| As an essential part of sphere,ecosystem shows its importance for human being and social economic development,is also known as life-support system on earth.The Yangtze River Economic Belt（YREB）has diverse ecosystem types and powerful ecosystem service functions,and is an important region to ensure ecological security in China.In recent years,the ecosystem of the Yangtze River Economic Belt has been strongly affected by human activities,which has restricted its social and economic development to some extent.Therefore,in order to quickly and effectively solve the problems existing in the process of ecosystem evolution in the Yangtze River Economic Belt,grasp the change rules of ecosystem services,and seek a balance between the Socioeconomic development and Ecological protection of the Yangtze River Economic Belt,In this paper,the characteristics of ecosystem pattern evolution,driving factors of ecosystem pattern evolution and ecosystem service value（ESV）assessment in the Yangtze River Economic Belt from 1990 to 2020 were analyzed.The main results show that:（1）The YREB has diverse ecosystems.Forest is largest ecosystem among others,which accounted more45%,followed by farmland ecosystem,which is around 30%.In the past 30 years,the most frequent changes of ecosystem in the study area were farmland and forest and grassland changed into town,Farmland and forest ecosystems transform each other.The area of farmland,grassland,bare land and other ecosystems decreased,and the area of farmland ecosystem decreased significantly by 5.39%;The area of urban,wetland and forest ecosystem increased,and the area of urban ecosystem changed the most,increasing by 95.82%.There are obvious temporal-spatial heterogeneity and obvious spatial agglomeration and diffusion effects in different regions of ecosystem change in different periods.During the past 30 years,the most severe changes of ecosystem were found in the lower reaches of 0-100 m above sea level and some middle reaches of the plain.It is followed by some provinces with an elevation of 100-500 meters and large urban agglomeration areas upstream.In the past 30 years,the dynamic attitude of each ecosystem type was different,and the urban area was the largest,accounting for 3.19%.The dynamic attitude of comprehensive ecosystem increased as a whole.The proportion of ecosystem area was different at different altitude（slope）and at different time at the same altitude（slope）.Urban ecosystem is mainly distributed in the area with elevation less than 100m（<5°）.With the increase of elevation（slope）,the proportion of farmland,wetland and urban area decreases gradually,while the proportion of forest and grassland increases gradually.At altitudes below 500m（<5°）,the forest area shrinks,while in other areas,the forest area increases.The area of farmland and grassland ecosystem decreased,while the area of urban and wetland increased in different elevation（slope）grades.（2）The changes of ecosystem pattern in the Yangtze Economic Belt are firstly influenced by driving factors such as overall economic level,fiscal revenue,industrial structure and urban construction,and then by regional population factors and foreign economic and trade factors.From 1990 to 2019,the comprehensive scores of driving factors of ecosystem pattern change in the Yangtze River Economic Belt showed an overall increasing trend.Ecological protection and land use policies are also one of the important driving forces of ecosystem pattern change in YREB.（3）1990-2020,the total value of services in the study area increased by 3.29%.Forest ecological service value accounted for the largest proportion,more than 56%.The value increment and growth rate of wetland ecosystem services were the highest,increasing by 17.57%;Farmland saw the biggest drop of 5.35%.The value of regulating service accounted for the largest proportion,over 71%.The value of each single service increased,and the growth rate of supply service was the highest,increasing by 5.67%.The temporal and spatial changes of total service value and individual service value are obvious on the whole.Spatially,the middle and high value areas of each single ecosystem service are mainly the low altitude area in the middle and lower reaches of the wetland ecosystem and the high altitude area in the upper reaches of the forest ecosystem.In terms of time,the region of single service value above middle and senior level shows a diffusion trend.In view of the above research results,in order to protect the sustainable development of the YREB,it is necessary to improve the ecosystem service function and ensure the ecological security of the river basin;cultivated land protection should be actively carried out to ensure national food security;We will optimize the spatial pattern of the ecosystem to ensure the ecological security of urban human settlements. |
