Study On Plant Community Structure And Spatio-temporal Pattern Of Seriphidium Transiliense Desert Grassland Based On Sheep Grazing Trajectory

Seriphidium semidesert grassland is an important spring and autumn pasture in Xinjiang region.In the course of grazing,because of the free feeding and wandering of animals,a large-scale displacement is formed in the space,which can greatly increase the landscape diversity on the space scale.By acquiring the real-time data of the moving track of sheep grazing,the actual moving path,the moving distance and the space-time track of the staying time in the process of animal grazing are analyzed as well as the measured data on the law of defecation on the grazing track,The regularity of sheep grazing track in grazing area was determined by trajectory algorithm,and the effects of grazing process on the state of desert grassland in seriphidium transiliense were discussed from two levels of species diversity and landscape diversity.Object: The aim of this study is to enrich the ecological research on the relationships between plants and animals by studying the plant community structure and the spatiotemporal pattern characteristics of the desert grassland of seriphidium transiliense based on the grazing track of Sheep To reveal the relationship between grazing behavior of herbivores can provide theoretical support for grazing management and restoration of this kind of grassland.Methods: Based on the analysis and processing of GPS data of Arc GIS,the grazing track of sheep was obtained,and the diversity characteristics of plant communities in seriphidium transiliense desert grassland were explained by field investigation,DCA and DCCA methods Then Mapinfo was used to characterize the landscape pattern.Results: 1)The walking speed and moving track characteristics of grazing sheep varied with grazing time,grazing season and grassland condition:In grazing season,the speed at which the sheep move with the seasons,the walking speed of grazing increased at first,then tended to be flat,then decreased and then increased;In the daily variation,the walking speed of sheep presented a parabola distribution,which increased first and then decreased and then increased;With the increasing of the slope,the velocity changes in a parabola.When the slope is 43,the velocity reaches its maximum value.2)The sheep formed obvious grazing gradient during grazing,and the grassland in the study area was divided into 8 community types,There is a clear boundary between each community type,and there is no obvious similarity between the communities,six major environmental factors affecting species distribution and community formation were identified:Soil organic matter,grazing intensity,amount of manure,litter,elevation and slope direction,The results of DCCA ranking reflected the actual ecological significance of each environmental factor,and provided a good environmental explanation for the species and community characteristics of desert grassland of grazing seriphidium transiliense.3)Grazing sheep foraging paths were different in spring and autumn.The grassland was divided into 4 community types by DCA analysis,and the diversity index of each community was different;Herbivore feeding behavior can effectively spread plant seeds over a long distance,and the seeds still have different germination rates after being spread through the digestive tract.The landscape pattern of the experimental area was reclassified by the "corridor" formed by grazing.Conclusion: In the desert grassland of seriphidium transiliense,the grazing trajectory caused by sheep grazing has a direct impact on the plant diversity,community composition and structure characteristics;The grassland landscape pattern was divided into different types by different grazing scales,and the "gallery" was established by using the trajectory buffer zone to illustrate the change of landscape pattern.