Italian Sclerophyllous and semi-deciduous forests

• Category: Forest Biomes.
• Geographic Location: Europe.
• Summary: This broadly distributed and diverse mixed forest biome of Mediterranean climates occurs throughout the coast of the Italian peninsula.

Although the term Mediterranean refers to a specific region that includes parts of Africa, Asia, and Europe, the climate of this type—cool or mild, wet winters and hot, dry summers—is actually common to temperate coastal systems throughout the world. As climate is an important determining factor in vegetation, some ecosystems in coastal California and Australia, for example, are actually quite similar structurally and functionally, though quite different compositionally, to the coastal forests typical of the Italian and French coasts and valleys.

At low elevations, these coastal forests typically are characterized by a mixed evergreen or semi-deciduous canopy with a diverse understory and herbaceous layer. While superficially similar to other coastal forests, certain local and regional factors, particularly the presence of mountains, make the sclerophyllous (thick-leaved scrub vegetation) and semi-deciduous forest types specific to the Italian peninsula and coastal France a unique biome.

This biome covers much of the Italian peninsula (as well as nearby islands, such as Ventotene) and parts of the southern coast of France, a total of 39,500 square miles (102,200 square kilometers). Most regional climatic variation here is the result of mountain ranges near the coast. With increasing altitude, local zones tend to sustain more precipitation increases and lower temperatures. Variation in edaphic (soil) conditions is more related to volcanic activity and the underlying bedrock types, which include dolomite, limestone, marl, sandstone, and schist-marl.

Thus, it is elevation that primarily dictates forest zonation and volcanic activity, while bedrock type dictates forest composition. Land cover here is a mix of broadleaf deciduous woodland (30 percent), evergreen woodland (30 percent), cropland (30 percent), dry grassland (5 percent), and inland water bodies (5 percent).

Vegetation

Forests at the lowest elevations, generally closest to the coasts, are dominated by a mix of evergreen sclerophyllous (hard, waxy) broadleaf species, such as the commercially important cork oak, and deciduous broadleaf species, such as downy oak and Manna ash. At higher elevations farther inland, the cooler temperatures and greater precipitation favor deciduous species, and forest compositions shift away from sclerophyllous vegetation.

As elevations increase still more, the cold-tolerant European beech becomes a dominant species, but the diverse woody flora include the endangered Lobel’s maple and coniferous species such as the locally abundant yew and relict populations of silver fir in the Apennine Mountain.

Forests at the highest elevations are no longer considered to be part of the Italian Sclerophyllous and Semi-Deciduous Forests biome; instead, they are included in the Apennine Deciduous Montane Forests biome. Many of these montane forests are also dominated by beech, and the distinction between the two biomes can be unclear. As the timberline—the elevation at which tree species drop out altogether in favor of subalpine and alpine vegetation—is approached, forest composition shifts from beech to pine and juniper, clarifying differences between these two biomes. Only near the summits of the highest mountains do elevations surpass the timberline.

As expected of a heterogenous forest type that covers such a broad range of climatic conditions, the understory and herbaceous flora of this biome are extremely diverse. Variation in aspect, as well as elevation, allow the massifs to support many species not found elsewhere, in other words, endemic. Many of the 3,300 plant species, perhaps 10 to 20 percent, found in this region are endemic here, with ranges restricted to small pockets of suitable habitat at various elevations in the mountains. The region’s abundance of orchid species is particularly noteworthy.

Wildlife

Italian sclerophyllous and semi-deciduous forests also contain a charismatic and ecologically important faunal component. In addition to an abundance of moth and butterfly species, more than 40 native mammal species occur in these forests, including the only populations of the Apennine brown bear; the storied Italian wolf; two marten species; and the Italian chamois, a species similar in form and function to the mountain goat.

Endemic frog and salamander species occur at elevations throughout the mountains, and many large birds of prey, such as the golden eagle, use rocky outcroppings as nesting habitat.

Human Activity Impact

Although many of the high-elevation forests remain intact, much of the forest at lower elevations has been structurally altered, and old growth is rare. Thus, although most of the region is forested, a plethora of even-aged stands, the result of clear-cutting during the late 19th and early 20th centuries, are in evidence. A large portion of the region is currently designated for conservation and is sparsely populated by humans, so given time and appropriate ecosystem management, it is possible that many of these even-aged stands can attain old growth.

Nonetheless, these forests are not safe from anthropogenic effects. Although human habitation of the mountainous areas is low, human densities in the coastal regions are growing, and forests in the mountains represent lucrative recreational development opportunities, such as ski resorts. Extraction of antimony and the planned construction of an underground nuclear power plant are typical of industrial activity that not only reduces water supply and carries the risk of soil and water pollution, but also necessitates the building of access roads and tunnels. Landscape fragmentation, a result of road building and ski-resort development, potentially threatens functionally important animal species that require broad home ranges, such as the Apennine brown bear and Italian wolf.

Finally, there are some threats to this system that humans can no longer control. Hot, dry summers and previous livestock grazing put these ecosystems at risk of both natural and human-ignited forest fires. Forest composition in some even-aged stands has shifted toward rockrose, a shrub species. Fires in rockrose stands can be particularly severe, because the species has ladder fuels, allowing fires to reach its canopy and causing fire to spread rapidly across the landscape. During the 21st century, regional temperatures are projected to increase due to global climate change. Severe climatic events, such as droughts, are projected to become more frequent, further increasing the likelihood of severe forest fires, and thus drastic habitat alteration, fragmentation, erosion, and species stress. The higher temperatures could also increase the risk of desertification in the area.

Conservation Efforts

In recognition of these threats, large parts of this biome have been classified for preservation, conservation, and protection. Examples of protected areas within the biome include the national parks of Abruzzo, Majella, Sibillini, Gran Sasso, and Laga Mountains, Foreste Casentinese, and Gargano. An astounding 28 percent of the region of Abruzzo alone is protected as parkland. Although much of this parkland is actually classified within the Apennine deciduous montane forest, this demonstrates that ecosystem conservation has been recognized as an important goal, and projected rates of loss and conversion of Italian sclerophyllous and semi-deciduous forest are lower.

Bibliography

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Loy, A., P. Genov, M. Galfo, M. G. Jacobone, and A. Vigna Taglianti. “Cranial Morphometrics of the Apennine Brown Bear (Ursus arctos marsicanus) and Preliminary Notes on the Relationships with Other Southern European Populations.” Italian Journal of Zoology 75, no. 1 (2008).

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World Wildlife Fund. “Mediterranean Forests, Woodlands and Scrubs.” 2012, . Accessed 19 Nov. 2024.