Spatial overlap between sympatric wild and domestic herbivores links to resource gradients

Abstract

In this study, we investigated the relationship between resource gradients and overlap between wild and domestic herbivores in a southern African ecosystem. We used an Enhanced Vegetation Index (EVI) to identify and test the presence of resource gradients i.e. vegetation greenness between agricultural areas and conservation areas in Southeastern Zimbabwe, part of the Great Limpopo Transfrontier Conservation Area. We then tested whether these resource gradients coincide with GPS collared cattle (Bos taurus) movements into wildlife areas, as well as drive spatial overlaps between cattle and the GPS collared African buffalo (Syncerus caffer). Results showed that resource gradients although variable, exist between the conservation area and surrounding agricultural area. Cattle used the conservation area less than expected during the dry season when vegetation greenness in the communal land was relatively lower than in the conservation area. Significant spatial segregation between cattle and buffalo occurred during the wet season and late dry season, while spatial aggregation occurred during the early dry season. Intensity of habitat overlap between cattle and buffalo during the early dry season was relatively high in habitats preferred by both species. Our results suggest that cattle movement into conservation areas is linked to resource gradients.