1. Metapopulation Theory
ES 100
10/20/06

2. Remember from last time:
Population ecology
Life Tables
Cohort-based vs. Static
Identifying vulnerable age stages
+ (in section)
Age-specific birth rate
Computing fitness, net reproductive rate and generation time
Population projections

3. Today: Metapopulation Theory Immigration and Emigration
Source and Sink Populations
Maintaining Genetic Diversity
Implications for Management

4. Is the Population Increasing, or Decreasing?
Fitness is one indication….. But…
Populations vary dramatically over time (boom/bust cycles)
Individuals move in (immigration) and out (emigration) of populations
Metapopulations (18.5 Bush)
Nt+1 = Nt + (B-D) + (I-E)

5. Populations across the landscape
Metapopulation: sum of multiple interacting sub-populations
sub-population A
sub-population C
sub-population B
sub-population D

6. Populations across the landscape
Most mating occurs within a sub-population
sub-population A
sub-population C
sub-population B
sub-population D

7. Populations across the landscape
Genetic diversity is maintained by exchange of genes between the sub-populations
sub-population A
sub-population C
sub-population B
sub-population D

8. Populations across the landscape
Some habitat patches are better than others
hot and dry
few nesting sites
most ideal
many
predators

9. Populations across the landscape
Sub-populations can be source populations or sink populations
sink
sink
hot and dry
source
few nesting sites
most ideal
many
predators
sink

10. Populations across the landscape
In source population habitats:
living conditions are good, so births meet or exceed deaths
competition may be great, forcing some members out
sink
sink
hot and dry
source
few nesting sites
most ideal
many
predators
sink

11. Populations across the landscape
If a sub-population goes extinct, it can be revived by recruits from another sub-population….
sinks are important too!
sink
source
locally extinct
source of recruits

12. Controls on immigration
Distance to source population
Lots of immigration
mainland
Little immigration
Obstacles
Mountains
Waterways
mountains
hills

13. Sample Metapopulation Data
Is this population assessment static or cohort based?
Which sub-population(s) are sources? Sinks?
Can you develop a life table for each sub-population?
Can you develop a life table for the total population?

14. Endangered Species: Mountain Pygmy-possum Burramys parvus

15. NEXT WEEK: Fun with Mathematical Models