#species colonization

Biogeography

A new and empty island initially has:

“High immigration and low extinction” for a new and empty island initially has. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Larger islands usually support more habitats and larger populations, lowering extinction risk; less isolated islands receive colonists more readily and may experience rescue effects. These mechanisms also apply to habitat fragments that function as ecological islands. The remaining alternatives—“High extinction and low immigration”, “Low immigration and high extinction”,

Ref: Biogeography, Lomolino et al., 5th Ed., Ch. 1-4

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Island

The 'source pool' refers to:

“Mainland or nearby habitat” for the 'source pool' refers to. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. At equilibrium, species identities can continue to turn over even when richness is approximately stable. The model predicts a balance of rates, not an absence of colonization or extinction. The remaining alternatives—“Island itself”, “Island vegetation”, “Predation pressures”—refer to different states, processes, or scales and therefore do not express the same causal relationship. Island b

Ref: The Theory of Island Biogeography, MacArthur & Wilson, Ch. 2-4

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Island

Factors primarily influencing colonization rates on islands:

“Distance from mainland” for factors primarily influencing colonization rates on islands. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Larger islands usually support more habitats and larger populations, lowering extinction risk; less isolated islands receive colonists more readily and may experience rescue effects. These mechanisms also apply to habitat fragments that function as ecological islands. The remaining alternatives—“Island shape”, “Island vegetation”, “Island altitude”—refer to diff

Ref: The Theory of Island Biogeography, MacArthur & Wilson, Ch. 2-4

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SUCCESSION

Which model suggests that any species can colonize and persist without help from others?

In the tolerance model of succession, any species capable of reaching a site may establish without needing earlier residents to improve the environment. Early and late species can therefore colonize independently, but later-successional species eventually dominate because they tolerate lower resource levels, live longer, or compete more effectively under conditions such as shade. Their success is not caused by facilitation; neither is establishment necessarily blocked by incumbents. Facilitation instead requires pioneers to create conditions needed by successors. Inhibition gives residents a n

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 20

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