The diet of pronghorn (Antilocapra Americana) in the tallgrass prairie.

Abstract

Pronghorn (Antilocapra americana) is a native fixture to the tallgrass prairie ecosystem. Pronghorn is a species known to consume significant quantities of forbs and shrubs when found in short and mixed-grass prairies. Understanding the diet of pronghorn in the tallgrass prairie is essential for knowing the role of pronghorn in the tallgrass prairie. The diet of pronghorn in the tallgrass prairie was assessed by using fecal analysis. Fecal pellets were collected in the Flint Hills of Kansas throughout the year beginning June 1995 and ending in August of 1996. The nutritional quality of pronghorn diet was also determined by investigating the amount of crude protein, net energy, calcium, and phosphorus in forage samples. During the winter months, pronghorn consumed graminoids and forbs, while shrubs were a dominant forage component in the summer and fall. The most commonly consumed grass was in the genus Poa. Sumac (Rhus spp.) was the most frequently consumed shrub, and was by far the most commonly consumed plant. Helianthus spp. was the most frequently found forb in the fecal pellets. An evaluation of the nutritional quality of available forage material indicated that samples of summer Rhus spp. contained adequate amounts of all daily nutritional requirements for pronghorn. Randomly collected summer and winter forage samples contained less than the estimated protein requirements for pronghorn. Therefore, pronghorn must be selective foragers to obtain all their nutritional requirements and survive in the tallgrass prairie. Fecal pH was determined to aid in identifying fecal pellets as pronghorn feces. I found that fecal pH did not change in regard to diet or season. The fecal pH observed in my study was slightly lower than that reported by other researchers. However, fecal pH could be used to distinguish pronghorn fecal pellets from mule deer (Odocoileus hemionus) fecal pellets because of differences in reported fecal pH. The fecal pH of pronghorn was too similar to the reported values o fwhite-tailed deer (Odocoileus virginianus) fecal pH to be used as an identification technique.