The geographical term for the boundary between two ecosystems is called an ecotone. Ecotones are transition areas where two or more ecosystems meet and may exhibit distinct ecological characteristics, including species composition and environmental conditions. These regions often support unique biodiversity, as they provide a blend of species from the adjoining ecosystems. Ecotones are important for studying environmental changes and biodiversity's responses to alterations in habitat, such as climate change or human impact, highlighting their significance in conservation and ecology.