Dunes, sand and coastal cliffs – sea coast in Andalusia
Transition territories between the sea and the continent: contrasting and extreme ecosystems.
The coast is the narrow zone of contact between the sea and the continent, a transition territory that not only passes from the liquid and salty condition to the terrestrial of weak mineralization. It offers a whole range of intermediate conditions that favor the presence of species adapted and specialized to each of the existing ecological niches. Therefore, it is not surprising that the coastline constitutes one of the most biodiverse territories.
It is easy to observe at the edge of the sea a succession of microhabitats ordered mainly by the rhythm of the tides. Note that the Atlantic coast has tides of greater amplitude than the Mediterranean one. The main differential element lies in the substrate that receives these tides. We can distinguish rocky coasts and sandy coasts, not to mention the estuaries (“coasts of water”) treated in the section of wetland ecosystems.
Offshore. The submerged rocks mainly serve as a substrate for innumerable seaweeds and the underwater sand bottoms for a select group of vascular plants, such as Posidonia oceanica and the Marine Zoostera, that have colonized the marine environment and form seagrass beds. These habitats offer refuge for a rich marine fauna of invertebrates and fish, highlighting shrimp, crabs, starfish, sea cucumbers, sea urchins, crabs, sea hares, nacras, cuttlefish, octopus, cnidarians, sponge, polychaete worms, clam mollusks and coral.
On the rocks. In the area of breakwater, live invertebrates capable of adapting to the constant changes in water levels from the possibility of being completely submerged to be totally exposed to the sun and the air with the descent of the tides. We find sea acorns, sea mealybugs, barnacles, periwinkles, crabs, mussels, chitons, anemones, hermit crabs …
The Flysch are sedimentary rocks accumulated in a closed ocean basin and common near Gibraltar. The rocky coast is colonized by algae and marine invertebrates.
The famous Cape of Trafalgar: one of the most beautiful beaches at sea coast in Andalusia and a picturesque lighthouse perched in the middle of the dunes.
Seagulls and gulls are the most representative seabirds on the coast.
Sea holly (Eryngium maritimum) is a perennial herb of the most emblematic of the flora of sand and dunes.
Landscape of dunes and stone pines, typical of the Spanish Mediterranean coast, illustrating the “fight” between the ever-shifting sands and the inexorable force of the vegetal kingdom.
Higher, where the tide does not reach, the lichens grow, pioneers that announce the beginning of the terrestrial environment.
Coastal sands. Long beaches and Atlantic dunes: They are dynamic and complex ecosystems affected by the action of wind and sea currents. They have extreme conditions due to their low capacity to retain water, nutrient shortages, high surface temperatures, substrate mobility and salt concentration.
The herbaceous vegetation allows to fix the dunes, highlighting typical species such as: European beachgrass (Ammophila arenaria), sea lily (Pancratium maritimum), Crete deervetches (Lotus creticus), cotton weed plant (Achillea maritima = Otanthus maritimus), yellow hornpoppy (Glaucium flavum), sea crossworts (Crucianella maritime), Cadiz blueweed (Echium gaditanum).
A little inland grow coastal juniper (Juniperus oxycedrus macrocarpa) and marine juniper (Juniperus phoenicea turbinata) accompanied by shrubs, such as Halimium halimifolium, Cistus libanotis, Thymus mastichina, etc. which are soon replaced by coastal forests of pine trees (Pinus pinea).
It is not uncommon to observe impressive black-colored beetles, belonging to the Tenebrionidae (Pimelia), Carabidae (Scarites occidentalis) or Scarabaeidae (Scarabaeus) families. The coastal birds par excellence are the seagulls and the terns, although the privileged position of the cliffs also allows you to easily observe other sea birds and shorebirds.
Finally, it is worthy to highlight on one side the dunes of Huelva coastline and the surroundings of Doñana, with a length of about 100 km that make up the most important dune system in Europe and on the other hand the Cliff of Barbate, located near the famous Cabo de Trafalgar, which is the highest in Andalusia with more than one hundred meters. Other coastal cliffs of interest are found on Cerro Maro Gordo and on the coast of Granada.
I love birding, but I don’t crave for ticking rarities … although I understand their appeal to some bird watchers. Having said that, I’m happy to have seen a small flock of sooty terns on the coast of Huelva.
Most spectacular cliff at Tajo de Barbate
The highest maritime cliff in Andalusia, with its 106 masl, is made up of calcarenites (compacted limestone sands). In the background looms the observation tower (‘Torre del Tajo’) which reminds us of the past presence of pirates on the Spanish coast. More curiously, the Tajo hostes a unique colony of Cattle Egret.