4.2.3 sampling animals

Question 1

techniques to catch invertebrates

Answer 1

• sweep nets
• pooter
• pitfall trap

Question 2

how are sweep nets/pooters used to catch invertebrates
what are these suitable for?

Answer 2

sweep net
- walk through habitat with stout net
- sweep net through vegetation in wide arcs
- small insects caught in net
- empty contents onto white sheet

pooter
- many animals may crawl/fly away
- use pooter to collect them before fly away

–> suitable for low vegetation which isn’t too woody

Question 3

how are pitfall traps used to catch invertebrates

Answer 3

• set in soil to catch small animals
• small container buried in soil with rim below surface
• contain little water/debris to stop animals crawling out
• should be sheltered if raining

Question 4

why do we catch small animals

Answer 4

estimate population size

Question 5

how do you know which technique to use to catch invertebrates

Answer 5

depends on habitat & which animals you wish to catch

Question 6

how can small mammals be trapped

Answer 6

= longworth trap

• doesn’t harm animal
• monitored regularly
• enables population size to be calculated by mark-and-recapture technique

Question 7

steps of mark-and-recapture technique

Answer 7

1. capture sample of animals
2. mark each individual (no harm) = C1
3. release marked animals & leave traps for another period of time
4. number captured on second occasion = C2 & number of already marked animals captured = C3
5. calculate total population with formula

Question 8

how can populations of larger animals be estimated

Answer 8

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