Fuels Reduction in a Western Coniferous Forest: Effects on Two Sympatric Ungulates and their Habitat

We evaluated effects of an experimental fuels reduction program on elk, mule deer, and their habitat at the Starkey Experimental Forest and Range (Starkey) in northeastern Oregon. From 2001 to 2003, 26 stands of true fir and Douglas-fir that suffered high rates of mortality from an outbreak of spruce budworm were selectively thinned (spring or summer) and burned (fall) while 27 similar stands were left untreated to serve as experimental controls. We used location data for elk and mule deer collected during spring (1 April–14 June) and summer (15 June–31 August) of 1999–2006 to compare use of treated and untreated stands through time and to evaluate effects of topography, roads, weather, interspecific competition, and stand size and shape on use of treated stands. In addition, we estimated percent cover, percent digestibility, and percent nitrogen (%N) of 16 important forage species in treatment and control stands at Starkey during spring and summer of 2005 and 2006. During spring, female elk selected burned stands and avoided control stands when determining where to establish home ranges. Use of treated stands by elk in spring, however, was not strongly related to environmental variables considered in our study. Conversely, in summer, female elk selected control stands and either avoided or used burned stands proportional to their availability. Also in contrast to results for spring, use of treated stands by elk in summer was strongly influenced by topography, proximity to open roads, stand size and shape, and competition with cattle. Patterns of stand use by female mule deer did not change significantly following fuels reduction, and mule deer avoided or used all stand types proportional to their availability in both seasons. Patterns of stand use also differed substantially between female and male elk. During spring, females selected older (4-year old) burns, whereas males avoided all treated stands. In addition, control stands were avoided by females but selected by males during spring. During summer, however, control stands were selected and treatment stands either avoided or used in proportion to their availability by both sexes. Finally, the influence of environmental variables such as topography and proximity to roads on stand use by elk differed markedly between the sexes in both seasons