13. Ecological techniques

• Why do we uses samples when investigating ecosystem

  Rarely possible to count and study every individual
• How do we measure plants or slow moving animals

  To measure abundance we use quadrants and random sampling
• Why do we use random sampling

  Avoid bias be representative and produce significant results
• How many quadrats do we have to use

  20
• How do we investigate distribution

  Systematic sampling and transects
• What is systematic sampling

  Sampling at intervals
• What is a like transect

  Every plant that touches the line gets identified
• What is a belt transect

  When quadrats are placed at regular intervals
• How do we measure abundance in moving animals

  Capture mark and release
• Population estimate =

  No. Caught and marked 1st X no. Caught 2nd / total recapture