258 research outputs found

    Histoire et agronomie : entre ruptures et durée

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    Climate change and rising energy costs will change everything: A new mindset and action plan for 21st Century public health

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    Western governments currently prioritize economic growth and the pursuit of profit above alternative goals of sustainability, health and equality. Climate change and rising energy costs are challenging this consensus. The realization of the transformation required to meet these challenges has provoked denial and conflict, but could lead to a more positive response which leads to a health dividend; enhanced well-being, less overconsumption and greater equality. This paper argues that public health can make its best contribution by adopting a new mindset, discourse, methodology and set of tasks

    ForĂȘts de montagne et changement climatique : impacts et adaptation

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    This review identifies the main impacts of climate change on mountain forests, mainly in Europe, and the management practices proposed for forest adaption. The rise in temperatures, more frequent droughts and the multiplication of extreme events should lead, especially below 1000m in altitude, to the disappearance of highly drought-intolerant tree species (spruce, Scots pine) and their replacement by deciduous trees. In addition, recruitment of some species (fir, beech) is observed at higher altitudes and the duration of the growing season is increasing. Management recommendations for forest adaptation to climate change focus on reducing tree species' vulnerability to water stress and pests, as well as increasing their resilience and ability to respond to extreme weather events. They require genetic improvements and practices that encourage the establishment of suitable species, reduce water consumption and reduce the exposure of stands to risk.Les impacts du changement climatique sur les forĂȘts de montagne sont dĂ©jĂ  perceptibles et les prĂ©visions nous montrent, par leurs contradictions, la complexitĂ© des phĂ©nomĂšnes en jeu. L'objectif de cette Ă©tude bibliographique est d'abord de caractĂ©riser les principaux effets du changement climatique, principalement dans les forĂȘts alpines, puis de prĂ©senter diffĂ©rentes options d'adaptation devant permettre de conserver les services actuellement fournis par la forĂȘt. L'Ă©picĂ©a, le sapin et le hĂȘtre, dominants dans les Alpes françaises, y sont privilĂ©giĂ©s

    ForĂȘts de montagne et changement climatique : impacts et adaptations

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    This review identifies the main impacts of climate change on mountain forests, mainly in Europe, and the management practices proposed for forest adaption. The rise in temperatures, more frequent droughts and the multiplication of extreme events should lead, especially below 1000m in altitude, to the disappearance of highly drought-intolerant tree species (spruce, Scots pine) and their replacement by deciduous trees. In addition, recruitment of some species (fir, beech) is observed at higher altitudes and the duration of the growing season is increasing. Management recommendations for forest adaptation to climate change focus on reducing tree species' vulnerability to water stress and pests, as well as increasing their resilience and ability to respond to extreme weather events. They require genetic improvements and practices that encourage the establishment of suitable species, reduce water consumption and reduce the exposure of stands to risk.Cette Ă©tude bibliographique recense les principaux impacts du changement climatique sur les forĂȘts de montagne, principalement europĂ©ennes, ainsi que les pratiques de gestion proposĂ©es pour adapter les forĂȘts Ă  ces changements. La hausse des tempĂ©ratures, les sĂ©cheresses plus frĂ©quentes et la multiplication des Ă©vĂšnements extrĂȘmes devraient entrainer, surtout en-deçà de 1000m d'altitude, une rĂ©duction des essences les moins tolĂ©rantes Ă  la sĂ©cheresse (Ă©picĂ©a, pin sylvestre) et leur remplacement par des feuillus. D'ores et dĂ©jĂ , le recrutement de certaines essences (sapin, hĂȘtre) est observĂ© Ă  des altitudes plus Ă©levĂ©es et la durĂ©e de la saison de vĂ©gĂ©tation augmente. Les prĂ©conisations de gestion pour l'adaptation des forĂȘts au changement climatique s'attachent Ă  rĂ©duire la vulnĂ©rabilitĂ© des essences au stress hydrique et aux parasites, ainsi qu'Ă  renforcer leur rĂ©silience et leur capacitĂ© de rĂ©ponse aux Ă©vĂšnements climatiques extrĂȘmes. Elles passent par des amĂ©liorations gĂ©nĂ©tiques et des pratiques qui favorisent l'installation d'espĂšces adaptĂ©es, rĂ©duisent la consommation d'eau et l'exposition des peuplements aux risques

    Cold hardening protects cereals from oxidative stress and necrotrophic fungal pathogenesis

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    The effects of cold hardening of cereals on their cross-tolerance to treatments leading to oxidative stress were investigated. Long-term exposure to low non-freezing temperatures provided partial protection to wheat and barley plants from the damage caused by paraquat and hydrogen peroxide treatments. It also conferred resistance in two barley cultivars to the necrotic symptoms and growth of the fungal phytopathogen Pyrenophora teres f. teres . Pathogen-induced oxidative burst was also reduced in cold hardened plants. The possible roles of host-derived redox factors and other signaling components in the observed forms of cereal cross-tolerance are discussed

    Effects of growth rate, size, and light availability on tree survival across life stages: a demographic analysis accounting for missing values and small sample sizes.

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    The data set supporting the results of this article is available in the Dryad repository, http://dx.doi.org/10.5061/dryad.6f4qs. Moustakas, A. and Evans, M. R. (2015) Effects of growth rate, size, and light availability on tree survival across life stages: a demographic analysis accounting for missing values.Plant survival is a key factor in forest dynamics and survival probabilities often vary across life stages. Studies specifically aimed at assessing tree survival are unusual and so data initially designed for other purposes often need to be used; such data are more likely to contain errors than data collected for this specific purpose

    Herbaceous perennial plants with short generation time have stronger responses to climate anomalies than those with longer generation time

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    There is an urgent need to synthesize the state of our knowledge on plant responses to climate. The availability of open-access data provide opportunities to examine quantitative generalizations regarding which biomes and species are most responsive to climate drivers. Here, we synthesize time series of structured population models from 162 populations of 62 plants, mostly herbaceous species from temperate biomes, to link plant population growth rates (λ) to precipitation and temperature drivers. We expect: (1) more pronounced demographic responses to precipitation than temperature, especially in arid biomes; and (2) a higher climate sensitivity in short-lived rather than long-lived species. We find that precipitation anomalies have a nearly three-fold larger effect on λ than temperature. Species with shorter generation time have much stronger absolute responses to climate anomalies. We conclude that key species-level traits can predict plant population responses to climate, and discuss the relevance of this generalization for conservation planning

    A synthesis of bacterial and archaeal phenotypic trait data

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    A synthesis of phenotypic and quantitative genomic traits is provided for bacteria and archaea, in the form of a scripted, reproducible workflow that standardizes and merges 26 sources. The resulting unified dataset covers 14 phenotypic traits, 5 quantitative genomic traits, and 4 environmental characteristics for approximately 170,000 strain-level and 15,000 species-aggregated records. It spans all habitats including soils, marine and fresh waters and sediments, host-associated and thermal. Trait data can find use in clarifying major dimensions of ecological strategy variation across species. They can also be used in conjunction with species and abundance sampling to characterize trait mixtures in communities and responses of traits along environmental gradients

    Predicting understory maximum shrubs cover using altitude and overstory basal area in different Mediterranean forests

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    In some areas of the Mediterranean basin where the understory stratum represents a critical fire hazard, managing the canopy cover to control the understory shrubby vegetation is an ecological alternative to the current mechanical management techniques. In this study, we determine the relationship between the overstory basal area and the cover of the understory shrubby vegetation for different dominant canopy species (Pinaceae and Fagaceae species) along a wide altitudinal gradient in the province of Catalonia (Spain). Analyses were conducted using data from the Spanish National Forest Inventory. At the regional scale, when all stands are analysed together, a strong negative relationship between mean shrub cover and site elevation was found. Among the Pinaceae species, we found fairly good relationships between stand basal area and the maximum development of the shrub stratum for species located at intermediate elevations (Pinus nigra, Pinus sylvestris). However, at the extremes of the elevationclimatic gradient (Pinus halepensis and Pinus uncinata stands), stand basal area explained very little of the shrub cover variation probably because microsite and topographic factors override its effect. Among the Fagaceae species, a negative relationship between basal area and the maximum development of the shrub stratum was found in Quercus humilis and Fagus sylvatica dominated stands but not in Quercus ilex. This can be due to the particular canopy structure and management history of Q. ilex stands. In conclusion, our study revealed a marked effect of the tree layer composition and the environment on the relationship between the development of the understory and overstory tree structure. More fine-grained studies are needed to provide forest managers with more detailed information about the relationship between these two forest strata

    Timing of Favorable Conditions, Competition and Fertility Interact to Govern Recruitment of Invasive Chinese Tallow Tree in Stressful Environments

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    The rate of new exotic recruitment following removal of adult invaders (reinvasion pressure) influences restoration outcomes and costs but is highly variable and poorly understood. We hypothesize that broad variation in average reinvasion pressure of Triadica sebifera (Chinese tallow tree, a major invader) arises from differences among habitats in spatiotemporal availability of realized recruitment windows. These windows are periods of variable duration long enough to permit establishment given local environmental conditions. We tested this hypothesis via a greenhouse mesocosm experiment that quantified how the duration of favorable moisture conditions prior to flood or drought stress (window duration), competition and nutrient availability influenced Triadica success in high stress environments. Window duration influenced pre-stress seedling abundance and size, growth during stress and final abundance; it interacted with other factors to affect final biomass and germination during stress. Stress type and competition impacted final size and biomass, plus germination, mortality and changes in size during stress. Final abundance also depended on competition and the interaction of window duration, stress type and competition. Fertilization interacted with competition and stress to influence biomass and changes in height, respectively, but did not affect Triadica abundance. Overall, longer window durations promoted Triadica establishment, competition and drought (relative to flood) suppressed establishment, and fertilization had weak effects. Interactions among factors frequently produced different effects in specific contexts. Results support our ‘outgrow the stress’ hypothesis and show that temporal availability of abiotic windows and factors that influence growth rates govern Triadica recruitment in stressful environments. These findings suggest that native seed addition can effectively suppress superior competitors in stressful environments. We also describe environmental scenarios where specific management methods may be more or less effective. Our results enable better niche-based estimates of local reinvasion pressure, which can improve restoration efficacy and efficiency by informing site selection and optimal Management
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