| Ecosystems provide important material and environmental foundations for human survival and reproduction.The regulating services,support services,supply services,and cultural services provided by ecosystems are a solid guarantee for high-quality economic and social development.Ecosystems in different regions are affected by nature and human society and economy.Various ecosystem services do not exist independently,and there is a non-linear relationship between ecosystem services that ebb and flow,increase and decrease at the same time.How to effectively manage the trade-off and synergistic relationship between regional ecosystem services has become a frontier scientific issue in the research of natural resource management and ecological protection.A systematic understanding of the tradeoffs and synergies between regional ecosystem services could provide scientific support for regional land space optimization and ecological environment protection,and has important reference significance for the formulation of policies for high-quality regional development.In this context,this thesis takes Fangxian,an ecologically important county in Northwest Hubei,as the study area,based on multi-source data,analyzes the spatio-temporal evolution of land use/land cover and landscape pattern changes in Fangxian from 2000 to 2020,and explores the characteristics of land use/land cover changes based on the In VEST model.The spatio-temporal evolution of the four ecosystem services in Fang County,including carbon storage services,water production services,soil conservation services,and habitat quality,and quantitatively analyzed the driving mechanism of their changes,and then explored the trade-offs and synergistic changes among ecosystem services.In conclusion:(1)From the perspective of the proportion of land use types in Fang County,84% of the land in Fang County is forest land,13% is cultivated land,3% is grassland,and the area of water and construction land is relatively small.During the period from 2000 to2020,the area of construction land changed the fastest.The construction land increased from 0.09% of the total area in 2000 to 0.45% of the total area.The main land sources are cultivated land and forest land.Cultivated land decreased from 13.30% to 13.11% of the total area,and forest land decreased from 83.64% to 83.48%.Construction land is the land use type with the largest change range,and its single dynamic degree is 19.20%,followed by the change of unused land,with a range of-0.95%.During the study period,the dynamic change degree of construction land showed a continuous upward trend,and the dynamic change degree showed a sharp jump during the period from 2010 to 2015,an increase of 66.25%.The dynamic change degree of forest land generally presents a downward trend,and basically the decline range of dynamic degree remains at about0.02%.(2)From the perspective of landscape pattern changes in Fangxian County,the overall landscape level of Fangxian County is good,and there are dominant patches with high connectivity,but the connectivity decreases with time.The degree of plaque aggregation was high,but as time went on,the plaque aggregation weakened.The types of patches increased,and the diversity of landscapes increased.(3)From the spatial-temporal evolution of Fangxian’s ecosystem services,Fangxian’s carbon storage showed a downward trend from 2000 to 2020,water production services showed a downward trend,soil conservation service fluctuations decreased,and habitat quality fluctuations increased.The high-value areas for carbon storage services are mainly high-altitude areas in Fang County,including towns such as Damuchang,Wutai Forest Farm,and Jiudao Township.This area has a wide range of forests and grasslands,a large area,and good vegetation coverage.Carbon storage is large.The low-value areas are concentrated in the low-altitude areas in the east and middle,including townships such as Chengguan Town and Jikou Township,mainly agricultural land,construction land and water areas.The distribution of water production services roughly forms a pattern of high in the west and south of Fangxian County,including towns such as Jiudao Township and Zhongba Township;low in the north and east of Fangxian County,including townships such as Chengguan Town,Qikou Township,and Damuchang Township.The spatial distribution of soil conservation services in Fangxian County from 2000 to 2020 was relatively uniform and stable.It was low in a few areas in the central and eastern regions,including Chengguan Town and Baihe Township,and high in most areas in the north,west,and south,including Damuchang and Shahe Township.Wait for the township.The spatial distribution of habitat quality is similar to that of carbon storage,and the interannual variation of spatial distribution is small.The habitat quality of forest and grassland areas in Fangxian County is relatively high,including towns such as Damuchang,Wutai Forest Farm,and Jiudao Township.Habitat quality in this area is low,including townships such as Chengguan Town and Qikou Township.(4)From the perspective of the driving mechanism of ecosystem services in Fang County,the annual vegetation coverage and population density in Fang County from2000 to 2020 have a great impact on the carbon storage services in Fang County.The county’s water production services have a greater impact.The interaction between the three influencing factors of NDVI,population density,and GDP and other factors has a significant impact on the level of soil conservation services.Habitat quality is greatly affected by NDVI,population density,and GDP.The forest and grassland area of Fang County should be increased as much as possible,and the vegetation coverage of the whole Fang County should be improved,so as to improve the overall ecosystem service level of Fang County.(5)From the perspective of the changes in the balance and synergy relationship of ecosystem services in Fang County,from 2000 to 2020,carbon storage and water production showed a trade-off relationship,and showed a trend of strengthening and then weakening;the relationship between soil conservation and water production There is a significant trade-off relationship between them,and the significant negative correlation is highly volatile and shows a sharp downward trend.The absolute value of the correlation has dropped from 0.1985 in 2000 to 0.0655 in 2020;the synergy between habitat quality and carbon storage has increased from From 2015 to 2020,it showed a continuous and increasing trend.From 2015 to 2020,it decreased slightly but still increased compared to2000.The correlation increased from 0.303 to 0.3529;there was a synergistic relationship between habitat quality and water yield,but decreased from 0.1551 in 2000 to 0.1171 in 2020;the synergistic relationship between habitat quality and soil conservation was slightly Enhanced,from 0.1558 in 2000 to 0.1742 in 2020.To sum up,the ecosystem services of Fang County are high,but with the development of social economy,the ecosystem services fluctuate and decline.In order to achieve the optimal benefits of ecosystem services,towns with low terrain such as Chengguan Town in the central part of Fangxian County should coordinate the proportion of cultivated land,building land and forest land,increase green infrastructure in towns,and improve landscape diversity in the southern and northern mountainous areas.Qualitatively,improve the connectivity between plaques,relieve trade-off pressure,and increase ecological benefits.The balance and synergistic relationship of each ecosystem service in Fangxian County are different.In the future,we should promote the coordinated development of ecosystem services in space,optimize and guarantee the ecological space of Fangxian County. |
