Practical skills · Data & graphs

Kite diagrams and zonation

Kite diagrams show zonation: changes in the distribution and abundance of species along an environmental gradient. Each kite represents one species. Its position shows where the species occurs, while its width shows relative abundance.

When could this come up?

In ESS, you may be asked to interpret zonation along a transect, compare species distributions, or suggest how an abiotic factor changes a community.

How to read a kite diagram

1. Read the axes

The x-axis shows distance from shoreline in metres. Each horizontal row represents one species. The vertical direction within a row shows the kite’s width, using the same abundance scale for every species.

2. Read abundance

Measure the complete vertical span across the kite, from its lower edge to its upper edge. Greater thickness means more organisms of that species. Both mirrored halves together represent the abundance; do not count them separately.

3. Find the range and peak

Follow the kite from left to right. Identify its first non-zero sample, its thickest point and its last non-zero sample. A pointed end at zero abundance is different from the last sample where organisms were recorded.

4. Explain the pattern

When asked to explain, connect the environmental gradient to a limiting factor or tolerance range, then to survival and reproduction, and finally to abundance. The diagram alone does not prove which factor caused the change.

Abundance is the number of organisms of one species. Species richness is the number of different species. Describe the data first; explain causes when asked.
Distance from shore: 30 m
Drag the vertical line left or right. Click the three frog markers to explore its start, peak and end.
🐸 Start here: click the three outlined dots on the frog kite. Each opens a clue. Read the other species yourself for the practice questions.
Distance from shore along a wetland transectAn illustrative shoreline on the left gives way to water on the right. The distance guide aligns with the kite diagram from zero to one hundred metres. Depth is schematic and is not measured by these abundance data.Shoreline · 0 mFarther from shore · 100 mIllustrative landscape · water depth is schematic
0 m100 m

Illustrative data · full vertical kite width = abundance · common scale for all species · counts between samples are interpolated estimates rounded to whole individuals

Reading the shape

The widest point of a kite shows where that species is most abundant.

Different species may reach their maximum abundance at different points because environmental conditions change along the transect.

The widest kite does not mean that more different species are present there. It only shows a greater abundance of that particular species.
The ESS connection

Conditions shape communities

Zonation occurs because environmental factors such as water depth, light, oxygen availability, temperature and substrate change along a transect. Species have different ranges of tolerance and optimum conditions, so their abundance changes as environmental conditions change.

Try it yourself

Type your answers, then select Check answer. You can revise and try again. Numerical answers are checked exactly and should always include the unit; written reasoning uses a key-idea checklist, not an official IB mark.

1. Identify the distance where frogs are most abundant. [1]

2. State the maximum abundance of water lilies and its distance. [2]

3. Compare the recorded distribution of frogs and fish. [2]

Use the first and last sampled distances with non-zero abundance.

4. Suggest why frog abundance decreases as water depth increases. [2]

IB ESS revision on FirstHandIB