Effects of river bed substrate composition on the diversity of individual

Control variables Water 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 eyes 2. Recordings of video 3. Ruler

Dependent variables Diversity of individual : 1.Large stream snail 2.Small long-armed shrimp 3.Mayfly nymph 4.Pond snail 5.Cheek goby 6.Water skater

Ways to measure dependent variables 1. by observation 2.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.