Field Techniques for Biologists (d) Monitoring populations Flashcards
Presence, absence or abundance of an indicator species can give information of…
Environmental qualities, such as presence of a pollutant.
Susceptible and favoured species can be used to…
Monitor an ecosystem
Absence or reduced population indicates that a species is…
Susceptible to some factor of the environment
Abundance or increased population indicates…
It is favoured by the conditions
Procedure for the mark and recapture technique as a method for estimating population size using the formula:
N=MC/R
Steps for mark and recapture:
- A sample of the population is captured and marked (M) and released.
- After an interval of time, a second sample is captured (C)
- If some of the individuals in this second sample are recaptured (R) then the total population N=MC/R
Markand Recapture assumes that…
All individuals have an equal chance of capture, that there is no immigration or emigration, and that individuals that are marked and released can mix fully and randomly with the total population.
Methods of marking animals include:
Banding, tagging, surgical implantation, painting and hair clipping
The method of marking and subsequent observation must…
Minimise the imact on the study species
