2.3 Island Biogeography

• What is island biogeography the study of?

  Species richness on islands
• Larger islands generally have more diverse habitats
• Islands closer to the mainland have higher colonization rates than those further away.
• What does the equilibrium theory of island biogeography state?

  Balance between immigration and extinction
• Immigration and extinction rates affect species diversity
• Order the steps in the process of island colonization and species diversification according to island biogeography theory.

  1️⃣ Immigration rate is high, extinction rate is low

  2️⃣ More species arrive, immigration rate decreases

  3️⃣ Extinction rate increases due to competition

  4️⃣ Equilibrium is reached when immigration equals extinction
• Match the concept with its effect on species richness.

  Island Size ↔️ Larger islands support more species

  Distance from Mainland ↔️ Closer islands have higher species richness
• Larger islands offer more diverse habitats, which supports higher species diversity.
• Islands closer to the mainland have a higher colonization rate.
• Larger island size leads to higher habitat and species diversity.
• The distance of an island from the mainland influences its species diversity.
• What two factors determine the equilibrium number of species on an island according to island biogeography theory?

  Immigration and extinction rates
• Order the factors affecting immigration and extinction rates on islands.

  1️⃣ Island size

  2️⃣ Island distance from mainland

  3️⃣ Habitat diversity

  4️⃣ Competition between species
• The equilibrium number of species on an island is reached when immigration rate equals extinction rate.
• The equilibrium in the equilibrium theory of island biogeography is reached when the immigration rate equals the extinction rate.
• The equilibrium theory of island biogeography states that the number of species on an island is a dynamic equilibrium between immigration rate and extinction rate.
• Match the factor with its effect on immigration or extinction rate:

  Island Size ↔️ Lower extinction rate

  Distance from Mainland ↔️ Higher immigration rate
• Island biogeography explains how island size and distance from the mainland influence species diversity.
• Steps in the colonization process according to the equilibrium theory of island biogeography:

  1️⃣ Island is first colonized

  2️⃣ Immigration rate is high, extinction rate is low

  3️⃣ As more species arrive, immigration rate decreases, extinction rate increases

  4️⃣ Equilibrium is reached when immigration rate equals extinction rate
• What two rates are key factors affecting species diversity on islands?

  Immigration and extinction
• A high extinction rate decreases species diversity on islands.
• A small island far from the mainland will have low species diversity due to a low immigration rate and a high extinction rate.
• What are the two primary determinants of island biogeography?

  Island size and distance
• Larger islands support higher species diversity due to more diverse habitats.
• What is an example of a large island with high species diversity?

  Borneo
• What is a key factor affecting species diversity on islands?

  Island size
• Larger islands support higher species diversity due to more diverse habitats
• Borneo has higher species diversity than Christmas Island due to its larger size and greater habitat diversity.
• What is the relationship between island size and species diversity called?

  Island biogeography
• Islands closer to the mainland have a higher colonization rate.
• Island size is more important than distance from the mainland for species diversity.

  False
• What two rates determine species diversity on an island according to the equilibrium theory?

  Immigration and extinction
• Steps in the equilibrium theory of island biogeography

  1️⃣ High immigration rate, low extinction rate

  2️⃣ Immigration rate decreases

  3️⃣ Extinction rate increases

  4️⃣ Equilibrium is reached
• Island size has no effect on immigration rate.
• What happens to species richness on a small island far from the mainland?

  Low species richness
• A high immigration rate increases species diversity.
• Island biogeography principles apply to fragmented habitats.
• Match the habitat type with its characteristics:

  Large habitat island ↔️ High biodiversity

  Small fragmented habitat ↔️ Low biodiversity

  Large fragmented habitat ↔️ Moderate biodiversity
• Larger islands tend to have higher species diversity due to more diverse habitats.
• What conservation strategy enhances species diversity by connecting isolated habitats?

  Creating corridors