Microagroecosystem models and their landscape ecological risk evolution in karst mountainous areas

Micro-spatial agroecosystem (AES) changes in karst mountain areas are a response to the human-land relationship of the human activity center. However, the changes and linkages between AESs and landscape ecological risks (LER) from a micro perspective in karst mountain areas (KMA) have not yet attracted in-depth attention from the academic community. This paper proposes the concept of microagroecosystems (MAESs) and constructs the MAES model based on the landscape development intensity (LDI) to evaluate the systematic landscape evolution rules and the LER intensity, which reflects the human-land relationship in KMA. We used the buffer ring with a 200 m cultivation range interval to categorize the MAES model into six models, namely, High-MidLow, High-Low-Medium, Medium-High-Low, Medium-Low-High, Medium-High-High, Low-Medium-High and Low-Medium-High, and the different models not only reflect the regional conditions but also represent the different stages of the evolution of AESs in KMAs. We found that AESs in karst mountainous areas are transforming from traditional food crop systems to economic fruit forest ecosystems, and at the same time, the gravity center of human activities is migrating from high to low altitude areas, and the ecological vitality of MAESs is showing a trend of enhancement. In addition, the regions with high altitudes and steep slopes in karst mountainous areas have a single landscape structure and are dominated by traditional food cultivation, while the regions with low altitudes and gentle slopes have a diverse landscape structure and are dominated by modern and sustainable agricultural development. Finally, we reveal that the LER in KMAs shows a trend of initial increase followed by subsequent decrease, the influence of the human-land relationship on the LER in the micro perspective is significant, and the coordination and trade-off between agricultural development and environmental protection is the key direction of development in the future. The study results can provide a reference for the rational allocation of landscape, ecological environment restoration, and optimization of regional humanland relationships in KMAs worldwide.