Impact of Cropland Reclamation on Ecological Security in the Yangtze River Economic Belt, China

Ecological security is important both for maintaining the function of an ecosystem and for providing ecosystem services to the human wellbeing. The impact of land use change/cover on ecological security has attracted considerable attention, whereas the role of cropland reclamation remains unclear. The indirect loss of ecological land that occurs upon the request of cropland requisition-compensation policies offer further changes to ecological security. In order to ascertain the impact of cropland reclamation on ecological security, in this study three scenarios are established, addressing cropland returning to ecological lands without a slope limitation, with a slope <25°, and with a reclaimed cropland slope ≥25°. This study was conducted in the Yangtze River economic belt (YREB) due to its important contribution to ecological security in China. Land uses in different scenarios in 2030 are projected using the land use simulation model LANDSCAPE. Accordingly, ecological security in each scenario was evaluated using the contribution–vigour–organization–resilience framework, comprising the variables carbon storage, water purification, water yield, habitat quality, net primary productivity, mean patch area, Shannon’s diversity index, largest patch index and contagion, as well as the normalized difference vegetation index. The results indicate that about 62% of YREB land is projected to remain stable in terms of ecological security, while about 21% will deteriorate and 17% will improve between 2015–2030. Land where ecological security is projected to improve is concentrated in areas where broad and connected croplands are distributed. The fact that a higher proportion of areas will deteriorate than improve suggests that the negative impact of cropland change on ecological security should not be ignored. Comparing different scenarios, croplands returning to ecological lands pose a particularly significant impact on ecological security, particularly in the upper reaches of the YREB, where steep croplands are concentrated.