Conservation impacts and the future of the black rhinoceros (Diceros bicornis)

Abstract

The African black rhinoceros (black rhino) as a species is critically endangered on the Red List of the International Union for the Conservation of Nature (IUCN). This list categorizes threatened species assessed for risks of extinction. The IUCN Green Status is a new global standard of measurement created by IUCN to help show how a species is functioning within the ecological system it inhabits, and how much it has recovered thanks to conservation action. For the new Green Status, we provide an assessment of four conservation impact measures for the black rhino – conservation legacy, conservation dependence, conservation gain and recovery potential. Time sequences of estimates for four subspecies of black rhinos, collated from data provided by range States and various sources in the literature, provide the basis of this evaluation. Our findings reveal that in the absence of conservation interventions, the year 2022 would only have seen 296 black rhinos compared to 6487 reported, a legacy of 6191 individuals. If conservation interventions had been stopped in 2022, there would be 3354 black rhinos in 2032, i.e. there is a conservation dependence of 3133 rhinos. If conservation interventions continue, there will be 8943 black rhinos in 2032, a conservation gain of 2456 individuals, compared to the number in 2022. Various global change drivers contribute to available habitat for 20 952 black rhinos in 2122. Our analysis illustrated that the rhino recovery potential by 2022 was 14 465. For this to continue and materialize fully, the authorities will need to consider introducing ecological equivalent subspecies into available habitat, within ranges of extinct subspecies.