Island biogeography

Islands in a landscape:

- Doesn't have to be an actual island

- Can be a:

○ A mountain

○ A forest

○ A pond

Loss of anti-predator defences (physical & behavioural)

• T.d Dodo

Loss of dispersal mechanisms

• T.d. thorugh seed or pollen distribution

• Intense specialisation (niches)

○ Islands tend to be very specialised

○ Size is an important factor

Iceland doensn't have any endemic (landlægur) species

- Too short of a time from colonisation

Equilibrium thoey of island biogeography:

- Rate of immigration or extiction per species richeness (biodiversity)

- The closer you are to the island the less extiction rate and more immigration

○ Viceversa for far away islands

- The size and location (how far away is it fromthe mainland) of the island matters:

Non-equilibrium effects:

- Different rates of clonisation and extinction between species according to dispersal mechanisms

- Some species will rely on other before they can occupy a new area (stenophagy)

- Anthropogenic impacts (hunting introduced species, land-use...)

Historical non-equilibrium theories:

Don't factor in evolution