Changes in Selection of Resources by Newly Introduced Bighorn Sheep

Wildlife movements through landscapes are influenced by the seasonal availability of resources including: food, water, cover, and space. Life-history characteristics of animals including sex, age, and reproductive status affect how animals use the landscape. Naïve animals introduced into a new area are required to learn the distribution and abundance of vital resources to subsist, thrive, and reproduce. I hypothesized that movement patterns and habitat selection by animals translocated to a new area would change over time, reflecting acclimation. I investigated how movement patterns and selection of resources by newly introduced California bighorn sheep (Ovis canadensis californiana) varied during two years following introduction into a new habitat during 2020-2021. I tested the hypothesis that newly introduced bighorn sheep would shift movements and patterns of seasonal resource selection between the first- and second-year following release as they become familiar with their new habitat and locations of resources. I used Brownian Bridge Movement Models to understand changes in habitat use, and resource selection functions to understand changes in selection of resources by bighorn sheep between years. My findings indicated that movement patterns were largely distributed throughout the study area during the first year, and exhibited a shift in habitat use and resource selection in year two as animals acclimated and became familiar with the distribution of resources. Steep slopes and high elevations were consistently selected during both years. Study animals selected areas close to water sources the first year, but moved further from water sources in the second year when they were familiar with the distribution of water in the study area. Shifts in distribution of sheep likely resulted from learned knowledge associated with the distribution of resources. Those findings show the importance of distribution of resources, especially the availability of steep slopes and water in arid environments to understanding movement patterns by newly introduced bighorn sheep. Further, my findings indicate that sheep were more widely distributed across the range when adult females were newly introduced and naive to their new habitat