Assessment of Browse Availability and Suitability for Black Rhino’s Re-Introduction in Northern Gonarezhou National Park, Southeastern Zimbabwe

Abstract

Wildlife reintroduction regulations require feasibility assessment to inform planning. The study aims to contribute to the existing knowledge on northern Gonarezhou National Park (GNP), southeastern Zimbabwe, prior to the black rhino re-introduction project. The study objective was to assess browse availability and suitability for black rhino re-introduction in northern GNP. We stratified the study area into two strata, i.e. north and south of Runde River in GNP. A total of 96 sample plots measuring 20 m × 30 m (i.e., 48 plots in each study stratum) were randomly placed across the study strata, between March and April 2011. Woody plant variables recorded are: shrub height, shrub canopy diameters, evidence of browsing on woody plants, number of shrubs and woody species. Principal browse frequency of occurrence and proportional quality of woody species were categorized and analyzed in combination with knowledge on the woody species’ value to black rhino diet. Preferred woody species were determined using browse suitability/electivity index. A total of 3201 woody plants were recorded across the study strata. Woody species diversity and black rhino’s browse suitability/electivity value significantly (p = 0.001) differed across the study strata. However, there were no significant differences in shrub density, shrub canopy volume and density of browsed plants. Common principal forages were recorded and included: knob thorn Acacia (Acacia nigrescens), small-leaved sickle-bush (Dichrostachys cineria) and tamboti (Spirostachys africana). The study suggested that black rhino’s browse suitability, preferred browse woody species, woody species diversity and proportional browse availability, as selected attributes are favorably more pronounced in the northern side of the Runde River in GNP, suggesting it is more suitable as a sanctuary for the black rhino re-introduction programme. It was recommended that black rhinos could be re-introduced in the northern GNP area provided other important factors such as law enforcement are taken into consideration.