Ecosystem engineer 827837 163094329 2007-10-08T14:17:12Z Mdd 113850 /* References */ [[Category:Systems ecology]] [[Image:Beaver.jpg|thumb|250px|[[Beavers]] are the stereotypical ecosystem engineer because of the effects their [[dams]] have on [[Channel (geography)|channel]] flow, [[geomorphology]], and [[ecology]].]] An '''ecosystem engineer''' is any [[organism]] that creates or modifies [[habitat (ecology)|habitats]]. Jones et al (1994) identified two different types of ecosystem engineers: *''Allogenic engineers'' modify [[the environment]] by mechanically changing materials from one form to another. [[Beaver]]s are archetypal ecosystem engineers; in the process of clearcutting and damming, beavers alter their [[ecosystem]] extensively. Different types and numbers of other organisms will thrive in the region of a beaver dam than would in a non-dammed region. [[Caterpillar]]s which create shelters from leaves are also creating shelters for other organisms which may occupy them either simultaneously or subsequently. *''Autogenic engineers'' modify the environment by modifying themselves. As trees grow, their trunks and branches create habitats for other living things. In the tropics, [[liana]]s connect trees, which allow many animals to travel exclusively through the forest canopy. [[Introduced species]] are often ecosystem engineers. [[Kudzu]], a leguminous plant introduced to the southeast U.S., changes the distribution and number of animal and bird species in the areas it invades. It also crowds out native plant species. The [[zebra mussel]] is an ecosystem engineer in North America. By providing refuge from [[predator]]s, it encourages the growth of freshwater [[invertebrate]]s through increasing microhabitats. Light penetration into infected lakes also improves, resulting in an increase in [[algae]]. ==References== * Haemig PD 2005. [http://www.ecology.info/ecosystem-engineers.htm Ecosystem Engineers: Organisms that create, modify and maintain habitats], EcologyInfo * Jones CG, Lawton JH and Shachak M 1994. Organisms as ecosystem engineers. ''Oikos'' 69: 373-386 * Jones CG, Lawton JH and Shachak M 1997. Positive and negative effects of organisms as physical ecosystem engineers. ''Ecology'' 78: 1946-1957 [[Category:Ecology]] [[Category:Systems ecology]] {{Link FA|he}} [[he:מין מהנדס סביבה]]