Promoting ecological sustainability in the arid farming-pastoral ecotone through optimal water allocation

Abstract

The ecological fragility of arid farming-pastoral ecotones is pronounced, and the promotion of regional ecological sustainability under the constraints of limited resources has become a crucial issue for these zones. This study presents a novel framework for evaluating ecological sustainability, quantifying its relationship with ecological water consumption, and optimizing water resources allocation for improving ecological sustainability. A fuzzy credibility-constrained stochastic multi-objective programming (FCCSMOP) model is applied to optimize regional water allocation schemes. The proposed approach has advantages in: (1) quantifying the water-driven dynamics of ecological sustainability at the county scale; (2) balancing economic, ecological, and social benefits; and (3) addressing randomness and fuzziness caused by hydrological variability and water managers’ preferences. This approach was applied to the northern foot of Yinshan Mountain (NFYM), Inner Mongolia Autonomous Region, China, leading to the following findings: (1) ecological sustainability in NFYM is poor, with 70.31% of the region having an ecological sustainability score below 0.43 in 2019; (2) there is a positive relationship between ecological sustainability and water consumption with the relatively high correlation (R² ∈ [0.39, 0.87]); (3) the FCCSMOP model can effectively address the multiple conflicting objectives, randomness, and fuzziness when generating optimal water allocation schemes. A comparison between the optimization results (normal year, β=0.75) and the status quo shows improvements of 5.60%, 19.45%, and 6.35% in ecological sustainability, water use efficiency, and the index of water use structure balance, respectively. The models and methods can also be applied to similar regions suffering water and ecological crisis.