Effects Of Grazing On Plant Community Phylogeny In Typical Grassland

Grazing interference is one of the most important factors in the construction of grassland plant community.The reasonable grazing method can make the grassland fully utilized while protecting the grassland ecosystem stability.In order to explore the phylogenetic diversity of the typical prairie plant community and the construction process and driving factors of the community structure,the sample sampling and the molecular DNA barcode technology were used to study the grazing grassland,and the phylogenetic relationships among the samples were directly depicted through the construction of phylogenetic tree,through the system.The growth diversity index,the Phylo Sor index net relationship index and the nearest relative index were used to quantify the phylogenetic diversity,the phylogenetic similarity and the community phylogenetic structure of the community.Soil water,total nitrogen,available nitrogen,total phosphorus,available phosphorus and total organic carbon were measured,and their effects on the development of the soil were analyzed.The results showed that:(1)Community phylogeny diversity index and community phylogeny similarity decreased with grazing gradient.(2)the index of the phylogenetic structure of the community showed a trend of aggregation to diverge and then to aggregation with the grazing gradient;the Net Relatedness index of the none grazing,mild grazing,severe grazing and very severe grazing four grazing gradients was greater than zero,and the phylogenetic structure of the community was dominated by habitat filtration,while the index of moderate grazing net Relatedness was less than zero,the phylogenetic structure is dominated by interspecific competition.(3)correlation analysis showed that soil water content was significantly correlated with community phylogeny diversity index,and soil total phosphorus was significantly correlated with the Net Relatedness index.(4)grazing changed the species composition of the community indirectly by changing the distribution of soil water content,which changed the diversity of the community system development,and the total phosphorus in the soil was generally deficient under the influence of grazing.The difference distribution stressed the phylogenetic structure of the community,which was the leading factor affecting the phylogenetic structure of the community.