2.1.16—Quadrat sampling
- Syllabus
- First assessment 2026
- Objective
- 2.1.16
- Level
- SL
Turn Quadrat Counts Into an Estimate
For non-mobile organisms, random quadrats estimate abundance from mean count × total area ÷ quadrat area.
Use counts for population size; percentage cover and frequency describe occupancy patterns, not direct individual totals.
Mean 4 plants per 1 m² quadrat across a 100 m² meadow estimates 400 plants.
Not directly; frequency tells how many quadrats contain the species, not the number per quadrat.
Do not multiply percentage cover by area and call it population size.