BIOL 351 Lecture Notes - Lecture 8: Metapopulation, Local Extinction, Habitat Fragmentation
7 Mar 2017
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BIOL 351 – Lecture 8
Introduction to metapopulations
What do e lear fro Wilso’s 99
experiment on Krakatau island birds?
1. Local populations are continuously
subject to colonization and extinction
2. Communities are continuously changing
What does MacArthur ad Wilso’s Theor of
Island Biogeography state?
The Theory of Island Biogeography states that:
- Distribution of species on island could be
interpreted as a balance between the
opposing forces of extinctions and
colonisations
- Book concerned with explaining the
equilibrium # of species on islands
- Deals with colonization and extinction,
but from a source area (mainland) to an
island
What can be said about the pattern of extinction
and immigration on islands?
- Extinction rate higher on small islands
- Immigration rate higher on islands closer
to mainland
- Distant islands attain species equilibrium
with fewer species than near islands
How does dispersal and the demography of
metapopulation work?
- Focusing on single species populations,
Levins (1970) proposed a simple model of
metapopulation dynamics
- The concept metapopulation was
introduced
- He distinguished between the dynamics
of single populations and a set of local
populations
What is a metapopulation?
Metapopulation is a set of local populations
(subpopulations) held together by dispersal
among them, driven by extinction and
colonization dynamics.
Will the metapopulation dynamic hold if we
assume independence among local populations?
The concept of metapopulation will not hold if
we assume independence among local
populations because the dynamics of
metapopulation will be the sum of the dynamics
exhibited by the local populations. The concept
of metapopulation is highly applicable to
problems of habitat fragmentation and the
conservation of species.
What are the 4 conditions necessary for
metapopulations?
1. Discrete habitat patches
2. Local extinction is apparent (ie. the risk of
extinction is present)
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