Mule Deer Responses to a Pinyon-Juniper Removal

Mule deer (Odocoileus hemionus) are a large-bodied herbivore that is declining in abundance throughout the Intermountain West for a suite of reasons. One of these reasons is expansion of single-leaf pinyon (Pinus monophylla) and Utah juniper (Juniperus osteosperma) into sagebrush communities in the Great Basin. Pinyon-juniper woodlands are adept at outcompeting herbaceous vegetation that is crucial for mule deer. We administered a pinyon-juniper removal treatment on mule deer winter range in the Toiyabe Range of central Nevada to assess changes in resource selection and diet diversity of mule deer following the treatment. The pinyon-juniper removal treatment was conducted in autumn of 2018. We captured 36 adult female mule deer in winter of 2018 and 2019, deploying GPS collars and collecting fecal samples. My resource selection function analysis revealed that mule deer exhibited increased selection for annual vegetation, perennial vegetation, and tree cover following pinyon-juniper removal. These results lend support to the efficacy of pinyon-juniper removal treatments for mule deer management. I then compared diversity of mule deer diets before and after our treatment. Although dietary diversity declined following our treatment, the preferred winter forage of mule, antelope bitterbrush (Purshia tridentata), formed a substantially higher component of mule deer diets than before treatment