Dehesas In Spain Research Articles

Montado Mediterranean Ecosystem (Soil–Pasture–Tree and Animals): A Review of Monitoring Technologies and Grazing Systems

Montado is an agro-silvo-pastoral ecosystem characteristic of the south of Portugal and called Dehesa in Spain. Its four fundamental components—soil, pasture, trees, and animals—as well as the climate make Montado a highly complex ecosystem. This review article provides an overview of the state of the art of Montado from the point of view of the agro-silvo-pastoral ecosystem and the scientific work carried out in this context. Thus, the aim is: (i) to describe and characterize the Montado ecosystem, as an agro-silvo-pastoral system; (ii) to reveal experimental tests carried out, technologies used or with the potential to be used in the monitoring of Montado; (iii) to address other technologies, carried out in similar and different agro-silvo-pastoral ecosystems from south Portugal. This review consists of three chapters: (a) components of Montado and their interactions; (b) advanced technologies for monitoring Montado; (c) grazing systems. No review article is known to provide an overview of Montado. Thus, it is essential to carry out research on grazing and its effects on the soil and pasture in the Montado ecosystem.

It's a keeper: Valuing the carbon storage service of Agroforestry ecosystems in the context of CAP Eco-Schemes

Agroforestry landscapes provide multiple benefits, including the capacity for storing carbon, thus contributing to climate change mitigation. In Portugal, the agroforestry system known as Montado (Dehesa in Spain) is heavily dependent on national and European financial incentives. Lack thereof, or insufficient level, often results in abandonment or intensification (increasing grazing pressure) of management practices. Carbon storage is a stock externality of agroforestry systems currently not targeted by CAP agri-environmental mechanisms. Hence, our work is aimed at assessing and valuing net carbon flow in agroforestry systems to guide a Payment for Ecosystem Services (PES) scheme targeting Montado landscapes in Portugal. We have assessed and valued net carbon flow for different land-use change scenarios (abandonment, maintenance, or grazing intensification), focusing on cork and holm oak-dominated Montado and using biomass equations. We applied different explicit carbon pricing mechanisms (market value, social cost, and shadow price) to determine a range of values suitable as financial rewards in the proposed PES scheme. For cork-oak Montado, our results suggest both abandonment and grazing intensification are linked to carbon emissions (−1.5 and −1.6tCO2eq.ha-1.year-1, respectively), whereas maintaining Montado results in carbon sequestration (+0.9tCO2eq.ha-1.year-1). Similar results were found for holm oak. Based on this biophysical assessment, we estimate that farmers willing to maintain Montado systems are eligible to be rewarded between 106 and 149€.ha-1.year-1 through a PES scheme for the increase in carbon storage they are providing. Incorporating the value of ecosystem services into direct financial rewards could ensure agroforestry systems are kept under sustainable management and continue to supply multiple benefits to society.

Remote-Sensing-Based Water Balance for Monitoring of Evapotranspiration and Water Stress of a Mediterranean Oak–Grass Savanna

Mediterranean oak savannas (known as dehesas in Spain) are exposed to numerous threats from natural and economic causes. A close monitoring of the use of water resources and the status of the vegetation in these ecosystems can be useful tools for maintaining the production of ecological services. This study explores the estimation of evapotranspiration (ET) and water stress over a dehesa by integrating remotely sensed data into a water balance using the FAO-56 approach (VI-ETo model). Special attention is paid to the different phenology and contribution to the system’s hydrology of the two main canopy layers of the system (tree + grass). The results showed that the model accurately reproduced the dynamics of the water consumed by the vegetation, with RMSE of 0.47 mm day−1 and low biases for both, the whole system and the grass layer, when compared with flux tower measurements. The ET/ETo ratio helped to identify periods of water stress, confirmed for the grassland by measured soil water content. The modeling scheme and Sentinel-2 temporal resolution allowed the reproduction of fast and isolated ET pulses, important for understanding the hydrologic behavior of the system, confirming the adequacy of this sensor for monitoring grasslands water dynamics.

The Montado/Dehesa Cow-Calf Production Systems in Portugal and Spain: An Economic and Resources’ Use Approach

The Montado in Portugal and Dehesa in Spain is a unique agro-silvo-pastoral system designed to overcome food needs in a scarce resource’s environment. The system competitiveness is not clear and it is now under severe threats, caused by extensification or abandonment of less fertile areas and by intensification in more fertile ones. The aim of the undertaken research is to compare the cow-calf production within these systems in Portugal and Spain, identifying their strengths and weaknesses and the main drivers of their evolution, and to compare these systems with other European countries’ systems, ranking their competitiveness and efficiency among other systems in the EU. The research indicates that Montado/Dehesa farms systems are dependent on the type of farming system, its context and management, i.e., on the decision and its context; so, in a context of Mediterranean land system changes, the future of the Montado/Dehesa ecosystem depends on the ability of the cow-calf production systems to face the future and to perceive the modifications needed to overcome new challenges and take advantage of new opportunities.

Pruning promotes the formation of an insufficient number of cavities for hollow-dependent birds in Iberian Holm-oak dehesas

Holm oak Quercus ilex dehesas cover large areas in the Mediterranean region, and constitute a paradigm of well preserved low-intensity agro-ecosystem supporting a high number of bird species. The canopy of holm oak trees is periodically pruned, but the role of pruning in the process of tree-hollow formation remains unstudied. Here I investigate the occurrence of tree-hollows in relation to tree characteristics (vitality, trunk diameter and fork height), infection by drilling Coleoptera and pruning intensity, and assess likely origin, use and suitability of hollows for non-excavator birds in dehesas of Spain. 26.3% of all sampled oaks had at least one hollow, and the number of pruning cuts predicted the occurrence of hollows. 97.0% of hollows were situated on pruning cuts suggesting that pruning may have favored decay cavity formation in Iberian dehesas. 43.6% of hollows were estimated suitable to hold the nest of a small-sized cavity-nesting bird, but only 11.9% might have potentially held the nest of a medium-sized cavity-nesting bird, rendering estimated 3.9 and 1.1 potential cavities/ha, respectively. The low densities of suitable hollows would point toward a lack of nest-sites which might limit cavity-nesting birds in holm oak dehesas. Future conservation actions targeting in protection of old and dead holm oak trees instead of selective removal, together with land-scale measurements of enhancement of riverine forests stands may enrich and ensure the persistence of cavity-using species in Iberian dehesas.

Using spatial models of temporal tree dynamics to evaluate the implementation of EU afforestation policies in rangelands of SW Spain

Iberian silvopastoral systems known as dehesas in Spain and montados in Portugal are undergoing a spatially polarized process by which many of the main areas lack tree recruitment, whereas marginal lands suffer abandonment and shrub encroachment. These ongoing processes should be considered when designing afforestation measures and policies. We analyzed the temporal tree dynamics in 800 randomly selected plots of 100 m radius in dehesas and treeless pasturelands of Extremadura by comparing aerial images taken in 1956 and 2012. Based on this data, spatial models that predict areas prone to undergo or lack natural tree recruitment were developed using three data mining algorithms: MARS (Multivariate Adaptive Regression Splines), Random Forest (RF) and Stochastic Gradient Boosting (TreeNet, TN). A number of 51 candidate environmental, physical and land use and cover spatial variables were used as predictors in models, from which the main 15 were selected. The statistical models developed were deployed to the spatial context of the rangelands in Extremadura and, separately, to the afforested areas performed under the UE First Afforestation of Agricultural Land program between 1992 and 2013. The percentage of area predicted as prone to tree recruitment was calculated in each case. The three data mining algorithms used showed high fitness and low misclassification rates. Although the drivers and patterns of the different models were similar, outstanding differences were observed among models attending the area prone to tree recruitment. A model ensemble was also produced as a map of agreement reflecting the majority vote among models. Despite these differences, when maps of the model results were related to the afforested surfaces, the three algorithms pointed to the similar conclusion, i.e., the afforestations performed in the studied rangelands barely discriminated between areas that already showed or lacked natural tree regeneration. In conclusion, data mining technics are suitable to develop high-performance spatial models of vegetation dynamics. These models are useful to help policy design, decision-making and assessment about the implementation of afforestation measures and could be used to improve the spatial targeting of future programs.

Contributions of Iberian Silvo-Pastoral Landscapes to the Well-Being of Contemporary Society

Assessments of society’s perceptions of rangeland systems offer insights into the motivations, cultural beliefs, and values that can support landscape conservation and the everyday decisions of landowners. Silvo-pastoral landscapes, the grazed oak woodlands known as montado in Portugal and dehesa in Spain, are the main rangelands of southwestern Iberia. At the interface of complex interactions between natural processes and human activities, they have potential to deliver multiple services at the ecosystem level. However, the actual rendering of their potential to the well-being of contemporary society has not been comprehensively documented. This paper aims to enrich research perspectives and identify benefits and challenging aspects of silvo-pastoral landscapes through the lens of society well-being. An integrated socioecological perspective is used to examine one case study in Portugal and one in Spain. To better understand their context, montado and dehesa are assessed relative to other landscape types in the studied areas. A qualitative approach assesses tangible but also intangible aspects. The interviewed stakeholders include members of rural communities, public authorities, land managers, and researchers. Results reveal similar benefits and challenges in montado and dehesa. Interviewees considered them to have numerous sociocultural and environmental benefits. These were mainly regulatory services but also intangible benefits such as cultural identity, aesthetic qualities, and local knowledge. Nevertheless, a rendering of their full potential to society well-being has numerous challenges. These systems were believed to struggle economically, due to the low prices for the goods produced and a high dependence on subsidies. Their environmental vulnerability was also highlighted. Critical challenges for future research and policy interventions are identified for both case studies. Moreover, we encourage the wider application of approaches to rangelands focusing on well-being, as they provide a complement to ecological and economic perspectives that can improve understanding of social-ecological systems.

Management of Montados and Dehesas for High Nature Value: an interdisciplinary pathway

Mediterranean oak woodlands, Montados in Portugal and Dehesas in Spain have long been acknowledged as potential land use systems of high nature and social value providing relevant ecosystem services and biodiversity conservation. Nevertheless, these systems are now under severe threat, both due to abandonment in certain areas and overuse in others, extremes that may be limited by appropriate management practices and strategies. The High Nature Value concept can be a pathway for the understanding and assessment of management practices best adapted to the balance of the Montado and Dehesa, and also to the assessment of the thresholds of change, so that the long term sustainability of the Montado systems is preserved. This special issue aims to contribute for the understanding of how the Montado and Dehesa classification as High Nature Value may be a path for sustainable management. This classification can be achieved by different ways and implies different components of the Montado, and thus the first four papers of this special issue address different approaches and methodologies for the identification of HNV Dehesas and Montados, the following seven papers deal mostly with the effect of management practices on biodiversity and other Dehesas and Montados values and finally the last two papers address the causes for Montado decline and suggest mitigation measures for that decline.

The Portuguese montado: conciliating ecological values with human demands within a dynamic agroforestry system

In the southwestern Iberian Peninsula, around 3.5–4.0 million ha of a multi-propose agroforestry system persist, where cork oak (Quercus suber L.), Holm oak [Quercus ilex L. subsp. rotundifolia (Lam.)], or a mixture of both species, coexist with pastures and crops (Acacio et al. 2010; Olea and San Miguel-Ayanz 2006; Pinto-Correira et al. 2011). They are called montado in Portugal and dehesa in Spain but represent quite different structures along a cline from 5 % to 65 % oak tree cover (Castro 2009; Moreno and Pulido 2009; Olea and San Miguel-Ayanz 2006). Montado constitutes simultaneously of a seminatural ecosystem, a multifunctional system and a cultural landscape (Fra Paleo 2010; Pinto-Correia and Godinho 2013; Santos and Thorne 2010). Based on tree density, the montado-dehesa can shape three functional landscapes. First, it is an open woodland where silvopastoral management is aimed not at timber production, but mainly at cork extraction (Castro 2009; Costa et al. 2011). Second, it may resemble a savannah-like oak parkland (30–50 trees per hectare) with multiple uses (forestry goods, seasonal agriculture and livestock grazing), while crown cover per tree was increased to produce acorns (Costa et al. 2010; Moreno and Pulido 2009). The bellow canopy stratum generally comprises pastures and agricultural fields in a rotation scheme that includes fallows, with Mediterranean shrubs artificially kept at low densities (Pinto-Correia et al. 2011). Third, it constitutes a scattered agrosylvopastoral land, often set on Holm oak, which is used primarily for grazing and/or cereal crops (Martin and Fernandez-Ales 2006; Plieninger 2007). The montado may be private or communal property (usually belonging to the municipality), often included in Iberian natural parks (Bugalho et al. 2011; Castro 2009; Moreno and Pulido 2009).

Erratum to: Agroforestry in Europe: a review of the disappearance of traditional systems and development of modern agroforestry practices, with emphasis on experiences in Germany

Agroforestry is a new name for a rather old practice. From a historical point of view, various agroforestry systems existed in Europe, of which the wood pastures (Neolithicum), the Dehesas in Spain (~4,500 years old) and the Hauberg of the Siegerland (established in the Middle Age) are the most prominent. Other widespread systems in Europe were hedgerows, windbreaks and Streuobst (orchard intercropping). Due to mechanisation and intensification of agriculture, trees have been progressively removed from agricultural fields and traditional agroforestry systems slowly disappeared. Today, agroforestry systems are again increasing in interest as they offer the potential to solve important ecological and, especially, biodiversity problems, while at the same time enabling the production of food, wood products and fodder for cattle. Although agroforestry systems offer many advantages, many farmers are sceptical of these systems and are critical and risk-averse with regard to adopting new practices. However, in comparison to traditional systems, modern agroforestry systems can be adapted to current farming practices. By selecting suitable trees and appropriate tree management, high-quality timber can be produced without influencing agricultural crops excessively. In future, agroforestry systems will become increasingly important as they offer the prospect of producing woody perennials for bioenergy on the same land area as food and/or fodder plants, while enhancing overall biodiversity.

Spatial distribution of the soil organic carbon pool in a Holm oak dehesa in Spain

AimsDehesas are agroforestry systems characterized by scattered trees among pastures, crops and/or fallows. A study at a Spanish dehesa has been carried out to estimate the spatial distribution of the soil organic carbon stock and to assess the influence of the tree cover.MethodsThe soil organic carbon stock was estimated from the five uppermost cm of the mineral soil with high spatial resolution at two plots with different grazing intensities. The Universal Kriging technique was used to assess the spatial distribution of the soil organic carbon stocks, using tree coverage within a buffering area as an auxiliary variable.ResultsA significant positive correlation between tree presence and soil organic carbon stocks up to distances of around 8 m from the trees was found. The tree crown cover within a buffer up to a distance similar to the crown radius around the point absorbed 30 % of the variance in the model for both grazing intensities, but residual variance showed stronger spatial autocorrelation under regular grazing conditions.ConclusionsTree cover increases soil organic carbon stocks, and can be satisfactorily estimated by means of crown parameters. However, other factors are involved in the spatial pattern of the soil organic carbon distribution. Livestock plays an interactive role together with tree presence in soil organic carbon distribution.

Introducing the montado, the cork and holm oak agroforestry system of Southern Portugal

The Portuguese montado is an agro-silvo pastoral system quite similar to the dehesa in Spain, and covering in Portugal most of the Southern region of the country, Alentejo. The trees in the montado are cork oh holm oak, and the system is mostly acknowledged due to the cork production, but also due to its singular savanna like land cover pattern, its multiple and complementary productions, the support of a diversity of ecosystems services and its biodiversity. The present special issue covers the diversity of components of the montado and of perspectives required to understand and assess the functioning of the system. This Editorial introduces the montado system, describes its extension and similarities to the dehesa in Spain, and addresses the multiple productions and externalities of the montado. It also refers to the several components of the system. It focus on the uniqueness and values of this system, stressing its potential and threats, and the requirements for integrated knowledge production. In the end of the Editorial, each one of the papers that compose the special issue are presented.

Land‐use changes may explain the recent range expansion of the Black‐shouldered Kite Elanus caeruleus in southern Europe

Occasional observations of Black‐shouldered Kites Elanus caeruleus in Europe date back to the mid‐19th century, but it was only recorded as a breeding species in the early 1960s in Portugal and a few years later in neighbouring Spain. This recent colonization, possibly from Africa where the species is abundant, may be due to climate change, land‐use changes in southern Europe, or both. As a first step to understanding this range expansion process we have developed a habitat selection model using data from the current strongholds of its European distribution. Comparing the proportion of different habitat types around 46 breeding sites and 45 randomly chosen plots, we have found that the area of cultivated parklands known as dehesas in Spain is a strong predictor of the current distribution range of breeding pairs of Black‐shouldered Kites. Specifically, the percentage of dehesas with planted cereal and a low density of trees (i.e. < 7 trees/ha and thus a savannah‐like habitat) within the study plots explained 44.6% of the residual deviance in our model. The minimal adequate model classified 81.3% of breeding sites and random plots correctly. Our results suggest that Black‐shouldered Kites may have taken advantage of the gradual increase of cultivated dehesas in the second half of the 20th century to expand its range in Europe. This particular type of dehesa is structurally similar to the African savannahs where the species thrives and may offer a higher density of rodents than traditional dehesas, which primarily contain pastureland for livestock ranching.