Search results for "Global changes"

Water-use efficiency and transpiration across European forests during the Anthropocene

2015

Considering the combined effects of CO2 fertilization and climate change drivers on plant physiology leads to a modest increase in simulated European forest transpiration in spite of the effects of CO2-induced stomatal closure. The Earth’s carbon and hydrologic cycles are intimately coupled by gas exchange through plant stomata1,2,3. However, uncertainties in the magnitude4,5,6 and consequences7,8 of the physiological responses9,10 of plants to elevated CO2 in natural environments hinders modelling of terrestrial water cycling and carbon storage11. Here we use annually resolved long-term δ13C tree-ring measurements across a European forest network to reconstruct the physiologically driven r…

Urban Heat Island and air quality, Dijon, winter 2014-2015.

2016

For the 2014-2015 Winter, thetemperature patterns and the Air Quality measured over the Grand Dijon urban area are studied together.Meteorological conditions favoring the development of an Urban Heat Island (UHI) are distinguished fromthose giving rise to pollution episodes. Winter UHI are next characterized, with radiative situations followedafter the sunset by relatively strong UHI (about 3°C), and days with no insolation during which anthropogenicheat is suspected to produce a small UHI (few tenths of °C).

Discriminating impacts of geomorphological and human factors on vineyard soil erosion (Burgundy, France)

2014

International audience; The Burgundy vineyards have been recognized for the high diversity of Terroirs, controlled by complex interactions between natural features, historical parameters and soil management practices. Vineyards are known to undergo substantial soil loss in comparison with other types of agricultural land. Hydric erosion on vineyards is controlled by complex interactions of natural and anthropogenic factors leading to intra-plot spatial heterogeneities of topsoil at a scale of a metre. Studying the relationship between soils and their degradation is crucial in this situation where soil sustainability is threatened. This study explores the relative influences of historical an…

Les relations entre qualité des cours d'eau et occupation du sol dans le Morvan : production et transfert de matières organiques en solution

2009

10 pages; National audience

The role of maternal effects in host-parasite interactions: examination of the development of the immune defense in a colonial seabird, the black-leg…

2004

One of the main aims of evolutionary biology is to understand the mechanisms responsible for the phenotypic variation on which natural selection can act. Maternal effects occur when a mother's phenotype or her environment influence her offspring's phenotype. Despite the importance of such effects for the ecology of host-parasite interactions, their role has been relatively neglected to date. In this thesis, we examined how mothers influence the immune defense of their young in an environment that varies in space and time. This work has primarily focused on a colonial seabird, the black-legged kittiwake (Rissa tridactyla). Using this model, we have first shown that specific maternal antibodi…

Inversions de température dans le Jura

2018

L'étude des inversions, événements climatiques qui provoquent de nombreux pics de pollution nocifs, est primordiale. Quatorze sites composés de deux stations proches et quatre autres mettant en relation une station de plaine avec une station de montagne permettent d'analyser la fréquence, l'intensité et la durée des inversions locales et régionales. La fréquence moyenne des inversions est élevée lors des tn (50 %) avec des maximums supérieurs à 70% en certains sites et en décembre. L'intensité des inversions tant locales que régionales est faible (respectivement 2°C et 1°C en moyenne). La durée des inversions est faible : 60 % d'entre elles concernent juste la fin de nuit. Parmi les inversi…

Sedimentation and tropical vegetation changes in Southern Benin (West Africa), carbon-13 tracing of organic matter dynamics and fluctuations of the s…

2007

12 pages; International audience

The energetic cost of humoral immunity in the Collared Dove, Streptopelia decaocto : is the magnitude sufficient to force energy-based trade-offs?

2005

International audience; 1. Energy saving is often suggested as the basis of a resource trade-off between immunocompetence and other fitness-relevant traits. This suggests that the energetic cost of an immune response is significant and sufficient to force trade-offs. To date, few studies have investigated the energetic cost of the humoral component of the immune system in birds and furthermore, existing results are contradictory. 2. We addressed this question through two experiments. In experiment 1, the basal metabolic rate (BMR) of Collared Doves, Streptopelia decaocto , challenged with sheep red blood cells (SRBC) was compared with the BMR of control birds. The energetic cost of immunity…

Can differences in microbial abundances help explain enhanced N2O emissions in a permanent grassland under elevated atmospheric CO2?

2011

Du ciel noir à l'environnement nocturne : la construction d'un nouveau front de protection de la nature

2020

International audience; Depuis les années 1970 plusieurs domaines d’expertise scientifique ont contribué à faire émerger une nouvelle dimension de la protection de l’environnement liés aux effets dégradants de la pollution lumineuse. Cette dernière constitue en soi un objet de controverse entre sciences, notamment sur les différentes façons de la saisir et la définir en tant qu’objet et que fait. Nous retiendrons ici pour qualifier cette forme de pollution le caractère d’un excès de lumière artificielle entrainant des impacts sur les écosystèmes et sur la santé humaine.L’histoire du mouvement de lutte contre l’expansion de l’éclairage artificiel commence à être relativement connue, dans le …