Diagnosing cropland's allowable range and spatial allocation in China's typical mountainous plateau area: An...

Natural capital serves as a major constraint that affects the sustainable development of mountainous plateau areas. Determining ecological carrying capacity (ECC), as the key to measuring the critical natural capital of cropland, is needed for sustainable development. This study aims to provide new insights into ECC by diagnosing whether human activities are within the allowable range of natural capital and whether the spatial allocation of natural capital is reasonable in such specific areas. Taking Yunnan Province, China as the study area, we proposed an improved Ecological Footprint (EF) model to evaluate cropland's ecological capacity (CEC), and then, a framework of balance evaluation and spatial optimal allocation was constructed to examine the cropland's allowable range and optimize its spatial allocation if found unreasonable. Results show the following. (1) The per capita CEC of Yunnan Province between 2009 and 2016 decreased from 0.103 ha/capita to 0.095 ha/capita, and the cropland ecological balance index (EBI) presented a "critical overload" state ranging from 0.433 to 0.463, at which the supply exceeded the demand. Hence, the cropland was not within the allowable range in terms of supply-demand balance. (2) The comprehensive Gini coefficient of CEC was 0.462-0.515, and the gravity center of CEC deviated from the geometric center and shifted toward the westward, thereby, CEC is neither balanced in terms of spatial allocation nor coordinated with the population, economy, and resource environment. (3) The spatial allocation pattern of the study area was grouped into five zones on the basis of the optimization model. These zones are key optimization zone, adjustment optimization zone, maintenance zone, reasonable reduction zone, and key reduction zone. Accordingly, the targeted and differentiated strategies were accordingly put forward. Our study can contribute to identifying the practical approach to sustainable ecosystem management in mountainous plateau areas from the perspective of ECC and are beneficial for decision-making as regards new policies on cropland protection and Chinese ecological civilization construction.