Effect of Different Variables on Species Distribution

Introduction

The distribution of a species is influenced by a variety of factors, which can be classified as:

• Abiotic factors (non-living): e.g., light intensity, temperature, water, and nutrients.
• Biotic factors (living): e.g., predators, competition, and disease. The method involves recording the percentage cover of a species across different coordinates and correlating it with an independent variable such as light intensity or soil pH.

Equipment List

• Quadrat
• 2 x tape measure
• Equipment to measure the independent variable (e.g., photometer for light intensity).

Method

1. Select a 5m x 5m sampling area:

• Use a random number generator to generate 10 random coordinates within this area.

2. Set up a grid:

• Use two tape measures to create a set of axes for coordinates.

3. Place the quadrat:

• At each random coordinate, place the quadrat with its bottom left corner on the coordinate.

4. Measure the percentage cover:

• Count how many of the quadrat's 100 squares contain the species of interest.
• A square should only be counted if 50% or more of it is covered.

5. Record abiotic data:

• At each coordinate, measure the independent variable. For example:
• Use a photometer to measure light intensity.
• Use a thermometer for temperature.

Risk Assessment

Hazard	Risk	Safety Precaution	In Emergency	Risk Level
Biohazard	Allergies; contamination	Wash hands after handling samples	Seek assistance	Low
Slippery surfaces	Slip hazard	Wear suitable footwear; avoid running	Seek medical attention if needed	Low

Graph/Analysing Data

• Plot a graph of percentage cover against the independent variable (e.g., light intensity or pH).
• Use statistical tests to analyse the data:
  • Spearman's rank correlation to determine the relationship between variables.
  • T-test or Chi-squared test to assess the significance of differences or associations.