A theoretical framework for multispecies coexistence in large herbivores based on functional traits and dietary data

Falko Buschke, Daryl Codron, Robert Pringle, Jürg Spaak

Modern Coexistence Theory (MCT) has long aimed to predict community structure, but empirical support remains scattered across unconnected case-studies from a narrow subset of systems where it is possible to quantify niche and fitness differences (e.g., pairwise interactions between fast-growing plants or protists). We sought a framework to apply MCT to a broader range of ecological scenarios by combining eDNA dietary data with life-history traits of mammal herbivores from diverse communities across three African savannas. Although this first application of the framework treated dietary niche differentiation as the sole mechanism for coexistence, it unveiled three conclusions about multispecies coexistence. First, dietary niche differentiation promoted coexistence but was insufficient to explain observed coexistence for all species. Second, modelled coexistence patterns in herbivore communities could not be predicted from species-level traits or pairwise comparisons. Third, herbivore diversity is generally robust to reductions in the number of plant resources, particularly when there is more dietary specialisation.