Assessment and optimization of urban ecological network resilience based on disturbance scenario simulations: A case study of Nanjing city

Urbanization has serious implications for the structure and function of ecological networks. Augmenting resilience offers a salient remedy to sustain ecological network stability, thereby leading to heightened ecological efficacy. Nevertheless, extant research pertaining to ecological network resilience predominantly centers around static assessment, disregarding the external dynamic disturbances as well as changes in resilience over long time-series. Furthermore, scant attention has been given to the simultaneous incorporation of both structural and functional attributes in the selection of indicators for resilience assessment. In this study, taking Nanjing as an example, with a five-year interval, we determined the spatial scope of the ecological networks in 2000–2020, used two disturbance scenario simulation methods, probabilistic attack and deterministic attack, and finally optimized the ecological network with the goal of resilience enhancement. The results show that (1) the resilience index thresholds of the ecological networks decreased from 0.43 to 0.37, and the network resilience became progressively worse, but the decline in resilience index thresholds decreased in recent years. (2) The phenomenon of resurgent functional resilience increased, and ecological network redundancy increased. (3) In recent years, critical resilience nodes evinced a trend characterized by a diminishment of significance in the central region and a concomitant enhancement of importance in the southern domain. (4) The functional and structural optimization strategies increased the resilience index thresholds by 0.06 and 0.11, respectively. This study advances the refinement of methodologies and frameworks germane to the dynamic assessment of ecological network resilience, thereby furnishing instructive guidance for the fortification of urban ecosystem resilience and the promotion of sustainable urban governance.