Urban Green Spaces as Refugia for Pollinators and Small Mammals with Evaluation of Biodiversity and Ecosystem Services

Abstract

Habitat fragmentation and loss of ecological connectivity are key causes of biodiversity loss associated with urbanization. Pollinator populations and ecosystem services, however, can be supported by urban green spaces, which can serve as critical refugia. This study compared the pollinator diversity of 462 urban landscapes from 85 metropolitan regions in the publicly available Dryad Urban Pollinator Diversity Dataset. The species richness and Shannon diversity indices were computed, and natural and developed green-space coverage were used as key habitat predictors. Pollinator richness showed a significant positive correlation with the amount of natural green space (r = 0.62, p < 0.001) as revealed by statistical analysis using Pearson correlation. Mean species richness of 23.4 ± 3.2 and Shannon index H’ = 2.88 ± 0.18 were found in high natural green space, while low natural green space had a mean species richness of 12.1 ± 2.5 and Shannon index H’ = 1.84 ± 0.14. The positive relationship between natural green space and pollinator diversity was confirmed by scatterplot analysis, thus improving the potential of urban ecosystems to provide services, including pollination stability and habitat resilience. The results highlight the importance of maintaining structurally complex, natural vegetation in cities. Such evidence-based urban planning can enhance the biodiversity refugia and multifunctional ecosystem services when these habitats are incorporated. Future work should combine small mammal occurrence, multi-trophic interactions, and longitudinal monitoring to better evaluate the resilience of urban habitat in the context of ongoing urbanization.