A holistic community (also referred to as closed or unitary) is an ecosystem where the species within the community are interdependent on each other for keeping balance and stability of the system. These communities are described as working like a superorganism, meaning that every species plays an important part in the overall well being of the ecosystem in which the community resides; much like the organelles within a cell, or even the cells making up one organism. Holistic communities have diffused boundaries, and an independent species range. Co-evolution is likely to be found in communities structured after this model, as a result of the interdependence and high rates of interaction found among the different populations. It is said that species compositions of communities change sharply at environmental edges (known as ecotones).
The ideas of a holistic community were introduced by plant ecologist Frederic Clements in 1916. These notions were countered by Henry Gleason in 1917, when he proposed the individualistic/open community concept (in applications to plants). Neither of these ecological concepts have been found to exist in entirety, both are theories which can be applied to communities. For example, a community's composition can be better explained by holism than individualism, or vice versa. This ecological concept is based on the broader concept of holism, which describes the functionality of any system as having many individual parts, all of which are extremely important to the system's viability.
"A community has been viewed as a superorganism with an integrity analogous to that of cells in an organism. This is the holistic or unitary view of a community, and one championed by Clements (1916). He regarded the community to be a highly integrated unit that operated very much within itself with little interaction with surrounding communities - a closed community."
- "Tropical Ecosystems and Ecological Concepts". google.com.