Recently 30 Years' Wu Zhu Mu Qin Grassland Vegetation Dynamics Research

Inner Mongolia grassland resources are quite rich,one of which that locates in the north of Xilinguole is Wuzhumuqin grassland.Wuzhumuqin grassland is the China's most typical temperate grassland.Grassland ecological environment is fragile.If there is no interference,grassland community of this climate life can maintain their own continuous,and if part of the grass is destroyed,the timely suppression and control of this damage can also be re-emerged.However the more serious damage is the more inevitable the emergence of retrograde successionbecomes,and even very likely to become a non-animal husbandry or barren land.Therefore,in the process of utilizing grassland resources,people have been declining,especially since the 1980 s,grassland degradation,ecological balance loss,desertification trend have been exacerbated.Vegetation is one of the important components of grassland ecosystem,and it is also the basis for ecosystem to maintain stable state and complex structure.Therefore,it is very important to study the dynamic changes of vegetation to provide objective scientific basis for the quantification and diagnosis of grassland degradation and the restoration and management of degraded grassland.It is very important to fundamentally reverse the situation of grassland ecological degradation and promote the sustainable utilization of grassland resources.Taking the Wuzhumuqin grassland in typical steppe area as study area,this paper is based on the five remote sensing images selected from1985 to 2015,the field sampling data and weather data in 2015 supported by ArcGis and ENVI software.The spatial distribution and variation trends of vegetation cover in Wuzhumuqin grassland were expounded indetail,and the natural and man-driven mechanism of vegetation coverage in Wuzhumuqin grassland was expounded.The main conclusions of this paper are as follows:(1)In the last century 80's,the Wuzhumuqin grassland had degraded in different degrees.By the 1990 s,vegetation continued to deteriorate,and this situation continued until after 2008.According to the data of wild sampling plots in 2015,in the grassland vegetation community,Carex duriuscula,Cleistogenes squarrosa,Chenopodium glaucum,Salsola collina,Allium polyrhizum,Caragana stenophylla,Artemisia.Health and other degradation indicating plant species are emerged,and occupy a large part of the sample plant species.The original Stipa grandis and Leymus chinensis densities become sparse.Therefore,the improvement of vegetation coverage shown in the image data can only tell that the vegetation is growing well.In the process of grassland restoration succession,the quality of the grass can not be neglected,and the grassland vegetation can not be restored.The grass has not yet reached the quality balance state and it is not enough to conclude that grassland ecology has been restored.(2)Temperature and precipitation are necessary conditions for plant growth.The precipitation is a factor that directly affects the change of vegetation coverage in the Wuzhumuqin grassland,and the high and low vegetation coverage is related to the seasonal distribution of precipitation.While the temperature affects the plant turning green,indirectly causes the exposition of soil surface or lose of soil moisture.In general,temperature and precipitation are important limiting factors for plant growth and contributed to changes in grassland characteristics.(3)On the whole,the change of vegetation in the Wuzhumuqin grassland is in good agreement with the adjustment of grassland policy,and the change of grassland vegetation is different under different grazing methods.