Lecture Nineteen - Metapopulation Models Flashcards
Give two reasons for deforestation.
- Making space.
- To use as timber.
What is the negative effect of deforestation?
It leaves fragments between habitats.
What is a closed population?
No exchange of individuals among populations.
What is an open population?
Individuals are able to move among populations.
Give two reasons for a closed population.
- Crossing between two populations is dangerous, e.g. presence of a predator.
- Could be a physical barrier, e.g. a canyon, an ocean, and unable to cross the boundary.
What is a metapopulation?
A collection of spatially isolated OPEN subpopulations connected by dispersal among them.
What is a deme?
A local population of organisms of one species that actively interbreed with one another within a metapopulation.
In what sort of landscape is the metapopulation concept likely to be relevant?
In fragmented landscapes.
Why can demes in a metapopulation be compared to christmas lights?
- Demes ‘wink’ in and out
- The total number of demes ‘in’ is constant.
Why is a metapopulation in equilibrium?
There should be more or less the same number of occupied demes at any one point.
Using Levin’s metapopulation model, what is the rate of change in the proportion of occupied patches if there are 10% more patches occupied each unit of time?
0.1
Give the equation for Levin’s metapopulation model including measurement of extinction and colonisation.
dP/dt = C - E
What is the equation for extinction rate?
E = eP
e = probability deme will go extinct during unit of time P = fraction of habitat patches occupied
Give the equation for metapopulation colonisation rate.
C = P(1- P)c
P = fraction of habitat patches occupied c = probability that a colonist encounters the patch and successfully colonises if it is unoccupied.
Give the equation for P hat, the equilibrium value of P.
1 - e/c
e = probability deme will go extinct during unit of time c = colonisation rate.
