River ecosystem (‘el Bajo Guadalquivir’)
The last section of the river, the Lower Guadalquivir (‘Tramo Bajo’) starts from Alcalá del Río, a locality near Seville, and is characterized by high sediment turbidity, low oxygen availability and gradual increase in salinity.
‘Brazos’: the three delta arms of the river. Brazo de Enmedio, the only active channel and more simply named Guadalquivir; Brazo de la Torre, western channel, isolated and ‘connected’ to the Río Guadiamar; Brazo del Este, isolated meander in the polder area.
‘Vueltas’: meanders of the river and the main tributaries (La Madre, Guadiamar).
‘Cortas’: eight channels built between 1795 and 1982 intersecting the meanders in order to facilitate navigation, reduce flooding in Seville and favor arable land.
Typical species: mainly estuarine fish (shad, numerous marine species) and highly migratory fish (sturgeons, eels) and their predators, ospreys, kingfishers and piscivorous ardeids; otters. Banks covered with white poplars and eucaliptus.
Lower Guadalquivir marsh (‘Las marismas’)
The marshes of the Lower Guadalquivir extend over an immense flat surface, a remnant of a great coastal lake known in antiquity and since then clogged. The clay substrate decreases the infiltrations and favors the flooding of this plain, where the numerous microreliefs acquire a great protagonism and determine the depth and the duration of the flooding. Hydrologie, complex by nature, has been immensely modified by human action. Today, the marshes are mainly fed by rainwater and occasional inflows from the watershed during heavy winter rains. These conditions are excessively variable, explaining the scarcity of “good years”.
‘Marismas‘: marshy areas of coastal estuaries, most often salt marshes, also including freshwater marshes connected upstream. The flooding being temporary and dependent on the relief, we can distinguish specific vegetation.
‘Marisma alta‘ (‘high’ marshes): salt marshes, sansouires and herbus.
‘Marisma baja‘ (‘low’ marshes): freshwater marshes, black marshes.
‘Vetas’ / ‘Paciles‘: non-floodable elevations in the middle of marshes, refuges for fauna and seat of human constructions.
‘Lucíos‘: depressions that maintain a period of prolonged flooding, sometimes of several seasons.
‘Caños‘: main channels running through the marismas.
Typical species: mainly all the aquatic avifauna for which Doñana is famous: ducks, geese, grebes, spoonbills, storks, herons, ibises, waders, rallids, marouettes and passerines populate the wetlands, … and also steppe birds which frequent the dry salt marshes: larks, gangas… Massive production of migratory dragonflies: Sympetrum fonscolombii, Aeshna mixta or Anax ephippiger and also the rare Dark spreadwing (Lestes macrostigma), a species with very strong population fluctuation.
The large-scale and planned transformations of Doñana mainly began in the 19th century and culminated after the Second World War. Historically, the destruction of the Marismas de Doñana also prompted the protectionist movement and the declaration of the national park.
Saltpans. Salinas de Bonanza (Sanlúcar de Barrameda)
Fish farming. Veta La Palma (not visitable)
Paddy fields. Isla Mayor.
Polders. Los Palacios.
Typical species: very impoverished fauna and flora, although avifauna can be abundant there under certain conditions. These environments have their importance during the summer season, during the estiage of the natural marshes, often offering the only refuges available for the water birds. Note the introduction to Isla Mayor, in the 1970s, of Red swamp crayfish (Procambarus clarkii) which proliferated and unfortunately invaded the entire watershed of the Guadalquivir. This introduction favored a local industry and a boom in the populations of birds capable of feeding on the crustacean (ardeids, ibis, etc.). These positive aspects should not hide a strong and irreversible negative impact on aquatic biodiversity.
Lagoons and ponds
Shallow water masses independent of the flood phases of the Marismas de Doñana. These are mainly enhorreic ponds and lagoons formed on the sandy lands of Abalario and other peripheral areas of the park. One of the highest densities of ponds listed. Few salt marshes, but a peripheral belt of helophytes.
Temporary Mediterranean ponds: small (<< 4ha).
Lagoons: Larger, deeper bodies of water with an extended hydroperiod, usually temporary.
Permanent lagoons: often old rehabilitated gravel pits or mini-reservoirs.
‘Zacayones’. artificial watering holes with a certain depth and a prolonged period of flooding.
Typical species: again, the avifauna of wetlands. Permanent water bodies are all the more favorable to resident populations of diving ducks and coots and host introduced populations of fish and American crayfish. These predators are disappearing from temporary Mediterranean pools which are home to a range of specific and threatened species: large branchiopods (eg Triops) and amphibians. Great abundance of amphibians, natterjack toads, etc. Diversity of dragonflies specific to lotic environments. Strong primary production of micro-organisms and massive abundances of aquatic beetles and water bugs in some lagoons. Water voles and their predators. Significant diversity of helophyte (waterside) and aquatic plants.
Coastline: beaches and dunes
La Vera: between ‘marismas’ and ‘cotos’
La Vera is the contact zone between the immense sand bar of El Puntal (sandy substrate) and the marshes of the Biological Reserve of Doñana (clay substrate). This narrow border constitutes in itself a separate ecosystem and runs along the ‘Caño de la Madre de las Marismas’ on its western bank.
La Vera is a small extension savannah supplied with fresh water filtered by the dunes; a ribbon of wet meadows assiduously grazed by herbivores (wild and feral mammals) where a few old cork oaks testify to the primitive extension of the cork grove while sheltering the famous Pajarera de Doñana.
… So attractive and unfortunately not accessible to visitors, only visible from the 4×4 del Puntal tour. Luckily, the superb La Madre marshes, easily visible from El Rocío, are the real starting point… The hermitage was not erected here by chance. As for the La Rocina circuit, it crosses the original cork oak forest.
Typical species: ecosystem where large herbivores (deer, fallow deer, wild boar), wild rabbits, water voles and their predators, carnivorous mammals (lynx, foxes, etc.) and birds of prey (black kites) are concentrated. La Pajarera hosts a colony of colonial birds (egrets, herons, cattle egrets, spoonbills) whose numbers are in sharp decline. Natterjack toads, Common Spadefoot.
MAtorrales: heathlands, maquis and garrigues
Terrestrial ecosystem dominated by shrubs. Nevertheless, the popular terms are ambiguous: the ‘monte mediterranéo‘, the Mediterranean forest, is a mosaic of matorral, meadows and trees in very variable density.
Monte blanco: ‘white’ moor/garrigue develops on sandy and particularly arid terrain. The most characteristic species being the Saltbush rockrose (Halimium halimifolium), with greyish foliage and spectacular yellow flowers, accompanied by False broom gorse (Stauracanthus genistoides), Yellow rockrose (Halimium commutatum), rosemary (Rosmarinus officinalis) and by other less common shrubs such as cistus (Cistus salvifolius, C. libanotis), lavender (Lavandula stoechas) and thyme such as Spanish wood marjoram (Thymus mastichina).
Monte negro: the ‘black’ moor or black maquis is a dense matorral with dark colors that colonizes soils which remain humid even during the summer. There dominate the Green heather (Erica scoparia) and the Provence gorse (Ulex parviflorus = Ulex australis), other species of Erica (E. umbellata, E. ciliaris) accompanied by heather (Calluna vulgaris), mirtle (Mirtus communis), filaria (Phillyrea angustifolia), bramble (Rubus ulmifolius), and gorse (Ulex minor, U. australis).
Sabinar: final stage of the white moor succession. Matorrals of Phoenician Juniper (Juniperus phoenicia turbinata) – rear dune distribution – and of Large-fruited Oxycedar Juniper (Juniperus oxycedrus ssp. macrocarpa) – on the seafront -.
Typical species: many vertebrates, birds, mammals and reptiles. Traditional estate of Iberian Lunx and Imperial Eagle. Butterflies, Orthoptera. Among the butterflies, the most abundant species are Pieris rapae, Leptotes pirithous, Lycaena phlaeas, Colias crocea and Pyronia cecilia. Note the Plebejus argus, a myrmecophilous species.
Locally referred to as ‘Coto‘, literally a hunting estate (Coto de Doña Ana, Coto del Rey, etc.); which recalls the importance of hunting activity in these territories, which are traditionally not exploited by agriculture.
Pine forests: large plantations of umbrella pines (Pinus pinea) more or less old and naturalized, often very homogeneous and dense (closed), promoting little biodiversity.
Olive woods: original forest of wild olive trees (Olea europaea sylvestris), of marginal distribution.
Sotos: riparian gallery forests distributed along watercourses. In particular, the sotos of La Rocina are dominated by the ash trees of the South (Fraxinus angustifolia) and the swamp willows (Salix atrocinerea).