Coral reefs are extensive and diverse marine communities.
Community ecology is an expanding and rich sub field of ecology. Communities are made of populations that interact with the environment and with each other.
An ecological community is a group of actually or potentially interacting species living in the same location. Communities are bound together by a shared environment and a network of influence each species has on the other. Ecologists investigate the factors that influence bio-diversity (variations of life forms), community structure, and the distribution and abundance of species. These factors include interactions with the abiotic (non-living chemical and physical factors) world and the diverse array of interactions that occur between species. Species interactions, including competition, predation, herbivory, parasitism and mutualisms, commensalism , are the basic for most of the research in community ecology.
Community ecologists not only study the structure of communities but also changes in that structure. What do volcanoes, glaciers, sand dunes, storms, agriculture, and fire have in common? They all initiate the process of change in communities.