On the Three Major Recycling Pathways in Terrestrial Ecosystems

Plants are the largest biomass component of most terrestrial ecosystems, and litter decomposition is considered the dominant process by which nutrients return to plants. We show that in terrestrial ecosystems, there are three major pathways by which plant biomass is degraded into forms that release nutrients again available to plants: microbial decomposition; vertebrate herbivory; and wildfires. These processes act at different spatial and temporal scales, have different niches, and generates different ecological and evolutionary feedbacks. This holistic view in which microbes, herbivores, and wildfires play a joint role in the functioning of ecosystems contributes to a better understanding of the diversity of mechanisms regulating the biosphere.