Maestre and colleagues collected data using a standardized field survey at 98 sites across 25 countries and 6 continents, fitted linear mixed models to data from all sites and grazing pressure levels, and then applied a multimodel inference procedure to select the set of best-fitting models. The authors found interactions between grazing and biodiversity in almost half of the best-fitting models, where increasing grazing pressure had positive effects on ecosystem services in colder sites with high plant species richness. However, increases in grazing pressure at warmer sites with high rainfall seasonality and low plant species richness interacted with soil properties to either increase or reduce the delivery of multiple ecosystem services. The authors’ findings highlight how increasing herbivore richness could enhance ecosystem service delivery across contrasting environmental and biodiversity conditions, enhancing soil carbon storage and reducing the negative impacts of increased grazing pressure.
Understanding ecosystem service drivers is essential to predict the fate of dryland ecosystems under increasing temperature, biodiversity loss and demand for animal products. Warmer drylands were most negatively affected by increasing grazing pressure, where a large proportion of the human population struggles with food security and relies heavily on livestock for subsistence. Although social aspects were not included in the study, Maestre and colleagues note that the interaction between grazing pressure and climate change in warmer drylands could lead to greater poverty, migration and/or social unrest — supporting arguments for conserving and restoring diverse plant communities to prevent land degradation and mitigating climate change in grazed drylands.
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