Pollinator Path Corridor
A solitary bee forages only 100 to 200 meters from her nest. Between Macalester and St. Thomas, that's a lot of roof, road and lawn. I built a connectivity model from drone imagery, LiDAR and field surveys to find where bees can move today, and where one new garden would matter most.
How the model was built
- Drone imagery to NDVI. Multispectral flights over the corridor, converted to vegetation greenness as a proxy for flowers.
- LiDAR to canopy height. Surface model minus terrain model, with the 0.5 to 3 m flowering layer scored highest.
- Foraging suitability. Weighted overlay: 60% NDVI, 40% canopy height, resampled to 1 m.
- Resistance surface. The cost for a bee to cross each cell, with height-graded building barriers.
- Least-cost network. Dijkstra cost-distance and optimal paths linking 14 pollinator gardens.
- Field check. Compared with 197 surveyed yards: higher-rated yards scored higher on the map (Spearman ρ = +0.327, p < 0.001).
Watch the bee move
What it means: the gap between campuses is the biggest barrier, back yards beat front yards (higher in 58% of 177 parcels), and sunny spots in already-suitable yards are the best places to plant next.
View code on GitHub