Habitat Selection of a Declining White-tailed Deer Herd in the Central Black Hills, South Dakota and Wyoming

Habitat selection, survival rates, the Black Hills National Forest Habitat Capability Model (HABCAP), and the USDA Forest Service Geographic Information System (GlS) data base were evaluated for a declining white-tailed deer (Odocoileus virginianus dacotensis) herd in the central Black Hills of South Dakota and Wyoming. From July 1993 through July 1996, 73 adult and yearling female and 12 adult and yearling male white-tailed deer were radiocollared and visually monitored. Habitat information was collected at 4,662 white-tailed deer locations and 1,087 random locations. Natural mortality (71 %) was the primary cause of female mortality , followed by harvest (22.5%) and accidental causes (6.5%). More females died in spring (53 .2%) than in fall (22.6%), winter ( 14.5%), or summer (9 .7%). Male mortality resulted from hunting in fall (66.7%) and natural causes (e.g., coyotes, dogs, malnutrition , sickness, or unknowns) in spring (33 .3%) Survival rates for all deer by year were 62.1 % in 1993, 51.1 % in 1994, 56.4% in 1995, and 53.9% in 1996 and were similar (f = 0.691) across years. During winter, white-tailed deer selected ponderosa pine- (Pinus ponderosa) deciduous and burned pine cover types. Overstory-understory habitats selected included pine/grass-forb, pine/bearberry (Arctostaphylos uva-ursi), pine/snowbeny (Symphoricarpos albus), burned pine/grass-forb, and pine/shrub habitats. Structural stages selected included sapling-pole pine stands with > 70% canopy cover, burned pine sapling-pole and saw-timber stands with < 40% canopy cover. Bedding locations were represented by saw-timber pine structural stages with >40% canopy cover and all sapling-pole pine structural stages; sapling-pole stands with >70% canopy cover received the greatest use. White-tailed deer primarily fed in pine saw-timber structural stage with less than 40% canopy cover. Overall, selected habitats contained lower amounts of grass/forb, shrubs, and litter than random locations. Male and female deer generally bedded in areas that were characterized by greater horizontal cover than feeding and random sites. When feeding and bedding sites were combined males selected areas that were characterized by greater levels of horizontal cover than females. Winter range cover types categorized by USDA Forest Service digital map data included pine, aspen (Populus tremuloides), grasslands, water, private land, but did not account for secondary cover layers. During summer, white-tailed deer selected pine-deciduous, aspen, aspen-coniferous, spruce (Picea glauca), and spruce-deciduous cover types. Overstory-understory habitats selected included pine/juniper (Juniperus communis), aspen/shrubs, spruce/juniper, and spruce/shrub habitats. Structural stages selected included pine, aspen, and spruce sapling pole stands with all levels (0-40%, 41-70%, 71-100%) of canopy cover. All habitat types (i.e., pine, aspen, and spruce) were used as bedding locations with pine sapling-pole structural stages with >70% canopy cover used most, whereas pine saw-timber structural stage with less than 40% canopy cover was primarily used for feeding. Females bedded in areas that were characterized by greater horizontal cover than feeding and random sites, whereas male feeding sites had greater horizontal cover characteristics than bedding or random locations. Summer range cover types categorized by USDA Forest Service digital map data included pine, aspen, spruce, grasslands, water, private land, non-vegetated, but did not account for secondary cover layers Based on the results of this study , I recommend that managers increase deciduous habitats, burned habitats, forage biomass, and tall shrub/sapling densities in the central Black Hills. Additionally, because disturbance factors may be forcing deer to use inferior habitats, I recommend reducing road densities in the central Black Hills. Because the white-tailed deer herd is declining, the revised coefficients for the HABCAP model may only represent use of suboptimal habitats in the central Black Hills. Therefore, the revised HABCAP coefficients presented in this study should be used as a tool to reevaluate the present HABCAP model used by the Black Hills National Forest. Finally, I recommend the USDA Forest Service incorporate horizontal cover and secondary cover information into their GIS and HABCAP model prior to using them in long term habitat decisions.