Practice question

An ecotone is the transition zone between two neighbouring ecosystems or communities. Because environmental conditions and resources overlap, it can contain species from both adjoining systems as well as edge specialists that occur mainly in the transition. This combination can produce the edge effect—locally elevated richness, abundance, or interaction intensity. Examples include a forest–grassland margin, an estuary between river and sea, or a marsh–upland boundary. Elevated diversity is not inevitable: abrupt human-created edges may exclude interior specialists, increase predation or invasion, and impose stressful microclimates. Nevertheless, the defining idea is mixed membership plus potential unique boundary species. A biome is a very large climatic vegetation unit, an ecotype is a genetically differentiated local population, and a clone is a set of genetically identical organisms; none denotes a community boundary. Ecotones may be sharp or broad and can shift with succession, hydrology, climate, or land use. Their mixed composition makes them important for studying species turnover and landscape connectivity, while their sensitivity to environmental change can make them useful ecological indicators.