IB Biology IA idea · Ecology and fieldwork

IB Biology IA idea: how trampling along a path changes plant cover

A path across the grass shows a clear border. Measure how plants change as you move away from the track.

Ecology and fieldwork
SL ideal
HL good
Fieldwork Extended Essay potential

By Photon Academy · Updated 13 November 2026

These ideas are starting points, not an IA to copy. Never copy an idea blindly: make the question, method and analysis your own, and check your plan with your teacher.

Example research question

To adapt, never to copy

How does distance from the centre of a well-used path (0, 1, 2, 3, 4 and 5 m) affect percent plant cover in 0.25 m² quadrats, along five transects laid across the path?

Change the system, the range or the method so the question is yours. Check it against the research question checklist in our Biology IA guide.

Variables

You change: distance from the centre of a well-used path, 6 or more stations from 0 to 5 m
You measure: percent plant cover and number of species per quadrat
You keep the same: same slope, soil and light
same quadrat size
same transect orientation
same time of year

Method

Lay several transects across a path and record cover and species in a quadrat at each station. Measure soil hardness with a simple penetrometer (a weighted rod dropped from a fixed height).

Data analysis

Mean cover and richness per distance with standard deviation across 5 or more transects, line graph, Spearman correlation with distance. Link to soil compaction.

How it works

You change Distance from path centre (m) and measure Plant cover (%) in Plants along a path, keeping Quadrat size, Transect spacing, Slope, Sampling date the same. Expect a graph of Plant cover / % against Distance from path centre / m: Cover recovers as trampling eases.

Make it yours

Compare two paths with different foot traffic counts.

Extended Essay angle

Extend to a wider disturbance gradient across a park or reserve with a long series of surveys.

Safety

Take care with: work outdoors.

Check permission; avoid damaging protected plants; be careful on slopes.

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