Land Cover Change And Its Driving Factors In Qinling Mountainous From 1980 To 2015

Land cover change is an important part of global environmental change research.Studying the spatial and temporal dynamics of land cover and its driving factors is helpful to reveal the interaction between natural environment and human society in the region,and is of great significance to the protection and management of ecosystems.Therefore,based on the data set of land cover in Qinling Mountainous from 1980 to 2015,this paper studied the spatial-temporal changes of land cover landscape pattern and its driving factors in Qinling Mountainous by using ArcGIS spatial analysis method,landscape pattern index method,principal component analysis and other methods.The following conclusions and progress were obtained in this study:(1)From 1980 to 2015,the Qinling Mountainous was dominated by forest land and grassland,accounting for 72%of the total area of the study area.The area of cultivated land,residential land,water use land and unused land was relatively small.The spatial distribution of land cover was closely related to the topography and landform of the study area.In the past35 years,the land cover change in the Qinling Mountainous was mainly due to the increase of construction land,with a net increase of 742.68 km~2.The grassland and cultivated land area decreased by 510.68 km~2 and 435.16 km~2,respectively,and the net increase of forest land was201.23 km~2.Relatively small changes in waters and unused land area.(2)From 1980 to 2015,the comprehensive impact of human activities on land cover in Qinling Mountainous increased first and then decreased.In the past 35 years,the trend of land cover transfer was mainly the transfer of forest land to construction land and cultivated land,and the transfer of cultivated land to forest land and grassland.The land cover transfer is mostly concentrated in the urban area of Xi’an and its surrounding areas,mainly due to the relatively low elevation of the area and the rapid development of urbanization.(3)In the past 35 years,the degree of landscape fragmentation in the Qinling Mountainous has gradually increased.The shape of the landscape has become complicated,the degree of landscape aggregation and connectivity have decreased,and the spatial distribution of the landscape pattern index has obvious topographical differentiation characteristics.The overall vulnerability of the landscape pattern in the Qinling Mountains is relatively low,and most of the areas are lower fragile and medium fragile.In the past 35 years,the vulnerability of landscape pattern has declined overall.Among them,the spatial pattern of low-vulnerability areas has changed significantly,mainly from Xi’an and Hanzhong to the surrounding areas.(4)In the past 35 years,the degree of human disturbance in the landscape pattern of the Qinling Mountains has gradually increased,and the area of severely disturbed areas has increased by 393 km~2.From east to west,the trend has gradually weakened.The north slope has greater interference than the southern slope,and the spatial distribution is“high in the east and low in the west”.The south slope is low,the north slope is high,the middle is low,and the periphery is high,and it has obvious spatial clustering characteristics.The greater the degree of human disturbance,the larger the plaque density,the landscape pattern vulnerability,and the Shannon diversity index,the smaller the maximum plaque index and the aggregation index;the influence of human disturbance degree on the landscape pattern vulnerability is gradually weakened,and the Shannon diversity index,The influence of the maximum plaque index gradually increased,and the effect on plaque density and aggregation index did not change significantly.(5)From 1980 to 2015,the degree of fragmentation of forest land and grassland landscape increased gradually.The disturbance of human activities and the change of climate factors affected the change of forest and grassland landscape pattern in Qinling Mountains.In the past 35 years,the connectivity of forest land and grassland landscape in the Qinling Mountains has decreased,the landscape heterogeneity has been enhanced and the landscape shape has become more complicated.The grassland has changed significantly compared with the forest land.In the spatial distribution,the spatial distribution pattern of forestland and grassland landscape pattern index is obvious,and it has certain topographic gradient under the action of topographic factors,especially the correlation with altitude.Human disturbance is the main driving factor affecting the change of forest and grassland landscape pattern in Qinling Mountains.The climatic factors are second.At the same time,the country’s macroeconomic policy adjustment has also played an important guiding role in the landscape pattern change.Therefore,in order to effectively protect the biodiversity,ecological environment safety and sustainable use of resources in the Qinling Mountainous,it is necessary to slow down the excessive impact of human activities on the Qinling Mountainous,especially to maintain the balance and integrity of forest land and grassland.