2.1d Monitoring populations

Question 1

What does indicator species show?

Answer 1

Presence, absence or abundance of indicator species can give information or environmental qualities, such as presence of a pollutant.

Question 2

What type of species can be used to monitor an ecosystem?

Answer 2

Susceptible and favoured species can be used to monitor an ecosystem. Absence or reduced population indicates a species is susceptible to some factor in the environment. Abundance or increased population indicates it is favoured by the conditions.

Question 3

Procedure for mark and recapture technique

Answer 3

This method 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.

Question 4

Methods of marking animals

Answer 4

banding, tagging, surgical implantation, painting and hair clipping

The method of marking and subsequent observation must minimise the impact of the study species.

Question 5

Banding

Answer 5

Bands (often metal) with an individual identifier are attached to the animal where it won’t impede their movement. If it isn’t possible or appropriate to physically recapture different colours of bands or sequences of colour bands, they can be used for remote identification (e.g. through binoculars). Often attached to bird’s legs.

Question 6

Tagging

Answer 6

Tags will vary according to the species. Can be as simple as a plastic tag with a number on it or tags can also be used for remote tracking e.g. radio transmitters. The tag has to be securely attached but also not interfere with the animal’s normal behavior.

Question 7

Surgical Implantation

Answer 7

Tags can be implanted to prevent them interfering with the animal. For example, external tags on fish make a large difference to their streamlining. Since the animal undergoes a surgical procedure there are implications for their welfare and for the expertise required.

Question 8

Painting

Answer 8

Non-toxic, biodegradable paints must be used. Care must also be taken that the paint does not blog skin surfaces for heat regulation, secretion or respiration. It is also important to consider the impact of scent and colour marking on animals

Question 9

Hair Clipping

Answer 9

A clearly identifiable section of hair removed can be used as very effective method of identification. Care has to be taken regarding size of clipping, distress to animal and social signals with animals.