A biocoenosis (alternatively, biocoenose or biocenose ), termed by Karl Möbius in 1877, describes all the interacting organisms living together in a specific habitat (or biotope). Biotic community , biological community, and ecological community are more common synonyms of biocenosis, all of which represent the same concepts. Three related descriptors are zoocoenosis for the faunal community, phytocoenosis for the floral community and microbiocoenosis for the microbial community within an ecosystem. The extent or geographical area of a biocenose is limited only by the requirement of a more or less uniform species composition.
An ecosystem, as originally defined by Tansley (1935), is a biotic community (or biocoenosis) along with its physical environment (or biotope as defined by many known ecologists).
The importance of the biocoenosis concept in ecology is its emphasis on the interrelationships among species in a geographical area. These interactions are as important as the physical factors to which each species is adapted and responding. In a very real sense, it is the specific biological community or biocoenosis that is adapted to conditions that prevail in a given place.
Biotic communities may be of varying sizes, and larger ones may contain smaller ones. The interactions between species are especially evident in food or feeding relationships. Therefore, a practical method of delineating biotic communities is to map the food network to identify which species feed upon which others and then determine the system boundary as the one that can be drawn through the fewest consumption links relative to the number of species within the boundary.
Mapping biotic communities is particularly important when identifying sites in need of environmental protection such as the British Site of Special Scientific Interest (SSSIs). The Australian Department of the Environment and Heritage maintains a register of Threatened Species and Threatened Ecological Communities under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).