[permaculture] Ecological facilitation - Wikipedia, the free encyclopedia

Lawrence London lfljvenaura at gmail.com
Mon Jul 6 23:30:12 EDT 2015


Ecological facilitation - Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Ecological_facilitation

Ecological facilitation
>From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Ecological_facilitation

Facilitation describes species interactions that benefit at least one of
the participants and cause harm to neither.[1] Facilitations can be
categorized as mutualisms, in which both species benefit, or commensalisms,
in which one species benefits and the other is unaffected. Much of classic
ecological theory (e.g., natural selection, niche separation,
metapopulation dynamics) has focused on negative interactions such as
predation and competition, but positive interactions (facilitation) are
receiving increasing focus in ecological research.[1][2][3][4][5] This
article addresses both the mechanisms of facilitation and the increasing
information available concerning the impacts of facilitation on community
ecology (https://en.wikipedia.org/wiki/Community_ecology).

Categories

There are two basic categories of facilitative interactions:
A mutualism is an interaction between species that is beneficial to both. A
familiar example of a mutualism is the relationship between flowering
plants and their pollinators.[2][3] The plant benefits from the spread of
pollen between flowers, while the pollinator receives some form of
nourishment, either from nectar or the pollen itself.
A commensalism is an interaction in which one species benefits and the
other species is unaffected. Epiphytes (plants growing on other plants,
usually trees) have a commensal relationship with their host plant because
the epiphyte benefits in some way (e.g., by escaping competition with
terrestrial plants or by gaining greater access to sunlight) while the host
plant is apparently unaffected.[3]

Strict categorization, however, is not possible for some complex species
interactions. For example, seed germination and survival in harsh
environments is often higher under so-called nurse plants than on open
ground.[1][3] A nurse plant is one with an established canopy, beneath
which germination and survival are more likely due to increased shade, soil
moisture, and nutrients. Thus, the relationship between seedlings and their
nurse plants is commensal. However, as the seedlings grow into established
plants, they are likely to compete with their former benefactors for
resources.[1][3]


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