An ecotone is a transition zone of varied natural vegetation occupying the boundary between two adjacent and differing plant communities. Ecological succession is a series of changes that occur in an ecological community over time. Ecological niche is a term for the position of a species within an ecosystem, describing both the range of conditions necessary for persistence of the species and its ecological role in the ecosystem. A climax community is the final stage of succession, remaining relatively unchanged until destroyed by an event such as fire or human interference.