Abstract
BackgroundThe functional diversity of arbuscular mycorrhizal fungi ( AMF) affects the resistance and resilience of plant communities to environmental stresses. However, considerable uncertainty remains about how the complex interactions among elevated atmospheric CO 2 (eCO 2 ), nitrogen deposition (eN), increased precipitation (eP), and warming (eT) affect AMF communities. These global change factors (GCFs) always occur simultaneously, and their interactions likely affect AMF community structure and assembly processes. In this study, the interactive effects of these four GCFs on AMF communities were explored in an open-top chamber field experiment in a semiarid grassland. ResultsElevated CO 2 , eN, eT, and eP and their interactions did not affect AM fungal biomass. The relative abundance of Paraglomus increased with N addition across treatment combinations, whereas that of Glomus decreased with N addition, especially combined with eT and eCO 2 . Precipitation, T, and N affected AMF phylogenetic α-diversity, and the three-way interaction among CO 2 , T, and N affected taxonomic and phylogenetic α-diversity. Nitrogen addition significantly affected the β-diversity of AMF communities. Both variable selection and dispersal limitation played major roles in shaping AMF communities, whereas homogeneous selection and homogenizing dispersal had almost no influence on AMF community assembly. The contribution of variable selection decreased under eCO 2 , eN and eT, but not under eP. The contribution of dispersal limitation decreased under eCO 2 , eT, and eP but it increased under eN. The assembly of AMF communities under the sixteen GCF combinations was strongly influenced by dispersal limitation, variable selection and ecological drift. ConclusionsElevated CO 2 , warming, N addition, and increased precipitation influenced different aspects of AMF communities. The interactive effects of the four GCFs on AMF communities were limited. Collectively, the results of this study suggest that AMF communities in semiarid grasslands can resist changes in the global climate.
Interactive effects of global change factors on terrestrial net primary productivity are treatment length and intensity dependent
