Study On The Influence Of Mineral Exploitation In Typical Grassland Zone On Grassland Degradation

Grassland plays an important role in the development of animal husbandry.Grassland ecosystem not only has irreplaceable natural ecological function,but also contains various mineral resources.However,the exploitation of mineral resources harms the ecological balance of grassland.With continuous expansion of mining area,the grassland around the mining area has become a serious ecologically damaged area.Based on this,the study area of this research is located in Xilinhot city,Inner Mongolia,which belongs to the typical grassland zone.The spatial analysis function of ARCGIS 10.1 and ENVI 5.1 was used on the basis of interpretation results by three period remote sensing images,and the study area had similar annual rainfall in the year of 2000,2008 and 2016,which were 191.90 mm,186.50mm and 189.60 mm respectively.Based on the analysis of the changes of land use,grassland degradation in the Xilinhot city,the concentric circles with different influence radius were drawn by taking the central point of the mining activity area.According to the degree of grassland degradation,the influence range of mining activities on the surrounding area was analyzed from the boundary of mining activity area.The key research results are as follows:1.Grassland,woodland and cultivated land were the main land use types in the research area.In the past 16 years,the conversion between each type was frequent,the area of grassland was decreasing year by year,and the expansion of all other kinds of land use types came from the decrease of grassland.Mining warehouse land,traffic land and residential area had expanded remarkably,as mining warehouse land expansion was the fastest with 1574.30%dynamic change degree.The area has expanded from 0.18km~2 in 2000 to 45.52 km~2 in 2016,which was mainly distributed in the northwest,eastern and western regions of Xilinhot city,and its main source was grassland.2.The grassland area of the city in 2016 was 12816.53km~2,which was mainly occupied by moderately degraded grassland,and the proportion of multi-grade degraded grassland had different distribution properties in each sumu(town)of the study area.3.Grassland degradation has appeared different change characteristics in all of the observed years,which means that severe degraded grassland dominated in 2000,and moderate degraded grassland dominated in 2008 and2016 respectively.The grassland degradation index(GDI)decreased from3.32 in 2000 to 2.32 in 2008 and 2.21 in 2016.Grassland improved from severe degradation to moderate degradation,the process of grassland degradation alleviated in a certain extent,but the grassland quality was not high on the whole.The variation of grassland degradation index between each sumu(town)was obvious.The trend of grassland continuous degradation and improvement coexisted simultaneously,and the grassland degradation situation was still quite severe.4.The spatial changes of degraded grassland in different grades were obvious and the speed of degradation in the northern and middle part of study area reduced in the last 16 years,and the situation in the east showed the improvement,and the grassland in the southern part of study area improved again after the degradation in around of the year of 2008,changed to that mild or no obvious degradation is main kind of grassland degradation grade.The variation of grassland degradation in each sumu was quite different,and grassland obviously improved in Aershanbaolage town,Chaokewula sumu,Baoligen sumu and Xilinhot city etc.Grassland in Baiyinkulun Pasture showed a change dynamic from degradation to improvement,while Baiyinxile Pasture showed contrary trend.5.The influence of mineral exploitation on grassland degradation indicated that the policy of"laissez-faire"management led to the degradation of large scale grassland in early 2000,and the area of severe degraded grassland was significant in the surrounding of the mining area.In 2008,the grassland degradation appeared improvement trend entirely,but influence of mining activity for grassland degradation was very obviously.With the expansion of mining activities,within 2 km of the maximum radius of influence,the grassland basically belonged to severe degradation grade.Along with the further expansion of industrial and mining storage land in2016,the radius of influence also extended,within 7 km of the maximum radius,the grassland basically belonged to severe degradation grade.Therefore,under the condition of relative stability of other influencing factors,as the industrial and mining storage land expanded,so did the radius of influence of mining activities and the distribution range of severe degraded grassland.So mineral exploitation was one of the leading factors which causes grassland degradation around the mining area.