Island Biogeography - AP Environmental Science

Maintains ecological balance. Critical species support ecosystem structure and function for other organisms.

Can reduce species richness. Top consumers can eliminate prey species and alter community structure.

Irregular shapes can enhance habitat diversity. Complex coastlines create more microhabitats and ecological niches.

Facilitate species dispersal. Connecting pathways allow species movement between isolated habitat patches.

Alters species immigration and extinction. Habitat modification and species introductions disrupt natural equilibrium dynamics.

Species distribution and richness. Examines how geographic factors influence species diversity patterns.

Creates new land for colonization. Eruptions form new islands available for species colonization and evolution.

Older islands generally have higher richness. Time allows more species to colonize and evolve on established islands.

Immigration and Extinction. These opposing forces determine the equilibrium number of species on islands.

Designing wildlife reserves. Theory guides optimal size and connectivity of protected areas.

Species richness increases with area. Mathematical relationship showing species number increases with habitat area.

Equilibrium species number. Theory predicts a stable species count when immigration equals extinction rates.

Greater isolation lowers immigration. Distance creates dispersal barriers that reduce successful colonization events.

Larger area lowers extinction rates. More space and resources reduce competition and support larger populations.

Smaller island size. Limited resources and habitat space increase competition and population vulnerability.

Greater isolation. Distance from source populations reduces colonization and immigration rates.

Smaller islands have less genetic diversity. Limited population size reduces genetic variation through founder effects.

Extinction Rate. Measures how frequently existing species disappear from islands permanently.

Field studies on archipelagos. Empirical research in natural island systems validates theoretical predictions.

Establishes initial communities. Pioneer species colonize new volcanic surfaces and begin ecosystem development.

Equilibrium. Dynamic balance reached when immigration and extinction rates are equal.

High levels of unique species. Isolation promotes evolution of species found nowhere else on Earth.

Increases extinction rates. Smaller, isolated habitat patches increase species vulnerability to local extinctions.

Larger island size. More area provides diverse habitats and resources for multiple species.

Immigration Rate. Measures how frequently new species successfully establish on islands.

Islands are isolated systems. Islands function as closed systems with limited immigration and emigration.

Barriers reduce dispersal. Physical obstacles limit species movement and colonization between habitats.

Can lead to habitat degradation. Human activities often disrupt natural ecosystems and native species.

They can increase extinction rates. Non-native species often outcompete or prey on endemic island species.