EE 12- Island Biogeography Lecture Notes

Vocabulary-style flashcards covering the fundamental concepts of island biogeography, including species-area relationships, equilibrium theory, and extinction prediction models.

Island Biogeography

A field of study, as presented by Rob Ewers, focused on predicting and explaining the number of species in a patch of land or on an island.

Arrhenius (1921)

Author of a study in the Journal of Ecology on weeds on Stockholm islands that established a power law relationship for species richness.

Species-Area Relationship (SAR)

The relationship used to predict the number of species in a region based on its size, represented by the formula $S = cA^z$.

Power Law Relationship

The mathematical relationship where the number of species follows the formula $\log(S) = k + z \times \log(A)$.

Watson (1859)

Credited with the first species-area curve for plants in Great Britain, as cited by Rozensweig (1995).

$$S = cA^z$$

The power law equation for the species-area relationship where $S$ is the number of species and $A$ is the area.

$$z$$

The slope of the species-area relationship when plotted on a log-log scale.

$$k$$

The constant in the log-transformed SAR equation, equivalent to $\log(c)$.

Antillean Birds SAR Equation

The specific relationship summarized as $\log(S) = 0.84 + 0.23 \log(A)$ according to Rozensweig (1995).

Antillean Reptiles SAR Equation

The specific relationship summarized as $\log(S) = 0.31 + 0.30 \log(A)$ according to Rozensweig (1995).

Robert MacArthur and E.O. Wilson

The scientists who developed the Theory of Island Biogeography in 1967.

Island Biogeography Theory (IBT)

A theory that explains why larger areas have more species and why more isolated areas have fewer species based on immigration and extinction.

Immigration Rate

The rate at which new species arrive on an island, which decreases as the number of species already present increases.

Extinction Rate

The rate at which species disappear from an island, which increases as the number of species already present increases.

$$\hat{S}$$

The symbol for equilibrium species richness, found at the point where the immigration rate curve and the extinction rate curve intersect.

Area Effect on Extinction

In IBT, large islands have a lower extinction rate compared to small islands.

Isolation Effect on Immigration

In IBT, islands that are near a source have a higher immigration rate compared to islands that are far away.

$$\hat{S}_{near}$$

The equilibrium species richness for islands close to a source, which is higher than the equilibrium richness for far islands.

$$\hat{S}_{large}$$

The equilibrium species richness for islands of a large size, which is higher than the equilibrium richness for small islands.

Egmont National Park

A national park in New Zealand used as an example for predicting how species numbers change following habitat loss.

Pimm and Askins (1995)

Researchers who authored a PNAS study on predicting extinction by applying the species-area relationship.

Extinction Prediction Formula

The equation $\frac{S_{new}}{S_{orig}} = (\frac{A_{new}}{A_{orig}})^z$ where $S$ is species and $A$ is area.

$$\frac{S_{new}}{S_{orig}}$$

The term representing the proportion of species remaining at the end of an area change.

$$\frac{A_{new}}{A_{orig}}$$

The term representing the proportion of habitat area remaining after habitat loss.

Standard $z$ value

The slope value of approximately $0.25$ frequently used in predicting extinction with the SAR.

0.84

The proportional species richness change when area is reduced by half ($0.5$) and $z \approx 0.25$.

1.19

The proportional species richness change when area is doubled ($2$) and $z \approx 0.25$.

Power (1972)

The author of a study published in Evolution regarding the number of bird species on Californian islands relative to area and isolation.

Isolation Predictor

The secondary factor in Island Biogeography that results in a negative relationship with the log(number of species).

Habitat Loss

A process of area reduction that leads to species loss, predictable via the species-area relationship curves.