Livestock grazing strongly affects biodiversity and ecosystem functioning in grasslands. However, it remains unclear how different grazing impact multiple biodiversity, ecosystem multifunctionality (EMF), and their relationship with the interactions of grazing duration, livestock type and climatic factors. Here, we conducted a global synthesis from 104 published studies. Our results showed that light and moderate grazing improved multi-diversity, but heavy grazing significantly decreased multi-diversity and EMF. The grazing-induced decrease of EMF intensified with grazing duration, and the reduction of multi-diversity and EMF under intensive grazing was stronger in more arid climates. The response of EMF increased linearly with that of multi-diversity under all grazing intensities. Moreover, grazing intensity reduced EMF largely via decreasing multi-diversity, whereas a shift of livestock type from small to large size promoted EMF by increasing multi-diversity. This study provides first empirical evidence and new insights into the relationship between multi-diversity and EMF under grazing in global grasslands.
Plant diversity and plant-consumer interactions likely interact to influence ecosystem carbon fluxes but experimental evidence is scarce. We examined how experimental removal of foliar fungi, soil fungi and arthropods from experimental prairies planted with 1, 4 or 16 plant species affected instantaneous rates of carbon uptake (GPP), ecosystem respiration (Re) and net ecosystem exchange (NEE). Increased plant diversity doubled plant biomass, in turn doubling GPP and Re, but NEE remained unchanged. Removing foliar fungi increased GPP and NEE, with greatest effects at low plant diversity. After accounting for plant biomass, we found that removing foliar fungi increased mass-specific flux rates by 48% by altering plant species composition and community-wide foliar nitrogen content. However, this elevated NEE effect disappeared when soil fungi and arthropods were also removed, demonstrating ecosystem-scale impacts of interactions among consumer groups. Thus, plant diversity and consumer context determine the effects of plant-fungal interactions on ecosystem carbon fluxes.