======Estimating Populations Using Quadrats======


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====Summary====                   
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====Procedure====  
  - Mark out the study area to be surveyed.
  - Use a random method to select coordinates, such as rolling dice for vertical and horizontal axes.
  - Place the quadrat at the chosen coordinates, ensuring consistent placement each time.
  - Identify and count all plants or slow-moving animals (e.g., snails, slugs) within the quadrat.
  - Repeat the sampling at least 25 times to improve reliability.
  - Use the counts to calculate an average number of organisms per quadrat.
  - Multiply the average by the total number of quadrats that could fit in the study area to estimate the population size.



====Links==== 
Quadrats - p68 - BBA Science: 
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Using quadrats to estimate population and biodiversity - Margaret Clark: 
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📄 Classification and biodiversity – WJEC - BBC Bitesize: [[https://www.bbc.co.uk/bitesize/guides/z9q982p/revision/4]]\\


====Variations====
  * Use quadrats of different sizes to compare effects on sampling accuracy.
  * Apply the method to both plant species and slow-moving animals to contrast results.
  * Combine quadrat sampling with a transect line to investigate how species vary across a habitat gradient.
  * Compare random sampling with systematic sampling to discuss bias.




====Safety Precautions====
  * Avoid disturbing or damaging plants and animals within the quadrat.
  * Take care when working outdoors (sun protection, insect repellent, hydration).
  * Watch for uneven ground to prevent trips and falls.
  * Wash hands after handling soil or organisms.




====Questions to Consider====
  * Why is random sampling important when using quadrats? (It prevents bias and ensures results are representative.)
  * Why should many samples be taken rather than just one or two? (More samples improve accuracy and reliability.)
  * How would the results change if quadrats were always placed in the same type of area? (It could bias the data, misrepresenting the true population.)
  * How can quadrat data be used to estimate biodiversity in an ecosystem? (By recording the number and variety of species within quadrats, scientists can calculate species richness and diversity.)