Theory of island biogeography

Definition

The theory of island biogeography explains how the size and distance of an island affect the number and diversity of species that inhabit it. This theory connects habitat preferences and species distribution, suggesting that larger islands support more species due to greater habitat diversity, while closer islands to the mainland are more accessible for colonization, resulting in higher species richness.

5 Must Know Facts For Your Next Test

1. Larger islands not only have more habitats but also provide more resources, allowing them to sustain a greater variety of species.
2. Islands located closer to the mainland typically have higher rates of colonization due to easier access for species dispersing from the mainland.
3. The balance between colonization and extinction rates helps determine the equilibrium number of species on an island, which is a key concept in the theory.
4. Habitat preferences play a vital role in how species interact with their environment and can influence patterns of colonization and extinction on islands.
5. The theory has practical applications in conservation biology, helping in the design of wildlife reserves and understanding biodiversity loss.

Review Questions

• How does the size of an island influence habitat preferences among different species?
  • The size of an island affects habitat preferences by providing more diverse environments for various species. Larger islands can support a greater range of habitats such as forests, grasslands, or wetlands, which cater to different ecological needs. This diversity allows for niche differentiation among species, enabling them to coexist and thrive based on their specific habitat requirements.
• Discuss how distance from the mainland impacts colonization rates according to the theory of island biogeography.
  • Distance from the mainland significantly affects colonization rates, as islands that are closer are more accessible for potential colonizers. Species migrating from the mainland have a higher likelihood of reaching nearby islands compared to those that are further away. This accessibility leads to higher rates of successful colonization, which subsequently increases species diversity on closer islands.
• Evaluate the implications of the theory of island biogeography on conservation strategies for fragmented habitats.
  • The implications of the theory of island biogeography on conservation strategies are profound, particularly regarding habitat fragmentation. Understanding how island size and distance influence species richness helps conservationists design wildlife reserves that mimic larger habitats and consider connectivity between patches. This approach is crucial for preventing extinctions by ensuring that species can migrate between fragmented areas, ultimately enhancing biodiversity and ecosystem resilience.

Related terms

Species-Area Relationship: A principle stating that larger areas tend to support more species, often illustrated by a logarithmic curve that shows the relationship between the size of an area and the number of species it contains.

Colonization:

The process by which new species establish themselves in a new habitat or area, significantly influenced by the proximity of that area to existing populations.

Extinction Rate: The rate at which species become extinct in a particular area, which can be influenced by factors like island size, available resources, and habitat stability.