Ecoagriculture Snapshot » The Dehesa and The Montado: Ecoagriculture Land Management Systems in Spain and Portugal
Spain and Portugal
|The dehesa and montado are characterized by savanna-like grasslands scattered with oak trees. Source: www.fssbirding.org.uk/|
|Animals are an integral part of the dehesa system: grazing prevents overgrowth of invasive plant species as well as helps with seed dispersal. Source: http://www.glosk.com|
|Cork production, and hence the cork oak tree population in the montado, are at risk due to increased use of synthetic bottle stoppers and screw caps in wine production. Source: wicanderscorkoakblog.com/greenbuilding/|
A large area of Southern Spain and Portugal (between 3 and 6 million hectares, depending on how it is measured) is characterized by savanna-like grasslands scattered with oak trees. Although at a glance the landscape may look simplistic, it is actually a complex agrosilvopastoral system that combines livestock raising and crop cultivation, while maintaining high levels of biodiversity. Known as “dehesas” in Spanish and “montados” in Portuguese, these systems developed over many centuries as a means to cultivate the land, due to the harsh and unpredictable Mediterranean climate.
The dehesa system originated in the south-west part of the Iberian peninsula as early as the Middle Ages. Oak tree forests were gradually thinned out and the land was ploughed to provide room for livestock grazing. The oak trees that remained grew larger and produced more acorns, which in turn provided additional food for the grazing animals. To further enhance acorn production, the trees were periodically pruned, and the trimmings were then used as fuel or fodder for the animals. The word “dehesa” comes from several Spanish words relating to grazing land for cattle used for ploughing. It is used to describe not only the agricultural system but also the whole landscape. ‘Latifundios’ are privately-owned dehesa estates usually consisting of 100 hectares or more of land. They account for up to 80% of the dehesa landscape.
Dehesas are made up of five major components: a tree layer, grass lands, crops, livestock and wildlife The most common types of trees in the dehesa are Holm oak (Quercus ilex) and Cork oak (Q. suber), although other deciduous oaks are also sometimes present. Holm oaks are used mostly for acorn production for livestock feed, while the bark from the Cork oak, which is harvested every ten years or so, is grown for its economic value. Other resources provided by the oaks include: wild mushrooms, charcoal, tannin, and firewood. The oak trees also provide many other crucial services to the dehesa system: they protect against soil erosion by decreasing the amount of water runoff as they absorb rainfall; their roots reach nutrients deep in the soil and bring them up closer to the surface, making them accessible to other vegetation; and they also prevent desertification by enhancing the structural complexity of the landscape. Cork oak trees recently stripped of their bark provide the additional benefit of 3 to 5 times higher levels of CO2 sequestration during bark regeneration.
Despite the harsh conditions of the climate and landscape, dehesas contain some of the highest levels of plant biodiversity in the world and provide shelter for many endangered species such as the Iberian lynx, Iberian eagle, Black vulture, Black stork, and crane.
The annual grasslands in the dehesa system are used primarily for livestock grazing, although the land is also used for planting crops such as barley, oats, rye, and other types of cereals, which provide food for both animals and humans. The crops require a long fallow period (4 to 10 years), but very few agricultural inputs like fertilizer or pesticides are needed.
Aside from serving an important economic role in the dehesa, livestock are crucial to the system because they help with important functions like seed dispersal (especially acorns) and controlling overgrowth of woody shrubs, helping reduce fire danger. Traditionally, livestock included various breeds of cattle, Merino sheep, Iberian pigs, and horses. Goats were also used to help control shrub growth and as a source of milk.
In the last 30 years the role of wild game animals has been increasing in importance, as hunting has also become a significant economic activity. As a consequence, species like red deer, wood-pigeon and wild boar have become desirable contributions to the dehesa. Unfortunately, the increased density of these species (resulting from farmers fencing in the animals), has had some negative effects on other traditional game animals, particularly wild rabbits. Their decline in turn affects some of the endemic predators, such as the Iberian eagle and Black vulture, which prey on the rabbits.
Although the dehesa and montado have been carefully designed to withstand unpredictable climates, these systems are vulnerable to fluctuations to market fluctuations. For example, growing global demand for meat has led to the specialization of beef and lamb production in many dehesas. Since dehesas are meant to be extensive pastoral systems, higher livestock densities put increased pressure on the landscape, affecting the diversity levels and diminishing the success rate of oak regeneration. Acorns are no longer dispersed as easily and saplings are eaten or trampled by the animals.
Dehesa farmers who rely on cork harvesting as a portion of their income are facing other obstacles resulting from changes in the wine market. Most of the over 15 billion cork bottle stoppers produced each year come from Spain and Portugal and provide up to 40,000 jobs. However, due to the problem of cork taint, synthetic bottle stoppers and metal screw caps have increased in their appeal as an alternative to cork and have replaced around 7% of the total wine stopper market. As these alternative bottle stoppers become more widely accepted by wine drinkers and adapted by wineries, the demand for cork bottle stoppers has decreased and some farmers have started to consider alternatives to harvesting cork. Eucalyptus trees have been common replacements of cork oak, but they require significantly higher levels of water and nutrients. Given the already low levels of both of these in the dehesa system, many see this to be an unsustainable alternative. Eucalyptus is also less fire resistant, so increased fire danger is another concern.
In spite of the challenges facing these systems, recent new initiatives are working to help them continue as productive ecoagriculture landscapes. Because dehesas and montados provide for such high levels of biodiversity, and contain so many unique animal and plant species, the land is considered to be one of the most important habitats in western Europe and has been given official “protected” status under the 92/43/EEC Habitat Directive. Additionally, programs like the World Wildlife Fund’s Cork Oak Landscapes Program are working to preserve the economic viability of cork harvesting by promoting the use of natural cork and creating awareness among wine consumers and producers about the negative consequences of switching to cork alternatives.
Even with the progress being made to preserve the integrity of the dehesa and montado systems, further coordination will be needed at local, national, and international levels to address the challenges presented by shifting markets to these important ecoagriculture systems.
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