Northeastern Spain and Southern France Mediterranean Forests

Category: Forest Biomes.

Geographic Location: Western Europe.

Summary: These diverse sclerophyllous forests, dominated by oaks (both deciduous and evergreen), wild olive, and carob have an outstanding environmental history linked to traditional land use.

These northeastern Spanish and southern French forest areas belong to the general context of the western Mediterranean basin, and they include a wide strip located around the coastline. They cover approximately 35,000 square miles (90,000 kilometers) from the Valencia and Catalonia regions in Spain, to the Gulf of Lyon and Provence region in southern France.

Due to the location, general bioclimatic conditions are typically mediterranean, characterized by temperate winters, with average temperatures of about 53 degrees F (12 degrees C), and hot summers, with average temperatures of about 77 degrees F (25 degrees C). Seasonal rainfall is low; the annual average is in the range of 14–30 inches (35–80 centimeters), concentrated during the spring and autumn, with a characteristic summer drought period.

Flora and Fauna

Under these conditions, the main forest communities that occur are: Mediterranean pine forests, Mediterranean oak forests, holm oak forests, and maquis or shrub vegetation. Mediterranean pine forests are present in basal areas, from the coastline up to 2,000 feet (600 meters). They are dominated by thermophilous (heat-loving) species well adapted to low water demand, poor soils, and to regular wildfire occurrence, mainly due to their high resprouting capacity. In this sense, the most extended forest communities are those dominated by Aleppo pine (Pinus halepensis) and maritime pine (Pinus pinaster).

In more coastal and drier environments, these pine forest stands may occur mixed with maquis shrubland; this dense and sclerophyllous (hard-leafed) formation—similar to Californian chaparral—is dominated by evergreen, thermophilous, and spiny shrub plants such as holly oak (Quercus coccifera), tree heath (Erica arborea), pourret (Ulex parviflorus), and Mediterranean dwarf palm (Chamaerops humilis), as well as key tree species like wild olive (Olea europaea var. sylvestris) and carob tree (Ceratonia siliqua).

Holm oak forests are perhaps the most outstanding Mediterranean sclerophyllous forest communities, because of their ecological characteristics and their abundance. These woods occur in a wide distribution area, ranging from basal to mid-mountain areas. Usually, these forest stands present a dense tree canopy dominated by holm oak (Quercus ilex), and an abundant and diverse understory of evergreen and thermophilous plants, well adapted to Mediterranean conditions (especially to low rainfall and summer drought); these include mastic (Pistacia lentiscus), rosemary (Rosmarinus officinalis), buckthorn (Rhamnus alaternus), and strawberry tree (Arbutus unedo).

In certain areas where summer drought is of lower occurrence, cork oak (Quercus suber) forest stands thrive. This tree is similar to holm oak, but differs from it mainly in its characteristic outer cork layer, an air-filled bark that protects the tree; perhaps the most famous and widespread use of this natural insulating material is in wine and champagne bottles.

In mid-mountain areas, sub-Mediterranean climate conditions arise with cooler, wetter conditions. In this context, Mediterranean oak forests occur, dominated by downy oak (Quercus pubescens) and Portuguese oak (Quercus faginea); its understory plants include common broom (Cytisus scoparius), wayfaring tree (Viburnum lantana), common hawthorn (Crataegus monogyna), or European box (Buxus sempervirens). These Mediterranean oaks are known as marcescent oaks, also called semi-deciduous oaks, due to their intermediate leaf strategy between evergreen and deciduous. Among the vascular plant population throughout the forests of this ecoregion, there is a 10 to 20 percent rate of endemism, that is, species found nowhere else on Earth. These areas are centers of biodiversity.

Of the vertebrates found in this ecoregion, there are only several large mammal species: the polecat (Mustela putorius), otter (Lutra lutra), and lynx. There is an abundance of bird species, especially along coastal areas. Coastal areas of this biome support some of Europe’s most important littoral wetlands. Commonly seen birds here are egret varieties, duck, tern, and heron. Raptor species include black vulture, osprey, and Elenora’s falcon.

This ecoregion has numerous areas that are internationally important for breeding and wintering birds. There are many fish species along the coast; four species are endemic to the Iberian Peninsula, in the Ebro Delta. The delta also sustains mollusks (both freshwater and saltwater), endemic shrimp, amphibians, and reptiles.

Human Impact

Western Mediterranean forests have a long and intense environmental history linked to traditional human land use. For centuries, holm oak has been widely harvested for firewood and charcoal extraction, as well as for timber used in construction and for making implements such as handles, cart wheels, and other tools. Tannins obtained from bark distillation are used in textile and leather work, and acorns feed livestock. This species became the most appreciated and used tree in this part of Europe.

Due to the long, historic use of these forests in addition to grazing and traditional agricultural practices, the forest surface in the western Mediterranean basin reached maximum levels of deforestation during the beginning of the 20th century. Since the 1940s and 1950s, traditional land uses in the western Mediterranean region have been profoundly changed due to demographic growth, abandonment of traditional land uses, mining of fossil fuels, rock quarrying, increased water consumption, increased industrialization, and urban sprawl. Because of deforestation and overgrazing, much of this more open land is now extremely susceptible to brushfire and forest fires.

This condition, compounded with the effects of climate change, is adding significant threats to the health of this biome. Global warming has sped the arrival of spring—by as much as two weeks—in many parts of this region; along with sharply increasing average air temperatures, this is resulting in major shifts in seed germination timing, groundwater availability, and fire regimes. Some migratory bird species have forgone their winter trip to Africa, opting to remain in Spain. Certain other terrestrial species—both plant and animal—must seek cooler habitats at higher elevations. At the same time, the Ebro Delta is experiencing impacts of sea-level rise, including saltwater intrusion, soil erosion, changes in sediment deposition, and related habitat disruption.

Bibliography

Barbero, M., G. Bonin, R. Loisel, and P. Quézel. “Changes and Disturbances of Forest Ecosystems Caused by Human Activities in the Western Part of the Mediterranean Basin.” Vegetatio 87 (1990).

Blondel, J. Aronson. Biology and Wildlife of the Mediterranean Region. Oxford, UK: Oxford University Press, 1999.

McNeill, J. M. The Mountains of the Mediterranean World. New York: Cambridge University Press, 1992.

Nocentini, Susanna, Davide Travaglini, and Bart Muys. "Managing Mediterranean Forests for Multiple Ecosystem Services: Research Progress and Knowledge." Current Forestry Reports, vol. 8, 2022, pp. 229-56. DOI: 10.1007/s40725-022-00167-w. Accessed 2 Sept. 2022.

Quézel, P., F. Médail, R. Loisel and M. Barbero. “Biodiversity and Conservation of Forest Species in the Mediterranean Basin.” Unasylva 50, no. 197 (February 1999).