Aims:

• To understand how to measure the distribution and abundance of species in an ecosystem.
• To practice using transects and quadrats for sampling.
• To learn how to analyze ecological data using statistical methods.

Definitions:

• Transect: A straight line along which ecological measurements are taken at regular intervals to study changes in a habitat.
• Quadrat: A square frame, usually 1m x 1m, used to isolate a sample area for study.
• Distribution: The way organisms are spread across an area.
• Abundance: The number of individuals of a species in a given area.

Method 1: Using Transects Purpose: To study how the distribution of organisms changes across a habitat.

1. Lay out a transect line: Stretch a tape measure or rope across the study area.
2. Place quadrats at regular intervals along the transect (e.g., every 2 meters).
3. Record the species present in each quadrat and count their abundance.
4. Analyze the data to observe patterns of distribution. For example, you may notice changes in plant species from a shaded area to an open area.

Method 2: Using Quadrats Purpose: To estimate the population size or abundance of organisms in a specific area.

5. Place the quadrat randomly within the study area to avoid bias.
6. Count the number of individual organisms of each species within the quadrat.
7. Repeat this process multiple times in different parts of the habitat to get a reliable average.
8. Calculate the mean number of organisms per quadrat. You can then scale this up to estimate the population in the entire area.

Data Analysis

• Mean: Average number of organisms per quadrat.
• Mode: The most common number of organisms found in the quadrats.
• Median: The middle value when the numbers of organisms are arranged in order. You can also represent your data using graphs or charts to identify trends in the ecosystem.