Urban connectivity plays a critical role in maintaining biodiversity within cities. However, urban landscapes tend to be highly fragmented, creating small patches of habitat that are separated by dense clusters of buildings, roads, and other infrastructure. Understanding how organisms navigate these complex environments is central to improving conservation planning in cities.
For species like native bees that depend on finding scattered floral and nesting resources, these gaps can hinder movement and foraging efforts. Researchers increasingly rely on spatial tools to map these movement challenges and test how different forms of urban design affect ecological flows. Spatial models that use publicly accessible data can be especially powerful because they allow researchers, planners, and community groups to explore connectivity issues without specialized or costly software.
Lundquist, M.J., Lovejoy, P.C., Fay, B.G., Hernandez, J.E. and Madrid, M. 2025. Bug roads: Modeling the green space connectivity and pollinator habitat in a large city using open GIS data and tools. Ecological Applications, 35(7): e70128. DOI: 10.1002/eap.70128.
New research addresses this growing need by modeling the movement pathways of pollinators across New York City to assess how green space distribution and building structure influence connectivity. The authors used open GIS datasets from the city and state, combined with open source tools such as QGIS and Python libraries, to map the shortest possible routes between more than 4000 managed green space patches.
They compared straight line Euclidean paths to realistic routes generated with Dijkstra’s algorithm, which forces paths to move around buildings. They also used publicly available LiDAR data to estimate plausible pollinator habitat within each property by identifying areas of low, medium, and high vegetation.
The study found that 86% of Euclidean paths between parks were blocked by buildings, and that real flight paths around those buildings were on average 20% longer than straight line distances. Many individual parks and clusters lacked enough vegetative cover to support bees with medium foraging ranges, which includes many solitary species. Foraging distances of 250-500 meters were particularly limited, indicating that pollinators with small movement capacities may struggle to move between habitat patches in highly built environments.
These results highlight how urban design shapes ecological connectivity, and why pollinator conservation in cities should consider both habitat quality and structural barriers. By revealing how urban structure shapes pollinator movement and habitat availability, the research provides a practical foundation for designing cities that better support well-connected pollinator populations.
The study also demonstrates the value of open source tools for conducting connectivity assessments that can be adapted and expanded by users in other cities. Because the analysis relies entirely on freely available datasets and software, other researchers and agencies can apply similar methods to identify key movement corridors and prioritize habitat improvements across multiple urban landscapes.
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