Island biogeography theory

Definition

Island biogeography theory is a concept that explains the dynamics of species diversity and distribution on islands, based on their size and distance from the mainland. This theory posits that larger islands tend to support more species due to their greater habitat variety and resources, while islands that are closer to the mainland have higher rates of immigration for new species. Understanding this theory is essential for addressing biodiversity loss and developing effective conservation strategies, particularly in fragmented habitats.

5 Must Know Facts For Your Next Test

1. Island biogeography theory was developed by Robert MacArthur and Edward O. Wilson in the 1960s, providing a framework for understanding species diversity patterns.
2. The theory highlights the importance of both immigration and extinction rates in determining the number of species found on an island.
3. Larger islands not only have more resources but also greater habitat diversity, allowing for more niches and thus supporting more species.
4. Islands further from the mainland experience lower rates of immigration, leading to potential decreases in species richness over time.
5. This theory has significant implications for conservation efforts, especially for island ecosystems facing threats from invasive species and climate change.

Review Questions

• How does island biogeography theory explain the relationship between island size and species diversity?
  • Island biogeography theory suggests that larger islands support more species due to their increased habitat variety and resources. This is because larger land areas can accommodate a wider range of ecological niches, allowing for greater biodiversity. Additionally, larger islands often have lower extinction rates as they can sustain larger populations, while smaller islands may struggle with resource limitations and higher vulnerability to extinction events.
• Discuss how isolation impacts the immigration rates of species to islands according to island biogeography theory.
  • Isolation plays a crucial role in the immigration rates of species to islands as per island biogeography theory. Islands that are located closer to the mainland typically have higher rates of species immigration due to shorter distances for organisms to travel. Conversely, isolated islands experience lower immigration rates, which can limit their ability to acquire new species and thus influence overall biodiversity. This factor can lead to distinct evolutionary paths for species on isolated islands.
• Evaluate the role of island biogeography theory in shaping modern conservation strategies for biodiversity loss.
  • Island biogeography theory is integral to modern conservation strategies as it provides insights into how habitat size and connectivity affect biodiversity. By understanding the principles of this theory, conservationists can prioritize larger, connected habitats that support more diverse ecosystems. Additionally, it emphasizes the need for creating wildlife corridors to facilitate species movement between fragmented habitats, ultimately helping to mitigate biodiversity loss caused by human activities and environmental changes.

Related terms

Habitat Fragmentation: The process by which larger habitats are divided into smaller, isolated patches, negatively impacting species survival and biodiversity.

Ecological Succession: The process of change in the species structure of an ecological community over time, which can be influenced by disturbances and the arrival of new species.

Endemism: The state of a species being unique to a specific geographic location, often seen in island ecosystems where species evolve in isolation.