Belle Isle Biodiversity: Sampling an Urban Ecosystem
Quadrat sampling and biodiversity indices, applied to a Detroit green space.
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Standards
HS-LS2-2 — Use mathematical representations to support and revise explanations based on evidence about factors affecting biodiversity and populations in ecosystems.
Why Does This Matter?
Belle Isle, a 982-acre island park in the Detroit River, is home to a designated Nature Zone with woodland, wetland, and shoreline habitats recovering alongside the river itself. Comparing biodiversity across different patches of green space — on Belle Isle, in a schoolyard, or in a neighborhood park — reveals how habitat quality shapes what actually lives there.
Objective
Estimate species richness and evenness in a sample area using quadrat sampling, and evaluate what the data suggests about ecosystem health.
Materials
- String or a 1m × 1m quadrat frame (4 meter sticks or PVC pipe pieces work)
- Field guide or plant/insect ID sheet (teacher-provided or a phone ID app)
- Clipboard, data sheet, pencil
- Optional (if a field visit isn't possible): the Belle Isle species dataset, belle_isle_species_inaturalist.csv (research-grade community-science observations from Belle Isle Park)
Safety: Watch footing on uneven ground. Do not touch unknown plants, mushrooms, or animals. Wash hands after outdoor sampling.
Procedure
- Choose a sample area (schoolyard edge, nearby park, or use the provided dataset).
- Place your quadrat randomly within the sample area.
- Identify and count every distinct species (plant, insect, or visible organism) inside the quadrat. Record each species and its count.
- Repeat for a total of 4 quadrats in the same habitat type, then repeat the full process in a second, different habitat type if possible (e.g. mowed grass vs. unmown edge).
- Calculate species richness (number of different species) for each habitat.
- Calculate the relative abundance of each species (count ÷ total organisms) to assess evenness — whether one species dominates or organisms are spread evenly.
Data Table
| Habitat / Quadrat # | Species observed | Count | Relative abundance (%) |
|---|---|---|---|
Analysis Questions
- Which habitat had higher species richness? What features of that habitat might explain the difference?
- Did one species dominate either habitat? What might cause low evenness in an ecosystem?
- Lake sturgeon returned to the Detroit River after decades of absence once habitat conditions improved. What would you expect to happen to a quadrat's biodiversity if its habitat quality improved over several years?
- If you were designing a vacant-lot restoration project in Detroit, what would you plant or change to increase biodiversity, based on your data?