Balancing Savanna Ungulate Diversity and Biomass: Optimal Human Use, Landscape Features, and Vegetation Types Under Varying Rainfall and Land Use.

To manage savanna ungulate communities in a changing environment, it is crucial to understand how their diversity and biomass change in relation to anthropogenic and environmental variables under different land uses and varying rainfall patterns. To this end, we analyzed fine-scale data collected during the drought year of 1999 and the year with normal rainfall, 2002, in the Maasai Mara National Reserve and on adjacent pastoral lands in Kenya. Ungulate diversity peaked within 2-4 km of bomas, settlements, and 1-3 km of water sources. In the year with normal rainfall, ungulate species richness decreased in the presence of sheep and goats, though it increased with fire. In the drought year, ungulate biomass increased with grass color and shrub cover in the Mara Reserve and with tree cover on pastoral lands. Species richness often peaked at lower levels of grass color, shrub, or tree cover than biomass did. Our results suggest that ungulate diversity peaks in pastoral landscapes when sheep and goat densities are low, and wildlife can access areas more than 3-4 km from settlements. Maintaining diverse vegetation resources in core protected areas and pastoral lands is essential to maintaining high ungulate species richness and minimizing biomass loss during drought years. This can be achieved by providing a variety of food sources and cover. Potential candidate sites for ungulate conservancies in the Mara region include landscapes with low slopes, elevations of up to 1700 m above sea level (masl), and locations within 2-3 km of water sources. Our results highlight how policy and governance can manage these variables to maximize ungulate diversity and minimize biomass loss in contexts where disturbance and resource supply are coupled. This can help alleviate the tension between pastoral use and conservation in protected areas and human-dominated African savannas.