L'utilisation par la viticulture française d'un exercice de prospective pour l'élaboration d'une stratégie d'adaptation au changement climatique

Foresight studies are regularly conducted at sectoral or geographical scales, in order to help policy makers and economic actors to define their strategy of adaptation to climate change (CC)

Species trait shifts in vegetation and soil seed bank during fen degradation

Fens in Central Europe are characterised by waterlogged organic substrate and low productivity. Human-induced changes due to drainage and mowing lead to changes in plant species composition from natural fen communities to fen meadows and later to over-drained, degraded meadows. Moderate drainage leads to increased vegetation productivity, and severe drainage results in frequent soil disturbances and less plant growth. In the present article, we analyse changes in plant trait combinations in the vegetation and the soil seed bank as well as changes in the seed bank types along gradient of drainage intensity. We hypothesize that an increase in productivity enhances traits related to persistence and that frequent disturbance selects for regeneration traits. We use multivariate statistics to analyse data from three disturbance levels: undisturbed fen, slightly drained fen meadow and severely drained degraded meadow. We found that the abundance of plants regenerating from seeds and accumulating persistent seed banks was increasing with degradation level, while plants reproducing vegetatively were gradually eliminated along the same trajectory. Plants with strong resprouting abilities increased during degradation. We also found that shifts in trait combinations were similar in the aboveground vegetation and in soil seed banks. We found that the density of short-term persistent seeds in the soil is highest in fen meadows and the density of long-term persistent seeds is highest in degraded meadows. The increase in abundance of species with strong regeneration traits at the cost of species with persistence-related traits has negative consequences for the restoration prospects of severely degraded sites

Gait instability measured by dual task gait test and leukoaraiosis.

International audienceObjective.– Gait unsteadiness is considered as the first step of major health concerns such as fall and dementia. Gait dysfunction has to be measured under dual task gait test (DTGT). The aim of this study was to investigate the relationships between DTGT and brain magnetic resonance imaging (MRI).Material and methods.– Data were collected through a Gait Instability Network including DTGT. Twenty-five patients aged less than 76 years old were tested (age: 71 ± 5 years, F: 8, M: 17, MMSE: 28 ± 2).Methods.– The assessment includes five successive steps: auto questionnaires, nurse evaluation, clinical balance tests, cognitive tests, medical examination, and DTGT. Gait analysis was provided by a three-axis accelerometer (Locometrix), three variables were selected: walking speed (WS), stride frequency (SF) and stride regularity index (SR). The Dual Task (DT) consists in walking and backward counting one by one from fifty. MRI including cortex trophycity, hippocampal Scheltens score, and age-related white matter changes (ARWMC) was performed under blind condition.Results.– Under DT condition, each gait variable decreases significantly. WS: from1.13 ± 0.24 to 0.98 ± 0.23 m/s (P = 0.02), SF: from 0.91 ± 0.09 to 0.79 ± 0.13 Hz (P < 0.001), SR: from 211 ± 51 to 160 ± 60 dimensionless (P < 0.002). Out of 25 patients, three had a vestibular disorder, one had post-stroke effects. No clinical explanation can be found for 21 patients other than hippocampal atrophy (Scheltens score 1.4 ± 0.6), and/or leukoaraiosis (ARWMC score: 4.3 ± 4.3).Discussion.– These results illustrate the interest of measuring not only walking speed and stride regularity, but also stride frequency under DTGT, and raise the question of the role of leukoaraiosis in gait instabilit

The relationships between soil seed bank, aboveground vegetation and disturbances in an eutropic alluvial wetland of Western France

International audienc

Conditions météorologiques défavorables qui ont un impact sur 21 pratiques viticoles en moyenne vallée de la Loire au moment de leur réalisation

<p>L'image montre en générale l'impact des conditions climatiques défavorables sur le développement et la croissance d'une culture dans ce cas c'est le vignoble. Ces conditions se résument par le vent, le sol, l'humidité, la température et la pluviométrie.</p