Animating the Carbon Cycle

This report presents estimates of the potential for conserving the top carnivore species (jaguar and puma), their herbivore prey species (white-tailed deer and collared peccary) and their interdependencies and tropic interactions to boost carbon capture and storage within tropical dry forests of Mexico in which all species are resident. The estimates come from deploying a new carbon cycle model that accounts for the direct and feedback effects of animals (consumption, respiration, and nutrient and carbon recycling) on net carbon capture and storage in plant, soil, and animal ecosystem compartments. The model was parameterized with published data based on ecological field studies of typical forest and related shrubland habitat in tropical dry forest ecosystems of central and southern Mexico. The model was solved for steady-state conditions (i.e., a balanced carbon budget) for three scenarios (1) a comparative baseline that excludes both animals; (2) a scenario that includes only the herbivore species; and (3) a scenario that includes the herbivore and predator species. The modeling reveals that conserving these species and their tropic interactions could increase carbon capture and storage by 3.2 times (range 1.68 – 4.7 times) above the level of ecosystem capture and storage in their absence. Considering the predator and prey species and vegetation together as a fully intact food web yields an estimated average yearly net ecosystem carbon capture and storage of 5.68 x 105 kg C per km2 per yr or 568 tonnes C per km2 per yr. Extrapolating the model estimates to the 18,389 km2 of Mexican dry tropical forests already safeguarded in parks and protected areas within Mexico that could support puma and jaguar home range needs reveals a potential to capture and store 10.4 million tonnes C per yr, or 38.3 million tonnes CO2 per yr. Thus, if conservation acted to ensure that the top predator and large herbivore community of pumas, jaguars, white-tailed deer, and peccaries are restored and protected to exist at their natural densities their impacts on carbon storage across Mexico’s tropical dry forest parks and protected areas could reach a level equivalent to ~1/10th of Mexico’s 2023 CO2 emissions from fossil fuel burning.