Canada has 20 major ecosystems -- ecozones, comprising 15 terrestrial units and 5 marine units. These ecozones are further subdivided into 53 ecoprovinces, 194 ecoregions, and 1,027 ecodistricts. These form the country's ecological land classification within the Ecological Land Classification framework adopted in 2017. They represent areas of the earth's surface representative of large and very generalized ecological units characterized by interactive and adjusting biotic and abiotic factors