Editing Biological interaction (section)

==Non-trophic interactions==

{{see also|Non-trophic networks|Foundation species}}

Some examples of non-trophic interactions are habitat modification, mutualism and competition for space. It has been suggested recently that non-trophic interactions can indirectly affect [[food web]] topology and [[trophic dynamics]] by affecting the species in the network and the strength of trophic links.<ref name="Kefi2015">{{Cite journal |last1=Kéfi |first1=Sonia |author-link=Sonia Kéfi |last2=Berlow |first2=Eric L. |last3=Wieters |first3=Evie A. |last4=Joppa |first4=Lucas N. |last5=Wood |first5=Spencer A. |last6=Brose |first6=Ulrich |last7=Navarrete |first7=Sergio A. |date=January 2015 |title=Network structure beyond food webs: mapping non-trophic and trophic interactions on Chilean rocky shores |journal=Ecology |volume=96 |issue=1 |pages=291–303 |doi=10.1890/13-1424.1 |pmid=26236914|doi-access=free |bibcode=2015Ecol...96..291K }}</ref><ref name="vanderZee2016">{{Cite journal |last1=van der Zee |first1=Els M. |last2=Angelini |first2=Christine |last3=Govers |first3=Laura L. |last4=Christianen |first4=Marjolijn J. A. |last5=Altieri |first5=Andrew H. |last6=van der Reijden |first6=Karin J. |last7=Silliman |first7=Brian R. |last8=van de Koppel |first8=Johan |last9=van der Geest |first9=Matthijs |last10=van Gils |first10=Jan A. |last11=van der Veer |first11=Henk W. |date=2016-03-16 |title=How habitat-modifying organisms structure the food web of two coastal ecosystems |journal=Proceedings. Biological Sciences |volume=283 |issue=1826 |pages=20152326 |doi=10.1098/rspb.2015.2326 |pmc=4810843 |pmid=26962135}}</ref><ref name="Sanders2014">{{Cite journal |last1=Sanders |first1=Dirk |last2=Jones |first2=Clive G. |last3=Thébault |first3=Elisa |last4=Bouma |first4=Tjeerd J. |last5=van der Heide |first5=Tjisse |last6=van Belzen |first6=Jim |last7=Barot |first7=Sébastien |date=May 2014 |title=Integrating ecosystem engineering and food webs |journal=Oikos |language=en |volume=123 |issue=5 |pages=513–524 |doi=10.1111/j.1600-0706.2013.01011.x|bibcode=2014Oikos.123..513S }}</ref> It is necessary to integrate trophic and non-trophic interactions in ecological network analyses.<ref name=Sanders2014 /><ref>{{Cite journal |last1=Kéfi |first1=Sonia |author-link=Sonia Kéfi |last2=Berlow |first2=Eric L. |last3=Wieters |first3=Evie A. |last4=Navarrete |first4=Sergio A. |last5=Petchey |first5=Owen L. |last6=Wood |first6=Spencer A. |last7=Boit |first7=Alice |last8=Joppa |first8=Lucas N. |last9=Lafferty |first9=Kevin D. |last10=Williams |first10=Richard J. |last11=Martinez |first11=Neo D. |date=April 2012 |title=More than a meal... integrating non-feeding interactions into food webs |journal=Ecology Letters |volume=15 |issue=4 |pages=291–300 |doi=10.1111/j.1461-0248.2011.01732.x |pmid=22313549|doi-access=free |bibcode=2012EcolL..15..291K }}</ref><ref>{{Cite journal |last1=Pilosof |first1=Shai |last2=Porter |first2=Mason A. |last3=Pascual |first3=Mercedes |last4=Kéfi |first4=Sonia |author-link4=Sonia Kéfi |date=2017-03-23 |title=The multilayer nature of ecological networks |journal=Nature Ecology & Evolution |volume=1 |issue=4 |pages=101 |doi=10.1038/s41559-017-0101 |pmid=28812678|arxiv=1511.04453 |bibcode=2017NatEE...1..101P |s2cid=11387365 }}</ref> The few empirical studies that address this suggest food web structures (network topologies) can be strongly influenced by species interactions outside the trophic network.<ref name=Kefi2015 /><ref name=vanderZee2016 /><ref name="Christianen2017">{{Cite journal |last1=Christianen |first1=Mja |last2=van der Heide |first2=T |last3=Holthuijsen |first3=Sj |last4=van der Reijden |first4=Kj |last5=Borst |first5=Acw |last6=Olff |first6=H |date=September 2017 |title=Biodiversity and food web indicators of community recovery in intertidal shellfish reefs |journal=Biological Conservation |language=en |volume=213 |pages=317–324 |doi=10.1016/j.biocon.2016.09.028|bibcode=2017BCons.213..317C |url=https://research.rug.nl/en/publications/biodiversity-and-food-web-indicators-of-community-recovery-in-intertidal-shellfish-reefs(05a2a9ea-5041-4c44-b44b-a21ba29c4799).html }}</ref> However these studies include only a limited number of coastal systems, and it remains unclear to what extent these findings can be generalized. Whether non-trophic interactions typically affect specific species, trophic levels, or functional groups within the food web, or, alternatively, indiscriminately mediate species and their trophic interactions throughout the network has yet to be resolved. [[Sessility (motility)|sessile]] species with generally low trophic levels seem to benefit more than others from non-trophic facilitation,<ref>{{Cite journal |last1=Miller |first1=Robert J. |last2=Page |first2=Henry M. |last3=Reed |first3=Daniel C. |date=December 2015 |title=Trophic versus structural effects of a marine foundation species, giant kelp (Macrocystis pyrifera) |journal=Oecologia |volume=179 |issue=4 |pages=1199–1209 |doi=10.1007/s00442-015-3441-0 |pmid=26358195|bibcode=2015Oecol.179.1199M |s2cid=18578916 }}</ref> though facilitation benefits higher trophic and more mobile species as well.<ref name=Christianen2017 /><ref name="vanderZee2015">{{Cite journal |last1=van der Zee |first1=Els M. |last2=Tielens |first2=Elske |last3=Holthuijsen |first3=Sander |last4=Donadi |first4=Serena |last5=Eriksson |first5=Britas Klemens |last6=van der Veer |first6=Henk W. |last7=Piersma |first7=Theunis |last8=Olff |first8=Han |last9=van der Heide |first9=Tjisse |date=April 2015 |title=Habitat modification drives benthic trophic diversity in an intertidal soft-bottom ecosystem |journal=Journal of Experimental Marine Biology and Ecology |volume=465 |pages=41–48 |doi=10.1016/j.jembe.2015.01.001 |bibcode=2015JEMBE.465...41V |url=http://www.vliz.be/imisdocs/publications/83/279583.pdf }}</ref><ref name="Angelini2014">{{Cite journal |last1=Angelini |first1=Christine |last2=Silliman |first2=Brian R. |date=January 2014 |title=Secondary foundation species as drivers of trophic and functional diversity: evidence from a tree-epiphyte system |journal=Ecology |volume=95 |issue=1 |pages=185–196 |doi=10.1890/13-0496.1 |pmid=24649658|bibcode=2014Ecol...95..185A }}</ref><ref name="Borst2018">{{Cite journal |last1=Borst |first1=Annieke C. W. |last2=Verberk |first2=Wilco C. E. P. |last3=Angelini |first3=Christine |last4=Schotanus |first4=Jildou |last5=Wolters |first5=Jan-Willem |last6=Christianen |first6=Marjolijn J. A. |last7=Zee |first7=Els M. van der |last8=Derksen-Hooijberg |first8=Marlous |last9=Heide |first9=Tjisse van der |date=2018-08-31 |title=Foundation species enhance food web complexity through non-trophic facilitation |journal=PLOS ONE |volume=13 |issue=8 |pages=e0199152 |doi=10.1371/journal.pone.0199152 |doi-access=free |pmc=6118353 |pmid=30169517|bibcode=2018PLoSO..1399152B }}</ref>