDFW) in capturing and placing GPS collars on males, and used an existing GPS dataset from females to investigate the extent to which sexual segregation was occurring in the Colockum herd. During summer, males selected steep slopes on north, west and south aspects at high elevations near water sources and roads. They selected vegetation with high photosynthetic activity modeled using a normalized difference vegetation index (NDVI) in forested and semi desert land cover types. During summer, females selected gentler slopes than males, and with primarily southwest aspects, also at high elevations near water sources and roads in forest and semi desert cover types. Females differed from males in referring to areas where vegetation had lower photosynthetic activity and shrub land cover. During winter, males selected moderate slopes with south and northeast aspects at moderate elevations near roads in forested, semi desert and shrub land cover types. During winter, females also selected moderate slopes, but with a broader variety of aspects than males did (south, west, and north). Like males, females selected shrub land, semi desert, and forest cover types at moderate distances from water. I concluded that predation risk, scramble competition and forage selection hypotheses are capable of explaining the differential use of habitats between males and females, depending on the season.

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