Effects of aridity on ecosystem functioning through plant diversity
The negative effects of aridity on ecosystem functioning were mainly mediated by a reduction in plant species richness, in this study, which was in accordance with earlier studies at local to global scales (Delgado-Baquerizo et al. 2013; Wang et al. 2014; Brookshire & Weaver 2015; DurĂ¡n et al. 2018). Global grasslands are mainly distributed in arid and semiarid regions, and water availability is the most important limiting factor for grassland structure and ecosystem functioning (Harpole et al. 2007; Merboldet al. 2009). Drought is predicted to become more severe in many places across the globe (Dai 2013; Sherwood & Fu 2014; Trenberthet al. 2014). In arid environment, water availability is the main driver of biological activities, and thus, an increase in aridity would have substantial effects on ecosystem structure and biogeochemical cycles (Austin et al. 2004; Schwinning & Sala 2004; Delgado-Baquerizo et al. 2013; Wang et al. 2014). The present findings indicate that adverse climatic conditions have direct and indirect negative effects on aboveground plant biomass production and SOC and that the deterioration of ecosystem functions was mostly mediated by a reduction in plant diversity. This finding suggests that the preservation of plant biodiversity can buffer decreased ecosystem functioning due to climate change.