| Since the reform and opening up,with the rapid development of Guangzhou's economy and society,land use change has made the ecosystem change obvious,and also brought a series of ecological and environmental problems.Therefore,this paper observes and studies the ecosystem of Guangzhou,explores the spatio-temporal evolution of multi-time and small-scale ecosystem service value and explores the driving factors and driving mechanism that cause its spatio-temporal evolution,it is of great significance to understand the changes of regional ecosystem,promote the rational development and utilization of land,and realize the coordinated development of social economy and ecological environment..Based on seven remote sensing maps of Guangzhou in 1975,1987,1995,2000,2005,2010 and 2015,this paper analyzes the land use layout and structure of Guangzhou from 1975 to 2015,calculates the ecosystem service value of Guangzhou on the basis of land use area,including the spatio-temporal evolution of ecosystem service value of Guangzhou from the overall pattern,different land types and grid scale.The driving factors of Guangzhou were identified and analyzed by principal component analysis,gradient analysis and correlation analysis.Finally the driving mechanism of spatio-temporal evolution of ecosystem service value in Guangzhou was further explored by geographic detector.The main conclusions are as follows:(1)Land use types in Guangzhou include woodland,grassland,waters,construction land,unused land and cultivated land.Woodland and cultivated land are the main types,but their proportion has decreased in recent years,and the proportion of construction land has increased rapidly.Woodland land and grassland are mainly distributed in the northern mountainous and hilly areas,while construction land and cultivated land are more distributed in plain areas and along rivers.The spatial distribution pattern of ecosystem service value in Guangzhou is closely related to the distribution of land use types,showing an obvious features of high in the north and low in the south,and the distribution area of high value shows an obvious process of expanding first and then shrinking,while the distribution area of low value shows an obvious process of shrinking first and then expanding.(2)From 1975 to 2015,the total value of ecosystem services in Guangzhou showed a process of "increase-decrease-increase-decrease" with the passage of time.It is increased from 1975 to 1995,it is decreased from 1995 to 2005,it is increased from 2005 to 2010 and it is decreased from 2010 to 2015.Over the past 40 years,the ecosystem service value of waters and construction land has increased,while the ecosystem service value of woodland,grassland,unused land and cultivated land has decreased.The total value of ecosystem services in Guangzhou increased slightly supplemented by the contribution of increased waters ecosystem service value during the study period.It is worth mentioning that the expansion of construction land ecosystem service value distribution area has increasingly become an important factor affecting the spatio-temporal evolution of ecosystem service value distribution area of other land types.(3)The spatial distribution of the regions with similar ecosystem service value tends to be dispersed,the spatial convergence of ecosystem service value is weakening and the spatial difference is becoming larger in Guangzhou.The smaller the scale,the more obvious the spatial regularity of ecosystem service value in Guangzhou.At the scale of 1 km*1 km,the distribution of high-high and low-low ecosystem service value in Guangzhou shows three big pieces and five small pieces.At the scale of 1 km*1 km,the centroid migration of ecosystem service value in Guangzhou is complex,which reflects the complexity of the spatio-temporal evolution of ecosystem service value.In addition,at the scale of 1 km*1 km,the region where ecosystem service value decreases dramatically,it evolves from point,line and surface to fragmentation distribution.(4)The natural and human drnving factors such as terrain,river,economy,urbanization,population,transportation and planning are the main factors affecting the value of ecosystem services in Guangzhou.Specific performance is as follows:the lower the altitude,the smaller the slope,the closer the river,the closer the economic center(industrial center),the closer the urban center,the closer the population center,and the closer the regional center with outstanding development of the master plan,the lower the value of ecosystem services per unit area;traffic is an exception,and its ecosystem service value per unit area is the lowest at a certain distance from traffic.(5)Based on the analysis of the grid which construction land was increased,it is found that the driving mechanism of spatio-temporal evolution of ecosystem service value in each period of Guangzhou in the past 40 years is different.A.From 1975 to 1987,natural condition played a leading role.Guangzhou's regional location advantage which is near rivers and flat terrain is obvious.Especially Tianhe and Huangpu in the suburbs became the bridgehead of urban expansion.Therefore ecosystem service value decreased rapidly in Tianhe and Huangpu,mainly in the form of point evolution.B.From 1987 to 1995,industrialization played an important role.The suburban industrialization of Guangzhou was obvious.The layout of industry is along the Pearl River and it led to the decrease of ecosystem service value on the Northern Bank of the Pearl River,mainly in linear evolution.C.From 1995 to 2005,urbanization played an important role.Especially under the radiation of the urban center,urbanization in the surrounding areas of urban center was accelerating,which led the region where ecosystem services value was decreased rapidly expand eastward,southward and northward continuously,mainly in the form of planar evolution.D.From 2005 to 2015,transportation played an important role,it promoted the development of Guangzhou from a single center to a multi-center,and under the radiation of urban center and the improvement of transportation network,the regional distribution of ecosystem service value decreased rapidly is more fragmented. |
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