Landscape ecological risk evaluation and driving factors in the lake basin of Central Yunnan Plateau

The lake basin of the Central Yunnan Plateau is located in the ecological security zone of southwest China. Therefore, it bears the important responsibility of drawing a new blueprint for ecological civilization. Assessing the landscape ecological risk of the basin and revealing the driving factors are key to guaranteeing the stability of its ecological function and controlling the ecological risk. Therefore, this study used the land use data of 2000, 2005, 2010, 2015, and 2020 to construct a long-term series landscape ecological risk assessment model using ArcGIS 10.8 and Fragstatas 4.2. Furthermore, spatial analysis tools were used to explore the spatial and temporal characteristics of the landscape ecological risk of the basin and its trend, whereas geographic probes were utilized to explore the influence mechanism of natural factors and socioeconomic factors on landscape ecological risk from the whole basin and in local areas. The results of the study showed that: 1) From 2000 to 2020, woodland and cultivated land were the largest landscapes in the lake basin of the Central Yunnan Plateau, accounting for more than 67% of the total basin area; unused land was the smallest, accounting for less than 0.2% of the total basin area, whereas construction land showed an expanding trend. 2) The ecological risk of the landscapes in the study area was dominated by medium-risk and medium-low-risk landscapes, which accounted for more than 50% of the total basin area. The high-risk area was located in the Wuhua District, Panlong District, Guandu District, and Xishan District north of Dianchi Lake, with an expanding trend to the northwest and southeast; medium-high-risk and medium-risk areas were mainly located in the Dianchi Lake Basin, which was constantly compressed to the center, whereas medium-low-risk and low-risk areas were closely connected, mainly located around the lakes and in the northern part of the basin, and expanding outward around these areas. 3) During the study period, most ecosystems in the basin were relatively stable, and more than 70% of the areas remained unchanged. The levels increased in relatively densely populated areas and did not change or even decrease in more ecologically favorable areas. The landscape ecosystems experienced the transformation process of improvement followed by deterioration, continuous deterioration, and then improvement. Overall, the landscape ecological risk showed a decreasing trend, and the ecosystems developed well. 4) From an overall perspective, the results of single-factor detection showed that the landscape ecological risk was mainly affected by factors such as the normalized difference in vegetation index and nighttime lighting. The results of interaction factor detection showed that the interaction of these factors enhanced the spatial evolution of landscape ecological risk compared with the individual factors, and the normalized difference in vegetation index, nighttime lighting, population density, and elevation had the greatest effect on landscape ecological risk. From a local perspective, natural factors have a greater influence on the evolution of ecological risk in the landscape than socioeconomic factors, mainly influenced by factors such as nighttime light, annual precipitation, and normalized difference vegetation index. Based on the findings of this study, suggestions for improving the ecological environment should focus on spatial differentiation patterns, changing characteristics, and the driving factors.