Study of interactions between different species within environments.

Studies under the guise of community ecology are interspecific competition, symbioses, trophic interactions (as well as resistance to trophic interactions), species diversity, and ecological succession.

Community ecology is the study of interspecific interactions, contrasting the intraspecic interactions studies under the guise of population ecology and interactions between not only different species but with non-living (abiotic) things as well, the latter as studied under the heading of ecosystem ecology.