63 research outputs found

    Log traceability and supply-chain verification by DNA markers in Fagus sylvatica L. in Italy

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    Verifying the match of a timber log with its population of origin represents a meaningful improvement for the preservation and valorisation of the wood chain.In this study, we tested the applicability of the molecular approach for tracing the supply chain of timber of European beech (Fagus sylvatica L.) to check if the declared source of timber truly complied with the declared origin.Samples were collected in four sawmills and in the declared forest standing populations. Different assignment tests for the “unknown” timber were used. Ordination pattern and STRUCTURE analyses identified three clusters and one case of mismatch between the analysed wood and the declared source. The Bayesian method (GeneClass2) and the machine learning approach (AssignPop) assigned 42-72% of the cases to the proper source, with higher uncertainty in one site.This study permitted to detect the lack of congruence of the declared wood source with the actual logging site by DNA markers, screening sampling reference populations (standing trees) and timber from sawmills. Thus, the application of DNA markers confirmed to be able to find failure in the wood supply chain. This application could act as a benchmark to further develop an independent supply-chain verification system that should be implemented as part of the inventory process

    Effects of warmer and drier climate conditions on plant composition and biomass production in a Mediterranean shrubland community

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    The last IPCC report predicts warmer and drier conditions for the future European climate and the Mediterranean basin could be highly sensible to future climatic change. In order to investigate how the forecast more stressing factors could affect Mediterranean shrubland ecosystems, an appropriate manipulation of the microclimate was carried out in an area covered by Mediterranean maquis aimed at extending the drought period and increasing the night-time temperature. Soil cover, plant growth, litterfall, leaf water status, and leaf nutritional status were monitored over three growing seasons. The manipulation altered the microclimate according to common scenarios, increasing mean annual night-time air temperature by about 1 °C and mean annual temperature by about 0.5 °C, and decreasing precipitation between 6-46% of the total rainfall during the growing seasons. A general increase of vegetation cover was observed in the whole community during the three years of experimentation. This positive temporal pattern was mainly observed in control and warming treatment, whereas in the drought treatment it was less evident. At species-specific level, a clear negative effect of drought treatment was observed for C. monspeliensis percentage cover. Shoot elongation was not significantly affected by the warming treatment. A significant negative effect of drought treatment was noticed in the 2001-2002 and 2002-2003 growing seasons. An increase of N and P concentrations in the drought treatment in Cistus was observed and it can be explained by the reduced shoot growth induced by the water shortage that we had observed in the same treatment. The absence of a concentration effect on the other two species could be the signal of the different behaviour with regard to a drier climate, and therefore could be a symptom of future change in species composition. We underline the need of longterm observation, because of the different responses of plants in the short and long- term conditions

    Una Nuova area sperimentale di lungo termine, per lo studio degli effetti dell'incremento della temperatura e del periodo di aridità in formazioni di sclerofille mediterranee

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    A new long-term experimental area for studying the effects of climate warming and seasonal drought on a Mediterranean shrubland community. Global changes, such as land use changes, altered atmosphere composition, and climate changes, have been altering the functioning of ecosystems with possible impacts on the degree of biodiversity. Temperature and water availability are the two main determinants of the functional processes of terrestrial ecosystems. Climatic changes could have strong effects on vulnerable ecosystems as Mediterranean shrublands/garrigue/maquis, where the growth and survival of the plants are strictly dependent on the drought and to the high summer temperature. Furthermore, other pressures, such as grazing and wildfires, occur frequently in the Mediterranean area. In order to assess the impacts of the temperature increase and precipitation reduction on Mediterranean shrublands, a new experimental area was established in Sardinia at the Porto Conte forest, Alghero (SS). A system of automatic roofs covers 6 experimental plots (20 m2), in order to simulate an increase of temperature during the night (3 plots) or to intercept the precipitations during a 2-3 months period (3 plots). Three additional plots are used as control. All the observations were conducted in other five European shrubland ecosystems, according to common protocols developed in the context of the European project VULCAN (www.vulcanproject.com). The studies of the different ecological and physiological processes are organised in working packages (Plant, Soil, Fauna, Water) and integrated in a risk assessments evaluation. The aim of this paper is to analyse the first two years of data, to demonstrate the microclimatic modifications induced by the experimental system

    Temperature Dependence of Soil Respiration Modulated by Thresholds in Soil Water Availability Across European Shrubland Ecosystems

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    Soil respiration (SR) is a major component of the global carbon cycle and plays a fundamental role in ecosystem feedback to climate change. Empirical modelling is an essential tool for predicting ecosystem responses to environmental change, and also provides important data for calibrating and corroborating process-based models. In this study, we evaluated the performance of three empirical temperature–SR response functions (exponential, Lloyd–Taylor and Gaussian) at seven shrublands located within three climatic regions (Atlantic, Mediterranean and Continental) across Europe. We investigated the performance of SR models by including the interaction between soil moisture and soil temperature. We found that the best fit for the temperature functions depended on the site-specific climatic conditions. Including soil moisture, we identified thresholds in the three different response functions that improved the model fit in all cases. The direct soil moisture effect on SR, however, was weak at the annual time scale. We conclude that the exponential soil temperature function may only be a good predictor for SR in a narrow temperature range, and that extrapolating predictions for future climate based on this function should be treated with caution as modelled outputs may underestimate SR. The addition of soil moisture thresholds improved the model fit at all sites, but had a far greater ecological significance in the wet Atlantic shrubland where a fundamental change in the soil CO2 efflux would likely have an impact on the whole carbon budget

    Temperature dependence of soil respiration modulated by thresholds in soil water availability across European shrubland ecosystems

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    Soil respiration (SR) is a major component of the global carbon cycle and plays a fundamental role in ecosystem feedback to climate change. Empirical modelling is an essential tool for predicting ecosystem responses to environmental change, and also provides important data for calibrating and corroborating process-based models. In this study, we evaluated the performance of three empirical temperature–SR response functions (exponential, Lloyd–Taylor and Gaussian) at seven shrublands located within three climatic regions (Atlantic, Mediterranean and Continental) across Europe. We investigated the performance of SR models by including the interaction between soil moisture and soil temperature. We found that the best fit for the temperature functions depended on the site-specific climatic conditions. Including soil moisture, we identified thresholds in the three different response functions that improved the model fit in all cases. The direct soil moisture effect on SR, however, was weak at the annual time scale. We conclude that the exponential soil temperature function may only be a good predictor for SR in a narrow temperature range, and that extrapolating predictions for future climate based on this function should be treated with caution as modelled outputs may underestimate SR. The addition of soil moisture thresholds improved the model fit at all sites, but had a far greater ecological significance in the wet Atlantic shrubland where a fundamental change in the soil CO2 efflux would likely have an impact on the whole carbon budget

    Identification of cork characters for phenotypic selection

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    Global change effects can determine major changes in species distribution and productivity. In the Mediterranean region of the severity of hot and dry periods is growing and an increased frequency of extreme events and a major vulnerability of natural ecosystems is evident. Cork oak (Quercus suber L.) is widely spread in the West Mediterranean region and its economic and social is important

    Shrubland primary production and soil respiration diverge along European climate gradient

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    Above- and belowground carbon (C) stores of terrestrial ecosystems are vulnerable to environmental change. Ecosystem C balances in response to environmental changes have been quantified at individual sites, but the magnitudes and directions of these responses along environmental gradients remain uncertain. Here we show the responses of ecosystem C to 8–12 years of experimental drought and night-time warming across an aridity gradient spanning seven European shrublands using indices of C assimilation (aboveground net primary production: aNPP) and soil C efflux (soil respiration: Rs). The changes of aNPP and Rs in response to drought indicated that wet systems had an overall risk of increased loss of C but drier systems did not. Warming had no consistent effect on aNPP across the climate gradient, but suppressed Rs more at the drier sites. Our findings suggest that above- and belowground C fluxes can decouple, and provide no evidence of acclimation to environmental change at a decadal timescale. aNPP and Rs especially differed in their sensitivity to drought and warming, with belowground processes being more sensitive to environmental change
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