Island biogeography

Definition

Island biogeography is the study of the distribution of species and ecosystems in oceanic islands and the processes that affect these distributions, focusing on how the size and distance of islands influence biodiversity. It connects ecological and evolutionary principles, showing how isolation impacts species richness, extinction rates, and colonization dynamics.

5 Must Know Facts For Your Next Test

1. Island biogeography highlights how larger islands generally support more species due to a greater range of habitats and resources compared to smaller islands.
2. Isolation affects colonization; islands farther from a mainland are less likely to receive new species, which can lead to lower biodiversity.
3. The theory also applies to 'habitat islands' found within larger landscapes, such as patches of forest or wetlands amidst urban areas.
4. In terms of conservation, understanding island biogeography is crucial for designing protected areas that effectively preserve biodiversity.
5. Species on islands often exhibit unique adaptations due to their isolated evolution, making island ecosystems critical for studying evolutionary processes.

Review Questions

• How does the size and distance of an island influence species richness according to island biogeography?
  • According to island biogeography, larger islands tend to have higher species richness because they provide more diverse habitats and resources. Additionally, islands that are closer to a mainland facilitate greater immigration rates, allowing more species to establish themselves. In contrast, smaller or more isolated islands experience higher extinction rates due to limited resources and isolation from new colonizers, ultimately leading to lower overall biodiversity.
• Discuss the implications of habitat fragmentation in relation to island biogeography principles.
  • Habitat fragmentation can be likened to the principles of island biogeography since it results in smaller, isolated patches of habitat that function similarly to islands. These fragmented habitats can decrease species richness by limiting the area available for species to thrive and increasing distances between patches, which hampers movement and colonization. Understanding this relationship helps in conservation efforts aimed at preserving biodiversity by creating wildlife corridors or managing landscapes more effectively.
• Evaluate the significance of endemism in island biogeography and its impact on conservation strategies.
  • Endemism plays a crucial role in island biogeography as many species found on islands have evolved uniquely due to their isolation. This uniqueness makes them particularly vulnerable to extinction when faced with environmental changes or human impacts. Conservation strategies must prioritize protecting these endemic species and their habitats because losing them would mean losing entire lineages that may not exist elsewhere. Hence, managing and conserving island ecosystems is essential not only for preserving biodiversity but also for maintaining evolutionary history.

Related terms

Equilibrium Theory:

A theory that describes the balance between immigration and extinction rates on islands, suggesting that species richness reaches a dynamic equilibrium based on island size and distance from the mainland.

Endemism:

The state of being unique to a defined geographic location, often observed on islands where species evolve in isolation, resulting in high levels of unique flora and fauna.

Habitat Fragmentation: The process where large habitats are divided into smaller, isolated patches, impacting biodiversity and species interactions, similar to how island biogeography examines isolated ecosystems.