Social-ecological system resilience of debris flow alluvial fans in the Awang basin, China.

Debris flow alluvial fans (DFAFs) are vulnerable, although they can be used as a natural resource. The relationships between different factors related to DFAF systems and between these factors and systems are important both for identifying the risks and opportunities presented by DFAFs and for tracking system status. In this regard, resilience may be used to characterize the status of a DFAF. This study aimed to explore the processes and mechanisms of interactions among the social, economic, and ecological factors related to DFAF with respect to resilience, and to discuss potential problems in a representative DFAF. Based on the site condition and characteristics of the Awang DFAF (China) in the period 1996-2017, we formed a comprehensive indicator evaluation framework by analyzing disturbance, function, and feedback. We also established a model for evaluating resilience by integrating the analytic hierarchy process (AHP) - an entropy evaluation method (EEM) and set pair analysis (SPA). The results showed that the system of the studied DFAF was dynamically stable. The domination of the ecological system was subsequently superseded by social and economic resilience. While disturbance had direct and immediate effects, coping ability was cumulative and characterized by hysteresis at a particular response time. Overall, resilience fluctuated within an acceptable range rather than linearly increasing or decreasing. This analysis illuminated the dynamic processes of DFAFs and contributed to the understanding and planning of system trade-offs and degraded-land utilization.