| Ecosystems are the basis for human survival and development.With rapid social and economic development,human activities have caused damage to the structure of ecosystems,leading to problems such as soil erosion,loss of biodiversity,and a decline in the quality of ecosystems and ecosystem service functions,posing serious challenges to the sustainable development of the region.The Guangxi Nanling Ecological Function Area(including Resources County,Longsheng Autonomous County,Sanjiang Dong Autonomous County and Rongshui Miao Autonomous County)is one of the first key ecological function areas for forests and biodiversity in the Nanling Mountains,and is located in the core area of the northwest Guizhou ecological barrier in the"one screen,six zones,one corridor and one sea"of the national ecological security pattern.It is particularly important to protect its ecological status.This paper uses remote sensing images,meteorological and environmental monitoring,socio-economic statistics and other data sources to assess the ecosystem pattern,quality and services from 2010 to 2020,and to analyse the spatial and temporal characteristics.Finally,the driving mechanisms of changes in the ecological status of functional areas were analysed in terms of both natural and anthropogenic influences.The main conclusions are as follows.(1)Ecosystem pattern is stable overall,but landscape fragmentation increases.2010-2020forest ecosystem area in Guangxi Nanling Ecological Function Area accounts for about more than 68%of the total area of the function area,and is the most dominant landscape type in the function area.In terms of spatial evolution,farmland in the southern part of Rongshui and grassland in Sanjiang were transformed into forests during the period 2010-2015,while the overall composition of the ecological pattern tended to stabilize,with increased patchy heterogeneity and landscape fragmentation during the period 2015-2020.The shift in ecosystem type occurs mainly between forest,shrub,grassland and farmland ecosystems.(2)The quality of the ecosystem increased significantly in the early stage,but stabilised in the later stage with a certain decline.2010-2020,the forest stock in Guangxi Nanling Ecological Function Area increased by 60.59%and the forest biomass increased by 52.79%,with the trend showing a faster growth in the early stage and a slower growth in the later stage.The area of grassland ecosystems in 2010,2015 and 2020 was 1522.32 km~2,608.93 km~2and 622.66km~2respectively,showing a trend of shrinkage followed by expansion,with the decreasing areas mainly distributed in Sanjiang and Resources;the Grassland Ecological Quality Index GDI was71.25%,82.75%and 80.75%respectively,improving from medium grade to good grade.The eutrophic index TLI∑of wetland ecosystems in Guangxi Nanling Ecological Function Area was 29.20,31.66 and 33.22 in 2010,2015 and 2020 respectively,with a trend of nutrient accumulation.(3)The overall improvement of ecosystem service function.2010,2015 and 2020,the water content per unit area of Guangxi Nanling Ecological Function Area were 694.27 mm,772.80 mm and 969.91 mm respectively,with a continuous trend of increasing water content function and spatial and temporal changes showing the characteristics of"overall improvement and local decline".The spatial and temporal changes show a"good overall,local decline"characteristic.During the period 2010-2020,the habitat quality values in the region were all above 0.8,with a slight downward trend in the change of biodiversity maintenance function.2010,2015 and 2020,the soil retention per unit area of Guangxi Nanling was 3018.33 t/(hm~2.a),3458.74 t/(hm~2.a),3832.57 t/(hm~2.a),with soil consolidation rates of 94.89%,98.65%and 99.23%.The soil consolidation rate is maintained at a high level,and the spatial and temporal change pattern of soil conservation function is more significant,with the increasing areas mainly distributed in Sanjiang and Resources,and the decreasing areas mainly distributed in Rongshui and Longsheng.(4)The ecological situation is greatly influenced by human factors.The ecosystem pattern is mainly characterised by the fragmentation of the spatial pattern of forest ecosystems,the area of farmland ecosystems decreasing before increasing,and the spatial distribution of urban ecosystems from scattered to contiguous;rainfall and ecological restoration projects promote the improvement of ecosystem quality,while temperature,agricultural production and urban development reduce the quality of ecosystems to a certain extent;ecosystem services and natural and human-influenced factors are significantly Ecosystem services are significantly related to natural and human-induced factors.Precipitation and ecological restoration projects are positively correlated with ecological service functions,while temperature,agricultural production and urbanisation are negatively correlated with ecological service functions.Therefore,in the context of climate change,optimising industrial structure and rational urbanisation construction are of great significance for the conservation of ecological conditions in the Guangxi Nanling Ecological Function Area. |
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