Editing Herbivore (section)

=== Mutualism ===
While much of the interaction of herbivory and plant defense is negative, with one individual reducing the fitness of the other, some is beneficial. This beneficial herbivory takes the form of [[Mutualism (biology)|mutualism]]s in which both partners benefit in some way from the interaction. [[Seed dispersal]] by herbivores and [[pollination]] are two forms of mutualistic herbivory in which the herbivore receives a food resource and the plant is aided in reproduction.<ref>{{cite journal|last1=Herrera|first1=C.M.|date=March 1985|title=Determinants of Plant-Animal Coevolution: The Case of Mutualistic Dispersal of Seeds by Vertebrates|journal=Oikos|volume=44|issue=1|pages=132–141|doi=10.2307/3544054|jstor=3544054|bibcode=1985Oikos..44..132H }}</ref> Plants can also be indirectly affected by herbivores through [[Nutrient cycle|nutrient recycling]], with plants benefiting from herbivores when nutrients are recycled very efficiently.<ref name=":5" /> Another form of plant-herbivore mutualism is physical changes to the environment and/or plant community structure by herbivores which serve as [[ecosystem engineer]]s, such as [[wallowing]] by bison.<ref>{{Cite journal|last1=Nickell|first1=Zachary|last2=Varriano|first2=Sofia|last3=Plemmons|first3=Eric|last4=Moran|first4=Matthew D.|date=September 2018|title=Ecosystem engineering by bison (Bison bison ) wallowing increases arthropod community heterogeneity in space and time|journal=Ecosphere|volume=9|issue=9|pages=e02436|doi=10.1002/ecs2.2436|issn=2150-8925|doi-access=free|bibcode=2018Ecosp...9E2436N }}</ref> Swans form a mutual relationship with the plant species that they [[forage]] by digging and disturbing the sediment which removes competing plants and subsequently allows colonization of other plant species.<ref name=":1" /><ref name=":3" />