Island biogeography

Definition

Island biogeography is the study of the distribution and diversity of species on islands and how these factors are influenced by isolation, size, and habitat diversity. This concept explains how the number of species on an island is determined by a balance between immigration rates and extinction rates, shaping the unique ecosystems found on islands compared to mainland areas.

5 Must Know Facts For Your Next Test

1. Islands can vary greatly in size and habitat types, which influences their biodiversity and species composition.
2. The distance from the mainland affects immigration rates; closer islands receive more incoming species compared to those further away.
3. Islands often have higher rates of endemism due to their isolation, leading to unique species that are not found anywhere else.
4. Habitat fragmentation can mimic island biogeography patterns on a smaller scale, affecting conservation efforts for terrestrial ecosystems.
5. Human activity, such as deforestation and pollution, poses significant threats to island ecosystems by increasing extinction rates.

Review Questions

• How does the size of an island influence its biodiversity according to island biogeography?
  • The size of an island significantly impacts its biodiversity because larger islands generally support more species than smaller ones. This is due to the greater availability of habitats and resources that larger islands provide, which can accommodate diverse organisms. Additionally, larger islands tend to have lower extinction rates because they can sustain larger populations, creating more stable ecosystems.
• Discuss how isolation affects species richness on islands as outlined in the concept of island biogeography.
  • Isolation plays a crucial role in determining species richness on islands. Islands that are closer to the mainland tend to have higher immigration rates of new species, which increases their biodiversity. Conversely, more isolated islands experience lower immigration rates and may have fewer species overall. This balance between immigration and extinction shapes the unique ecological dynamics observed in isolated island environments.
• Evaluate the implications of island biogeography for conservation strategies aimed at preserving biodiversity.
  • Understanding island biogeography has significant implications for conservation strategies. The principles of immigration and extinction highlight the importance of preserving larger habitats and maintaining connectivity between them to support species populations. Conservation efforts should prioritize protecting large areas and restoring fragmented habitats to prevent local extinctions. Additionally, recognizing the unique biodiversity of isolated regions can inform targeted conservation initiatives for endemic species threatened by human activities.

Related terms

Species-Area Relationship: A principle that states larger islands typically support more species than smaller ones, due to greater habitat diversity and resources.

Equilibrium Theory: A theory that describes how the number of species on an island reaches a stable equilibrium based on immigration and extinction rates.

Endemism:

The occurrence of species that are native to a specific geographic area, often seen in isolated islands where species evolve independently.