Spatiotemporal Change Of Social-Ecological System Resilience And Its Influencing Factors In Loess Hilly-Gully Region Of Central Gansu

As an indispensable part of the Loess Plateau,Loess Hilly-gully Region is characterized with fragile ecological environment and severe economic poverty,which seriously affecting the regional ecosystem and sustainable development of human society.Longxi County of Gansu Province is located in Hilly-gully Region of the Loess Plateau,specifically,the junction of hilly area of the Loess Plateau and Qinling Mountains branch.With great fragmented terrain feature,low precipitation,high evaporation,soil loosens and water shortage,it is a typical ecological fragile area of the Loess Plateau.At the same time it is also one of the key counties of national poverty alleviation and a major county of the national poverty-stricken counties in the Liupan Mountain Area.From the perspective of social-ecological system concept,Loess Hilly-gully Region of Central Gansu is concerned.Based on the RS/GIS technology,Landsat TM/ETM+/OLI remote sensing data,land use data and socioeconomic data,this thesis constructs the social-ecological system resilience evaluation index system from the two dimensions as vulnerability and coping capacity and three sub-systems as society,economy and ecology.Taking Longxi County of Gansu Province as an example,the entropy method,analytic hierarchy process,comprehensive index method and obstacle degree model are used to measure the social-ecological system resilience of Longxi County from 1995 to 2015.Besides,the main influencing factors affecting the social-ecological system resilience in the research area are analyzed.Combining with principle of adaptive management philosophy and the diagnosis results of obstacle degree model,the adaptive management strategies of social-ecological system are given and perfected,the thesis aims to improve and promote the process of sustainable development of human society in Loess Hilly-gully Region of Central Gansu.The preliminary conclusions are as followed:(1)The vulnerability of social-ecological system tends to increase in the research area from 1995 to 2015.The overall change between 1995 and 2005 was greater than that between 2005 and 2015 with Kezhai Town and Wenfeng Town accounting for the largest changes.From 1995 to 2005,the vulnerability of other towns,except Mahe Town and Tonganyi Town,shows an upward trend.From 2005 to 2015,the vulnerability of other towns,except Caizi Town,Tonganyi Town,Mahe Town and Hongwei Town,shows a downward trend.The relatively high-value regions of vulnerability are mainly distributed in Gongchang Town and Wenfeng Town in the south of the region and Shouyang Town in the central part.The relatively low-value regions cover the whole research area but mainly gather in Biyan Town in the southwest of the region.(2)The coping capacity of social-ecological system tends to decrease in the research area from 1995 to 2015.The overall downward trend between 1995 and 2005 is greater than that between 2005 and 2015 with Kezhai Town and Mahe Town take the top spot.From 1995 to 2005,the coping capacity of other towns has shown a downward trend except Kezhai Town,Quanjiawan Town,Yuntian Town and Tonganyi Town.From 2005 to 2015,except for Gongchang Town,Wenfeng Town,Biyan Town,Heping Town,Shuangquan Town,Dexing Town and Shouyang Town,the coping capacity of other towns has shown a downward trend.The relatively high-value regions of the coping capacity are mainly distributed in Gongchang Town and Wenfeng Town in the south of the region and the surrounding region except the southeastern towns.The relatively low-value regions are mainly distributed in Hongwei Town in the northeast,Shuangquan Town in the northwest,Biyan Town in the southwest and Yongji Town in the southeast of the region.(3)The social-ecological system resilience is slowly weakening in the research area from 1995 to 2015.The overall trend between 1995 and 2005 is more significant than that between 2005 and 2015.The change in Kezhai and Biyan Town are the most obvious examples.From 1995 to 2005,the resilience of other towns shows a trend of growth,except Yongji Town,Gongchang Town,Biyan Town,Mahe Town and Tonganyi Town.From 2005 to 2015,the resilience of other towns shows a downward trend except Hongwei Town,Mahe Town,Tonganyi Town and Weiyang Town.The relatively high-value regions of the resilience are mainly distributed in Gongchang Town,Wenfeng Town in the south of the region and Shouyang Town in the central part.The relatively low-value regions of the resilience are mainly distributed in Biyan Town in the southwest,Dexing Town in the northwest,Hongwei Town in the northeast,Yongji,Heping and Weiyang Town in the southeast of the region.(4)The improvement of social-ecological system resilience is the result of mutual influence and interaction among various sub-systems.By using the obstacle model to figure out the influencing factors,this thesis concludes that the main obstacles of the ecological subsystem are the effective irrigated area,the proportion of natural disaster area in damaged area,the forest and grass coverage and the afforestation area.The main obstacles of the economic subsystem are the employments of the secondary industry,the total retail sales of social goods,the net income of farmers and the economic density.The main obstacles of the social subsystem are the rural electricity consumption,the proportion of non-agricultural population,the number of beds in health care institutions and the local fiscal expenditures.Relatively speaking,the socioeconomic factors create a higher degree of obstacles in the research area.(5)In terms of the optimizing adaptive management strategies in the social-ecological system,the thesis holds that the ecological subsystem needs to advocate new ideas to build a water-saving society and strengthen ecological restoration and remediation based on local conditions.Moreover,scientific overall plan in the resource management and allocation should be strengthened.The economic subsystem requires the improvement in modern agricultural infrastructure system,optimization in agricultural structure combining with local characteristics,and promoting the production and consumption of green energy.The social subsystem needs to establish a stable and lasting policy system for strengthening the government's comprehensive management capabilities.Especially,it is very important to enhance the learning ability of the whole society in this research area.