The Duero Basin

The Spanish North Plateau or the Spanish Duero basin is located in the southern foothills of the Cantabrian Ranges in the north-western quadrant of the Iberian Peninsula. It was formed by the action of the Duero river and its tributaries on both the right and left. The climate can be considered continental between dry and humid. The vegetation in this territory is very varied, and several groups can be differentiated based on their structure and physiognomy, and based on the soil and climate variability in this area. These groups are: (1) Forest and woodlands dominated by Quercus rotundifolia, Quercus pyrenaica, Quercus faginea, Juniperus thurifera, Juniperus oxycedrus. (2) Riparian ecosystems formed by willows (Salix neotricha), poplars (Populus alba and Populus nigra), ashes (Fraxinus angustifolia), alders (Alnus glutinosa), elms (Ulmus minor) and shrubby willows (Salix salviifolia, Salix elaeagnos subsp. angustifolia). (3) Seral scrub, including spiny nanoshrublands dominated by Rosa sp. pl., Rubus sp. pl., broom communities formed by several species in the genera Cytisus and Genista, hygrophilous or non-hygrophilous heathlands, with a predominance of species from the genus Erica, secondary scrub communities dominated by Cistaceae and Lamiaceae or Thymus sp. pl. communities, and nitrophilous scrub dominated by Artemisia sp. and Santolina sp. (4) Gypsophilous vegetation. (5) Grasslands of a wide diversity starting with communities of Nardus stricta, and continuing with communities of Celtica gigantea, Poa bulbosa, Agrostis castellana, rushy pastures dominated by Juncus sp. pl., meadows, communities of Festuca elegans subsp. merinoi and Stipa sp. pl. (6) Herbaceous ruderal and assorted vegetation with widely differing communities of the Stellarietea mediae, with both a roadway ruderal character and also present in rain-fed and irrigated croplands and grasslands produced by human and animal action. (7) Aquatic vegetation, including riparian herbaceous communities, peat bogs, lakes and pools communities, reed communities, reed beds, megaforbic communities and pioneer annual and dwarf perennial isoetid communities on periodically flooded bare soils. (8) Salt marshes. (9) Rock vegetation. (10) Vegetation series.