Grasslands cover similar to 30% of the Earth's terrestrial surface and provide many ecosystem services. Many grasslands are heavily managed to maximize these services for human benefit, but the outcome of management is anticipated to be increasingly influenced by various aspects of climate change and elevated atmospheric CO2. The relative importance of global change vs. land management on grasslands is largely unknown. 2. A meta-analysis is used here to examine drivers at both scales primarily targeting services provided by grasslands relating to plant productivity (above- and below-ground biomass) and soil processes (nutrients and soil respiration) in 38 manipulative experiments published in the last decade. We specifically target effects of (i) single and combined land management practices (LMs), (ii) single and combined factors relating to broad-scale climate change and elevated CO2, and (iii) combined management practices and changes to climate and CO2. Collectively, this examines the general efficacy of global change models in predicting changes to grassland functioning. 3. We found that combinations of management practices had approximately double the explanatory power for variation in grassland services compared with individual or interactive effects of factors associated with climate change and CO2. These interacting management practices such as nutrient additions and defoliation predominantly influenced functions associated with productivity or biomass both below and above ground. The effects of interacting factors of climate and CO2 influenced a wider range of ecosystem functions, but the magnitude of these effects was relatively smaller. 4. Interactions between management practices or between climate change/CO2 factors always had higher explanatory power than any factor in isolation indicating that multivariate synergistic models of environmental change can better describe impacts on ecosystem function in plant communities (e.g. relative to univariate climate-based models). Given that the magnitude and direction (positive or negative) of the interactions varied widely, this also implies that the outcomes of these multivariate interactions can vary spatially, temporally or by immediate context (e.g. management prescriptions). 5. Synthesis. Although our work confirms how climate change and CO2 can affect many ecosystem-based functional attributes, it suggests that combinations of LMs remain the dominant set of factors in determining the performance of grassland plant communities. Land management may thus be critical for influencing projected responses to future climate change and elevated CO2 in models of grassland function at least for factors relating to primary production.
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vignette|redresse=1.35|Températures moyennes de l'air en surface de 2011 à 2020 par rapport à une moyenne de référence de 1951 à 1980. vignette|redresse=1.35|Température observée par la NASA par rapport à la moyenne de 1850-1900 comme référence préindustrielle. Le principal facteur d'augmentation des températures mondiales à l'ère industrielle est l'activité humaine, les forces naturelles ajoutant de la variabilité. vignette|redresse=1.35|L'énergie circule entre l'espace, l'atmosphère et la surface de la Terre.
Les écosystèmes procurent de nombreux services dits services écologiques ou services écosystémiques. Certains étant vitaux pour de nombreuses espèces ou groupes d'espèces (comme la pollinisation), ils sont généralement classés comme bien commun et/ou bien public. Les notions d'évaluation (économique et parfois marchande) de la biodiversité et des services fournis par les écosystèmes, basées sur une vision anthropocentrée de la nature, ont émergé dans les années 1970-1990 avec notamment les travaux de Westman (1977), puis de Randall (1988), Pearce & Moran en 1994 et de Perrings (1995).
vignette| Dérision du déni du réchauffement climatique. Le « déni du réchauffement climatique » est une attitude de dénégation face au consensus scientifique sur le réchauffement climatique. Certaines personnes admettent qu'il y a un réel changement, allant dans le sens d'un réchauffement global, mais nient que ce changement a une origine ou une part anthropique ; ils l'attribuent exclusivement aux variations naturelles du climat.
Learn about how the quality of water is a direct result of complex bio-geo-chemical interactions, and about how to use these processes to mitigate water quality issues.
Organisé en deux parties, ce cours présente les bases théoriques et pratiques des systèmes d’information géographique, ne nécessitant pas de connaissances préalables en informatique. En suivant cette
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Global change exposes ecosystems to changes in the frequency, magnitude, and concomitancy of disturbances, which impact the composition and functioning of these systems. Here, we experimentally evaluate the effects of salinity disturbances and eutrophicati ...
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