CP 8: Quadrats & Transects

• What is the core practical objective mentioned in the study material?

  Investigate the relationship between organisms and their environment using field-work techniques.
• What field-work techniques are used in the core practical?

  • Quadrats
  • Belt transects
• What is the purpose of using a belt transect in this investigation?

  To study the effect of abiotic factors on the abundance of low-growing plants.
• What will the transect stretch between?

  Open ground and heavy shade under a large tree.
• What must you decide before starting the investigation?

  Which abiotic factors to measure and how to measure them.
• What is the first question you need to answer in the investigation?

  Which abiotic factors will you measure and how will you measure them?
• What is the second question you need to answer in the investigation?

  Which plants will you record?
• What are some common UK grassland plants listed in the study material?

  • Red clover
  • White clover
  • Daisy
  • Dandelion
  • Buttercup
  • Yarrow
  • Speedwell
  • Plantain
• What is the first step in setting up the transect line?

  Peg out a long tape measure (at least 20m) on the ground.
• How should the transect line be positioned?

  Starting where there is no shade and ending in heavy shade.
• At what intervals should measurements be made along the transect line?

  Every 1 meter.
• Where should the quadrat be placed during the investigation?

  At a measurement point on the transect line.
• What should you do after placing the quadrat?

  Measure the abiotic factors at that point and record them.
• What should you record in the quadrat?

  The abundance of the selected plants.

  
• What should you do after recording data at one measurement point?

  Repeat steps C to E at each measurement point along the transect.
• What data should be collected along the transect?

  • Distance (m)
  • pH
  • Light intensity (Lux)
  • Species present (e.g., Grass, Daisy, Clover, etc.)
• What is the final question to consider after collecting data?

  What can you conclude from your results?
• What is the aim of the field investigation?

  To estimate the population size of a plant species and investigate the effect of variation in a factor on its distribution.
• What are the two main aims of the field investigation?

  • Estimate the population size of a plant species using random sampling.
  • Investigate the effect of variation in a factor on the distribution of a plant species using continuous sampling with a transect line.
• What equipment is needed for the field investigation?

  A frame quadrat, tape measures, clipboard, pen, and paper.
• What is the size of the frame quadrat used in the investigation?

  25 cm by 25 cm.
• What is the method for estimating the population size of a plant species?

  1. Use a random number generator for coordinates.
  2. Set down the quadrat at the coordinates.
  3. Count and record the number of the required plant species.
  4. Repeat for 9 more samples.
  5. Estimate population size using the formula:

  $\text{Population size} =$$\frac{\text{total area}}{\text{area of quadrat}} \times \text{mean number of individuals in a quadrat}$
• What is the first step in Method A for estimating population size?

  Use a random number generator to obtain 2 numbers for coordinates.
• Why is it important to repeat the sampling process in Method A?

  To ensure a more accurate estimate of the population size.
• What is the formula used to estimate the population size?

  $\text{Population size} =$$\frac{\text{total area}}{\text{area of quadrat}} \times \text{mean number of individuals in a quadrat}$
• What is the method for investigating the effect of an abiotic factor on plant distribution?

  1. Write a hypothesis about the effect of an abiotic factor (e.g., light intensity).
  2. Lay down a tape measure from a tree to an open area.
  3. Place the quadrat at the '0' end of the tape measure.
  4. Count and record the number of plants.
  5. Move the quadrat 5 m up the tape measure and repeat.
  6. Gather data from the class for mean number of plants.
  7. Plot a graph of 'number of plants' against the ecological gradient.
  8. Compare results to the hypothesis.
• What should be recorded in the table during Method B?

  The number of plants counted at each quadrat position.
• What is the purpose of plotting a graph in Method B?

  To visualize the relationship between the number of plants and the ecological gradient.
• What are the controlled variables in the field investigation?

  • Size of quadrats
  • Number of repetitions in each site
  • Method of counting
  • Coordinate system at each site
• What factors should be considered beyond the measured abiotic factor?

  • Other abiotic factors affecting distribution
  • Time of day variations
  • Seasonal changes
• What are some sources of error in the field investigation?

  Certain species may be too small to see or difficult to identify, and the sample size may be too small to be representative.
• What is the risk assessment mentioned in the study material?

  Certain plants may cause allergic reactions or cuts, so wear gloves when handling.
• What is the significance of using a random number generator in the investigation?

  It ensures that the sampling locations are unbiased and representative of the area.