The Impact Of Human Activities On The Landscape Pattern In Guanzhong Area

Since the reform and opening up,China's economy has developed rapidly,population growth is rapid,and urbanization process is accelerating.At the same time,more and more intensive human activities have deepened the development and utilization of land.In recent years,the study of human activities and landscape patterns has become a hot issue of concern to many scholars.Guanzhong area has been the economic and cultural center of the western region since ancient times.Its terrain has basins,plateaus and mountains.Since the beginning of the 21st century,as an important area of China's western development strategy,the population,economic and environmental pressures facing Guanzhong region have become prominent.Therefore,it is of great significance to study the temporal and spatial variation characteristics of human activities and landscape pattern in Guanzhong area,and to explore the impact of human activities on landscape pattern,so as to guide the more rational development and utilization of land resources,coordinate the relationship between human and land,and protect the ecological environment in Guanzhong area.Based on the project of Central University,the data of 30 m grid land use/land cover and socio-economic statistics of Guanzhong area in 1980,1995,2005 and 2015 are used as the basis.Firstly,a reasonable spatial grid is established and determined by using GIS technology,and the hemeroby representing the intensity of human activities in Guanzhong area is quantitatively calculated during the research period.The spatial and temporal variation characteristics of human disturbance in Guanzhong area are analyzed by grading research.Then,based on the analysis of the dynamic evolution of landscape pattern in Guanzhong area and the landscape ecology index method,the standard method and the moving window method under Fragstats 4.2 software are used.The spatial and temporal changes of landscape pattern in Guanzhong area in recent 40 years were analyzed by selecting reasonable landscape pattern index suitable for the characteristics of the study area.Finally,based on the analysis of driving force of the hemeroby and landscape pattern,the Pearson correlation analysis method in SPSS22 was used to test the significance by double-tail test.The statistical relationship between hemeroby and landscape pattern indices was discussed.Based on this,OLS spatial regression model was established in ArcGIS 10.2,and the impact of human activities on landscape pattern was explored.Through the research,the main conclusions are as follows:(1)In the past 40 years,the spatial and temporal variations of human disturbance in Guanzhong area have shown some regularities.In terms of spatial change:Based on the calculation of hemeroby in the scale of 1 km grid,analyzing from the four levels of slight disturbance,moderate disturbance,severe disturbance and serious disturbance,it is found that the hemeroby in Guanzhong area has shown a gradation change law with Weihe Basin as the central axis and Xi,an City as the core,weakening to the north and south sides in recent 40 years.In terms of time change and annual change rate,the hemeroby in Guanzhong area showed an increasing trend from 1980 to 2015,showing different characteristics in different periods.From 1980 to 1995,the main growth areas of hemeroby in Guanzhong area were concentrated in the urban center.The maximum difference of hemeroby change reached 7.45 in some regions,which is the maximum of the growth of hemeroby change in three periods.But overall,the area of negative growth of hemeroby in this period is larger,and the intensity of human activities is relatively low.From 1995 to 2005,the positive growth areas of hemeroby mainly concentrated in counties,city centers and along main roads.The areas with negative growth of hemeroby in the initial stage mostly turned into positive growth.The maximum difference within the region of annual change rate is 1.21,which indicates that although the hemeroby in Guanzhong area during this period increased,the differences within the region gradually increase.From 2005 to 2015,the hemeroby showed an explosive growth in the whole region.Overall,the growth of hemeroby showed a trend of northward development.The annual variation rate in different regions had a maximum difference of 1.30,and the spatial difference was more significant(2)Landscape types in Guanzhong area changed frequently from 1980 to 2015.The main landscape types in Guanzhong area are arable land,woodland,grassland and construction land,of which arable land area is the largest.In the past 40 years,the arable land and unused land landscape in Guanzhong area have been greatly reduced,and the grassland and water landscape have also been reduced to a certain extent.The arable land is mainly converted into urban and rural,industrial and mining,residential land,accounting for 59.73%of the total arable land.On the contrary,the area of construction land(urban and rural,industrial and mining,residential land)has increased significantly.and the forest land has also increased slightly.(3)In the past 40 years,the landscape pattern fragmentation in Guanzhong area has shown the change of first strengthening and then weakening,overall strengthening,the diversity and complexity are increasing.Spatially,there are obvious regional differences in the characteristics of the landscape pattern in Guanzhong area.From the time variation analysis of landscape pattern index based on standard method,the NP,the LPI and the AREA MN were decreased,instead that the DIVISION was increased.In addition,the CONTAG was decreased and SDHI and SHEI were increased in Guanzhong area from 1980 to 2005.After 2005,the fragmentation degree of landscape decreased,but it still showed the trend of the fragmentation strengthening and the diversity and complexity of landscape continued to increase in the whole research period.Based on the analysis of spatial change of landscape pattern index by moving window method,the AREA MN and the AI of Weihe basin gradually increased,the FRAC_MN and the SHDI decreased from 1980 to 2015.Because the northern foot of Qinling Mountains belongs to the ecological protection area,the landscape pattern changes little.With the development of economy in Guanzhong area,the Weibei Plateau shows a trend of decreasing low-value area of AREA_MN,decreasing high-value area of FRAC_MN,low AI and enhancing landscape SHDI.(4)There is a significant correlation between human activities and landscape pattern in Guanzhong area,and human activities have a significant impact on landscape pattern.Pearson correlation analysis matrix showed that the hemeroby in Guanzhong area was positively correlated with the average patch area and aggregation index,and negatively correlated with the average fractal dimension and fragrance diversity index.Based on OLS spatial regression analysis method,taking hemeroby in different years as independent variable,and the different landscape pattern index in corresponding years as dependent variable,established a spatial regression analysis model.The results show that human activities in Guanzhong area have contributed more and more to landscape pattern during the research period.