Using Quadrats to Investigate the Abundance of Species

A quadrat is a square frame, typically 1m x 1m, used in ecology and geography to isolate a standard unit of area for study of the distribution of an item over a large area.
Quadrats provide a method of sampling in ecological investigations. They allow scientists to obtain meaningful data representing a larger area.
Quadrats are usually randomly placed within a habitat to avoid bias in the results.
The number or type of species within each quadrat (species abundance) is counted - either individually or as a percentage cover if species are hard to separate.
The more quadrats used, the more reliable the results will be.
Using a quadrat can help you determine the population size of an organism in a given area. It’s important to repeat the quadrat sampling a number of times in different areas of the study region to increase reliability.
This data can then be used to calculate biodiversity – the measure of the variety of all the different species of organisms within a particular ecosystem.
Abiotic factors such as temperature, light intensity, pH and moisture levels could also be measured to see how they affect the distribution and abundance of species.
One limitation of using quadrats is that they may not be suitable for mobile or rare species because the chance of including these in the sample is low.