The Influence Of Human Activities On The Spatiotemporal Pattern Of Vegetation Cover In China

Vegetation is an important part of terrestrial ecosystems and an important indicator for ecological environment monitoring,ecological risk and vulnerability assessment.With the enhancement of human activities,vegetation changes have profoundly recorded the imprint of human activities.In the short term,the dynamic evolution of vegetation is mainly caused by human stress caused by direct and indirect effects of human activities,whether global,regional or local.The impact of humans on vegetation exceeds the natural factors in speed and extent.The impact of human activities on vegetation has become an important part of ecological environment protection.Based on quantitative remote sensing technology and GIS analysis method,this paper establishes a model to quantitatively calculate the impact of human activities on vegetation cover in China from 2001 to 2015,and comprehensively studies the changes of human activities from time and space,and analyzes its future evolution trend.This has important practical significance for objectively understanding the changes in China's ecological environment,and provides decision support for China's ecological environment protection and construction.Initially got the following conclusions:(1)From 2001 to 2015,the annual average impact of human activities on vegetation cover in China was-0.0102,and the damage effect was greater than the protective effect.The area affected by positive and negative impact areas was 48.41% and 51.59%,respectively.Greater than positive impact.The role of human activities has promoted the improvement of vegetation in the western Sichuan Basin,the middle and lower reaches of the Yangtze River,the southwestern part of the North China Plain,the central Loess Plateau,the central Inner Mongolia Plateau and the southern part of the Qinghai-Tibet Plateau,and led to the Songnen Plain,the Liaohe Plain,and the Hunshandake.Vegetation damage in parts of the northern part of the sand,northern and southern parts of the North China Plain,the Ordos Plateau,and the Tarim River Basin.In general,the ecological environment in the “key” areas that people are paying attention to is obviously improved,while in other “unpopular” areas,human beings have not effectively curbed the ecological environment.The current implementation of environmental protection measures has certain limitations.How to rationally allocate environmental resources and formulate comprehensive and effective measures is the biggest challenge facing China's current environmental protection.The impact of human activities on vegetation cover in China is obviously changing with altitude.Human activities at the elevations of 1600-3200 m and 3400-4300 m are positively affected.Under the influence of human activities,the vegetation in the northwest region improved significantly,and the vegetation in the other seven major human geography integrated areas was damaged to varying degrees.Among them,the central China region had the most damage.In the past 15 years,human activities have had a positive impact on forest land,and have negative impacts on grassland,cultivated land and urban and rural construction land.Among them,the most damage to urban and rural construction land.(2)From 2001 to 2015,the impact of human activities on China's vegetation coverage was negative,and the overall performance was a negative trend of weakening fluctuations.Human damage to the ecological environment was effectively contained.The activities of human activities on the vegetation in South China,Southwest China,Qinghai and Tibetan areas are increasing;the vegetation in Central China still has a destructive effect,but the degree is reduced;in North China,Northwest China and Northeast China,the damage of human activities to vegetation is weakening,and finally Breaking through the critical point,it becomes positively affected and continuously enhanced;the disturbance effect of human activities on vegetation in East China is changed from protection to destruction.In the past 15 years,the impact of human activities on forest vegetation has been positive and has been continuously enhanced;the damage to grassland and cultivated land vegetation has been improved,and the degree of vegetation damage to urban and rural construction land has been increasing.(3)Analysis of the center of gravity transfer model shows that under the action of human activities,vegetation cover in eastern and northern China is improving day by day,and the damage of vegetation in human activities in the west and south is increasing.In the past 15 years,the center of gravity and the negative impact have been the largest moving distance in the northeast region.The impact of human activities on the vegetation coverage in this area has changed significantly in spatial distribution and degree of influence.(4)In terms of space,the impact of human activities on China's vegetation cover is mainly due to the negative impact of weakening,with an area accounting for 28.14%,and the significance is good.The damage of human vegetation in a considerable part of China is obviously improved.The environment is getting better.The western part of the Northeast Plain,the Liaohe Plain,the Haihe Plain,and the southeastern part of the Ordos Plateau are mainly positively affected.The eastern part of the Northeast Plain and the southeastern part of the North China Plain are mainly affected by the weakening trend;in the Hulun Buir Grassland,the Inner Mongolia Plateau and Some areas of the Loess Plateau mainly showed a negative impact weakening trend;in the Loess Plateau,Shandong hills and peninsula,and parts of the northern part of the Tianshan Mountains,the negative impact enhanced trend.(5)From 2001 to 2015,the average value of Hurst index was 0.4968.The reverse characteristics of human activities on the change of vegetation cover in China were stronger than the same direction.Among them,15.59% of the regions showed negative impact and then weakened.In the North China Plain,the southeastern part of the Ordos Plateau,and the Bohai Sea region,vegetation cover continues to improve under the influence of human activities;in the Loess Plateau,central Yunnan,human activities continue to aggravate ecological damage;in the eastern part of the Northeast Plain and parts of the North China Plain,human activities are affecting the persistence.Weakening;Hulunbeier grassland,part of the Mongolian plateau showed a negative impact after the first negative impact;the northern part of the Tianshan Mountains had a negative impact and then weakened.