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#mainland

2 public questions tagged with this topic.

Biogeography Complete

Islands closer to the mainland typically show:

“Higher immigration rates” for islands closer to the mainland typically show. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Island biogeography explains species richness as a dynamic balance between immigration and extinction. Immigration generally declines as an island fills with species, whereas extinction rises as more species divide finite area and maintain smaller populations. The remaining alternatives—“Lower immigration rates”, “Higher extinction rates”, “No change in immigration rates”—refer to different states, processes, or scales and therefore do not express the same causal relationship. 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. Linking the wording to measurable consequences for fitness, abundance, or flux gives the conclusion its scientific meaning and prevents a purely mnemonic interpretation.

Ref: Biogeography, Lomolino et al., 5th Ed., Ch. 5-8

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Biogeography Complete

Mainland, in the context of island biogeography, is defined as:

“Initial habitat of immigrant species” for mainland, in the context of island biogeography, is defined as. 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—“Nearby islands”, “Mountain tops”, “Desert habitats”—refer to different states, processes, or scales and therefore do not express the same causal relationship. Island biogeography explains species richness as a dynamic balance between immigration and extinction. Immigration generally declines as an island fills with species, whereas extinction rises as more species divide finite area and maintain smaller populations. The cited framing is therefore most useful when treated as a conditional biological claim, with assumptions about scale and environmental context kept explicit.

Ref: Biogeography, Lomolino et al., 5th Ed., Ch. 5-8

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