A 3D Planting Structure-Based Scenario Strategy to Mitigate Seasonal Instability of Urban Green Phenology and Gaps in Pollination Functions

Honeybees are widely recognized as representative pollinator species due to their high pollination efficiency and frequent visitation. However, climate warming intensifies temporal mismatches between plant flowering and insect activity, resulting in seasonal resource gaps for foragers and weakened ecological networks. Urban landscape, in contrast, can provide substantial opportunities to create habitats and movement corridors through strategic planting and adaptive management.

This research proposes a node-based urban planting scenario framework to reduce seasonal phenological asynchrony and evaluate outcomes across micro- and macro-scale. Unlike previous studies that have assessed habitat suitability primarily based on the presence or area of green spaces, we focus on habitat usability for pollinators by explicitly considering (i) continuity of flowering resources and (ii) multidimensional planting structures with vertical, horizontal, and temporal differentiation. We further examine how these planting strategies can co-deliver microclimatic regulation and broader landscape-scale ecosystem service outcomes.

This case study targets on Eunpyeong-gu and Mapo-gu in Seoul, South Korea, where forest, urban, and river systems are spatially continuous but are not effectively functioning as habitats or movement corridors. Using GIS, we identify key patches that can support movement and seasonal functional turnover; these patches are treated as nodes and assembled into a connectivity network. Planting strategies are then designed along three dimensions: (1) vertical multilayer vegetation to diversify strata and microhabitats, (2) horizontal linear/areal expansion to improve stepping-stone connectivity, and (3) temporal phenology-based planting to extend flowering continuity. Strategies are applied to forest-, urban-, and river-type patches. Microclimatic effects are simulated using ENVI-met, while landscape-scale functional connectivity and ecosystem service implications are assessed using InVEST.

Patches were selected by considering honeybee flight range, inter-patch distance and size, and the seasonal distribution of flowering plants. Among typology-specific planting strategies, forest-type patches benefited from vertical planting, which enhanced understory flowering and provided refuge for survival. Urban small-scale plantings showed high pollination efficiency, but high impervious surfaces necessitated securing horizontal connectivity essential for addressing seasonal asynchrony. In river-type patches, continuous buffer planting enhanced mobility, while connectivity with adjacent ground-level green spaces remained a critical consideration. Macro-scale scenario analysis showed that integrating typology-specific optimal planting strategies strengthened the connectivity index by increasing mobility and access to alternative resources across the forest–urban–river continuum, beyond alleviating micro-scale food gaps. These outcomes have implications not only for managed honeybees but also for broader pollinator communities that depend on temporally continuous floral resources.

Overall, this research redefines honeybee habitat conservation from a multi-scale spatial organization perspective that incorporates behavioral characteristics and temporal resource use. The proposed framework explicitly links phenological gaps to landscape connectivity—rather than green space extent—offering a transferable NbS-informed approach for designing urban green networks that stabilize seasonal resources while supporting co-benefits.

Following are results of a study on the "Convergence and Open Sharing System" Project, supported by the Ministry of Education and National Research Foundation of Korea