Get to know the Habitat

Coastal dunes

Next time you go to the beach, keep your eyes peeled for the diversity around you, starting with the dunes. This habitat is more than just sand; it is home to hundreds of species, including many protected plants and birds.

Mainland Portugal has more than 900 kilometres of coastline facing the Atlantic Ocean. About half of the coast is made up of rock formations while the other half is protected by dunes. To the west, the coastal dunes extend from Espinho in the north to Vila Nova de Milfontes in the Alentejo, with some interruptions, and dunes are also common in some areas of the Algarve coastline.

All of these dunes constitute a living and extremely dynamic system, which is formed and moved by sediments transported and deposited by the wind. As long as the terrain permits it, they may spread over extensive areas, creating a natural barrier parallel to the coast (an important ecosystem service), and continue inland for kilometres.

Whenever the wind subsides and the sand settles, the coastal plants – small herbaceous species – begin to take root. It is these plants that help create the primary dune (also called the white or mobile dune). Beach grass (Ammophila arenaria subsp. arundinacea) is one of the dominant species here, responsible for stabilising the sands, but others are equally common, such as sea spurge (Euphorbia paralias), Crucianella maritima, and the cotton weed plant (Otanthus maritimus).

The vegetation becomes more abundant and diverse in the depressions of these dunes and interdune areas, which are more sheltered from the wind and may accumulate water, and where the finer sediments and organic matter enrich the soil. Here, small shrubs are also common (some can also be seen on the primary dune), such as Artemisia campestris subsp. maritima, and Thymus carnosus, the latter being more common in the south of the country.

The biodiversity of the vegetation changes in what are known as secondary or grey dunes, due to the greater presence of organic matter in the soil, with larger shrubs and trees common in the elevations and depressions. Here, pine forests have been planted to halt the advance of the sands towards the interior. Maritime pines (Pinus pinaster) and stone pines (Pinus pinea) coexist with many other species of wild plants, from the Portuguese crowberry (Corema album) and the firetree (Myrica faya) to the Juniperus turbinata, as well as the narrow-leaved mock privet (Phillyrea angustifolia) and the mastic (Pistacia lentiscus).

When vegetation develops and covers the sands, the secondary dunes shelter small mammals and, closer to the sea, it is more common to see insects, including dragonflies, butterflies, grasshoppers, crickets, beetles, and scarabs, as well as arachnids, and sometimes amphibians and reptiles. But in the dune ecosystem, birds are the main species and their diversity is surprising. There are species that come from far away to spend the winter, such as the northern gannet (Morus bassanus) and the great cormorant (Phalocrocorax carbo), or those that come to enjoy the summer, such as the common tern (Sterna hirundo) and the greater short-toed lark (Calandrella brachydactyla).

On the primary dune, you can see the Kentish plover (Charadrius alexandrinus), the little tern (Sternula albifrons), and the crested lark (Galerida cristata). In the grey dune area where the forest begins, it is frequently possible to spot robins (Erithacus rubecula), countless tits, and even birds of prey, such as sparrowhawks (Accipiter nisus) and goshawks (Accipiter gentillis).

Several of these species are protected in Portugal, as are the dune systems that serve as their habitat, such as the São Jacinto Dunes Nature Reserve or the Troia Dunes Botanical Reserve, part of the Sado Estuary Nature Reserve. The Natura 2000 Network Sectoral Plan includes multiple dune habitats, from embryonic mobile dunes (habitat 2110) to dunes with Pinus pinea or Pinus pinaster ssp. atlantica forests (2270).

Did you know that…

  • Crossing the dunes, whether on foot or in any kind of vehicle, is one of the main causes of destruction of these habitats and puts the eggs and young of birds that nest in the sand at risk. To regenerate the dunes, fences have been put in place and vegetation planted, which help to retain the sand and to strengthen the dunes, thus preserving the services the ecosystem provides: as a habitat and as a natural barrier, which slows down the advance of the sea and the intensity of the wind, preserving the coastline and preventing erosion.
  • The plants that form part of the dune ecosystem share the ability to live in the sand (in botany, they are known as psammophiles) and a possess a wide range of adaptive characteristics to help them withstand strong winds, high salinity, huge temperature variations, excessive light, and a lack of water and other nutrients. Some are able to expel salt through their leaves (for example, the Atriplex genus), some store it inside their cells, some have succulent leaves and stems where they store water, others have long roots that capture water deeper in the ground, like beach grass and Artemisia campestris subsp. maritima.
  • The Salir do Porto dune in São Martinho do Porto, around the mouth of the River Tornada, has been described as one of the largest in Europe. It is thought to have been around 200 metres long and 50 metres high. However, as the top (crest) and extent of the dunes are constantly altered by the action of the wind, determining whether it is the largest is no easy task.

How do we care for dune habitats?

Several dune habitats of Community interest listed in the Habitats Directive (Annex I) have been identified in Monte Feio, belonging to The Navigator Company, which is located near Sines:

  • Habitat 2260 “Dunes with Cisto-Lavenduletalia sclerophyllous vegetation“. This is the predominant habitat on this property and is where the largest number of species of conservation interest can be found. The preservation of shrub species that do not exist anywhere else in the world, except in the southwest or south of Portugal, is a priority here. Among them you can find Thymus capitellatus, for instance, an endemic species on the Vicentine Coast protected by the Habitats Directive, Santolina impressa, only found between Setúbal and Sines and also protected by this directive, and Stauracanthus spectabilis, which is only found on the southwest coast and in the Algarve “barrocal”. The aim is to preserve areas with a high density of these plants, while at the same time monitoring and controlling invasive species such as Carpobrotus edulis and acacias.
  • Habitat 2150 “Atlantic decalcified fixed dunes”. Some gorse groves dominated by the endemic Ulex australis subsp. welwitschianus species have been identified, in which other species typical of this habitat are also present, such as the common heather (Calluna vulgaris) and labdanums (Cistus ladanifer).
  • Habitat 2250Coastal dunes with Juniperus spp”. In Monte Feio, there are shrub habitats dominated by the Juniperus turbinata subsp. turbinata, which are also home to the highly valued Portuguese crowberry (Corema album).
  • Habitat 2270 “Dunes with forests of Pinus pinea and Pinus pinaster ssp. Atlantica”, in this instance, dominated by the maritime pine, which attract diverse species of protected flora under their canopies.
  • Habitat 2330 “Inland dunes with open meadows of Corynephorus and Agrostis”, which also include the formations present in the coastal dunes of the Atlantic belt. This occurs in a patchwork with the other habitats and is made up of what are known as psammophilous groves of pioneer plants and perennials, along with the presence of grey hair-grass (Corynephorus canescens).

In the grey dunes and sandy soil of Monte Feio, a total of 69 species of plants have been identified, 14 of which have protected status, and 18 species of birds, all protected by different international conventions – Habitats, Bern, Bonn, or CITES. In addition to the plants mentioned above, others have been sighted, such as Mediterranean buckthorn (Rhamnus alaternus), Asparagus aphyllus, Halimium halimifolium, and Sesamoides purpurascens, and birds such as sparrowhawks (Accipiter nisus), carrion crows (Corvus corone), and the great spotted woodpecker (Dendrocopos major).

Amongst the measures to preserve them and maintain or improve habitats, soil mobilisation activities are avoided, and the selective control of vegetation – to defend the forest against fire – is carried out using motorised manual means and in alternate locations over time.