In Andalusia, the dehesa landscape dominates. Situated in the interface between the rural and the natural, the question is whether the protection of the dehesas serves to protect the cultural heritage or the biodiversity

After WW2, the green revolution paved the way for making Europe self-sufficient regarding food. Helped by the EU, this industrialisation increased global production by introducing high-yielding varieties and streamlined animal production systems. Though highly efficient, the shift also caused widespread deterioration of biodiversity, degrading soils, lowering the groundwater tables, increasing salinisation and deforestation, and introducing a regime of pesticides. Further, widespread rural inequalities lead to migration out of the countryside and, in the last decades, widespread abandonment of marginal lands. The disappearance of traditional knowledge of agricultural systems, such as in the transhumance in the Mediterranean and the bocage systems in France, should be added to this list. Although not all agricultural landscapes today look like Mecklenburg in Northern Germany with its vast agro-industrial landscapes featuring fields up to 100 ha, or the “Zone Agroindustrielle” east of Paris, the devastation of the cultural landscapes has been widespread.

This development has also been the case in Spain. Nevertheless, the Iberian peninsula is still home to five of the EU’s seven internationally recognised “Globally Important Agricultural Heritage Systems”, so-called GIAHS, a system set up by FAO in 2002. The Iberian Peninsula was recently surveyed with the GIAHS model to recognise further agroecosystems worth preserving as intangible heritage. The criteria are food and livelihood security, agro-biodiversity, local and traditional knowledge systems, distinctive cultural values, and specific features of landscapes and seascapes. By developing these criteria and utilising GIS, the Spanish authorities have pinpointed fifty potential sites worth protecting.

Significant are the sites belonging to 56% of the farmland in Spain known as “dehesas” (and in Portugal as “montados”). Half of this typical landscape in the southwestern part of the Iberian Peninsula is found in the northern part of Andalusia in the Sierra de Aracena y Picos de Aroche stretching north of the Guadalquivir from Huelva, Seville, Cordoba, and Baeza. Originally covered by woods hosting gall, cork and holm oaks, this landscape was cleared to make way for the dehesas. As well as grazing livestock, mostly cows and fighting bulls, the dehesas – or defences, originally meaning a reserved pasture – were and are used for the production of cork, firewood, and charcoal, as well as grazing. Some of the villages flanking the dehesas date back to prehistoric times, while others owe their existence to the out-migration of the Muslim population after the Reconquista and the slow Castilian repopulation. Most villages grew up around fortress-like churches or hilltop castles constructed to deter the Portuguese to the west and the Nasrid kingdom at Grenada to the east.

As it stands today, the dehesa-landscape was the immediate result of the Castillian conquest, when the Muslim population gradually migrated from leaving an abandoned landscape where natural ecosystems were allowed to take over. For a short while, much of the the landscape was used for activities such as hunting, fishing, and beekeeping. Only gradually did the exploitation of the landscape characterised by “modern” dehesas – that is, enclosed pasturelands – take over after the final conquest of the Nasrid kingdom and the population growth following the wars and plagues, which marred the 14th and 15th centuries.

Although it is believed the system with dehesas existed in Roman, Byzantine and later Islamic times, the present-day version thus dates to the period of repopulation, which occurred in the later Middle Ages. Their main function was to serve as more or less common, more or less privately owned pastures for drought cattle. One common feature was the active prohibition against pigs and poultry accused of uprooting the ground and fouling the water. However, the dehesas were not just used for drought cattle. Sometimes, dehesas were enclosed and used for regular cattle ranging by larger landowners and the cities located along the Guadalquivir.

Today, these dehesas are recognised by the EU as farmlands with a “High Natural and Cultural Value”, implying these agroforestry systems also score high on biodiversity. Protected as a specific EU habitat, much of the landscape featuring the dehesas is recognised as Natura 2000.

Two Forms of Conservation Policies

However, the question remains how to preserve this unique cultural landscape and/or its nature best? And further: is it worth protecting the dehesa-landscape from a biodiversity perspective?

One system set up by the Spanish authorities is the identification of the belt as a network of Protected Natural Areas, parts of which – as said – have also been designated Natura 2000. However, this system is challenged by the abandonment by people of the traditional sylva–pastoral landscape, with an accompanying shift from pigs to poultry, horses, and olive groves, but also furthering the encroaching scrub and forest.

Another option, though, is inducing forest expansion together with more or less active rewilding, returning to the “Reconquista” landscape with its natural barriers of Mediterranean wild forests used as open nature reserves and hunting grounds. This is, to some degree, the policy adopted by the National Parks spread along the Northern border of Andalusia. Apparently, these parks struggle to integrate the abandoned farmland into their natural range without losing the distinctive fauna and flora characteristic of the dehesas.

These two policies and options have been claimed to represent two adverse methods of conservation where the cultural and natural landscapes are set apart and not allowed to mingle, thus establishing what in the literature has been termed a “cultural severance”.

“The progressive degradation and marginalisation of the rural landscape and the associated deterioration of environmental and social conditions are factors correlated with the increasing land abandonment of smallholder farming over the past decades”, writes Villodre et al. in a recent article (Villodre 2023)”, on behalf of the cultural-landscape-faction. They posit that “among the main arguments against rewilding are the loss of valuable cultural landscapes and high nature value farming systems, the decrease in landscape heterogeneity or the negative impacts on biodiversity and ecosystem Services”. In a project led by the University of Extremadura and carried out together with stakeholders, plans have been laid to enrich the grassland of the dehesas by bettering the regeneration of trees and the sowing of fodder crops.

Opposed to this, the Nature-landscape-faction argues for a type of (passive) rewilding, letting the abandoned details being swallowed by the wilder natural landscape dominating the sierras.

One example of such a more integrated landscape is the UNESCO Global Geopark – the Sierra Norte de Sevilla Natural Park – characterised by rich and diversified nature. This is a landscape of gently rolling hills clad in dense evergreen oaks, which covers 177.000 ha and is very sparsely populated. However, a third of the park is still taken up with dehesas, where pigs continue to graze. Thus, the dehesas borders a rich landscape of wilder nature inhabited by boars, deer, otters, badgers, wolves, polecats, and wild cats, while overflown with eagles, griffons, black vultures, black storks, red kites, and eagle owls. Also, the landscape is teeming with a significant population of endangered butterflies. Thus, in a situation where the wild nature of Europe is endangered, the preservation of large tracts of abandoned dehesas should seem an unnecessary luxury. When all is said and done, a dehesa is an enclosed pasture more or less extensively exploited for grazing and coppice. The upholding of a dehesa, thus, does not depend on the next-door neighbouring dehesas. As opposed to this, wild nature needs large tracts of undisturbed land where animals and plants can roam. Why, then, should we preserve and protect the dehesas?

Arguably, however, the dehesas sustain high levels of biodiversity if kept under an adequate management regime. This is the main conclusion of a meta-survey carried out in 2022 (Rodríguez-Rojo 2022). In general, the dehesas, with their intermediate tree covers, scrub patches, and natural microclimates, offer a varied and beneficial home to a wide variety of species thriving in a mosaic landscape. However, if the management becomes too proactive – for instance, removing dead tree stumps and clearing shrubs, the advantages tend to disappear. “Small-scale features and natural microhabitats such as traditional stone walls, canopy shrubs, piles of pruning debris, or temporary watercourses have been shown to contribute substantially to the biodiversity of macroinvertebrates, reptiles, and small mammals, writes Rodríguez-Rojo et al. (2022)

On a more detailed level, other studies of the dehesas considered as low-input farming agroforestry systems have shown that, taken as a whole, the dehesas do feature significant numbers of species and rich biodiversity. However, systematically measuring flora and fauna on nine general habitat categories inside dehesas from wood pastures to water bodies, it was shown that abundance and species richness varied widely and that the proportion of shared species was low among the different micro-habitats. The most important conclusion was that the high diversity of the dehesas depended on the coexistence within the farms of habitats, which, although marginal, seemed to harbour a disproportionally high number of species compared to the small areas out of the whole which they occupied. This might mean that it is, in fact, not the dehesas as such, but rather the wilder fringes which support their value as natural reserves. (Moreno et al. 2016). In short: heterogeneity seems to be the key to the high biodiversity attached to the dehesas.

Another study has also demonstrated this conclusion carried out in 2020 when a group of scientists published an index on how to evaluate threatened biodiversity (Diaz 2020). Lucky for us, they applied their model to the forests of Andalusia comprising the following habitats: Oak forests, other forests, shrubland, grassland and dehesas. The method employed consisted of selecting threatened species according to the official regional red list and evaluating their status according to a weighted index of differences in threat status, sensitivity to disturbance, and their functional role. The final list included 224 species: 81 plants, 76 birds, 31 mammals, 22 anthropods, six reptiles, five amphibians, and three molluscs. Fine-scale maps covering 43,864 km2 were then plotted with the biodiversity index calculated for each threatened species registered. Based on this, the scientists found that the dehesas averaged a conservation value of only 80-150. Albeit more than the oak forest (40-100) and the other forests (50-110), the best results were found in shrubland and grassland bordering the dehesas and yielding 200-250.

From Passive to Active Rewilding

Pondering the diverse habitats– dehesas, grasslands, shrublands and forests –  it appears they each contribute and have a role to play. However, the quality of biodiversity seems to be attached less to the different habitats and rather the mixture of the different intermingling zones in the sierras – with wilder nature in the inner hills and mountains bordered by semi-open shrub- and grassland, which in their turn is adjoined by the dehesas and the traditional silvopastoral farms on the gently sloping countryside reaching down to the banks of the river and its tributaries. To name one example, the griffon vultures are best served in a semi-open landscape filled with carrion from both wild deer and livestock, while reforestation or monocultures like olive groves hinder their survival in the sierras.

Perhaps, the real solution is to accept that returning to an actively rewilded landscape might solve the problem. What we do know is that the forestry landscape of the sierras in the Southwestern Iberian Peninsula before the neolithic revolution consisted of the fluctuating landscape where wild roaming animals – aurochs, wild horses, boars and numerous top predators such as lions, wolves, bears and lynx roamed the terrain, slowly opening up the woodland to turn it into a semi-open grassland much like the traditional dehesas looked like before they were fenced in, and claimed as private property.

However, advancing active rewilding will involve the traditional Spanish farmers abandoning their role as custodians of the cultural landscape of their dehesas, agroforestry farms, and famed products. On the other hand, though, they may gain a new and less stressful role as custodians of the wild nature currently reclaiming the sierras of Southern Spain.

Unfortunately, as long as agribusinesses and lobbyists support the discourse on cultural landscapes as part of the national heritage, this may not happen, despite the vested interests in nature tourism and the economics of climate adaptation, which should lead the way.

SOURCES:

Prioritising conservation actions towards the sustainability of the dehesa by integrating the demands of society
By Carlos Parra-López, Samir Sayadi, Guillermo Garcia-Garcia, Saker Ben Abdallah, and Carmen Carmona-Torres
In: Agricultural Systems (2023), Vol 206.

Characterization of potential Spanish territories for creating a national network associated with the Globally Important Agricultural Heritage Systems
By Cintya Elizabeth Manrique Anticona, Jos´é Luis Yagüe Blanco, and Isabel Cristina Pascual Castano.
In: Land Use Policy (2023) vol 131.

Origin, Typology and Evolution of the Dehesas in the south of the Iberian Peninsula during the Late Middle Ages (13th to 15th Centuries AD)
By Maria Antonia Carmona Ruiz
In: Landscapes and Resources in the Bronze Age of Southern Spain. RessourcenKulturen(2022) vol 17 (pp. 135-144.

Exploring the causes of high biodiversity of Iberian dehesas: the importance of wood pastures and marginal habitats
By Gerardo Moreno, Guillermo Gonzalez-Bornay, Fernando Pulido, María Lourdes Lopez-Diaz, Manuel Bertomeu, Enrique Juárez & Mario Diaz
In: Agroforestry Systems (2016) vol 90, pp 87-105

Which Factors Favour Biodiversity in Iberian Dehesas?
by Maria Pilar Rodríguez-Rojo, Sonia Roig, Celia López-Carrasco, María Manuela Redondo García, and Daniel Sánchez-Mata
In: Sustainability (2022) Vol 14 no 4

Abandonment and management in Spanish dehesa systems: Effects on soil features and plant species richness and composition
By Reyes Tárrega, Leonor Calvo, Ángela Taboada, Sergio García-Tejero, and Elena Marcos
In: Forest Ecology and Management (2009) 257(2):731-738

The perception of tourism sustainability by stakeholders. The case study of the “Sierra de Aracena y Picos de Aroche” Nature Park, “Sierra Norte de Sevilla” Nature Park and “Sierra de Hornachuelos” Nature Park (Andalusia, Spain)
By María Bahamonde-Rodríguez, F. Javier García-Delgado, and Giedrė Šadeikaitė
In: Land( 2022), vol 11

Land use and land cover dynamics in the dehesa of Sierra Morena Biosphere Reserve (Sierra Norte de Sevilla Natural Park, Spain), 1956-2007
By Juan Manuel Mancilla-Leytón, Antonio Puerto-Marchena and Ángel Martín-Vicente
In: Madera bosques (2017) vol.23 no.2

A comprehensive index for threatened biodiversity valuation
By Mario Díaz, Elena D. Concepción, José L. Oviedo, Alejandro Caparrós, Begoña Á. Farizo, and Pablo Campos
In: Ecological Indicators (2020) Vol 108

Willingness to accept for rewilding farmland in environmentally sensitive areas
By Rubén Granado-Díaz, Anastasio J. Villanueva, and José A. Gómez-Limón
In: Land Use Policy (2022) Vol 116