L6 Metapopulations and connectivity

Question 1

Explain a metapopulation:

Answer 1

“a population of populations” (Levins, 1970)
A group of populations that are separated by space but consist of the same species. These spatially separated populations interact as individual members move from one population to another.
Connectivity within the pops are as important as single population dynamics (Shtilerman & Stone, 2015).

Question 2

Describe connectivity and what is the relevance/why is it important to metapopulations?

Answer 2

Ease of dispersal between fragments.
Connectivity between metapops has relevance to climate change, environmental stochasticity and synergies within this.
NOTE: emigration from ‘donor’ pops can become a drain when using this method for reintroductions in conservation.

Question 3

What is a ‘donor’ population?

Answer 3

The original population used to source individuals to translocate in conservation management.

Question 4

Human habitat change often leads to fragmentation, how does this affect metapops?

Answer 4

It can cause the breakdown of dispersal and connectivity between pops. This in turn breaks down dynamics and natural metapop structure increasing the risk of extinction. (wilson et al., 2015)

Question 5

What are the 4 assumptions of a metapopulation?

Answer 5

1) they are local breeding populations
2) No single population is large enough to ensure long-term persistence
3) Recolonisation is possible
4) local dynamics are asynchronous (not being extirpated & colonizing at the same time)

Question 6

what is the term if single populations in a metapop are large enough to ensure long-term persistence without connectivity?

Answer 6

Mainland-island Metapopulation

Question 7

what is migration to an ecologist?

Answer 7

large, seasonal movements of animals

also temporal such as Diurnal migration in plankton

Question 8

what is migration to a population geneticist?

Answer 8

Gene flow

Question 9

What is philopatry?

Answer 9

Home lovers

Philopatry is the tendency of an organism to stay in or habitually return to a particular area.

Question 10

What two types of methods are used to measure connectivity?

Answer 10

1) Demographic - who moved, where & when
change in sex ratios and age structures. i.e. satellite tags
2) Genetic - (covered with Mairi). Easier to estimate some parameters but indirect.

Question 11

Give an example of a demographic connectivity measurement method and how it’s used

Answer 11

Radio telemetry:
GPS-radio telemetry allows us to follow and track animal movements.
first depth recorders attatched to Weddell seals in 1965

Question 12

What is landscape genetics?

Answer 12

Research into the effect of landscapes / barriers / fragmentation on gene flow and evolutionary processes. Can combine GPS and genetics to evaluate this.