Citation

Karp AT, Koerner SE, Hempson GP, Abraham JO, Anderson TM, Bond WJ, Burkepile DE, Fillion EN, Goheen JR, Guyton JA, Kartzinel TR, Kimuyu DM, Mohanbabu N, Palmer TM, Porensky LM, Pringle RM, Ritchie ME, Smith MD, Thompson DI, Young TP, Staver AC. Ecol Lett 2024; 27(6): e14450.

Copyright

(Copyright © 2024, Blackwell Publishing)

DOI

10.1111/ele.14450

PMID

38857323

Abstract

Fire and herbivory interact to alter ecosystems and carbon cycling. In savannas, herbivores can reduce fire activity by removing grass biomass, but the size of these effects and what regulates them remain uncertain. To examine grazing effects on fuels and fire regimes across African savannas, we combined data from herbivore exclosure experiments with remotely sensed data on fire activity and herbivore density. We show that, broadly across African savannas, grazing herbivores substantially reduce both herbaceous biomass and fire activity. The size of these effects was strongly associated with grazing herbivore densities, and surprisingly, was mostly consistent across different environments. A one-zebra increase in herbivore biomass density (~100 kg/km(2) of metabolic biomass) resulted in a ~53 kg/ha reduction in standing herbaceous biomass and a ~0.43 percentage point reduction in burned area. Our results indicate that fire models can be improved by incorporating grazing effects on grass biomass.

Language: en

Keywords

Animals; Africa; fire; *Biomass; *Fires; *Grassland; *Herbivory; burned area; grazing; herbivore exclusion; megafauna; Poaceae/physiology; savanna