Effects Of Plateau Pika Disturbance On Soil Quality Of Alpine Meadows

The source area of the Yellow River is an important part of the ecological security of "two screens and three belts" in China,and it is also the key area of the construction of the ecological security barrier system in the "14th Five Year Plan".In recent years,affected by climate change and increasingly severe human activities,the alpine meadow in the source region of the Yellow River has been continuously degraded.In order to effectively improve the regional ecological environment,measures have been taken to prohibit overgrazing and enclosure in China.The impact of animal husbandry on alpine meadow is gradually decreasing,but the sustained activities of plateau pika have always affected the alpine meadow ecosystem.Soil is an important part of alpine meadow ecosystem,soil quality has a direct and far-reaching impact on the sustainable development of alpine meadow ecological balance.Ochotona curzoniae is a unique and common soil disturbance organism in the source region of the Yellow River.It changes soil properties through multiple behaviors,and then affects the ecosystem function of alpine meadow.Therefore,the study on the relationship between soil quality and pika activity in alpine meadow can provide basis and reference for further determining the direction and method of ecological management in the source area of the Yellow River,and is of great significance for ecological construction in the source area of the Yellow River.In this study,Xinghai County,Maqin county and Zeku County of the source area of the Yellow River are selected as the research area.The differences of soil physical,chemical and biological properties of different research areas are analyzed comprehensively.Through the difference analysis and principal component analysis,the important data sets and minimum data sets indexes for evaluating soil quality of Alpine Meadow under the interference of plateau pikes are established,The effects of the activity and the intensity of the disturbance on the physical and chemical properties and biological activities of the soil were further studied.The influence of the disturbance and the intensity on the soil quality was quantitatively evaluated,and the influence of the disturbance on the soil quality of alpine meadow was revealed.The main conclusions are as follows:(1)Soil moisture content,soil sand content,soil organic matter,total phosphorus and cation exchange capacity in s,l and Z areas disturbed by pika were significantly higher than those in non-disturbed areas,and the average total phosphorus and cation exchange capacity were 21.35% and 23.53% higher than those in non-disturbed areas.The contents of clay and silt,available phosphorus,invertase activity and urease activity in the non-disturbance area were significantly higher than those in the disturbance area,and the urease activity in the nondisturbance area was 2.25 times of that in the disturbance area.The content of available phosphorus and soil urease activity in l area were significantly higher than those in S and Z area.(2)Soil water content,total phosphorus,available phosphorus,soil invertase activity and catalase activity decreased first and then increased with the increase of disturbance degree.Soil total nitrogen increased with the increase of disturbance degree,while soil urease activity decreased all the time.(3)MDS-SQI and SDS-SQI showed a significant positive correlation in the study area.,and the minimum data set could scientifically,accurately and efficiently evaluate the soil quality of alpine meadow.The disturbance of pika reduced the soil quality in the study area,and the soil quality in the bare spot habitat area and vegetation coverage area was better than that in the random area.The soil quality index in the random disturbance area and vegetation coverage area decreased at first and then increased with the increase of disturbance degree.