Practice question

An ecotone is a transition zone where two adjacent ecosystems or communities meet, such as the boundary between forest and grassland or between freshwater and marine systems. It may contain species from both neighbouring habitats plus organisms specialized for the boundary conditions. This overlap and added habitat heterogeneity can produce an edge effect, often expressed as increased richness or abundance at the interface. Highest diversity is not guaranteed: sharp edges can expose interior species to predators, invasive species, wind, desiccation, or human disturbance, and some ecotones are stressful. The term identifies the zone in which edge effects are expected, while the actual response depends on scale and species. An ecocline is a gradual change in community composition along an environmental gradient; an ecotone is often treated as a more distinct transition, though usage can overlap. An ecotype is a genetically differentiated population adapted to local conditions, and an ecosystem includes organisms plus their physical environment. The ecotone concept therefore explains the coexistence of neighbouring assemblages and occasional unique edge specialists, providing a mechanistic basis for elevated boundary diversity.