Global food production should at least double by the end of this century to meet the needs of the... more Global food production should at least double by the end of this century to meet the needs of the increasing human population. However, crop yield potential has stagnated (Ray et al. 2012), and some reduction in the crop yields is expected as consequence of climate change (Brisson et al. 2010). The increasing number of early warm events in temperate regions are causing heat-stress during the grain filling phase, and drought during the period of stem elongation. This has strong negative consequences on crop yields. In the last few years, in several regions of Spain, cereal crops have not been harvested because of the lack of grain in the plants. Consequently, new cropping practices that mitigate the harmful effects of climate change, and crop species and cultivars better adapted to new climate conditions, are demanded by farmers.
Tradução de leaflet do projeto AGFORWARD - O Montado (Dehesa em Espanha) é um ecossistema silvopa... more Tradução de leaflet do projeto AGFORWARD - O Montado (Dehesa em Espanha) é um ecossistema silvopastoril artificial. Tem biodiversidade elevada, mas pode ter baixa produção, sobretudo no verão e inverno. Por isso, os agricultores podem ter de recorrer a fontes externas de forragem, com prejuízo da sustentabilidade económica deste sistema. A instalação de pastagens permanentes ricas em leguminosas pode ser positiva para agricultores e/ou criadores de gado, reduzindo diferenças sazonais de produção e o período crítico para o pastoreio. O uso de variedades comerciais de espécies nativas minimizará o risco para as comunidades autóctones. Estes benefícios potenciais foram demonstrados em sete montados da Extremadura Espanhola, em parcelas semeadas com leguminosas, em diferentes períodos nos últimos 20 anos.
La dehesa è un ecosistema silvo-pastorale caratterizzato da un'alta biodiversità ma la produz... more La dehesa è un ecosistema silvo-pastorale caratterizzato da un'alta biodiversità ma la produzione dei suoi pascoli può essere molto bassa. Creare pascoli ricchi di legumi può migliorarne molto la resa stagionale riducendo il periodo critico di pascolo per i bovini - Dehesa is a silvo-pastoral ecosystem characterised by a high biodiversity, but pasture production can be low, especially in winter and summer. Establishing permanent pastures rich in legumes could result in a substantial positive change for farmers and stock breeders by mitigating seasonal yeld differences, and reducing the critical grazing period for cattle.
Leaflet do projeto AGFORWARD - As primeiras impressões são, frequentemente, que a presença de árv... more Leaflet do projeto AGFORWARD - As primeiras impressões são, frequentemente, que a presença de árvores em sistemas pastoris irá reduzir a produção de pasto devido à competição pela água e luz. No entanto, outros efeitos na dinâmica do sistema e na disponibilidade da água podem ser benéficos para o ciclo de nutrientes e para o rendimento e a produtividade da pastagem. A presença de árvores afeta a velocidade do vento e a temperatura, criando um microclima mais ameno devido ao ensombramento. Este microclima pode melhorar a produção de pasto e a sua disponibilidade.
Adaptive forest management (AFM) is an urgent need because of the uncertainty regarding how chang... more Adaptive forest management (AFM) is an urgent need because of the uncertainty regarding how changes in the climate will affect the structure, composition and function of forests during the next decades. Current research initiatives for the long-term monitoring of impacts of silviculture are scattered and not integrated into research networks, with the consequent losses of opportunities and capacity for action. To increase the scientific and practical impacts of these experiences, it is necessary to establish logical frameworks that harmonize the information and help us to define the most appropriate treatments. In this context, a number of research groups in Spain have produced research achievements and know-how during the last decades that can allow for the improvement in AFM. These groups address the issue of AFM from different fields, such as ecophysiology, ecohydrology and forest ecology, thus resulting in valuable but dispersed expertise. The main objective of this work is to i...
Agroforestry systems and legume sowing have been reported as efficient in terms of soil function,... more Agroforestry systems and legume sowing have been reported as efficient in terms of soil function, gaining momentum as environmentally sustainable agricultural practices. This paper examines how the soil microbial community of Mediterranean pastures responds to legume-enrichment. We used phospholipid fatty acids profiling (PLFA) to measure microbial community composition, community-level physiological profiling (CLPP) to measure their activity and functional diversity, and analysed soil labile and bulk organic carbon in four wood pastures. Each site included a triplet of treatments composed of a native pasture (Control) and two native pastures enriched with a legume-rich mixture sowed ≤ 7 (young) and ≥ 11 (old) years ago, and two habitats (under tree canopy vs open pasture). The sites were fertilized with varying amounts of phosphorous. We found large variations among legume-plot ages and habitats, with microbial biomass, diversity and CLPP-activity higher in the legume-plots than in the control plots, and under tree than in open pastures. The community shift after sowing was driven by increased abundance of gram-negative bacteria and arbuscular mycorrhizal fungi, and decreased saprophytic fungi. Soil bulk and labile C stocks steadily increased after the sowing, and were related to legume abundance, P-fertilization and forage yield, both directly and indirectly, through the positive effect on microbial biomass and CLPP-activity. The shift in microbial community structure together with the increased soil C stocks, soil P and likely N fixed by legumes form a positive legacy that can help to enhance the productivity and climate-resilience of pastures, although this needs further research.
Grazed Mediterranean open woodlands, as the Iberian dehesa, are an outstanding example of silvopa... more Grazed Mediterranean open woodlands, as the Iberian dehesa, are an outstanding example of silvopastoral system where shrub encroachment has been proposed as an effective means to facilitate tree seedling recruitment and ensure the system persistence. The aim of this essay is to test the effects of different intensity of shrub encroachment on different fodder components of the system: acorn production, forage shrub and grassland yield. Metabolic Energy (ME) was increased by R. sphaerocarpa due to the increase of grass production and the contribution of shrub fodder in addition to the supply of acorns. Instead, the ME supplied by C. ladanifer layer, did not compensate the reduction in grassland and acorn production because of the low metabolic energy that C. ladanifer canopy provides.
Ranching generally causes a progressive deforestation. Nevertheless in Mediterranean countries tr... more Ranching generally causes a progressive deforestation. Nevertheless in Mediterranean countries trees are still present in many pastoral systems, here referred to as silvopastoral systems (SPs). Trees provide products as fruits as human food, fruits or leaves as fodder, wood and firewood, environmental services like patches of soil fertility and shelter for animals, and environmental goods such as carbon sequestration, water yield and quality and reinforced biodiversity. However, most of the SPs locate in marginal areas, have low commercial profitability and are subject to two divergent trends, intensification and extensification or abandonment that compromise their long-term persistence. Here we analyzed current threats/constraints and new challenges for the future of SPs based on experience gained in Iberian dehesas. We stress the need of a comprehensive and categorized map of SPs and a database of management practices as adaptive solutions to environmental and socioeconomical cont...
Iberian dehesa is usually defined as two-layered silvopastoral system, where native grasses cohab... more Iberian dehesa is usually defined as two-layered silvopastoral system, where native grasses cohabit with a scattered widely-space tree layer. In the last two decades, an intense debate has been developed on the sustainability of this simplified type of dehesa. While some authors argue that that the forest cycle has been disrupted in most dehesas, where the lack of regeneration is an inherent problem to their exploitation, other authors have showed that dehesa degradation is easily reversible if certain abandonment is periodically exerted. The coexistence of two-layered plots with multilayered plots (encroached open woodlands) and mono-layered plots (either closed forest or mono-pasture/monocrops) has been a common feature of dehesas, as result of a systematic combination of agricultural, pastoral, and forestry uses. Different structures of vegetation depend on land use, giving a mosaic at both estate and landscape scales. These mosaic-type systems allow finding several scenarios of plant-to-plant interactions, mostly at belowground level. A key issue for sustainable management of oak woodland is to understand the complexity of the plant-to-plant relationships and their consequences in the ecosystem functioning in terms of productivity and stability. The competitive abilities of component systems are modified by the environment conditions. Dehesas, as most savanna systems, exhibit a low rainfall with high variability within and between years as well as a high evaporative demand during the summer. Indeed, water availability is one of the major ecological factors influencing either natural savannas or man-made open woodlands. Although most of the available studies have focused different aspects of the mature tree-grass interactions, we also present here some recent results on tree-tree, tree-shrub, shrub-seedling and seedling-grass interactions, explained mostly in terms of competition for soil water and nutrients. Trees can modify the soil and microclimate environment much more than understorey usually can, but tree characteristics often confer them a clear competitive advantage and they can strongly out-compete understorey. The net balance of positive-negative interactions varies with the age of trees: while the balance can favor grasses face to seedlings, the contrary can be expected when tree grows. Similarly, while shrubs could favor seedling recruitment, shrubs could affect negatively tree growth and productivity. These changes should be taken into account for defining dehesa structure and determining management practices in order to optimize the use of physical and chemical resources that are spatially and temporally patchy. From our results, it is described how generally holm-oak trees favor understorey forage production through a direct positive effect of shade and improved soil fertility (facilitation). The rooting system together the slow-growing attitude of many oak species could determine a low competitive potential of oaks with herbaceous layer. Its low competitiveness together with its capacity to thrive in poor soils make oaks genre very suitable for long-term agroforestry systems in Iberian Peninsula. However, although a certain complementary uses of soil resources seems occur for trees and native grasses (very distinct root system profile), the potential benefit of trees has a small actual facilitative effect because the competitive use of soil water by trees overrides its positive effects, especially under semi-arid conditions. As consequence, the net balance of trees on pasture yield is very variably with situations where pasture yield is widely increased in the vicinity of the trees and others where the contrary is found. Tree clearance practiced in dehesas affects positively the development of the understory pasture, but also the single tree functions which take advantage of the low tree density characteristic of dehesas. Tree roots access water through a large volume of soil resources (especially water) unused by pasture layer. As a consequence, lower stand density is, better tree water status, grow and acorn production is. This dependence of tree functioning
Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial eco... more Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database wi...
Conversion of semi-natural habitats, such as field margins, fallows, hedgerows, grassland, woodlo... more Conversion of semi-natural habitats, such as field margins, fallows, hedgerows, grassland, woodlots and forests, to agricultural land could increase agricultural production and help meet rising global food demand. Yet, the extent to which such habitat loss would impact biodiversity and wild species is unknown. Here we survey species richness for four taxa (vascular plants, earthworms, spiders, wild bees) and agricultural yield across a range of arable, grassland, mixed, horticulture, permanent crop, for organic and non-organic agricultural land on 169 farms across 10 European regions. We find that semi-natural habitats currently constitute 23% of land area with 49% of species unique to these habitats. We estimate that conversion of semi-natural land that achieves a 10% increase in agricultural production will have the greatest impact on biodiversity in arable systems and the least impact in grassland systems, with organic practices having better species retention than non-organic pr...
Iberian man-made oak savannahs (so called dehesas) are traditional silvopastoral systems with a h... more Iberian man-made oak savannahs (so called dehesas) are traditional silvopastoral systems with a high natural value. Scattered trees provide shelter and additional food to livestock (cattle in our study sites), which also makes possible for animals depending on trees in a grass-dominated landscape to be present. We compared dehesas with nearby treeless grasslands to assess the effects of oaks on ant communities. Formica subrufa, a species associated with decayed wood, was by far the most abundant species, especially in savannahs. Taxa specialized in warm habitats were the most common both in dehesas and grasslands, as expected in areas with a Mediterranean climate. Within dehesas, the number of species was higher below oak canopies than outside tree cover. Compared to treeless grasslands, the presence of oaks resulted in a higher species richness of aphid-herding and predator ants, probably because trees offer shelter and resources to predators. The presence of oaks changed also the ...
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Remote Sensing (RS) has traditionally provided estimates of key biophysical properties controllin... more Remote Sensing (RS) has traditionally provided estimates of key biophysical properties controlling light interaction with the canopy (e.g., chlorophyll content (C ab) or leaf area index (LAI)). However, recent and upcoming developments in hyperspectral RS are expected to lead to a new generation of products such as vegetation functional traits that control leaf carbon and water gas exchange. This information is pivotal to improve our understanding and capability to predict biosphere-atmosphere fluxes at global scale. Yet, the retrieval of key functional traits such as maximum carboxylation rate (V cmax) or the Ball-Berry stomatal sensitivity parameter (m) remains challenging, as they only have a weak and indirect influence on optical reflectance factors. Recently, the assimilation of different observations in coupled soilvegetation-atmosphere transfer (SVAT) and radiative transfer models (RTM) is allowing V cmax and m estimates; notably using the Soil Canopy Observation of Photosynthesis and Energy fluxes (SCOPE) model. In this work we assess the potential of airborne and satellite emulated hyperspectral imagery jointly with eddy covariance (EC) data for the retrieval of functional traits. Specifically, we made use of time series of gross primary production (GPP) and thermal irradiance measured with net radiometers, together with 17 hyperspectral airborne images. The potential of satellite-borne sensors was tested with emulated EnMAP imagery from the airborne data. EnMAP was selected because of the availability of the emulator, and because is one of the foreseen hyperspectral satellite missions expected to contribute to a new generation of RS products. We estimated ecosystem functional traits by inverting the senSCOPE model, a novel version of SCOPE
Sun-Induced fluorescence at 760 nm (F760) is increasingly being used to predict gross primary pro... more Sun-Induced fluorescence at 760 nm (F760) is increasingly being used to predict gross primary production (GPP) through light use efficiency (LUE) modeling, even though the mechanistic processes that link the two are not well understood. We analyzed the effect of nitrogen (N) and phosphorous (P) availability on the processes that link GPP and F760 in a Mediterranean grassland manipulated with nutrient addition. To do so, we used a combination of process-based modeling with Soil-Canopy Observation of Photosynthesis and Energy (SCOPE), and statistical analyses such as path modeling. With this study, we uncover the mechanisms that link the fertilization-driven changes in canopy nitrogen concentration (N%) to the observed changes in F760 and GPP. N addition changed plant community structure and increased canopy chlorophyll content, which jointly led to changes in photosynthetic active radiation (APAR), ultimately affecting both GPP and F760. Changes in the abundance of graminoids, (%gram...
Tree–grass ecosystems are widely distributed. However, their phenology has not yet been fully cha... more Tree–grass ecosystems are widely distributed. However, their phenology has not yet been fully characterized. The technique of repeated digital photographs for plant phenology monitoring (hereafter referred as PhenoCam) provide opportunities for long-term monitoring of plant phenology, and extracting phenological transition dates (PTDs, e.g., start of the growing season). Here, we aim to evaluate the utility of near-infrared-enabled PhenoCam for monitoring the phenology of structure (i.e., greenness) and physiology (i.e., gross primary productivity—GPP) at four tree–grass Mediterranean sites. We computed four vegetation indexes (VIs) from PhenoCams: (1) green chromatic coordinates (GCC), (2) normalized difference vegetation index (CamNDVI), (3) near-infrared reflectance of vegetation index (CamNIRv), and (4) ratio vegetation index (CamRVI). GPP is derived from eddy covariance flux tower measurement. Then, we extracted PTDs and their uncertainty from different VIs and GPP. The consist...
Global food production should at least double by the end of this century to meet the needs of the... more Global food production should at least double by the end of this century to meet the needs of the increasing human population. However, crop yield potential has stagnated (Ray et al. 2012), and some reduction in the crop yields is expected as consequence of climate change (Brisson et al. 2010). The increasing number of early warm events in temperate regions are causing heat-stress during the grain filling phase, and drought during the period of stem elongation. This has strong negative consequences on crop yields. In the last few years, in several regions of Spain, cereal crops have not been harvested because of the lack of grain in the plants. Consequently, new cropping practices that mitigate the harmful effects of climate change, and crop species and cultivars better adapted to new climate conditions, are demanded by farmers.
Tradução de leaflet do projeto AGFORWARD - O Montado (Dehesa em Espanha) é um ecossistema silvopa... more Tradução de leaflet do projeto AGFORWARD - O Montado (Dehesa em Espanha) é um ecossistema silvopastoril artificial. Tem biodiversidade elevada, mas pode ter baixa produção, sobretudo no verão e inverno. Por isso, os agricultores podem ter de recorrer a fontes externas de forragem, com prejuízo da sustentabilidade económica deste sistema. A instalação de pastagens permanentes ricas em leguminosas pode ser positiva para agricultores e/ou criadores de gado, reduzindo diferenças sazonais de produção e o período crítico para o pastoreio. O uso de variedades comerciais de espécies nativas minimizará o risco para as comunidades autóctones. Estes benefícios potenciais foram demonstrados em sete montados da Extremadura Espanhola, em parcelas semeadas com leguminosas, em diferentes períodos nos últimos 20 anos.
La dehesa è un ecosistema silvo-pastorale caratterizzato da un'alta biodiversità ma la produz... more La dehesa è un ecosistema silvo-pastorale caratterizzato da un'alta biodiversità ma la produzione dei suoi pascoli può essere molto bassa. Creare pascoli ricchi di legumi può migliorarne molto la resa stagionale riducendo il periodo critico di pascolo per i bovini - Dehesa is a silvo-pastoral ecosystem characterised by a high biodiversity, but pasture production can be low, especially in winter and summer. Establishing permanent pastures rich in legumes could result in a substantial positive change for farmers and stock breeders by mitigating seasonal yeld differences, and reducing the critical grazing period for cattle.
Leaflet do projeto AGFORWARD - As primeiras impressões são, frequentemente, que a presença de árv... more Leaflet do projeto AGFORWARD - As primeiras impressões são, frequentemente, que a presença de árvores em sistemas pastoris irá reduzir a produção de pasto devido à competição pela água e luz. No entanto, outros efeitos na dinâmica do sistema e na disponibilidade da água podem ser benéficos para o ciclo de nutrientes e para o rendimento e a produtividade da pastagem. A presença de árvores afeta a velocidade do vento e a temperatura, criando um microclima mais ameno devido ao ensombramento. Este microclima pode melhorar a produção de pasto e a sua disponibilidade.
Adaptive forest management (AFM) is an urgent need because of the uncertainty regarding how chang... more Adaptive forest management (AFM) is an urgent need because of the uncertainty regarding how changes in the climate will affect the structure, composition and function of forests during the next decades. Current research initiatives for the long-term monitoring of impacts of silviculture are scattered and not integrated into research networks, with the consequent losses of opportunities and capacity for action. To increase the scientific and practical impacts of these experiences, it is necessary to establish logical frameworks that harmonize the information and help us to define the most appropriate treatments. In this context, a number of research groups in Spain have produced research achievements and know-how during the last decades that can allow for the improvement in AFM. These groups address the issue of AFM from different fields, such as ecophysiology, ecohydrology and forest ecology, thus resulting in valuable but dispersed expertise. The main objective of this work is to i...
Agroforestry systems and legume sowing have been reported as efficient in terms of soil function,... more Agroforestry systems and legume sowing have been reported as efficient in terms of soil function, gaining momentum as environmentally sustainable agricultural practices. This paper examines how the soil microbial community of Mediterranean pastures responds to legume-enrichment. We used phospholipid fatty acids profiling (PLFA) to measure microbial community composition, community-level physiological profiling (CLPP) to measure their activity and functional diversity, and analysed soil labile and bulk organic carbon in four wood pastures. Each site included a triplet of treatments composed of a native pasture (Control) and two native pastures enriched with a legume-rich mixture sowed ≤ 7 (young) and ≥ 11 (old) years ago, and two habitats (under tree canopy vs open pasture). The sites were fertilized with varying amounts of phosphorous. We found large variations among legume-plot ages and habitats, with microbial biomass, diversity and CLPP-activity higher in the legume-plots than in the control plots, and under tree than in open pastures. The community shift after sowing was driven by increased abundance of gram-negative bacteria and arbuscular mycorrhizal fungi, and decreased saprophytic fungi. Soil bulk and labile C stocks steadily increased after the sowing, and were related to legume abundance, P-fertilization and forage yield, both directly and indirectly, through the positive effect on microbial biomass and CLPP-activity. The shift in microbial community structure together with the increased soil C stocks, soil P and likely N fixed by legumes form a positive legacy that can help to enhance the productivity and climate-resilience of pastures, although this needs further research.
Grazed Mediterranean open woodlands, as the Iberian dehesa, are an outstanding example of silvopa... more Grazed Mediterranean open woodlands, as the Iberian dehesa, are an outstanding example of silvopastoral system where shrub encroachment has been proposed as an effective means to facilitate tree seedling recruitment and ensure the system persistence. The aim of this essay is to test the effects of different intensity of shrub encroachment on different fodder components of the system: acorn production, forage shrub and grassland yield. Metabolic Energy (ME) was increased by R. sphaerocarpa due to the increase of grass production and the contribution of shrub fodder in addition to the supply of acorns. Instead, the ME supplied by C. ladanifer layer, did not compensate the reduction in grassland and acorn production because of the low metabolic energy that C. ladanifer canopy provides.
Ranching generally causes a progressive deforestation. Nevertheless in Mediterranean countries tr... more Ranching generally causes a progressive deforestation. Nevertheless in Mediterranean countries trees are still present in many pastoral systems, here referred to as silvopastoral systems (SPs). Trees provide products as fruits as human food, fruits or leaves as fodder, wood and firewood, environmental services like patches of soil fertility and shelter for animals, and environmental goods such as carbon sequestration, water yield and quality and reinforced biodiversity. However, most of the SPs locate in marginal areas, have low commercial profitability and are subject to two divergent trends, intensification and extensification or abandonment that compromise their long-term persistence. Here we analyzed current threats/constraints and new challenges for the future of SPs based on experience gained in Iberian dehesas. We stress the need of a comprehensive and categorized map of SPs and a database of management practices as adaptive solutions to environmental and socioeconomical cont...
Iberian dehesa is usually defined as two-layered silvopastoral system, where native grasses cohab... more Iberian dehesa is usually defined as two-layered silvopastoral system, where native grasses cohabit with a scattered widely-space tree layer. In the last two decades, an intense debate has been developed on the sustainability of this simplified type of dehesa. While some authors argue that that the forest cycle has been disrupted in most dehesas, where the lack of regeneration is an inherent problem to their exploitation, other authors have showed that dehesa degradation is easily reversible if certain abandonment is periodically exerted. The coexistence of two-layered plots with multilayered plots (encroached open woodlands) and mono-layered plots (either closed forest or mono-pasture/monocrops) has been a common feature of dehesas, as result of a systematic combination of agricultural, pastoral, and forestry uses. Different structures of vegetation depend on land use, giving a mosaic at both estate and landscape scales. These mosaic-type systems allow finding several scenarios of plant-to-plant interactions, mostly at belowground level. A key issue for sustainable management of oak woodland is to understand the complexity of the plant-to-plant relationships and their consequences in the ecosystem functioning in terms of productivity and stability. The competitive abilities of component systems are modified by the environment conditions. Dehesas, as most savanna systems, exhibit a low rainfall with high variability within and between years as well as a high evaporative demand during the summer. Indeed, water availability is one of the major ecological factors influencing either natural savannas or man-made open woodlands. Although most of the available studies have focused different aspects of the mature tree-grass interactions, we also present here some recent results on tree-tree, tree-shrub, shrub-seedling and seedling-grass interactions, explained mostly in terms of competition for soil water and nutrients. Trees can modify the soil and microclimate environment much more than understorey usually can, but tree characteristics often confer them a clear competitive advantage and they can strongly out-compete understorey. The net balance of positive-negative interactions varies with the age of trees: while the balance can favor grasses face to seedlings, the contrary can be expected when tree grows. Similarly, while shrubs could favor seedling recruitment, shrubs could affect negatively tree growth and productivity. These changes should be taken into account for defining dehesa structure and determining management practices in order to optimize the use of physical and chemical resources that are spatially and temporally patchy. From our results, it is described how generally holm-oak trees favor understorey forage production through a direct positive effect of shade and improved soil fertility (facilitation). The rooting system together the slow-growing attitude of many oak species could determine a low competitive potential of oaks with herbaceous layer. Its low competitiveness together with its capacity to thrive in poor soils make oaks genre very suitable for long-term agroforestry systems in Iberian Peninsula. However, although a certain complementary uses of soil resources seems occur for trees and native grasses (very distinct root system profile), the potential benefit of trees has a small actual facilitative effect because the competitive use of soil water by trees overrides its positive effects, especially under semi-arid conditions. As consequence, the net balance of trees on pasture yield is very variably with situations where pasture yield is widely increased in the vicinity of the trees and others where the contrary is found. Tree clearance practiced in dehesas affects positively the development of the understory pasture, but also the single tree functions which take advantage of the low tree density characteristic of dehesas. Tree roots access water through a large volume of soil resources (especially water) unused by pasture layer. As a consequence, lower stand density is, better tree water status, grow and acorn production is. This dependence of tree functioning
Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial eco... more Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database wi...
Conversion of semi-natural habitats, such as field margins, fallows, hedgerows, grassland, woodlo... more Conversion of semi-natural habitats, such as field margins, fallows, hedgerows, grassland, woodlots and forests, to agricultural land could increase agricultural production and help meet rising global food demand. Yet, the extent to which such habitat loss would impact biodiversity and wild species is unknown. Here we survey species richness for four taxa (vascular plants, earthworms, spiders, wild bees) and agricultural yield across a range of arable, grassland, mixed, horticulture, permanent crop, for organic and non-organic agricultural land on 169 farms across 10 European regions. We find that semi-natural habitats currently constitute 23% of land area with 49% of species unique to these habitats. We estimate that conversion of semi-natural land that achieves a 10% increase in agricultural production will have the greatest impact on biodiversity in arable systems and the least impact in grassland systems, with organic practices having better species retention than non-organic pr...
Iberian man-made oak savannahs (so called dehesas) are traditional silvopastoral systems with a h... more Iberian man-made oak savannahs (so called dehesas) are traditional silvopastoral systems with a high natural value. Scattered trees provide shelter and additional food to livestock (cattle in our study sites), which also makes possible for animals depending on trees in a grass-dominated landscape to be present. We compared dehesas with nearby treeless grasslands to assess the effects of oaks on ant communities. Formica subrufa, a species associated with decayed wood, was by far the most abundant species, especially in savannahs. Taxa specialized in warm habitats were the most common both in dehesas and grasslands, as expected in areas with a Mediterranean climate. Within dehesas, the number of species was higher below oak canopies than outside tree cover. Compared to treeless grasslands, the presence of oaks resulted in a higher species richness of aphid-herding and predator ants, probably because trees offer shelter and resources to predators. The presence of oaks changed also the ...
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Remote Sensing (RS) has traditionally provided estimates of key biophysical properties controllin... more Remote Sensing (RS) has traditionally provided estimates of key biophysical properties controlling light interaction with the canopy (e.g., chlorophyll content (C ab) or leaf area index (LAI)). However, recent and upcoming developments in hyperspectral RS are expected to lead to a new generation of products such as vegetation functional traits that control leaf carbon and water gas exchange. This information is pivotal to improve our understanding and capability to predict biosphere-atmosphere fluxes at global scale. Yet, the retrieval of key functional traits such as maximum carboxylation rate (V cmax) or the Ball-Berry stomatal sensitivity parameter (m) remains challenging, as they only have a weak and indirect influence on optical reflectance factors. Recently, the assimilation of different observations in coupled soilvegetation-atmosphere transfer (SVAT) and radiative transfer models (RTM) is allowing V cmax and m estimates; notably using the Soil Canopy Observation of Photosynthesis and Energy fluxes (SCOPE) model. In this work we assess the potential of airborne and satellite emulated hyperspectral imagery jointly with eddy covariance (EC) data for the retrieval of functional traits. Specifically, we made use of time series of gross primary production (GPP) and thermal irradiance measured with net radiometers, together with 17 hyperspectral airborne images. The potential of satellite-borne sensors was tested with emulated EnMAP imagery from the airborne data. EnMAP was selected because of the availability of the emulator, and because is one of the foreseen hyperspectral satellite missions expected to contribute to a new generation of RS products. We estimated ecosystem functional traits by inverting the senSCOPE model, a novel version of SCOPE
Sun-Induced fluorescence at 760 nm (F760) is increasingly being used to predict gross primary pro... more Sun-Induced fluorescence at 760 nm (F760) is increasingly being used to predict gross primary production (GPP) through light use efficiency (LUE) modeling, even though the mechanistic processes that link the two are not well understood. We analyzed the effect of nitrogen (N) and phosphorous (P) availability on the processes that link GPP and F760 in a Mediterranean grassland manipulated with nutrient addition. To do so, we used a combination of process-based modeling with Soil-Canopy Observation of Photosynthesis and Energy (SCOPE), and statistical analyses such as path modeling. With this study, we uncover the mechanisms that link the fertilization-driven changes in canopy nitrogen concentration (N%) to the observed changes in F760 and GPP. N addition changed plant community structure and increased canopy chlorophyll content, which jointly led to changes in photosynthetic active radiation (APAR), ultimately affecting both GPP and F760. Changes in the abundance of graminoids, (%gram...
Tree–grass ecosystems are widely distributed. However, their phenology has not yet been fully cha... more Tree–grass ecosystems are widely distributed. However, their phenology has not yet been fully characterized. The technique of repeated digital photographs for plant phenology monitoring (hereafter referred as PhenoCam) provide opportunities for long-term monitoring of plant phenology, and extracting phenological transition dates (PTDs, e.g., start of the growing season). Here, we aim to evaluate the utility of near-infrared-enabled PhenoCam for monitoring the phenology of structure (i.e., greenness) and physiology (i.e., gross primary productivity—GPP) at four tree–grass Mediterranean sites. We computed four vegetation indexes (VIs) from PhenoCams: (1) green chromatic coordinates (GCC), (2) normalized difference vegetation index (CamNDVI), (3) near-infrared reflectance of vegetation index (CamNIRv), and (4) ratio vegetation index (CamRVI). GPP is derived from eddy covariance flux tower measurement. Then, we extracted PTDs and their uncertainty from different VIs and GPP. The consist...
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Papers by Gerardo Moreno