Plant diversity mediates the response of ecosystem multifunctionality to climate factor in Eastern Eurasian Steppe

Climate factors can impact the multifunctionality of steppe ecosystem by altering plant diversity. The pivotal role of diversity in mediating these effects is of paramount importance. Given that various facets of plant diversity exhibit diverse responses to climate change and impart distinct impacts on steppe ecosystem multifunctionality, the elucidation of how different dimensions of diversity mediate the effects of climate factors on steppe ecosystem multifunctionality assumes significance. The study area of this research was the typical steppe in Hulun Buir. Its main objective was to examine the direct and indirect impacts of climate factors on plant diversity and ecosystem multifunctionality. The findings showed that, in terms of the role played by climatic factors, precipitation had a greater effect on species diversity, while functional diversity and phylogenetic diversity were mainly influenced by temperature. The impact of climatic factors on below-ground ecosystem multifunctionality was notably substantial. With regard to the mediating role of plant diversity, species diversity played a greater role in moderating the effects of climatic factors on above- and below-ground ecosystem multifunctionality, while functional and phylogenetic diversity were important in mediating the effects of above- and below-ground ecosystem multifunctionality, respectively. To summarize, this study elucidates the correlation between multiple plant community diversities and ecosystem multifunctionality in a typical steppe under climate change, along with the potential mechanisms through which plant diversity moderates the influence of climate factors on ecosystem multifunctionality. Overall, species diversity and functional diversity take precedence over phylogenetic diversity, which can better predict the ecosystem multifunctionality of steppe and provide guidance for the conservation and sustainability of steppe plant diversity.