White-tailed deer use of rangeland following browse rejuvenation.

Abstract

Mechanical top growth removal of certain shrub species stimulates sprouting and temporarily increases nutritional quality, availability, and yield of browse. We determined the effects of (1) roller chopping separate portions of rangeland, dominated by guajillo (Acacia berlandieri Benth.) and blackbrush acacia (A. rigidula Benth.), during consecutive years and (2) disking separate portions of rangeland, dominated by dense whitebrush (Aloysia lyciodes Cham.) thickets, during consecutive years on white-tailed deer (Odocoileus virginianus Raf.) use of the treated areas. Separate, adjacent portions of guajillo and blackbrush acacia-dominated rangeland were roller chopped in a pattern of alternating treated and untreated strips each year during summer for 4 consecutive years (1985-1988) on an area in Duval County, Tex., and for 2 years (1988-1989) on areas in Duval and McMullen counties, Texas. Whitebrush-dominated rangeland was disced in a similar pattern during 2 years (1988-1989). Twenty percent of each study site was treated each year. Estimated deer density in the roller-chopped area in Duval County was higher than estimated deer density in an untreated area during 1985-1987 and in 1989. Roller chopping in study areas in Duval and McMullen counties increased deer fecal pellet-group densities (groups ha-1 day-1) relative to untreated sites in winter, spring, and summer 1989 and when averaged over the 21-month study. Discing dense whitebrush-dominated sites increased pellet-group densities relative to untreated sites in spring and summer 1989 and when averaged across the 21-month study period. Increased deer use of treated areas was probably a function of several factors, including increased forb availability and increased nighttime visibility for predator detection.