Factors affecting hyrax presence/absence and population size

Abstract

Understanding the factors influencing whether a species is present or absent in an ecosystem and how these factors affect their population size is crucial for conservation initiatives. There are two species of hyraxes in the Serengeti National Park (SENAPA): the rock hyrax (Procavia johnstoni) and the bush hyrax (Heterohyrax brucei). These two species live predominantly on kopjes (rock outcrops), forming a metapopulation community. This study is focused on the factors that affect hyrax presence/absence and population size. To assess this, I included factors such as human premises, habitat type, kopje size, and the proportions of trees, grasses, shrubs, and rocks on these types of kopjes. My field technique included point observations with three visits per kopje at different times of the day (i.e., early morning, late morning, and evening). The results show that the most important variables for hyrax presence are the habitat type and proportion of shrubs. The results also show that hyrax population size is positively affected by human premises, possibly caused by fewer predators and higher food availability in these areas. My field observations are consistent with other studies on hyrax absence in some kopjes in SENAPA. However, with the limited time period of the study, it is difficult to firmly conclude the possible reasons for hyrax absence, requiring further research for future conservation purposes.

Keywords: rock hyrax, Procavia johnstoni, bush hyrax, Heterohyrax brucei, kopjes, human premises, habitat, Serengeti, Tanzania