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University of Nevada Reno (2021)

Habitat Selection of Female Desert Bighorn Sheep : Tradeoffs Associated with Reproduction

Blum, Marcus Earl

Titre : Habitat Selection of Female Desert Bighorn Sheep : Tradeoffs Associated with Reproduction

Auteur : Blum, Marcus Earl

Université de soutenance : University of Nevada Reno

Grade : Doctor of Philosophy in Ecology, Evolution, and Conservation Biology 2021

Animals select habitat types that enhance their ability to survive, reproduce, and therefore enhance reproductive fitness. Selection for specific habitat types often varies within populations based on season, habitat availability, sex, age, reproductive status, and other characteristics. Therefore, we expect habitat selection to be changing throughout the lifetime of an individual to meet the metabolic and nutritional constraints of specific periods. For instance, reproductive status, especially provisioning dependent young, is commonly linked to changes in behavior of female ungulates that results in variation in resource selection around parturition. Around parturition, female ungulates are commonly linked to tradeoffs between maternal nutritional condition and survival of offspring. These tradeoffs are hypothesized to take place because they allow females to increase their reproductive fitness by enhancing the likelihood that their offspring survives to recruitment. Understanding these shifts in habitat selection are essential to proper management and the conservation of ungulates.I was interested in documenting the variation in habitat selection of female bighorn sheep (Ovis canadensis nelsoni) around parturition, in addition to characterizing composition and quality of diets of females based on time of year and the provisioning status of individuals. This period is critical to female ungulates because their choice of habitat components also influences survival of their offspring and ultimately, the female’s reproductive fitness. I used 2 populations of desert bighorn sheep in west-central Nevada, to study how ungulates adjust habitat selection around parturition. I investigated habitat selection of female desert bighorn sheep from the beginning of their third trimester until weaning of offspring. Furthermore, I investigated how females selected parturition sites and neonates selected bed sites immediately following birth. To accomplish this goal, I captured adult and neonatal bighorn sheep and equipped individuals with very high frequency (VHF) and global positioning system (GPS) radio-collars from 2016 to 2018. Additionally, I collected fecal samples from female bighorn sheep throughout the year and within the parturition season, based on pregnancy and provisioning status of individuals.


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