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Abstract While most research on nutrient cycling has focused on plant–soil interactions or soil decomposers, recent studies highlight the emerging role of terrestrial mammals in contributing to biogeochemical cycles, a field known as zoogeochemistry. More than half of all mammal species are found in tropical forests, ecosystems currently experiencing high rates of defaunation. In this context, ongoing defaunation may limit our understanding of the role mammals play in nutrient cycling in these diverse ecosystems. To investigate the effects of ground‐dwelling mammals on nutrient cycling in tropical forests, we conducted a field experiment in the Atlantic Forest of Brazil using a long‐term (14‐year) mammal exclusion experiment. Over 1 year, we monitored terrestrial mammals, estimated their biomass using a mammalian biomass index, and collected litter and soil samples during the dry and wet seasons. The mammalian biomass index was dominated by large frugivores (peccaries, red brocket deer, and lowland tapir) but also included small‐ and medium‐sized mammals. Season emerged as the dominant driver of variation in litter and soil properties, and spatial heterogeneity among plot pairs also accounted for a substantial portion of this variation. In contrast, the effects of mammalian biomass were more limited and interacted with seasonality. Mammalian biomass reduced litter lignin, increased litter diversity and potassium content across seasons, and increased soil pH. These changes likely represent short‐term responses of belowground systems to the physical impacts of ground‐dwelling frugivorous mammals, such as foraging and bioturbation, rather than long‐term shifts in vegetation composition. Together, these results suggest that ground‐dwelling mammals may accelerate nutrient cycling in tropical forests.
Ribeiro et al. (Fri,) studied this question.