Sampling

• Why do we take samples to estimate population size?

  Counting every organism is time-consuming and error-prone
• What is the purpose of random sampling?

  To avoid bias in sample selection
• What type of sampling is used for uneven distributions?

  Line transect sampling
• How does a large sample size improve population estimates?

  It ensures better representation of the population
• What are the two initial options for sampling methods?

  • Sampling motile organisms
  • Sampling slow-moving or non-motile organisms
• What is the size of a typical quadrat used in sampling?

  50 cm by 50 cm
• What is the first step in random sampling?

  Take measures at a right angle
• How do you generate coordinates for random sampling?

  Using a random number generator
• What data collection methods can be used in random sampling?

  Density, percentage cover, or local frequency
• How many times should you repeat the sampling process?

  At least 30 times
• What is a line transect used for?

  To sample uneven distributions
• Why is random sampling not suitable for uneven distributions?

  It may miss key areas of interest
• What are the two types of transects mentioned?

  • Belt transect (uninterrupted)
  • Interrupted belt transect
• When would you use an interrupted belt transect?

  For measuring long distances efficiently
• What is a key marking point often missed in transect descriptions?

  Precise placement of the transect
• What is local frequency in sampling?

  Counting squares with species present
• How do you calculate local frequency percentage?

  Number of occupied squares divided by 100
• How do you estimate density in a quadrat?

  Count the number of one species in area
• What is the formula to estimate total population size using density?

  Total = density in quadrat × total area
• What is percentage cover in sampling?

  Estimating full squares covered by species
• What are the pros of using local frequency?

  Quick and useful for large areas
• What are the cons of using density?

  Time-consuming and requires clear identification
• What is a downside of percentage cover?

  It is subjective and can vary by observer
• What are the pros and cons of the three sampling methods?

  Local Frequency:

  • Pros: Quick, useful for large areas
  • Cons: Poor accuracy, overlapping plants

  
  

  Density:

  • Pros: More accurate for distinguishable plants
  • Cons: Time-consuming, requires clear identification

  
  

  Percentage Cover:

  • Pros: Quicker than density, useful for difficult species
  • Cons: Subjective, overlapping plants not counted