Facilitation and the Organization
of Plant Communities
| 1. | Introduction |
| 2. | What mechanisms cause positive interactions |
| 3. | Can we predict when positive or negative interactions may be important? |
| 4. | What do positive interactions mean for community theory? |
Current plant community ecology, as presented in most textbooks, often promotes the perspective that communities are produced only by the traits of populations and that assemblages of different plant species exist primarily because each shares adaptations to particular abiotic conditions. To some degree, this perspective leads to the conclusion that plant communities are simply a handy typological construct. However, a large body of research accruing during the last 30 years demonstrates that many if not most plant communities have fascinating interdependent characteristics, and although they are not “organic entities,” it is clear that many species create conditions that are crucial for the occurrence and abundance of other species. This research is the focus of this chapter.
continuum. A distribution of many species along a gradient in which each species appears to be distributed randomly with respect to other species
facilitation. The positive effect of one species on another
holistic communities. The idea that species within a community are highly interdependent, forming organism-like units
hydraulic lift. The process by which some plant species passively move water from deep in the soil profile, where water potentials are high, to more shallow regions where water potentials are low
indirect interactions. Interactions between two species that are modified by a third species
individualistic communities. The idea that communities are fundamentally groups of populations that occur together primarily because they share adaptations to the same abiotic environment; communities do not have organism-like qualities
niche complementarity. The condition in which different niches result in variation in the utilization of resources or space
As the discipline of ecology emerged from its biogeographic origins in the early 1900s, two strikingly polar views on the nature of plant communities vied for recognition, and the conflict established a precedent for ecological thought today. Initially, the view of Frederic Clements was ascendant with most ecologists accepting the idea that
(T)he community is an organic entity. As an or-
ganism the community arises, grows, and dies.
Furthermore, each community is able to reproduce
itself, repeating with essential fidelity the stages of
its development… comparable in its chief features
with the life history of an individual plant. (Clem-
ents, F. E. 1916. Plant Succession. Washington, DC:
The Carnegie Institution, Publication 242)
This holistic perspective, however, was replaced in the middle of the 1900s by new ideas promoted by Henry Gleason. In this new individualistic world view, the community “is merely the resultant of two factors, the fluctuating and fortuitous immigration of plants and an equally fluctuating and variable environment… not
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Questia, a part of Gale, Cengage Learning. www.questia.com
Publication information:
Book title: The Princeton Guide to Ecology.
Contributors: Simon A. Levin - Editor.
Publisher: Princeton University Press.
Place of publication: Princeton, NJ.
Publication year: 2012.
Page number: 282.
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