The Effect of Large Animal Removal or Protection under the Future of Climate Change

Abstract. Large mammal populations are declining worldwide, yet their impact as biotic drivers of terrestrial carbon and energy exchange with the atmosphere remains poorly represented in ecosystem modelling approaches. Animal processes, like herbivory and predation, shape vegetation structure and composition that governs photosynthetic carbon uptake. This influence is rarely quantified relative to other drivers like climate change and rising CO2 levels. Here, we apply a generic, process-based, multi-trophic modelling framework that integrates the two models LPJ-GUESS and Madingley. Using this framework, we simulated the impact of large herbivore and carnivore removal across two European and two African biomes, under both constant climate conditions and climate change scenarios.

Under constant climate, the removal of large herbivores increased leaf biomass, a proxy for canopy photosynthetic capacity. However, the impacts of climate change, including changes in atmospheric CO₂ on leaf biomass were much larger. In contrast, the removal of large carnivores reduced leaf biomass, reflecting the release of herbivores from predation and subsequent increases in their abundance. In African biomes, this effects rivals those of a low-warming climate change scenario.

To investigate recovery potential, we compared African savanna simulations with and without neighbouring grid cells with modelled trophic structures intact. We found that herbivore biomass could only recover in the vicinity of such protected areas. Our findings underscore the importance of conserving large mammal populations under climate change.