Topic 14 - Metapopulations

How do populations increase in size

births, immigration

How do populations decrease in size

deaths, emigration

per capita

per individual

Metapopulation

population consisting of many smaller local populations that interact

Local populations are

In discrete locations (patches)

Exchange individuals (i.e. immigrate/emigrate)

Not synchronized with other populations

Population size

Local population sizes (in patches) fluctuate due to interactions with environment

what do populations in larger patches have?

• Greater population sizes
• More resources (higher K)
• Greater habitat heterogeneity
• Greater genetic variability
• Lower local extinction rates
• Greater population stability

Some patches have poor quality habitat/resources

Results in lower K

dispersal

Movement of individuals between patches

stable equilibrium

Constant # occupied patches

Source

relatively high K (large size, good quality)
- may act as source to neighboring patches
- (emigration > immigration, b > d)

Sink

relatively low K (small size, poor quality)
- receives individuals, but has negative growth rate
- (immigration > emigration, d > b)

Landscape mode

a conceptual and mathematical framework that accounts for:
• Differences of habitat size and quality
• Connectivity / dispersal between habitats