Effects Of Livestock And Plateau Zokor (Myospalax Baileyi) On Plant Diversity And Productivity In Alpine Meadow

Effects of herbivores on plant diversity and productivity are controversy,and it is generally believed that there is a competitive relationship between wild herbivores and livestock.In this study,two experiments were conducted on different areas of the Tibetan Plateau.In the first experiment,a free-grazing grassland and a five-year fencing site were selected as controls in sub-alpine meadows in the eastern part of the Tibetan Plateau.Three years of continuous monitoring were conducted to study plant diversity,productivity,plant abandance,and plant functional characteristics response to grazing.In the second experiment,the number of vegetation species,species cover,and zokor mound density of 24 30 m × 30 m plots were investigated by using the grid method in the alpine meadow of Henan county,Qinghai province.In order to answer the role of underground zokors in the maintenance of plant diversity in alpine meadows and whether or not the zokors would compete for food resources with livestock.The main findings are as follows:(1)Long-term free grazing significantly reduced plant species richness and above-ground biomass compared to fences.Overall,the biomass of common species was not significantly different between fencing and grazing.(2)Grazing relative to the fence significantly reduced the biomass and richness of grasses and forb,but increased the relative proportion of sedge plants;Grazing significantly changes the abundance and biomass of perennial plants relative to the fence,but has no significant effect on the biomass of annual plants;Grazing significantly reduces the richness,biomass,and abundance of tall plants relative to fences;Grazing relative to the fence significantly affects the richness and biomass of stoloniferous,rhizomatous plants,and rosettes;From a palatability point of view,grazing has a more significant effect on unpalatable and low-palatable plants than palatable plants.(3)The plateau zokor disturbance had no significant effect on species richness,(4)Shannon-Wiener diversity index,Simpson dominance index,and evenness of grassland plants.With the increase of the interference intensity of plateau zokor,the total biomass of grassland plant communities decreased,but the coverage of dominant species E.nutans,increased significantly,and the biomass of forb decreased.In summary,Compared with fences of more than five years,free grazing is not conducive to the improvement of plant diversity and productivity.Grazing is more conducive to forb,dwarf plants,and annual plants.Stoloniferous plants and rosettes,unpalatable plants.This shows that compared with simple classification,a multiple functional groups classifications can make us more fully understand the response of plant trait response to grazing disturbance.Zokors disturance caused a significant decline in the above-ground productivity of the vegetation,had no effect on plant diversity,did not meet the “intermediate disturbance hypothesis,” and indicated that there was no apparent food-competition relationship between the zokor and livestock.