Published Online: 16 MAY 2011
Copyright © 2001 John Wiley & Sons, Ltd. All rights reserved.
How to Cite
Wilkinson, D. M. 2011. Dispersal: Biogeography. eLS. .
- Published Online: 16 MAY 2011
Dispersal is one of the fundamental processes in biogeography, crucial to understanding the distribution of organisms. The most basic distinction between different types of dispersal is between organisms that disperse using their own energy and those that use energy from the environment. Dispersal can lead to two main patterns of range expansion. Either a population can slowly expand from the margins of its geographical range or a small number of individuals can disperse to a new location some distance from the current edge of the species range, or a combination of both of these processes can occur. Humans have assisted the dispersal of many organisms to new parts of the world – sometimes leading to problems when they become pests in their new range. Understanding dispersal is also important in attempting to predict how organisms will respond to climate change.
There are three fundamental processes in biogeography: evolution, extinction and dispersal.
The most basic distinction between types of dispersal is between organisms that disperse using their own energy (active dispersal) and those that use energy from the environment (passive dispersal).
Much of biodiversity is microscopic; organisms of this size can often be easily dispersed by air or water currents.
Many larger animals are capable of dispersal under their own power, especially ones that can fly such as birds and bats.
Individual organisms can sometimes appear at a location well outside their normal range, such individuals are referred to as vagrants.
There are two main patterns of range expansion ‘diffusion’ and ‘jump dispersal’.
Vicariance biogeography is an alternative to dispersal biogeography, which downplays the importance of dispersal, replacing it with the idea that a taxon's range can be divided by the formation of physical barriers.
A key applied question is whether organisms will be able to disperse at a speed that will allow them to track future climate change.
Human influence has had a big role in reducing the effects of dispersal barriers by moving organisms around the world.
When a species is dispersed to another part of the world by human actions, its main parasites and predators can be left behind; occasionally this can cause a dramatic increase in its population at the new site and the introduced organism can become a pest species.
- climate change;
- jump dispersal;