9th International Deer Biology Congress

AUTHORS: Tanya M. Roerick, Department of Fish, Wildlife and Conservation Ecology, New Mexico State University, Las Cruces, NM; James W. Cain III*, U.S. Geological Survey, New Mexico Cooperative Fish and Wildlife Research Unit

ABSTRACT: Decades of fire suppression, logging, and overgrazing have altered the conditions of southwestern forests resulting in increased densities of small diameter trees and an overall increase in fuel loads. These increasing tree densities have been associated with decreases in biodiversity, reduced habitat quality, degraded foraging conditions for ungulates, and more frequent and severe wildfires. In response, land managers are increasingly implementing landscape-scale forest restoration treatments through the use of prescribed fire and forest thinning in an attempt to mitigate the risk of catastrophic wildfires and improve habitat conditions for a variety of wildlife species. Similar vegetation treatments are commonly implemented by wildlife managers specifically to improve habitat conditions for mule deer (Odocoileus hemionus). We monitored responses of female mule deer to forest restoration treatments and wildfires in northern New Mexico. Our specific objectives were to: 1) assess changes in abundance of key forage species; 2) estimate differences in forage quality; and 3) determine habitat selection patterns of mule deer in relation to recent wildfires, forest restoration treatments (including the time since treatments), and other habitat characteristics. Herbaceous forage biomass was greater in wildfire burned areas than prescribed burns, forest thinning, and untreated areas. Oak forage biomass was greater in wildfire burned areas compared to prescribed burns, forest thinning, and untreated areas. Thinned areas tended to have higher oak forage biomass than untreated areas. Mule deer selected for areas burned by prescribed fire and avoided wildfire burned and thinned areas less than 5 years old. Mule deer strongly selected for thinned areas >5 years old. At both the landscape and within home range scale, grasslands were avoided during all seasons, pinyon-juniper woodlands were selected for in winter, and oak vegetation and mixed conifer forests were selected during summer. Data collected during our study suggests mule deer benefit from recent prescribed burns and older forest thinning. The lack of selection for wildfire burned areas was unexpected given the differences in forage biomass observed. Knowledge of the short- and long-term effects of restoration treatments will provide managers with guidance for making informed decisions regarding implementation of vegetation treatments to benefit mule deer.