Gradients of Forage Biomass and Ungulate Use Near Wildlife Water Developments

Abstract

Abstract The addition of wildlife water developments (i.e., catchments) to arid areas may concentrate foraging by desert ungulates and decrease forage availability near catchments. We looked for gradients in forage biomass and use by mule deer (Odocoileus hemionus) and bighorn sheep (Ovis canadensis) along dry riparian streams near catchments. We measured forage biomass and pellet group density in transects following vegetation along edges of desert washes near catchments and in control washes with catchments >3 km away. Ungulate use, as reflected by pellet group density, was greatest in washes with catchments in place >3 years. There was some evidence for a gradient in pellet density in spring (slope = −0.012, P = 0.088) and summer (slope = −0.013, P = 0.015), and for differences between catchment and control transects in all seasons (13–46 pellet groups/ha, P ≤ 0.077). We found no evidence of an effect of catchments on forage biomass in nearby washes: we detected no gradient in forage biomass nor an ove...