ecological sampling Flashcards
what are the methods of ecological sampling
- direct observation
- capture-recapture
- line transect
- quadrat sampling
describe direct observation
refers to counting each organism apart of a species individually
describe quadrat sampling
quadrat sampling is a variation of direct observation in which only small areas are looked at. This involves using a square frame to collect data on species within the boundary
describe line transects
involves a line being placed down and recording all things which touch the line. Line transects are used to study environments that have changes in environmental factors
describe capture-recapture
Individuals from a certain population are trapped, collected and marked and then released back into the environment. Later, another lot of individuals are captured, the recaptured organisms can be used as an indicator of the total population.
advantages of direct observation
- very accurate
disadvantages of direct observation
- time-consuming
- intrusive
advantages of quadrat sampling
- fast
- cheap
- not very intrusive
disadvantages of quadrat sampling
- not good for moving populations
- can miss species
advantages of line transects
- fast
- cheap
- shows changes in the environment
- not intrusive
disadvantages of line transects
- not good for moving populations
- doesn’t reflect the entire area
advantages of capture-recapture sampling
- good method of tracking populations
disadvantages of capture-recapture sampling
- can be intrusive and harmful to species
- timing can be difficult
population size formula
no. individuals in selected quadrats/no. selected quadrats x total no. quadrats
population density formula
population size/area
