Response of mule deer to habitat modification near natural gas development

Mule deer ( Odocoileus hemionus ) are known to shift habitat use in response to environmental modifications, including those associated with energy development. Their specific behavioral responses, however, and capacities to habituate to particular aspects of energy development have not been effectively studied. We examined mule deer response to habitat alteration near natural gas wells in Las Animas County, Colorado, USA in 2008—2010, an area experiencing development for extraction of natural gas. We created 10-1 ha openings in forests adjacent to 10 wells by removing standing trees in 2008, with concomitant establishment of 10 1-ha control sites adjacent to the same wells. On each site, we estimated deer use, indexed by pellet density, before and after tree removal. Concurrently, we measured plant production, cover, nutritional quality, species composition and biomass removed by deer and other large herbivores. Species richness and diversity and graminoid and forb cover and biomass increased on cut sites following tree removal. Use increased following tree removal on cut and control sites, but was greater on cut sites in 2010. Herbivores removed negligible quantities of vegetation on control sites in both years, suggesting that control sites may have been used primarily for concealment. Mule deer demonstrated the behavioral capacity to habituate to habitat modifications and other environmental changes associated with development for the extraction of energy. Managing forage and habitat availability appears to have the potential to affect the type of response and degree of habituation by mule deer to such development.