Effects of river bed substrate composition

on the diversity of individual

Control variablesWater depth

Rate of water flow

Ways to measure controlled variables

1. Water depth: use a ruler to measure the depth of river bed

2. Rate of water flow : use flometer to ensure the rate of water flow is constant

Independent variables

Different types of river bed substrate composition : 1.Bare rock

2.Gravel(around 4mm to 64mm)3.Sand (around 0.075mm in diameter)

Ways to measure independent

variables

1. Observation by naked eyes2. Recordings of video

3. Ruler

Dependent variablesDiversity of individual :

1. Large stream snail2. Small long-armed

shrimp3. Mayfly nymph

4. Pond snail5. Cheek goby6. Water skater

Ways to measure dependent variables

1. by observation2.comparison with pictorial

guide

Hypothesis

River bed with more sand and gravel has a higher diversity of animal species.

Measurement of area 1

Measurement of area 2

Results

We find out that river bed with more sand and gravel has a higher diversity of animal species.

Analysis

Since river bed with more sand and gravel provides more shelter for the animals to live in,river bed with

more sand and gravel has a higher diversity of animal species.