Early ecological security warning of cultivated lands using RF-MLP integration model: A case study on China's main grain-producing areas

The evaluation and early warning of the ecological security of cultivated land are crucial to food security and social stability in the post-epidemic era. In this study, we construct a cultivated ecological security assessment index system based on the pressure-state-response (PSR) model in the main grain-producing areas of China. The entropy method and the multi-factor comprehensive weighting method are used to evaluate the ecological security of the cultivated land in the study area from 2007 to 2018. We propose an integrated model that combines random forest (RF) and multilayer perceptron (MLP), i.e., RF-MLP, to estimate ecological security levels of cultivated lands in the study area from 2019 to 2028. We also present specific policy suggestions to improve the ecological status of cultivated lands. We found that: (1) the ecological security index (E index) of cultivated land showed an overall upward trend from 0.6379 in 2006 to 0.7754 in 2018, despite the fact that this increasing pattern was not considerably strong. The warning situation was changed from medium warning to light warning. The warning levels present a notable spatial imbalance, with higher warning levels occurring in the northern provinces. (2) From 2019 to 2028, although the E index of cultivated land in the main grain-producing areas is expected to be further improved, its values are between 0.7 and 0.8, with most provinces lying in the light warning grades. During the forecasting period, the spatial pattern of the warning situations is stable. In some regions, e.g., North and Northeast China, the cultivated land ecology is expected to be developed towards a positive direction. Although the ecological security of cultivated land in the middle and lower reaches of the Yangtze River region is generally satisfactory, the E index presents a declining trend, thus demanding further attention. The results from this study are expected to benefit decision-makers in designing mitigating strategies for better ecological security management and maintenance of cultivated lands in China's main grain-producing areas.