Effects Of Changes In Plan Resource Input Patterns On Soil Nematode And Microbial Communities Under Different Climatic Zones

Plant–soil interactions are important for soil biodiversity and corresponding structure and functioning of terrestrial communities.Plants can fuel soil food webs by determining the quantity and quality of basal resources(i.e.rhizodeposits,shoot and root litter).Plant species identity and species and functional group diversities are key players in determining the abundance,diversity and trophic levels of soil biota.In the context of global change,the plant functional groups of terrestrial ecosystems have also undergone tremendous changes,resulting in changes in plant-derived resources input,and thus affecting the important components of soil food webs,such as soil nematode and soil microbial communities.As basal components of soil food webs,soil microorganisms are tightly linked to higher trophic level organisms,such as soil nematodes.Nematodes comprise 80% of all multicellular organisms and are a highly diverse invertebrate group.Soil nematodes are ubiquitous and play a major role in decomposition,nutrient transformation,and energy transfer.The features of soil microbes,nematodes and the plant-soil interactions offer great potential for assessing the impacts of variations in plant-derived resources input on soil biodiversity in soil food webs.Here we will explore the effects of variations in plant-derived resources input on soil biodiversity in soil food webs based on the field manipulative experiments,including litter reduction,shrub and herb removal,and tree roots removal treatments established in three typical forest ecosystems in different climatic zones.Our aims are: 1)to explore the effects of different plant-derived resources on soil biodiversity;2)to explore to explore the relative importance of same plant-derive resources in different climatic zones in explaining variation in soil nematode and microbial communities.The key findings are as follows:(1)Litter removal decreased the abundance and biomass of fungal-feeding nematodes,the abundance of predatory nematodes in Changbaishan.In addition,litter removal also decreased the biomass of fungal-feeding nematodes in Baotianman.The biomass of nematodes in Changbaishan and Baotianman was greater than that in Dinghushan.In most cases,litter removal decreased the biomass of nematodes in Changbaishan and Baotianman.Shrub and herb removal increased the abundance of plant-feeding nematodes in Chanbaishan.There was an interactive effect between litter removaland shrub and herb removal on the abundance of predatory and total nematodes in Changbaishan.Specifically,litter removal alone decreased the abundance of predatory and total nematodes.The joint removal of litter and shrub and herb did not affect the abundance of predatory and total nematodes.However,the abundance and biomass of nematodes in Dinghushan were not affected by litter removal and/or shrub and herb removal.Shrub and herb removal decreased the diversity of soil nematodes in Baotianman.Litter removal increased the abundance of bacterial species in Changbaishan soil but decreased the abundance of bacterial species in Baotianman and Dinghushan There were more abundant bacterial species increased in response to shrub and herb removal in Dinghushan compared with the other sites.(2)Tree roots removal decreased the abundance of plant-feeding nematodes in Changbaishan,the abundance of fungal-feeding nematodes in Baotianman,and the biomass of plant-feeding nematodes in all of the three sites.Litter removal decreased the diversity of nematodes in Changbaishan and Baotianman.Tree roots removal decreased the diversity of nematodes in Dinghushan.In addition,tree roots removal increased the abundance of soil archaea,bacteria and fungi in the three sites.Litter removal increased the soil bacterial diversity in Changbaishan,and tree root removal increased the richness index and diversity index of soil bacteria in Baotianman and Dinghushan.Tree roots removal decreased the biomass of most soil microbial groups in Changbaishan.Furthermore,Litter removal alone,decreased the fungal biomass in Baotianman.However,the joint removal of litter and tree roots was not affected the fungal biomass in Baotianman.Litter removal alone,decreased or tend to decrease the arbuscular mycorrhizal fungal,gram positive bacterial,bacterial biomass and total microbial biomass in Baotianman.However,the joint removal of litter and tree roots was not affected the arbuscular mycorrhizal fungal,gram positive bacterial,bacterial biomass and total microbial biomass in Baotianman;However,the biomass of most microbial groups was not affected by root removal and/or litter removal in Dinghushan.In summary,the effects of litter removal on soil nematode and microbial communities were slightly greater than that of shrub and herb removal in Changbaishan and Baotianman.No differences of soil nematode and microbial communities in response to litter removal,and shrub and herb removal were found in Dinghushan.This indicates that litter contributes more to the stability and complexity of soil food webs in high latitudes.The contribution of shrubs and herbs to the stability and complexity of soil food webs in low latitudes was greater than that in the high latitudes.The effects of tree roots removal on soil nematode and microbial communities were greater than that of litter removal in Changbaishan,Baotianman and Dinghushan,indicating that root-derived resources play a more important role in fueling soil nematode and soil microbial communities than that of litter-derived resources.