Summer Habitat Use of Female Mule Deer in Oregon

Mule deer (Odocoileus hemionus hemionus) populations have been declining throughout their range and loss or deterioration of habitat has been associated with observed trends. An understanding of the relative importance of landscape characteristics in affecting mule deer distribution will allow wildlife managers that alter habitat to make predictions regarding future use by mule deer, which is likely to influence mule deer population size and recruitment. We radio-marked 376 adult female mule deer with global positioning system-collars from 2006-2012 in south-central Oregon, USA, to evaluate summer habitat use. We used multiple linear regression to develop a resource utilization function (RUF) model for mule deer to relate landscape characteristics to the height of a utilization distribution estimated with a Brownian bridge movement model. We validated the predictive capacity of the RUF model with locations from an independent dataset of 95 deer that summered within our study area. Our best model describing mule deer habitat use included 5 covariates: overstory canopy cover, slope, distance to forest edge, distance to intermittent or perennial streams, and distance to dirt roads. Predicted intensity of use peaked at roughly 40% canopy cover and decreased with increasing slope and distance from forest edge. Predicted use was greater closer to streams and decreased, albeit slightly, with increasing distance from dirt roads. Model validation revealed our model predicted summer habitat use by mule deer very well. Our results provide a basis for predicting effects of future land management actions on mule deer habitat use on summer range. Forest management prescriptions that maintain canopy cover around 40% and create forest edge may benefit mule deer in south-central Oregon and other forested ecosystems, particularly if these prescriptions are implemented on areas with gentle slopes and access to streams. (c) 2019 The Wildlife Society.