Ecosystems that are maintained by direct or indirect access to groundwater and rely on the flow or chemical characteristics of groundwater for some or all their water requirements, are collectively known as Groundwater Dependent Ecosystems (GDEs). GDEs can exist above and with the subterranean environment. GDEs above the subterranean environment thrive when natural groundwater levels are maintained such that groundwater is accessible from the land surface, thereby providing service, such as supporting biodiversity, providing baseflows in river, water purification, pollinator habitat, flood control, water supply and recreational opportunities=
GDEs and associated aquatic ecosystems are important to protect as they provide many ecosystem services. A few GDEs, such as some wetlands , are important habitats for migratory birds, or rare plant and invertebrate species, and protected by international and local agreements and legislation. The special environmental conditions of GDEs favor the occurrence of highly specialized and regionally restricted species, thus increasing their value for overall biodiversity.