Sampling 4.2.2 and 4.2.3 Flashcards
How do you prepare for the sampling of a habitat?
- Keys to identify the different species
- Camera - record specimens and locations
- Suitable clothing and footwear
- Apparatus for sampling
- Somewhere to record observations
When may it be helpful to modify the random sampling technique?
If the habitat is not homogenous (even)
What are ethical considerations of sampling
- Should consider the effect your presence will have on a habitat
- Any sampling should cause as little disturbance as possible
How can plants be sampled?
Can count the:
- Number of individual plants e.g. large trees
- % cover occupied by each species
What is quadrating?
- Square frame used to define sample area
- Divided quadrant makes estimating easier e.g. One square=1&
- Point frame to help. 10 needles, 10 positions. 1 needle = 1%. Possible to have more than 100% using point frame
What is a pooter?
Used to collect animals before they fly away
What is a tullgren funnel?
- Collecting small animals from leaf litter
- Light drives them down
- Animals fall into the collecting jar
How are animals trapped?
- Small animals in a Longworth trap
- Estimate population size by mark-and-recapture technique
Explain the capture, mark, and recapture technique
- Capture as many animals as you can in a defined period of time
- Count them and mark them in a way that causes no harm. The number captured = C1
- Release them to mix in the population
- After a few weeks/days capture the species over the same time period
- Count how many are captured =C2
The number of already marked animals captured on the second occasion = C3
Population = (C1 x C2) DIVIDED BY (C3)
How is population size calculated?
(Number in 1st sample x number in 2nd sample) DIVIDED BY (Number in 2nd sample previously marked)
What are 4 limitations of sampling?
- No death, immigration, or emigration
- Identical sampling methods
- Marking does not affect the survival rate of the animals
- Animals may learn the trap is harmless or contains food, or avoids due to not liking the experience
What are 2 other techniques of sampling?
- Tagging
- Ringing
Why do we sample? (3 reasons)
- To see how human activities may be affecting an area
- Environmental impact assessment prior to planning developments
- Importance of maintaining habitats and reducing the damage we do to them
How can we sample?
You can multiply up the number of individuals of each species found, in order to estimate the number in the whole area/habitat
What is random sampling?
Sites inside a habitat are randomly selected. E.g. using randomly generated numbers.
