Spatial and temporal variation in Ungulate landscape use in relation to resources and constraints

Abstract

Ungulate resource use and distribution are shaped by resources and constraints present in the environment, which are in turn modified by herbivory. Knowing the relationships between ungulates and their environment is particularly critical when managing enclosed areas, which can contain only a limited amount and variety of resources. When resources are limited and used by many species, competition can arise with the result that some species decline in number and may eventually disappear. To investigate how ungulate landscape use varies in relation to resources and constraints in an enclosed area, four ungulate species, one generalist, plains zebra, and three specialists, black and blue wildebeest, and red hartebeest, were observed foraging over one year at Telperion and Ezemvelo nature reserves, a grassland-savanna transition zone in the eastern Highveld of South Africa. Distance between the species, elevation and forage characteristics such as grass greenness, biomass, height and distribution were compared at used and available locations at feeding patch and landscape scale across the East and West sections of the reserves. Red hartebeest and black wildebeest were mainly limited to the West section of the reserves, while blue wildebeest and zebra selected areas on both sections. Large burnt areas were selected by both wildebeest species at landscape scale while being avoided at feeding patch scale, confirming the importance of investigating different spatial scales. Changes in season triggered changes in grass selection in all species. In the dry season, red hartebeest and black wildebeest switched to feeding patches offering more biomass, blue wildebeest accepted taller grass and zebra used less green feeding patches than in other seasons. In addition, results suggest the presence of interspecific competition between black and blue wildebeest at both spatial scales, and an inability for both red hartebeest and black wildebeest to use the eastern half of the study area, probably due to lack of grass of adequate quality. Therefore, this study shows how resources and constraints interact to shaping ungulate distribution and resource use, underlining the importance of considering different spatial scales, and giving important insight for management.