Construction And Optimization Of Ecological Security Pattern Based On Ecosystem Service Supply And Demand Of Guizhou Province In China

Ecological protection and restoration of territorial space based on ecological security pattern(ESP)has become an important way to solve the contradiction between urban construction and ecological protection,which is of great significance for regional ecosystem management and sustainable development.The Guizhou Province,a representative karst mountainous region with the fragile ecosystem in the southwest of China,was used as the study region.According to the landscape ecology and landscape sustainability theory,this study adopted multi-source datasets such as land use types and socio-economic data in different periods,and comprehensively applied the In VEST model,cold and hot spot analysis,landscape connectivity and the circuit theory.The supply and demand of three typical ecosystem services(water yield(WY),soil conservation(SC)and carbon sequestration(CS))in Guizhou Province in the past 20years were analyzed to reveal the dynamic relationship between the supply and demand of ecosystem services.This research evaluated the ecosystem service supply and demand risk by constructing a comprehensive framework that represented eight risk levels using four indicators.Moreover,the ESP of Guizhou Province was constructed based on the ecosystem service supply and demand and landscape connectivity.Finally,the strategies and optimization of the ecological protection and restoration of territorial space were conducted on the key regions of the ESP.The results showed that:(1)The supply of the three typical ecosystem services(i.e.,WY,SC and CS)in Guizhou Province showed an increasing trend from 2000 to 2020.The supply of SC,WY and CS increased by 7.013 billion tons,5.127 billion tons and 1.591 billion tons,respectively.Spatially,the WY and SC supply trend manifested a banded feature,and the supply trend gradually increased from south to north.The CS supply trend increased in most regions but degraded in the mountainous regions.Although the demand of the three ecosystem services was also increasing gradually,their supply can meet the demand on the whole.In addition,the ecosystem service supply and demand were showed an obvious heterogeneity in space.There is an obvious spatial mismatch between these ecosystem service supply and demand,and this difference is mainly reflected in the built-up area in different cities.The supply and demand ratio of ecosystem services was slightly greater than 0,indicating that the supply exceeded the demand.Notably,the WY and SC supply trend and their supply and demand trends were declining in various degreed,showing that the ecological supply of these ecosystem services was increasing at a much slower pace than that of the human demand.(2)The ecosystem service supply and demand risk(ESSDR)of different ecosystem services in the study area were at a safe level.On the whole,the area of the CS,WY and SC ESSDR at safe and relatively safe level were 92.71%,61.71%and67.06%of the study area,respectively.Spatially,the ESSDR of CS was at a safe level in most regions except the built-up regions.The ESSDR of WY and SC gradually increased from the north to the south,and they were mainly at the vulnerable state in the southern of the study area.The area of WY and SC ESSDR at the vulnerable level accounted for 28.57%and 28.52%of the study area,respectively.In the same way,the ESSDR of WY and CS were at higher risk level in the built-up area.(3)The ecological security pattern(ESP)of Guizhou Province consists of 48ecological sources,95 corridors and many nodes.The ecological sources were mainly distributed in the southeast and north of the study area,accounting for 19.66%of the total area of the study area.The average length of corridors was 43.70 km,and their importance gradually increased from the southwest to northeast in space.Importantly,the corridors in the west and southwest of the study area are narrow and long,while the ones in the opposite direction are relatively dense and short.The spatial distribution of the ecological nodes was similar with the corridors.Moreover,the area of ecological barriers was 1259.30 km~2,and they mainly distributed in the central and western corridors,which had a great negative impact on species migration.(4)Based on the ESSDR of the three typical ecosystem services and the ESP of Guizhou Province,the study area was divided into four zones for ecological protection and restoration of the territorial space through the ecological zoning index(i.e.,ecological core zone,ecological buffer zone,ecological control area and ecological restoration zone).According to the ecological background conditions and environmental problems in different ecological zones,the systematic suggestions were proposed for the ecological protection and restoration of the territorial space to optimize the ESP.This research can provide scientific basis for landscape sustainable planning and ecosystem management,and give a novel idea into the ESP construction that can provide a valuable reference for the ecological protection and restoration programs of the territorial space.