Habitat Affinities for White-tailed Deer and Rio Grande Wild Turkey at the Griffith League Ranch, Bastrop County, Texas

Abstract

Game animal research throughout the range of southern pine forests is extensive, but the reasons for low populations of white-tailed deer and Rio Grande wild turkey in the isolated Lost Pines region of Bastrop County, Texas, were not well understood. I characterized the vegetative communities on a 2012 ha ranch in the Lost Pines and related white-tailed deer and wild turkey abundance and distribution to available habitats. I measured woody plant cover and density in summer 2002 and assessed herbaceous cover, horizontal obscurity, duff depth, and percent canopy cover once per calendar season from summer 2002 to spring 2003. I estimated white-tailed deer abundance using a non-linear spotlight transect method and used GPS locations of sightings of both deer and wild turkeys to assess distribution and habitat affinity within a geographic information system. I found three major habitat types: pine forest, oak-juniper woodland, and grassland (improved pasture). Loblolly pine with an understory of yaupon dominated pine forests, which had higher woody plant density (7257 plants/ha), greater duff accumulation (60.2 mm), higher canopy coverage (87.1 %), and lower visibility based on VPB measurements than oak-juniper woodlands (4419 plants/ha, 40.2 mm duff, 74.4% canopy). Post oak and blackjack oak mixed with eastern red cedar characterized oak-juniper woodlands. Pine and oak habitats showed sparse herbaceous plant cover (1.2% and 5.0%, respectively). Distance analysis estimated deer density at 0.010 deer/ha (20 deer on the ranch). Wild turkey abundance was approximately 20-30 individuals based on incidental sightings. Both species were associated with grassland habitat more than expected based on availability. Wild turkeys also appeared to favor oak-juniper woodlands over pine forests, while deer showed no preference for either. Long-term lack of management on the ranch has produced forest habitat that produces little food available to white-tailed deer and wild turkeys so they must utilize the grasslands for foraging. A combination of thinning, clear-cutting, and prescribed fire is recommended to increase forage quantity and quality. Future research should address the effectiveness of management practices in the Lost Pines compared to more mesic southern pine forests to the east.