This is a particular set of living and non living components that form a habitat that can be used by an organism. For example, a crack in a piece of stone, can be classed a an ecological niche. This may collect some water, minerals from the rock and may be able to support a moss or plant. A nich may also be defined as a section within a food web that is occupied by an organism. Obviously, as the structural complexity of the habitat increases, the range of temp, water, shade and therefore available niches also increases.
Communities are groups of organisms that live in a specified area.
They may occupy one or many niches within an ecosystem. It should be capable of existence independently of other ecosystems. An ecossytem could be a lake or desert island. They are often the most important species within a trophic level e.g. A decomposer, primary producer or apex predator. The loss of these species will therefore have a major impact on the way the ecosystem functions.