Editing Ecosystem engineer (section)

==Types==
Jones et al.<ref>{{cite journal | last1 = Jones | first1 = CG | last2 = Lawton | first2 = JH | last3 = Shachak | first3 = M | year = 1994 | title = Organisms as ecosystem engineers | journal = Oikos | volume = 69 | issue = 3| pages = 373–386 | doi=10.2307/3545850| jstor = 3545850 | bibcode = 1994Oikos..69..373J }}</ref> identified two different types of ecosystem engineers:

===Allogenic engineers===

Allogenic engineers modify the [[biophysical environment]] by mechanically changing living or nonliving materials from one form to another. [[Beaver]]s are the original model for ecosystem engineers; in the process of [[clearcutting]] and damming, beavers alter their [[ecosystem]] extensively. The addition of a dam will change both the distribution and the abundance of many organisms in the area.<ref name= Haemig /> [[Caterpillars]] are another example in that by creating shelters from leaves, they are also creating shelters for other organisms which may occupy them either simultaneously or subsequently.<ref>{{cite journal | last1 = Jones | first1 = CG | last2 = Lawton | first2 = JH | last3 = Shachak | first3 = M | year = 1997 | title = Positive and negative effects of organisms as physical ecosystem engineers | journal = Ecology | volume = 78 | issue = 7| pages = 1946–1957 | doi=10.2307/2265935| jstor = 2265935 }}</ref> An additional example may be that of [[woodpecker]]s or other birds who create holes in trees for them to nest in. Once these birds are through with them, the holes are used by other species of birds or mammals for housing.<ref name= Haemig />

===Autogenic engineers===

Autogenic engineers modify the environment by modifying themselves. Trees are an example of this; as they grow, their trunks and branches create habitats for other living things, which may include squirrels, birds or insects. In the tropics, [[liana]]s connect trees, which allow many animals to travel exclusively through the forest canopy.<ref>{{cite web |url=http://www.eoearth.org/article/Ecosystem_engineer |title=Ecosystem engineer}}</ref>{{better source needed|date=June 2021}}