Regulation Of Plant Diversity On Soil Fungal Community Response To Drought And Plant Invasion

Biodiversity is very important for human survival and development,in particular,soil biodiversity helps to improve the resistance level of crops to diseases,pests and abiotic environmental stress,and regulates the composition of arthropod community in farmland.However,today’s global climate change and biological invasion seriously threaten soil biodiversity.Therefore,how to protect soil biodiversity has become an urgent scientific problem to be solved in plant protection.Recent studies have found that plant communities can regulate the composition of soil microorganisms,which provides an idea for the protection of soil biodiversity.However,there is still a lack of research on how plant diversity regulates the response of soil microorganisms to climate change and alien plant invasion.In view of this,by constructing 270 plant communities with different plant richness(4,12 and 24),this study carried out field control experiments to simulate drought(control,reduce 50% rainfall and 80% rainfall)and plant invasion(the proportion of invasion and native plant initial plant),and discussed:1)the response of biological yield and community structure of plant communities with different richness to drought and plant invasion;2)The response of soil fungi to drought and plant invasion in plant communities with different richness and its relationship with plant communities are expected to provide theoretical and practical guidance for the protection of soil microbial diversity and its ecological functions(such as improving plant disease resistance or insect resistance).The main findings are as follows:1)Drought,plant richness and the occurrence of alien species all significantly affect the productivity of plant community,but there is no significant interaction between these factors,it is shown that the biomass of plant community is lower than that 50% when the rainfall decreases by 80%;The biomass of plant community increased with the increase of species richness,and reached the maximum when the plant richness was 12;With the increase of the occurrence of alien species,the biomass of plant community first decreases,then increases and then decreases,it is the largest when the proportion of exotic plants is half and the smallest when the proportion is100%.It was found that there was a significant positive correlation between plant coverage and biomass.2)Plant richness has a significant effect on the number of insects,that is,the number of insects decreases with the increase of plant richness.There is a significant interaction between plant richness and the occurrence proportion of alien species,which jointly affects the occurrence level of plant pests: pest occurrence in the plant community composed of invasive species is significantly lower than that in the native plant community,only when the occurrence proportion of native species is more than50%,the pest occurrence decreases with the increase of plant richness.3)Drought treatment significantly affected the diversity of soil fungi.For example,the diversity and uniformity of soil fungi,the diversity level of Saprotroph and Symbiotroph bacteria decreased with the increase of drought intensity.In addition,drought treatment significantly changed the soil fungal community structure,but had no significant effect on the relative occurrence of 10 phyla and 10 genera with the largest relative abundance.4)There was a significant positive correlation between soil microbial diversity(evenness index)and plant community diversity(Shannon index and Evenness index);Soil microbial diversity(Shannon index and Evenness index)was significantly positively correlated with the coverage of plant communities.According to the analysis of different classification levels(fungi otu or genera)or functional groups(pathogens,Saprotroph and Symbiotroph),the total biomass of plant community significantly affects the composition of soil fungal community.In conclusion,the biomass of field plant community,the abundance and diversity of soil fungi are affected by drought and alien plant invasion.The increase of plant diversity can significantly improve the diversity of soil fungi,indirectly(change biomass)regulate the structure of fungal community,and has the potential to alleviate the adverse effects of drought and alien plant invasion on soil fungal community.