A utilization pattern by deer and cattle on Whitespar Watershed B in the Arizona chaparral

Abstract

In the Arizona chaparral south of Prescott, the "browsed-class" method was first employed to estimate browse utilization by deer and cattle on two key areas within the Whitespar Experimental Watershed B. By analyzing the utilization pattern in its environmental and biological context, an attempt was made to discern its most important causes and implications. Slope position, vegetation density, and percentage slope were found to be highly significant in their effects on browse utilization. Ridge location and distance up drainage were not found to be significant though their two-way interactions among themselves and slope position were. These factors combined to create a utilization pattern that varied widely over the study area. This implied that the true deer carrying capacity of the watershed was being established far below its potential set by food. However, it was concluded that cattle and climate had a profound influence on the deer population through the browse resource, and that the utilization pattern was a product of a deer-cattle-food equilibrium. A conceptual framework was developed for use in investigating equilibrium relationships, population regulation mechanisms, and ungulate food competition from the study of utilization patterns.