Exploring Our Fluid Earth

Teaching Science as Inquiry

 

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Activity: Sampling for Abundance - Transects and Quadrats

 

Materials

To create study site:
  • Colored cards or other items to represent different categories
  • Optional: Blankets, boxes, and other materials to create a complex study site 
 
To sample study site for abundance:
  • Transect
  • Quadrat
  • Clipboard
  • Pencil
  • Transect data sheet
  • Quadrat data sheet
  • Skewer
  • Optional: Objects representing physical and chemical sensors
 

Procedure

  1. Create a study site in your classroom or go to a study site designated by your teacher. 
  2. Observe the study site and make predictions. Which category do you think is most abundant? Which category is least abundant?
  3. Use your predictions to make a hypothesis about the abundance of categories at your study site. 
  4. As a class, plan how to conduct your data collection accurately and in the span of time allocated by your teacher. You will need to make decisions about:
    1. How to place the transect(s) 
    2. How long the transect(s) will be and how far apart transects will be from each other
    3. How frequently you will collect transect point intercept data 
    4. At which transect points you will place your quadrat(s)
    5. How you will place your quadrat in relation to the transect 
    6. Whether you will use the squares modification for the quadrat percent cover method 
    7. How you will standardize your categorization of species and substrates
  5. If necessary, customize the data sheets to reflect your study site, including transect length and where quadrats will be laid.
  6. Collect data following the class procedure. Use a skewer to assist in accurately determining what is directly at a transect point or quadrat intercept. 
  7. Optional: Your group may be given objects representing physical and chemical sensors, which can measure certain parameters. Determine where you should place your sensor(s) to collect data that will allow you to draw useful inferences about the interaction between the biotic and abiotic factors in the environment. 
  8. Compile class data. 
  9. Analyze, share and present this data.

 

Activity Questions

 

  1. Explain why your class chose to use the sampling scheme you determined, including the sensors if you used them.
  2. Why was it important to have a class procedure for data collection? What would happen if you did not follow the class procedure?
  3. Compare the transect point intercept, quadrat point intercept, and quadrat percent cover data. What are the similarities and differences in category abundance?
  4. What are the pros and cons of each sampling method for your study area:
    1. Transect point intercept
    2. Quadrat point intercept
    3. Quadrat percent cover
  5. What are potential sources of error for each sampling method?
  6. Compare the transect and quadrat data to the actual study site. Do you think the sampling methods accurately sampled this area? Why or why not?
  7. What is the importance of the information at the top of the transect data sheet, including start and end times, location, date, and transect line number?
  8. If you had to survey the study site again, what would you do differently? Be specific.
  9. Different sampling techniques work better in different areas. Think about how you would use transects and/or quadrats to accurately and efficiently sample the following areas to gain the most information about the site:
    1. A crater on Mars
    2. A deep-sea vent
    3. A parking lot
Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.