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Metapopulations
Why Conservation
and Conservation
Biology ?
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Habitat destruction & fragmentation
Overharvesting (MCF)
Exotic species
Extinction cascades
Genetic, spatial, and climate (change) effects
• Human population pressure
• Increased extinction & extinction debt
Island Biogeography Revisited
Figure 25.8
Island birds
Bighorn Sheep persistence
depends on initial population size
Population Viability Analysis
Table 25.4 Birds on Californian Channel Islands
Persistence as a function of initial population size
A line-up of examples of threatened taxa
(Table 25.1)
3 Standard Levels of Threat
Figure 25.2
Invasive Species (Exotics)
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A consequence of human mobility
Biotic effects on natural species assemblies
Parasite release
Particularly problematic on islands
Introduction of natural enemies may work, but ..
Virulence is subject to natural selection
Myxoma virus in rabbits
Figure 12.34
Invasive Species (Exotics)
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A consequence of human mobility
Biotic effects on natural species assemblies
Parasite release
Particularly problematic on islands
Introduction of natural enemies may work, but ..
• The invasive garden ant, Lasius neglectus, in
Europe
The interplay of many factors
Extinction vortexes towards extinction
Figure 25.5
Effects of Fragmentation
• Genetic erosion
and inbreeding
• Demographic
stochasticity
• Edge effects (50 m for
birds?)
Figure 25.9
Modelling Approaches
25.11 Dynamics of subpopulations
Data:
25.12 Checkerspot butterflies
Analytical and Simulation Approaches
25.14 Mean time to extinction
as function of carrying capacity
Ve = Variance in r due to
environmental conditions
25.15 Cumulative probability of
elephant extinction over 1000
years for 6 habitats without
culling
Gorilla extinction with different
recolonisation probability
25.16
How to go about in practice ?
25.13
Decision tree
Sumatran rhino’s:
pE = extinction
probability in 30
Years
E(pE) = Expected
Value
$ = Cost
The endemism hotspot approach
Figure 25.19
Carsten Rahbek ZMUC
Ongoing Research:
Large blue butterflies in the genus Maculinea
• 5 European species
Paintings by Richard Lewington
Large blue butterflies in the genus Maculinea
• 5 European species
• Parasites of Myrmica
ant colonies
Large blue butterflies in the genus Maculinea
• 5 European species
• Parasites of Myrmica
ant colonies
• Dependent on specific
host plants
Fra: Flora Danica
Large blue butterflies in the genus Maculinea
• 5 European species
• Parasites of Myrmica
ant colonies
• Dependent on specific
host plants
• Vulnerable, threatened,
endangered or locally
extinct
The life cycle of Maculinea alcon
The European distribution of M. alcon
Geographical variation in host use
Elmes et al. (1989) Memorabilia Zoologica 48, 55-68.
Is this due to:
Cryptic species?
Regional host availability?
Local host switching?
Myrmica rubra
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Myrmica ruginodis
Myrmica scabrinodis
Geographical variation in allozymes
Gadeberg & Boomsma (1997) Journal of Insect Conservation 1, 99-111
Læsø
Råbjerg Mile
Tved
Idom
Vejers
Fanø
Frøslev
Gyttegård
Geographical variation in host use
Myrmica rubra
Læsø
Råbjerg Mile
M. ruginodis
Tved
M. scabrinodis
Idom
Vejers
Frøslev
Gyttegård
The Main Study Populations
Læsø
3 populations studied in detail
 Cross-infection experiments
 Surface chemistry
Vejers
Gyttegård
Laboratory adoption of Maculinea alcon
MacMan: A large EU program on
Maculinea butterflies
Issues to be dealt with in a longer course
• What are the relative importances of genetic,
environmental, and demographic factors for
long term persistence of populations ?
• Why are long term monitoring studies
important?
• Why are invasive species (ants particularly)
nasty ?