Biosphere Reserves are certified territories with the purpose of harmonizing the preservation of biological and cultural diversity with economic and social development. In May 2013 the Terres de l'Ebre was declared a UNESCO Biosphere, thanks to its rich landscape, the representativeness of its Mediterranean ecosystems and its biodiversity preservation model.
In terms of natural heritage, the Tierras del Ebro region has a revealing share of biodiversity in its geographical environment. Its situation, the radical combination of structure and morphology and the diversity of forms of relief explain the great variety of landscapes and habitats and existing biodiversity. In little more than 30 kilometres, the territory passes from sea level to characteristic relays of the 1,500 meters of altitude: from the flat delta to mountain ranges and plateaus of interior, passing through tectonic cuvettes, and the valley and fluvial deposits of the Ebro river.