Chunhua Li

This study focuses on the Kunming municipal area, located in the low-latitude plateau of southwestern China, utilizing remote sensing image data from four distinct periods between 2005 and 2020 to analyze changes in its green landscape patterns. Net primary productivity (NPP) was employed as a metric for carbon sequestration analysis to assess variations in NPP within the Kunming municipal area. Based on Pearson correlation analysis and the XGBoost-SHAP model, the correlations, important indicators, and responses of changes in the green space patterns of the Kunming municipal area to changes in carbon sequestration were analyzed and combined with policy and human factors. The findings indicate the following: (1) From 2005 to 2020, the area proportions of various green space types within the Kunming municipal area were ranked as follows: forest land > grassland > cultivated land > water bodies. (2) Between 2005 and 2015, the patch shapes of green spaces became increasingly complex, with heightened fragmentation among patches. After 2015, this complexity was reduced while connectivity continued to decline alongside an increase in the landscape heterogeneity and richness. (3) Over the period from 2005 to 2020, NPP values for cultivated land, forest land, and grassland exhibited a trend of decreasing and then increasing, reaching their lowest point in 2010. High NPP areas were predominantly found in regions characterized by a hilly topography, elevated altitudes, and substantial natural vegetation cover. (4) There was a significant correlation between green space pattern indices and NPP (p < 0.01), with SHDI, CONTAG, and DIVISION identified as three critical indices influencing NPP. The relationship between landscape patterns and carbon sequestration was most pronounced during the period from 2015 to 2020, followed by that from 2005 to 2010.

A key means of promoting the high-quality development of karst areas is the maintenance of the area’s ecological security. A full recognition of the special ecological function of karst areas, as well as their significance to the surrounding region’s ecological, economic, and social development, is crucial in strengthening the overall strategic deployment of the national ecological construction and the protection and sustainable development of karst landscapes around the globe. In this study, the karst landscape of Puzhehei, Qiubei County, Wenshan Prefecture, Yunnan Province, China, was used as the research object. This study identified ecological source sites through a combination of morphological spatial pattern analysis and landscape connectivity assessment. As a result, 10 factors were selected to construct a comprehensive ecological resistance surface from the natural environment and socio-economic perspective; the resistance surface was corrected by combining the sensitivity of rocky desertification. An ecological corridor and ecological nodes were identified to construct the ecological security pattern based on the minimum cumulative resistance model and circuit theory. The results show that (1) the source areas of the Puzhehei karst landscape ecological protection comprised 11 core area patches with the landscape connectivity index of (dPC) ≥ 10, with a total area of 166.6572 km², which constituted 46.06% of the total study area, and the ecological source area totaled 77.275 km², or 21.36% of the total study area; (2) there were 78 potential ecological corridors in the Puzhehei karst region, with a total length of 545.186 km, including 12 key corridors and 66 general corridors; (3) a total of 51 ecological nodes were identified, including 11 “source-type ecological nodes”, 30 “ecological pinch points”, and 10 “ecological obstacles”, including 16 key ecological nodes. This study provides a theoretical basis for the integration of Puzhehei Nature Reserve, as well as a reference for the ecologically sustainable development of similar karst areas.