Antonio D. del Campo

Changes in the protein profile of Quercus ilex leaves in response to drought stress and recovery.

To characterize the molecular response of holm oak to drought stress and its capacity to recover 9-month-old Quercus ilex seedlings were subjected to three treatments for a 14-d period: (i) continuous watering to field capacity (control plants, W), (ii) no irrigation (drought treatment, D), and (iii) no irrigation for 7d followed by a watering period of 7d (recovery treatment, R). In drought plants, leaf water potential decreased from -0.72 (day 0) to -0.99MPa (day 7), and -1.50MPa (day 14). Shoot relative water content decreased from 49.3% (day 0) to 47.7% (day 7) and 40.8% (day 14). Photosystem II quantum yield decreased from 0.80 (day 0) to 0.72 (day 7) and 0.73 (day 14). Plants subjected to water withholding for 7d reached, after a 7-d rewatering period, values similar to those of continuously irrigated control plants. Changes in the leaf protein pattern in response to drought and recovery treatments were analyzed by using a proteomic approach. Twenty-three different spots were observed when comparing the two-dimensional electrophoresis profile of control to both drought and recovered plants. From these, 14 proteins were identified from tryptic peptides tandem mass spectra by using the new Paragon algorithm present in the ProteinPilot software. The proteins identified belong to the photosynthesis, carbohydrate and nitrogen metabolism, and stress-related protein functional categories.

Relationships between site and stock quality in Pinus halepensis Mill. reforestation on semiarid landscapes in eastern Spain

The influence of site and stock quality factors in Aleppo pine (Pinus halepensis Mill.) plantation establishment has been studied. Five stocklots with a contrasting seedling quality were planted on six different sites showing different ecologic conditions in a same regional context. This reciprocal study indicated that site factors (climate, meteorology and soil) explained most of the variability found over stock quality factors (material and performance attributes) in the overall performance results (F values for final survival were 64.2 and 14.1 for site and stocklot, respectively). There were significant interactions between both factors in survival (F = 2.03 for final survival) and first growth, indicating that the seedling quality attributes associated with a better performance depended on site conditions, with physiological attributes being more dependent on the site than morphological attributes. The lower the site quality (poor performance), the higher the importance of stock quality, especially that related with seedling size and macronutrient content, which showed positive correlations (p < 0.05) with survival, yielding differences of over 30% between stocklots. In general, a milder climate and a shallow site meant a higher mortality. The meteorology during the two years after planting confirmed this trend as survival was preferably correlated with temperature variables instead of with precipitation. In the first year, climate factors affected seedling performance more than the soil texture, whereas, in the second, growth was correlated (p < 0.01) with clay and silt percentages, confirming a predominant effect of site over time. Soil depth is discussed as a basic variable possessing a determinant influence on the overall results.RésuméOn a étudié l’influence de la station et de la qualité des plants dans des plantations de pin d’Alep (Pinus halepensis). Cinq lots de plants de qualité contrastée ont été plantés dans six sites différant par leurs qualités stationnelles dans un même contexte régional. Cette étude réciproque a montré que les facteurs liés à la station (climat, météorologie et sol) expliquaient la plus grande part de la variabilité des résultats obtenus (les valeurs de F pour la survie définitive étaient de 64,2 et 14,1 respectivement pour la station et le lot de plant) avant la qualité des plants. Des interactions significatives on été détectées entre les deux facteurs pour ce qui concerne la survie (F = 2,03 pour la survie définitive) et la croissance de première année. Ce résultat montre que l’impact des critères de qualité (celui des caractères physiologiques plus que celui des caractères morphologiques) sur la survie varie en fonction de la station. La qualité des plants est d’autant plus importante que la station est peu productive, et la dimension des plants et le contenu en macronutriments révèlent des corrélations positives (p < 0,05) avec la survie, conduisant à des différences de plus de 30 % entre les lots de plants. En général, un climat plus doux et un sol peu profond conduisaient à une plus forte mortalité. Les conditions météorologiques pendant les deux premières années après plantation ont confirmé cette tendance puisque la survie était corrélée avec les variables thermiques plutôt qu’avec les précipitations. Pendant la première année, les facteurs climatiques ont plus influencé les performances des plants que la texture du sol, alors que la deuxième année la croissance était corrélée (p < 0,05) avec le pourcentage d’argile et de limon confirmant l’effet prédominant de la station après la phase d’installation. La profondeur du sol a eu une influence déterminante sur l’ensemble des résultats.

Relationship between root growth potential and field performance in Aleppo pine

Commercial stocks of Aleppo pine in Spain vary in quality, but there is no accepted standard for evaluating quality. A RGP test was applied to six commercial seedling stocklots at two dates (November, February) and under two test conditions (growth-chamber, greenhouse). The RGP’s predictive ability was evaluated on two contrasting sites. There was a considerable variation in the RGP depending on application date, test conditions and stock factors. The RGP results for November were correlated with each other but they did not explain outplanting performance. The February results in the growth-chamber correlated well with survival at both sites. Regression models explained survival both in the lower (R2 = 97%) and in the higher (R2 = 92%) quality sites. RGP has a valid predictive ability for this species although it is sensitive to the test conditions. In this sense, a shorter and more intensive test performed right before planting may be more reliable.RésuméLes productions commerciales de plants de pin d’Alep en Espagne présentent une importante variabilité de qualité, mais aucun test standardisé d’évaluation de la qualité des plants n’a été élaboré. Un test de potentiel de croissance racinaire a été conduit sur des plants de six lots commerciaux de pin d’Alep à deux dates (novembre et février) et dans deux conditions de test différentes (chambre de croissance et serre) Le potentiel de croissance racinaire (RGP) a été évalué sur deux sites écologiquement contrastés. RGP a fortement varié avec la date, les sites de plantation et les lots de plants. Les évaluations de RGP étaient corrélées entre elles en novembre, sans expliquer les taux de réussite en plantation. Les valeurs de RGP évaluées en février en chambre de croissance ont présenté de bonnes corrélations avec la survie des plants dans les deux sites. Les modèles de régression ont expliqué la survie des plants à la fois dans le site faiblement productif (R2 = 97 %) et dans le site productif (R2 = 92 %). RGP présente un fort potentiel prédictif cette espèce bien qu’il soit sensible aux conditions de test. Dans ce sens, un test plus court et plus intensif réalisé bien avant la plantation peut être plus fiable.

Adjustment of Forest Management Strategies to Changing Climate

Research work on the influence of global warming on forests predicts a rise in air temperature and changes in precipitation for a large part of Europe. Climate change has been forecast to increase runoff and nutrient leaching from the boreal catchments. Windiness, cloudiness and more frequent extreme-weather events are expected in the temperate region. The Mediterranean region is expected to suffer considerable impacts because of increased drought conditions. The need to understand and control the hydrological role of forests is rising, especially in upper watershed areas (headwaters), where forest expansion and stocking may result in water scarcity downstream. However, observations and studies of natural processes related to the water cycle suggest that forests and water are interrelated in complex ways. Therefore, forests should not be defined and treated as mere consumers of water significantly influencing runoff, but also as natural filters and reservoirs. Forest management systems and operations will have to be adapted to changes in forest composition and distribution within new water and disturbance regimes. Water protection measures like buffer zones and sedimentation ponds will gain in importance, and in general, a new water-yield or water-saving silviculture will play an important role in future forest management.

A hydroeconomic modeling framework for optimal integrated management of forest and water

Forests play a determinant role in the hydrologic cycle, with water being the most important ecosystem service they provide in semiarid regions. However, this contribution is usually neither quantified nor explicitly valued. The aim of this study is to develop a novel hydroeconomic modeling framework for assessing and designing the optimal integrated forest and water management for forested catchments. The optimization model explicitly integrates changes in water yield in the stands (increase in groundwater recharge) induced by forest management and the value of the additional water provided to the system. The model determines the optimal schedule of silvicultural interventions in the stands of the catchment in order to maximize the total net benefit in the system. Canopy cover and biomass evolution over time were simulated using growth and yield allometric equations specific for the species in Mediterranean conditions. Silvicultural operation costs according to stand density and canopy cover were modeled using local cost databases. Groundwater recharge was simulated using HYDRUS, calibrated and validated with data from the experimental plots. In order to illustrate the presented modeling framework, a case study was carried out in a planted pine forest (Pinus halepensis Mill.) located in south-western Valencia province (Spain). The optimized scenario increased groundwater recharge. This novel modeling framework can be used in the design of a “payment for environmental services” scheme in which water beneficiaries could contribute to fund and promote efficient forest management operations.

Drought Tolerance in Pinus halepensis Seed Sources As Identified by Distinctive Physiological and Molecular Markers

Drought is one of the main constraints determining forest species growth, survival and productivity, and therefore one of the main limitations for reforestation or afforestation. The aim of this study is to characterize the drought response at the physiological and molecular level of different Pinus halepensis (common name Aleppo pine) seed sources, previously characterized in field trials as drought-sensitive or drought-tolerant. This approach aims to identify different traits capable of predicting the ability of formerly uncharacterized seedlings to cope with drought stress. Gas-exchange, water potential, photosynthetic pigments, soluble sugars, free amino acids, glutathione and proteomic analyses were carried out on control and drought-stressed seedlings in greenhouse conditions. Gas-exchange determinations were also assessed in field-planted seedlings in order to validate the greenhouse experimental conditions. Drought-tolerant seed sources presented higher values of photosynthetic rates, water use efficiency, photosynthetic pigments and soluble carbohydrates concentrations. We observed the same pattern of variation of photosynthesis rate and maximal efficiency of PSII in field. Interestingly drought-tolerant seed sources exhibited increased levels of glutathione, methionine and cysteine. The proteomic profile of drought tolerant seedlings identified two heat shock proteins and an enzyme related to methionine biosynthesis that were not present in drought sensitive seedlings, pointing to the synthesis of sulfur amino acids as a limiting factor for drought tolerance in Pinus halepensis. Our results established physiological and molecular traits useful as distinctive markers to predict drought tolerance in Pinus halepensis provenances that could be reliably used in reforestation programs in drought prone areas.

Ecohydrological-Based Forest Management in Semi-arid Climate

The role of forests on the provision and regulation of non-marketed ecosystem services is well known (Thorsen et al. 2014). This is especially important in areas like the Mediterranean, where protective forests play a major role against soil erosion and degradation, landscape quality and stabilization of the hydrological cycle. Socio-economic and cultural changes affecting rural society from the 1960s have produced a demographic decline, and with it, an abandonment of rural activities, leading to an expansion and densification of forest and scrub. Forest encroachment may decrease the streamflow from upper catchments (Gallart and Llorens 2004); this study reports a decrease in average annual flow of major Spanish rivers between 37 and 59%, partly explained by the densification of upstream forests, and increasing interception loss. Moreover, some Mediterranean basins (e.g. Segura and Jucar in Spain) present very serious problems of water scarcity, because of a combination of low/irregular rainfall and high rates of evapotranspiration, that has resulted in overuse of groundwater resources (Estrela et al. 2000a, b). These problems may even endanger urban water supply (approx. 15% of the total water supply in Spain). In addition, the Mediterranean region is already suffering some significant impacts of the climate change, such as longer dry seasons, or lower soil moisture content (Giorgi and Lionello 2008; Garcia-Ruiz et al. 2011). All these issues have raised concern about the importance of forests and water interactions in the Mediterranean (Birot et al. 2011).

Evaluación temprana de técnicas de restauración forestal mediante fluorescencia de la clorofila y diagnóstico de vitalidad de brinzales de encina (Quercus ilex sub. ballota)

Resumen es: La fluorescencia de la clorofila a (FCa) se ha aplicado para estudiar procesos de fotoproteccion de la hoja para disipar el exceso de energia absorbida q...

Hydrology-oriented forest management trade-offs. A modeling framework coupling field data, simulation results and Bayesian Networks

Hydrology-oriented forest management sets water as key factor of the forest management for adaptation due to water is the most limiting factor in the Mediterranean forest ecosystems. The aim of this study was to apply Bayesian Network modeling to assess potential indirect effects and trade-offs when hydrology-oriented forest management is applied to a real Mediterranean forest ecosystem. Water, carbon and nitrogen cycles, and forest fire risk were included in the modeling framework. Field data from experimental plots were employed to calibrate and validate the mechanistic Biome-BGCMuSo model that simulates the storage and flux of water, carbon, and nitrogen between the ecosystem and the atmosphere. Many other 50-year long scenarios with different conditions to the ones measured in the field experiment were simulated and the outcomes employed to build the Bayesian Network in a linked chain of models. Hydrology-oriented forest management was very positive insofar as more water was made available to the stand because of an interception reduction. This resource was made available to the stand, which increased the evapotranspiration and its components, the soil water content and a slightly increase of deep percolation. Conversely, Stemflow was drastically reduced. No effect was observed on Runof due to the thinning treatment. The soil organic carbon content was also increased which in turn caused a greater respiration. The long-term effect of the thinning treatment on the LAI was very positive. This was undoubtedly due to the increased vigor generated by the greater availability of water and nutrients for the stand and the reduction of competence between trees. This greater activity resulted in an increase in GPP and vegetation carbon, and therefore, we would expect a higher carbon sequestration. It is worth emphasizing that this extra amount of water and nutrients was taken up by the stand and did not entail any loss of nutrients.

Distinctive physiological and molecular responses to cold stress among cold-tolerant and cold-sensitive Pinus halepensis seed sources

BackgroundForest species ranges are confined by environmental limitations such as cold stress. The natural range shifts of pine forests due to climate change and proactive-assisted population migration may each be constrained by the ability of pine species to tolerate low temperatures, especially in northern latitudes or in high altitudes. The aim of this study is to characterize the response of cold-tolerant versus cold-sensitive Pinus halepensis (P. halepensis) seedlings at the physiological and the molecular level under controlled cold conditions to identify distinctive features which allow us to explain the phenotypic difference. With this objective gas-exchange and water potential was determined and the photosynthetic pigments, soluble sugars, glutathione and free amino acids content were measured in seedlings of different provenances under control and cold stress conditions.ResultsGlucose and fructose content can be highlighted as a potential distinctive trait for cold-tolerant P. halepensis seedlings. At the amino acid level, there was a significant increase and accumulation of glutathione, proline, glutamic acid, histidine, arginine and tryptophan along with a significant decrease of glycine.ConclusionOur results established that the main difference between cold-tolerant and cold-sensitive seedlings of P. halepensis is the ability to accumulate the antioxidant glutathione and osmolytes such as glucose and fructose, proline and arginine.