Hábitats

We are working with the most significant semi-natural habitats in the Atlantic zone of the Iberian Peninsula, such as Atlantic wet heaths (4020*) and their landscape mosaics with bog, mire and fen habitats (7110*, 7130*, 7140, and 7230), as well as acidophilic dry heaths (4030) and cushion heaths (4090), mountain grasslands (6230*), semi-natural dry grasslands (6210*), and calcareous grasslands (6170). All of them are Habitats of Community Interest, and the asterisk (*) indicates that the habitat is a priority according to the Habitats Directive.

There are almost 21,000 hectares of Habitats of Community Interest in open mountainous zones, and a significant percentage are considered to be priority habitats that are in danger of disappearance, with the European Union having particular responsibility for their conservation.

4020*
Atlantic wet heathlands

Galicia

These are open vegetation formations with few shrubs, dominated by heaths and gorses (Erica spp., Calluna vulgaris, Ulex spp., and others). They are generally found on acidic, poorly drained soils with a tendency to form boggy conditions, very sensitive to summer droughts, and occupying enclaves that maintain a high level of moisture. The flora in these habitats shows a high level of biodiversity and uniqueness.

These are heaths of low-to-medium height with a woody layer consisting of various species (Erica mackayana, Erica tetralix, Erica ciliaris, Erica cinerea, Calluna vulgaris, Daboecia cantabrica, and Ulex gallii). Some herbaceous species are also usually present, such as Deschampsia flexuosa, Juncus squarrosus, and Carum verticillatum, among others.

In the northern mountain ranges of Galicia, where we are working with the RURALtXA! project, the endemic heath Erica mackayana dominates over other members of the Ericaceae family. This species flowers from July through November, with umbel-type inflorescence and leaves covered in soft hairs, resulting in the appearance of an impressive pink carpet of vegetation.

4030
Acidophilic dry heaths

Galicia and Euskadi

These are habitats with medium-height shrubby vegetation, where various heath species dominate (Erica spp.), accompanied by common heather (Calluna vulgaris) and sometimes gorse (Ulex spp.). There is often an abundant presence of common bracken (Pteridium aquilinum), and in cooler areas at higher elevations, these habitats may be dominated by blueberry (Vaccinium myrtillus) and tree heath (Erica arborea). There are also a variety of subtypes that can be distinguished in Euskadi: high mountain heath habitats with Erica arborea, blueberry, and Atlantic and sub-Atlantic heaths.

These types of shrubland habitats tend to occur in areas with high rainfall levels (semi-wet to very wet climates), on soils that are acidic either because of the siliceous nature of the substrate or from leaching and decalcification of the soil by rainfall. These habitats are very extensive on the Atlantic side of the Euskadi mountains, where they are commonly found on the lower slopes of hills and mountains, and they also appear on the Mediterranean side but with less abundance. In low-and mid-altitude locations, gorses (Ulex europaeus and U. gallii) are often found mixed in with the dominant heaths. In mountain areas, vegetation dominated by blueberry and high heaths with Erica arborea generally appear at higher altitudes with cooler and foggier conditions.

This is a habitat type primarily associated with extensive cattle grazing. However, these vegetation formations may also be used for honey production, with seasonal operations being set up to take advantage of the flowering season.

4090
Endemic oro-Mediterranean heaths with gorse

Euskadi

This habitat type includes shrublands that normally have cushion-forming shrubs, and grass and shrub mosaics of medium height, broadly distributed on hills, slopes, peaks, and rocky cliffs, on calcareous or loamy soils. This vegetation type occurs all the way from sea level to the peaks of Euskadi mountains. In almost all cases, there is an abundance of aulaga (Genista hispanica subsp. occidentalis) and common heath (Erica vagans), which gives this vegetation type its unique appearance. It also explains the names of “pre-heathland” or “calcareous heathland” that are often applied to this wide variety of vegetation groupings. Typically there are also two types of grasses found in these habitats, the wide leaf tor-grass (Brachypodium pinnatum), and alpine oatgrass (Helictotrichon cantabricum) which grows in large distinctive tufts. In some cases there may be an abundance of other plants such as junipers (Juniperus spp.), boxwoods (Buxus sempervirens), or rosemary (Rosmarinus officinalis).

Although this is a habitat type distributed throughout Euskadi, it is abundantly present in the area between the region’s central and southern mountain ranges. It has less representation to the north, where it is found on limestone substrates along the coast as well as at higher mountain elevations. In the areas where the RURALtXA! project is taking place, the Arkamo-Gibijo-Arrastariathis SAC represents a key space for conservation of this habitat type.

6210*
Semi-dry grasslands with Brachypodium pinnatum (* important orchid sites)
(* lugares con orquídeas notables)

Euskadi

This habitat type consists of pastures dominated by grasses, with high diversity in their floral composition. When they are rich in orchids, they are considered to be a priority Habitat of Community Interest under the Habitats Directive. In many cases the species known as tor-grass is dominant (Brachypodium pinnatum), but in other cases there are various dominant grasses, with notable examples being Bromus erectus and Festuca gr. rubra. When grazing practices are abandoned, particular shrubs and mat-forming grasses from adjacent habitats have a tendency to invade, especially those from habitat 4090, with evolution towards that habitat occurring over time. This process also occurs when cultivation is abandoned, with that situation favouring the entrance of herbaceous plants to the detriment of grasses and shrubs, which take several years to colonise previously cultivated land areas.

In the mid-northern areas of Euskadi, in wet and very wet climates, these grassland habitats occupy areas with relatively dry soils, while in the southern areas, they are found in situations that are not too wet or too dry, and these grasses tend to be displaced by more hygrophilous grasses when soil moisture levels increase, or by more xerophilous grasses when increasing soil dryness is accompanied by a drier climate. The most common use for these habitats is for extensive grazing of sheep and cattle, and when human management of these grasslands is performed in an appropriate manner, they become hay meadows.

In general, this habitat is well-represented in Euskadi on both the Atlantic and Mediterranean sides of the region’s mountain ranges. In the mountainous areas of Euskadi where the RURALtXA! project is taking place, this habitat type is especially common in Aralar and Arkamo-Gibijo-Arrastaria.

6230*
Mountain grasslands

Euskadi

Mountain grasslands have a unique physical appearance, characterised by the formation of green carpets of plant life, which remain fresh until the end of summer. They are dominated by herbaceous plants, especially certain types of grasses that grow in the form of mats. They are adapted to a cycle of renewal after being grazed upon by livestock, and they are also resistant to being tread upon by hooves. These plants are also considered to be of high quality and value for grazing.

These low, open grasslands are typically found in mountain areas with cool, wet climates, and their origins go all the way back to the Neolithic, to the early days of cattle domestication and initiation of grazing practices. In Euskadi these practices have been in existence for thousands of years, and they have led to the origin and development of these mountain grasslands, where ongoing grazing and treading by livestock keep these habitats free from woody vegetation.

The high rainfall levels associated with the local wet or very wet climates produce acidification in the soils, and as a result of this, an acidophilic floral community develops, even though in many cases these grasslands are growing on limestone formations. These grassland habitats usually do not dry out in summer, except in areas with the thinnest soils, which are characterised by grasses such as Agrostis curtisii.

There are various subtypes of this habitat in Euskadi. The most extensive are the sparse mountain grasslands that are found in areas subject to grazing (Aralar, Aizkorri-Aratz, Gorbeia, etc.). In contrast, the habitat subtypes dominated by Nardus stricta are found only very locally in Euskadi, with some small examples existing in mountainous areas where the RURALtXA! project is being implemented, such as in Gorbeia. Finally, there are grassland habitat subtypes that favour siliceous soils, dominated by Agrostis curtisii, and also grasslands with Cynodon dactylon, which normally grow on the shallow soils found on steep slopes and mountain peaks.

7110*
Active raised bogs

Galicia

As the name indicates, these are bog vegetation formations (with organic matter accumulating as peat), on acidic soils poor in mineral nutrients. They are fed primarily by rainwater and become saturated because of the morphology of the land.

These habitats are dominated by sphagnum mosses (Sphagnum spp.), which are plants that decompose very slowly under flooded and poorly drained conditions, with organic remains accumulating as peat deposits. The presence of Sphagnum pylaesii is especially notable because it is a Species of Community Interest according to the Habitats Directive.

Other plant species characteristic of this habitat type are insectivores from the genera Drosera and Pinguicola, and sedges such as Eriophorum angustifolium and various species of Carex.

In the mountainous areas of Galicia where the RURALtXA! project is being implemented, we can find carnivorous plants that are very characteristic of this habitat. These are plants that have developed methods for trapping insects, because in order to survive in these bog areas (which are poor in nitrogen), they need to supplement their nutritional needs with protein from the living creatures they capture. Species from the genus Drosera have leaves with extensions that produce a type of sticky substance known as mucilage, with each of these tentacle-like structures having several drops of it at the end. In a similar way, species from the genus Pinguicola have leaves covered in sticky hairs with glands that attract and then immobilise insects.

The combination of these floral species create a habitat type known as active raised bogs, which is a name given to habitats with bog vegetation that creates peat, causing its height to increase.

7130*
Active blanket bogs

Galicia

These habitats are extremely rare on the Iberian Peninsula. They appear in very localised enclaves in the Cantabrian mountain ranges and in the oceanic mountains of Galicia in the provinces of Lugo and A Coruña. Some examples are found in the Serra do Xistral SAC, which is included in the Natura 2000 network, and which is one of the areas where the RURALtXA! project is being implemented.

These bog habitats tend to occur in relatively flat or slightly sloping landscapes with poor drainage, in areas with oceanic climates characterised by high rainfall levels. They accumulate organic matter in the form of peat, with water collecting on their surface primarily through rainfall, dew, or fog. Although in all of these habitats sphagnum mosses play an important role, sedges (Carex durieui) and grasses (Molinia caerulea) appear in higher proportions than in the case of the raised bogs. However, as with raised bog habitats, these bogs are referred to as active because they continue to accumulate peat.

Active blanket bogs show a high level of floral homogeneity. They are characterised by having an extremely dense herbaceous layer dominated by sedges (Eriophorum angustifolium and Carex durieui) and grasses (Molinia caerulea and Deschampsia flexuosa), which are usually accompanied by a much lower presence of species frequently found in the shrubland habitats of northern Galicia, such as Erica mackayana, Erica cinerea, and Calluna vulgaris. Other indicator species include those from the genus Sphagnum, with Sphagnum pylaesii being especially noteworthy because it is classified as a species of priority interest according to the Habitats Directive. There are also plants that propagate as bulbs, such as Narcissus bulbocodium.

By acting like sponges, these ecosystems play an extremely important role in controlling the hydrological cycle and improving water quality. In the current context of climate change, they also perform the vital function of capturing and storing carbon in their peat deposits, which in some areas of these mountain ranges can have a depth of many metres.