Florida Magnolia Density Map

Geocoded observations of Magnolia spp. across Florida — sourced from iNaturalist and GBIF

— observations — species
Heatmap density
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choropleth off

Data Sources

iNaturalist

Research-grade citizen science observations of Magnolia in Florida (place_id 21, taxon 82096).

api.inaturalist.org/v1/observations

GBIF

Aggregated occurrence records from herbaria, NEON, and other research datasets — genus Magnolia, hasCoordinate=true.

api.gbif.org/v1/occurrence/search

US Census ACS (2022)

5-year American Community Survey — county-level population estimates used to normalize observation counts (per 100,000 people).

api.census.gov/data/2022/acs/acs5

TIGERweb

US Census Bureau county boundary polygons (TIGER/Line) for spatial joining of observations to counties.

tigerweb.geo.census.gov

USDA FIA

Forest Inventory & Analysis program — actual tree records from standardized field plots. Ground-truth ecological tree counts (SPCDs 650–658).

apps.fs.usda.gov/fia/datamart

Notes

  • Records are de-duplicated between iNaturalist and GBIF based on coordinates (~50m), species, and date.
  • Coordinates for vulnerable species (e.g., Magnolia ashei) may be obscured by ~25 km on iNaturalist for conservation reasons.
  • The heatmap uses kernel density estimation — denser observations produce hotter cells. Adjust intensity with the slider above.
  • Cultivated specimens excluded: iNaturalist observations are filtered to captive=false and known non-native ornamental species (M. soulangeana, M. liliiflora, M. champaca, M. figo, etc.) are removed. GBIF records flagged as managed/introduced are also excluded.
  • Per-capita choropleth normalizes observation counts by county population to correct for urban observer-effort bias. Rural panhandle counties (Liberty, Franklin, Gadsden) emerge as true Magnolia hotspots — these contain Apalachicola National Forest, the core range of M. ashei.
  • FIA tree count shows actual trees recorded on USDA Forest Service inventory plots — the gold-standard ecological measure. FIA plots are systematically distributed (~1 per 6,000 forested acres), so this isn't biased by where citizens go birding. Compare FIA to per-capita to see how well crowdsourced data reflects ground truth.