|Abstract:
This article aims to explain the basics of the Quadrat Sampling Technique, its advantages and disadvantages plus its applications in daily lives.
Quadrat sampling is a classic tool for the study of ecology, especially biodiversity. It is an
important method by which organisms in a certain proportion (sample) of the habitat are
counted directly. It is used to estimate population abundance (number), density, frequency
and distributions. The quadrat method has been widely used in studying less active or
slow-moving land plants and animals. Quadrat is a square-framed structure made from
wood, metal, or plastic. Normally, a quadrat will be divided into several parts of the same
size to estimate the coverage percentage of a species. The size of the quadrat depends on
the types and sizes of organisms, the area of study, the distribution, and the density of the
organisms to be studied. Quadrat sampling methods are time-tested sampling techniques
that are best suited for coastal areas where access to a habitat is relatively easy.
Important Assumptions of Quadrat Sampling Technique:
● The number of individuals in each quadrat is counted.
● The size of the quadrats is known.
● The quadrat samples are representative of the study area as a whole.
Figure 1.1: How a typical quadrat looks like
Here’s a summary of how to calculate the frequency, density, and percentage coverage:
● Frequency
○ Refers to the probability of obtaining an individual of an organism in each
quadrat.
● Density
○ Average number of individual species per unit area of study.
● Percentage Coverage
○ Surface area covered by the species studied.
○ Percentage coverage is the percentage surface area covered by the species.
Advantages:
● Easy to use, inexpensive.
● It is suitable for studying plants, slow-moving animals and faster-moving
animals with a small range.
● It requires the researcher to perform the work in the field and without much
care.
● It measures abundance and only needs cheap equipment.
Disadvantages:
● There exists biases in favour of slow-moving species
● Only able to collect species that are present in the sampling time and not
buried deeper in sediment.
● It is a low estimate of taxonomic richness and assemblage composition.
● It also has low detectability of among-site differences in assemblage
composition.
● Some animals may experience harm if the scientist collects the population
within the quadrat rather than studying it in the field.
Applications:
● Broadly used in plant studies
● Applied heavily in ecology especially biodiversity
● Used to find taxonomic richness of slow-moving species in a certain area
● It is the best measure of finding taxonomic richness in coastal areas
● Used in evaluating the impact of weathering, trampling, or erosion in an
ecosystem or at a cliff or rock face.
Hope this helps :)
References:
1. https://www.statisticalaid.com/quadrat-sampling-application-with-advantages-and-dis
advantages/
2. https://www.weacademia.com/my/biology/form-5/biology-f5-chapter-9/biology-f5-chap
ter-9-2
OUR AUTHOR
MELWIN CHENG CHOON LEI
Hey there! I'm Melwin, a Yayasan Khazanah Scholar currently doing my A-Levels at Kolej Yayasan UEM before studying abroad. I'm intending to pursue Molecular & Cellular Biology but I enjoy history, politics, and philosophy too as it helps add an element of humanity into our worldview.
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