Plio-Pleistocene African megaherbivore losses associated with community biomass restructuring

Faysal Bibi, Juan L. Cantalapiedra

Fossil abundance data can reveal ecological dynamics underpinning taxonomic declines. Using fossil dental metrics, we reconstructed body mass and mass-abundance distributions in Late Miocene to recent African large mammal communities. Despite collection biases, fossil and extant mass-abundance distributions are highly similar, with unimodal distributions likely reflecting savanna environments. Above 45 kg, abundance decreases exponentially with mass, with slopes close to -0.75 as predicted by metabolic scaling. Furthermore, communities prior to ~4 Ma had significantly more large-sized individuals, with a greater proportion of total biomass allocated in larger size categories, than did later communities. Over time, individuals and biomass were redistributed into smaller size categories, reflecting a gradual loss of large-sized individuals from the fossil record, and paralleling the long-term decline of Plio-Pleistocene large mammal diversity.