9th International Deer Biology Congress

AUTHORS: Marcus E. Blum, Department of Natural Resources and Environmental Science, University of Nevada Reno; Kelley M. Stewart, Department of Natural Resources and Environmental Science, University of Nevada Reno; Kevin Shoemaker, Department of Natural Resources and Environmental Science, University of Nevada Reno; Thomas Dilts, Department of Natural Resources and Environmental Science, University of Nevada Reno; Cody Schroeder, Department of Natural Resources and Environmental Science, University of Nevada Reno and Nevada Department of Wildlife; Mitchell Gritts, Nevada Department of Wildlife

ABSTRACT: Migration is an important ecological phenomenon that allows ungulates to increase their exposure to high quality nutrients throughout the year. Although much is known about ungulate migration strategies, causes of migration, and habitat selection on seasonal ranges; few studies have identified those variables that are selected within migratory corridors. Additionally, there is limited information regarding how wildlife managers should account for shifts in corridors caused by seasonal and annual changes in resource availability and climatic conditions. To address this, we examined movement patterns and resource selection along migration routes to understand the effects of environmental stochasticity on corridor selection and the habitat preferences within the migration corridors of female mule deer, Odocoileus hemionus. We captured and applied radio collars to female mule deer (n=98) on their migratory pathway in the Pequop Mountains of eastern Nevada from 2012-2017. We used Brownian Bridge Movement Models to delineate stopover sites for each individual during seasonal migrations. We then used a machine learning analysis, random forest, to determine which climatic and environmental variables individuals selected across seasons in stopover locations and along movement paths within the migration corridors through a step-selection framework. We also compared corridors annually to determine the differences that existed due to environmental stochasticity and if corridors shifted in response to these environmental changes. Our research will benefit scientists by describing mule deer habitat selection within different parts of migration corridors which will allow them to identify high priority zones along migration routes where no collar information is available. It will also give managers a better understanding of environmental impacts on migration corridor selection as well as how corridors change in a stochastic environment. This research will assist managers with the conservation of vital corridors for migratory ungulates and address the importance of managing for larger and multiple corridors across the landscape.