关键词: 生态安全格局, 土地利用变化模拟, Markov-PLUS模型, 生境质量, 昆明

Abstract:

Ecological security is the foundation for achieving sustainable development and ecological civilization. To achieve ecological security, we must protect ecosystems, especially biodiversity and ecosystem services, from global warming and extensive human activities. Future land use change simulations provide critical knowledge for regional development planning and the formulation of sustainable development strategies. Ecological security is one of the most important aspects of land use planning. Therefore, future land use simulations must also consider ecological security. However, existing studies on land use change simulations demonstrate notable deficiencies in integrating ecological security dimensions, thereby limiting their capacity to provide adequate knowledge support for ecological civilization construction and sustainable development goals. To address this challenge, this study focuses on Kunming, the capital city of Yunnan Province in China, and conducts land use simulations for 2030 and 2050 under an ecological security pattern framework. Kunming is one of the most biodiverse cities in the world, and its future land use planning needs to pay special attention to biodiversity conservation and maintenance of key ecosystem services. Therefore, it is very representative to take Kunming as the study area to carry out land use simulation incorporating ecological security patterns. This study comprises three key aspects. First, we constructed an ecological security pattern for the study area, including the delineation of ecological source regions and identification of critical ecological corridors. Specifically, we evaluated habitat quality using the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model, selected regions with high habitat quality, and integrated key nature reserves and scenic areas into the selected regions to delineate the final ecological source regions. Subsequently, based on elevation, slope, land use, distance to road, and normalized differential vegetation index, we obtained an ecological resistance surface that characterizes the amount of resistance experienced by species when they migrate between ecological source regions. Then, based on the ecological resistance surface and the ecological source regions, and utilizing the minimum cumulative resistance (MCR) model, we identified the least-cost paths between all patches, that is, the ecological corridors that facilitate species movement and ecosystem connectivity between the identified ecological source regions. Next, we used a gravity model to screen for the critical ecological corridors. In the second section of this study, based on satellite-based land use maps for 2010 and 2020, we conducted land use simulations for 2030 and 2050 with two scenarios, including the baseline scenario, which projected natural development trends based solely on historical transition probabilities, and the ecological security scenario, which incorporated constraints from the constructed ecological security pattern to prioritize ecological conservation and sustainability. In both scenarios, the Markov model was used for land use area projection, and the Patch-generating Land Use Simulation (PLUS) model was used for the simulation of the spatial pattern of land use. In the spatial simulation, we considered 10 factors that drive spatial changes in land use, including slope, elevation, distance to water systems, distance to railways, distance to roads, distance to settlements, average annual temperature, annual precipitation, gross domestic product, and population density. In the last section of this study, we compared the land use simulation results for the two scenarios in terms of the land use area and spatial patterns. The major findings of this study are as follows: 1) the ecological security pattern in Kunming encompasses 15 ecological source regions with a total area of approximately 7400 km², which accounts for 35.2% of the total area of Kunming, and 43 critical ecological corridors with a total length of approximately 1150 km. The distribution of the ecological source regions exhibited a distinct spatial pattern, with clusters concentrated in the western and northern regions of the study area and a fragmented distribution in the eastern region. The critical ecological corridors predominantly traverse central and southern Kunming, effectively enhancing connectivity among the ecological source regions and mitigating habitat fragmentation. 2) The Kappa coefficient of the land use simulation was 0.79, and the overall accuracy of the land use simulation was 87%, indicating that the Markov-PLUS model passed the accuracy verification. Under the ecological security scenario, the projected land use changes for 2030 and 2050 demonstrated restricted urban expansion inside the designated ecological source regions and critical ecological corridors, with ecological land (forest and grassland) maintaining high coverage. The prediction results showed that the proportions of forest land in Kunming in 2030 and 2050 will be 56.61% and 62.94%, respectively. This scenario aligns with regional sustainability goals by prioritizing ecological conservation. In contrast, the baseline scenario projected uncontrolled urban sprawl, characterized by the encroachment of built-up areas into ecologically sensitive zones (e.g., grassland and water areas). Notably, by 2050, urban expansion threatens to gradually infiltrate the shoreline of Dianchi Lake, exacerbating the high ecological risks. The advantage of this study is that given the insufficient consideration of ecological security in existing land use simulation research, we constructed an ecological security pattern, identified key ecological source regions and important ecological corridors, and set them as restrictive areas in the prediction by the PLUS model. The simulation results are more in line with the needs of sustainable development and ecological civilization in China. In terms of policy applications, the land-use simulation results for 2030 and 2050 in Kunming and the derived ecological security pattern offer critical insights for formulating evidence-based land use planning strategies. Specifically, the predicted spatial patterns of land use and ecological security can enhance the delineation of urban growth boundaries, permanent basic farmland protection red lines, and ecological protection red lines in the study area. The ecological security pattern we have delineated can also be used in the planning of nature reserves, which is also an important aspect of the construction of ecological civilization. In addition, by integrating 43 critical ecological corridors into land use planning, our results support biodiversity conservation by mitigating habitat fragmentation in the Dianchi Lake Watershed. This study has some shortcomings that this study should be considered by decision-makers and scholars in subsequent applications and studies. When selecting the driving factors of land use change, the actual situation of Kunming was not adequately considered, nor was the effectiveness of these factors in improving the simulation accuracy evaluated. In the future, the selection of driving factors should be optimized based on the characteristics of Kunming to further improve the simulation accuracy.

Key words: ecological safety pattern, simulation of land use change, Markov-PLUS model, habitat quality, Kunming