On The Correlation Between The Occupancy Of The Plateau Pika(Ochotona Curzoniae) And Grassland Degradation

The plateau pika is one of the main biological interference factors in the alpine meadow ecosystem of the Qinghai Tibet Plateau,which affects the biological community and vegetation composition of the alpine meadow.Exploring the impact of the plateau pika on the alpine meadow ecosystem has always been an important topic in the related field of the plateau pika.In the meanwhile,the problem of grassland degradation has been widely concerned because of the importance and particularity of the geographical location of the Qinghai-Tibet Plateau.A high density of plateau pika was generally included in the degraded grassland,which proposed a controversial issue regarding the relationship between Plateau Pika and grassland degradation.On the one hand,there are always grassland degradation problems or phenomena in the areas existing plateau pika.On the other hand,before the problems of the grasslanddegradation after killing plateau pika have not been effectively solved,new problems have occurred.The current studies concerning plateau pika indicate that plateau pika not only changes the soil porosity,but also significantly increases the soil fixation capacity of carbon and nitrogen in its habitat,which affects the evenness of plants and the diversity of local animals and plants.Unfortunately,the above mentioned studies are generally concentrated on Qinghai Province with only a small scale.Thus,the characteristics of plateau pika and its habitat were studied in central Tibet during 2017-2018.In different seasons and sample locations,quadrat was set up,the data of the number of plateau pika burrows in the sample lines and the altitude,plant coverage,bare land coverage,desertification coverage and plant species of their habitats were recorded.The differences of habitat characteristics between the two classes of plateau pika in winter and summer were analyzed by approximate t-test.The relationship between the number of burrows and vegetation coverage,bare land coverage and desertification coverage were analyzed by Poisson regression model of generalized linear model.And the influence of altitude on the above factors were also studied.The purpose of this study is to explore the relationship between plateau pika and grassland degradation in a large scale,so as to provide beneficial reference for further work on grassland restoration and sustainable utilization and development of the Qinghai-Tibet Plateau.The results indicate that there are significant differences in the number of plant species and altitude in habitat of plateau pika(?=0.003,SE=0.073,P<0.001).There is no significant relationship between burrow density and vegetation coverage,desertification coverage and bare land coverage.There was a significant negative correlation between the determined results of vegetation coverage and desertification coverage in habitat of plateau pika(t =-11.733,df = 350,P<0.000001).The results demonstrate that Plateau Pika is not the main cause of grassland degradation,and the main cause of grassland degradation is the decrease of vegetation coverage.The obtained results provide a theoretical basis for future control of grassland degradation.