White-tailed Deer Overabundance: A Threat to Regeneration of Golden-cheeked Warbler Habitat

Abstract

Texas oak (Quercus buckleyi), found throughout the Hill Country is a preferred browse species o f white-tailed deer (Odocoileus virginianus) and an important component o f golden-cheeked warbler (Dendroica chrysoparid) habitat. Degradation o f Texas oak populations by overabundance o f white-tailed deer will most likely affect the structure o f Hill Country forests by curtailing recruitment o f Texas oak, thus reducing the replacement o f older trees and ultimately altering golden-cheeked warbler habitat. Objectives o f my study were to develop a baseline vegetative analysis o f golden-cheeked warbler habitat at Barton Creek Habitat Preserve, an area with a high density o f deer, and to compare Texas oak seedling recruitment in areas with low and moderate densities of deer to seedling recruitment at Barton Creek Habitat Preserve. A baseline vegetational survey included: counting Texas oak seedlings in 50 stations in areas o f golden-cheeked warbler habitat. Stations consisted o f 21 1 m rectangular quadrats placed at 5 m intervals along 4 transects each 25 m long that radiated in the 4 cardinal directions from a center point. To ascertain Texas oak recruitment, at other sites with low and moderate deer densities, Texas oak seedlings were counted at 50 stations on Training Area 13B at Fort Hood, Texas and Spring Pasture at Kerr Wildlife Management Area using the same methodology.

The fewest number o f seedlings occurred at Barton Creek Habitat Preserve, the site with the highest white-tailed deer density (1 deer/2.67 ha). The mean number of seedlings was 1.56 per m2. Many stations did not have any seedling recruitment. The majority o f stations contained 1 -7 Texas oak seedlings per m2 with 1 station having a quadrat containing!3. Spring Pasture on the Kerr WMA had a moderate amount o f Texas oak seedlings (9.04 seedlings per m2) and a moderate deer density (1 deer/4.59 ha). All stations contained seedling recruitment. Texas oak seedling recruitment at stations ranged from 1 -2 7 per m. Fort Hood had the most Texas oak seedling per station (33.7) and the lowest deer density (1 deer/24.28 ha). All stations contained seedling recruitment. Texas oak seedling recruitment at stations ranged from 3 -9 1 . At Barton Creek Habitat Preserve understory vegetative density and canopy cover were measured.