Island Biogeography

Download 457 b.
Hajmi457 b.

Island Biogeography

Island Biogeography

  • Colonization - arrival

    • float
    • fly
    • swim
    • be carried
    • wind (seeds, spores)

Surtsey (1963)

Plant colonization - Surtsey

Krakatau (1833)

Colonization - Krakatau

Characteristics of Island Species

Maquire (Ecol. Monog. 33:161-185)

  • Placed bowls of nutrient solution at various distances and heights from a pond.

  • Some bowls increased, then decreased in one species as others moved in.

  • The number of new species/unit time decreased with time. They finally reached an equilibrium state.

  • Different bowls had different species assemblages.

MacArthur and Wilson

Enclosing the “island”

Simberloff - equilibrium

Size relationships

  • If same distance from mainland, immigration should be the same

Small Islands - high turnover rate

  • Microtus pennsylvanicus (meadow vole)

  • Clethrionomys gapperi (red-backed vole)

  • 12 red-backed voles introduced to Rock Island

Inland Islands

  • Mountain tops in New Guinea

Species/Area relationships

Nonequilibrium theory

Relationship to Distance

  • Extinction is not likely to be affected by remoteness

MacArthur-Wilson model predictions

  • Number of species should remain constant over time

  • Some species should become extinct over time

  • Extinctions balanced by immigrations

  • Turnover rate of species should vary with island area and distance from a source of immigrants

Assembly rules

  • Worked out by Jared Diamond

  • Three sets of rules determining the species mix on an island

    • Incidence functions
    • Compatibility rules
    • Combination rules

Incidence Functions

  • Incidence functions place species into 3 groups:

    • Species only on species rich islands.
    • Tramps - on species rich islands and with lower probability on species poor islands.
    • Super tramps - only on species poor islands.

Compatibility rules

  • Built from mutually exclusive ranges of pairs of species.

  • Certain closely related species cannot co-exist.

Combination rules

  • Based on diffuse competition rather than direct.

  • Prevents certain groups of species from co-existing.

  • Calculates the probability of a given combination being found together on an island of a given size

  • The only stochastic part is the order of arrival of the first colonists.

Example: Cuba

Download 457 b.

Do'stlaringiz bilan baham:

Ma'lumotlar bazasi mualliflik huquqi bilan himoyalangan © 2020
ma'muriyatiga murojaat qiling