Spatio-temporal distribution of white-tailed deer (Odocoileus virginianus) relative to prescribed burns on rangeland in South Texas

Abstract

Overgrazing and fire suppression has left much rangeland in poor condition for various wildlife species. Prescribed fire is one range improvement practice used to restore degraded wildlife habitat. I determined the effect of prescribed fire on whitetailed deer (Odocoileus virginianus) spatial and temporal distribution, in the presence of cattle grazing. Three 40 ha patches, constituting 10% and 6% of the land area in the lesser and greater Yellow Bluff pasture, respectively, were burned in September 2005. To determine habitat use and distribution of deer relative to these burns 3 bucks and 3 does were netted from a helicopter and fitted with Global Positioning System (GPS) telemetry collars (Lotek™ GPS_3300S) for a period of 30 days during each season. For estimation of spatial distribution of deer, the collars were programmed to take a position fix every hour to reduce problems associated with spatial autocorrelation. For 12 days within this period the collars recorded animal location every 5 minutes to compare habitat use with 6–9 GPS collars (GPS_3300LR) placed on cattle. This allowed me to examine fine-scale movements of deer relative to cattle. Trials were conducted prior to the burn and in each season for one year after the burn. Areas to be burned were not favored by deer. A month after the burn in Fall 2005 there was an increase in use of the burned areas by deer. Deer preference for burned areas fell in Spring and Summer 2006, but in Fall 2006 females dramatically increased their use of the burns. This is possibly an artifact of small sample size and the random selection of individuals. Interaction between deer and cattle was minimal, as they inhabited different areas. When cattle moved within approximately 50 m of a stationary deer the deer was likely to move away. Vegetation measurements showed no significant change in shrub cover and density and a decline in available herbaceous forage on both treatment and control sites in the second year. The lack of vegetative response because of drought conditions was likely the cause of the lack of response by the deer to the burns.