Why are larger islands expected to have more species?
“Reduced extinction rates” for why are larger islands expected to have more species. 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 predation pressures”, “Limited resources”, “Less immigration”—refer
Ref: Biogeography, Lomolino et al., 5th Ed., Ch. 5-8