ENWC314 Chapter Notes - Chapter 3: United States Forest Service, Introduced Species, Environmental Factor

• School: University of Delaware
• Department: Entomology and Wildlife Conservation
• Course: ENWC314
• Professor: Emara Marlene

Document Summary

Simplest explanation for why a species is not found in a particular area is that is has not been able to reach the area. The movement, or dispersal, of organisms can occur by two mechanisms. Diffusion is a common form of dispersal involving the gradual spread of a population across hospitable terrain. It results from the movement of many individuals over several generations. Jump dispersal is the movement of individual organisms across large distances, usually over unsuitable terrain, to a new area where they establish another population. This form of dispersal occurs in a short time during the life of an individual: the spread of the gypsy moth, an introduced pest. The european gypsy moth is an example of a species that has spread by both mechanisms of dispersal. In 1868/1869, ettiene leopold trouvelot brought some gypsy moth eggs from france to his home in massachusetts; a few of the caterpillars that hatched from the eggs escaped.