Module 10: Island Biogeography

Flashcards covering key vocabulary related to the Model of Island Biogeography, including experimental evidence, the mechanics of colonization and extinction curves, the effects of island size and distance, and the vulnerability of island species to invasive species.

Simberloff and Wilson Experiment

A classic experiment involving fumigation of islands off the coast of Florida to remove invertebrates, followed by observing recolonization rates to test the effect of island distance on species numbers.

Island Distance and Species Recolonization

Experimental results showing that islands closer to a mainland were rapidly recolonized by more invertebrate species than far islands, demonstrating that proximity increases colonization likelihood.

Model of Island Biogeography

A scientific model used to predict the number of species on an island based on its size and distance from the mainland, considering rates of colonization by new species and extinction of existing species.

Colonization Curve (Island Biogeography)

Represents the rate at which new species arrive on an island; it is high when few species are present and declines as the number of species increases due to fewer available new colonizers.

Extinction Curve (Island Biogeography)

Represents the rate at which species go extinct on an island; it is low when few species are present and increases as the number of species grows due to increased competition, predation, or parasitism.

Equilibrium (Island Biogeography)

The point on the island biogeography model where the rate of colonization by new species is exactly offset by the rate of extinction of existing species, determining the stable number of species (S) on an island.

Effect of Large Island (Island Biogeography)

In the model of island biogeography, larger islands have a lower extinction rate because they can support larger populations, making them less likely to go extinct, and thus tend to contain more species.

Effect of Far Island (Island Biogeography)

In the model of island biogeography, islands farther from the mainland experience a lower rate of colonization because fewer species successfully disperse to them, resulting in fewer species overall.

Combined Effects (Island Biogeography)

The island biogeography model predicts that large islands near a mainland (SLN) will have the highest number of species, while small islands far from a mainland (SSF) will have the lowest number of species.

Vulnerability of Island Species

Many species native to islands are particularly susceptible to invasive species because they have often evolved as specialists, sometimes lacking defenses against predators or pathogens that are absent in their isolated environments.

Island Specialists

Species native to islands that have evolved to thrive under specific, often isolated, conditions, which can lead to a narrow diet and a lack of evolved defenses against predators or pathogens.

Generalist (Invasive Species)

Invasive species that can thrive under a wide range of environmental conditions and consume diverse food items, making them highly successful at colonizing new areas and often outcompeting or preying on native specialist species.

Brown Tree Snake (Boiga irregularis)

An invasive predator accidentally introduced to Guam that caused the decline or extinction of numerous native bird, bat, and lizard species due to the native fauna's lack of evolved defenses against tree snakes.

Avian Malaria (Hawaii)

A disease caused by a pathogen carried by mosquitoes that was accidentally introduced to the Hawaiian Islands, leading to dramatic declines and extinctions in native bird populations that had not evolved defenses against it.

Conservation Implications of Island Biogeography

The principles of island biogeography guide conservation efforts by suggesting that protecting larger tracts of habitat and those closer to other protected areas will preserve a greater number of species.

Island Species Extinction Rates

Due to their vulnerability, island species account for a disproportionately high percentage of extinctions; approximately half of all animal extinctions and 90% of bird extinctions in the last 400 years have been island species.