Ecosystem Engineers, Keystone Species

Abstract

This entry focuses on two ecological phenomena. The first is “keystone species” which is defined by Paine 1 as a species (mostly of high trophic status) whose activities exert a disproportionate influence on the patterns of species occurrence, distribution, and density in a community. The second is the concept of “ecosystem engineers” defined by Jones et al. [2 as organisms that directly or indirectly modulate the availability of resources (other than themselves) to other species by causing physical state changes in biotic or abiotic materials.