Biogeog, Sobero 2007

What is a niche?

The environmental conditions and ecological interactions that allow a species to survive and reproduce.

What three factors determine species distributions?

Environmental suitability, biotic interactions, and dispersal ability.

What is a Grinnellian niche?

A niche defined by broad-scale abiotic conditions (e.g. climate).

What is an Eltonian niche?

A niche defined by biotic interactions and resource use.

What are scenopoetic variables?

Abiotic environmental conditions that organisms do not consume (e.g. temperature, rainfall).

What are bionomic variables?

Resources that can be consumed and competed for.

Which niche concept is based on scenopoetic variables?

Grinnellian niche.

Which niche concept is based on bionomic variables?

Eltonian niche.

What is the fundamental Grinnellian niche?

All abiotic conditions where a species could persist indefinitely.

What is the realized Grinnellian niche?

The portion of the fundamental niche actually occupied after biotic constraints.

How can a realized niche become smaller than a fundamental niche?

Through competition, predation, or pathogens.

Why are Grinnellian niches easier to model?

Climate and environmental data are widely available.

Why are Eltonian niches harder to model?

Biotic interactions are complex, dynamic, and local.

What is an occupied distribution?

The area where a species actually occurs.

What is a source-sink distribution?

A species occurs in some areas where populations are not self-sustaining.

At what scale are abiotic factors most important?

Broad spatial scales.

At what scale are biotic interactions most important?

Local spatial scales.

Exam summary?

Species distributions depend on climate (Grinnellian niche), biotic interactions (Eltonian niche), and dispersal ability.