Nutritional content of forage in Sonoran pronghorn habitat, Arizona

Abstract

I determined if Sonoran pronghorn (Antilocapra americana sonoriensis) could meet water and mineral requirements through consumption of forage. I sampled vegetation using dry weight rank and comparative yield methods in southwestern Arizona from June 1995 to May 1996 to determine preformed water, nutrient content, mineral content, and vegetation abundance. Water and nutrient content of plants varied between 2 sites and among 5 seasons (P ≤ 0.05). Plants consumed by pronghorn were higher in moisture and nutrients (P ≤ 0.05) than non-forage species. I constructed a model for Sonoran pronghorn diet based on field data. I used the model to describe dietary intake. Water intake predicted by diet models ranged from 1.1 to 6.1 L/animal/day; often exceeding predicted total water requirements (1.8-3.4 L/animal/day). Models predicted that forage provided adequate water for pronghorn during 5 seasons at 1 of 2 study sites and deficiencies for 5 of 11 minerals at both study sites.