Using historical data to establish baselines for conservation: The black rhinoceros (Diceros bicornis) of the Serengeti as a case study

Illegal hunting of rhinoceros in East Africa was widespread in the late 1970s. Today, rhinoceros numbers remain perilously low. The Eastern black rhinoceros (Diceros bicornis michaeli) is restricted to protected areas within Kenya and Tanzania and the few protected areas in Kenya where rhinoceroses are found are reaching carrying capacity. The Serengeti-Mara Ecosystem represents the best potential site for population growth of the Eastern black rhinoceros. Populations within the Serengeti-Mara Ecosystem remain low and augmentation of the current population has been proposed. Using historical census data collected prior to the illegal hunting that occurring in the 1970s, we determined the historical distribution and population of rhinoceros in the Masai Mara National Reserve and Serengeti National Park. The population was approximately 460 animals. We developed a habitat suitability model for the black rhinoceros using the spatial location of historical count data matched with contemporary vegetation and landscape variables. Illegal hunting still remains a significant threat to the rhinoceros. Therefore, we determined areas where the likelihood of a rhinoceros being discovered and then targeted by illegal hunters was highest. This information can be used by managers as a starting point for an assessment for reintroduction if other factors are taken into account. This case study exemplifies the importance and potentially unforeseen applications of long term ecological datasets for species conservation.