Identification of a wetland ecological network for urban heat island effect mitigation in Changchun, China

Abstract

The rapid development of cities has led to severe fragmentation of wetland landscapes, destroying their ecological function in climate regulation. However, most studies on the climate regulation services of wetlands focused on isolated wetland units, ignoring the overall function of wetland networks. The climate regulation function of wetlands can be improved by integrating fragmented wetland resources and building a stable wetland network. A case study was carried out in Changchun City, China, to improve the method of identifying ecological networks by considering the network energy flows. First, morphological spatial pattern analysis and landscape connectivity index combined with the wetland cooling index were used to identify ecological sources with high cooling capacity, and an ecological resistance surface was constructed with surface temperature as the main factor. The minimum cumulative resistance model was then used to identify the ecological network, which was then optimized by integrating patches as stepping stones to form the optimized ecological network. Finally, the importance of ecological corridors was evaluated by identifying ventilation corridors and integrated with the complex network theory to determine the ecological network robustness. We found that the degree of fragmentation in the studied wetlands was relatively high, and that construction of an ecological network with patches as stepping stones can improve its robustness. Each component in the ecological network had a high potential to mitigate the urban heat island effect, which can be further promoted by ecological corridors with high ventilation potential. Mutations in ecological nodes that cause network robustness played a key role in maintaining ecological network stability. This improved methodology effectively improves the scientific and practical application of wetland networks to mitigate the urban heat island effect and provides regions facing the contradiction of rapid development and wetland protection with strategies to reduce the threat of this effect.