Wildflower areas within revitalized agricultural matrices boost small mammal populations but not breeding Barn Owls

Agro-ecosystems have recently experienced dramatic losses of biodiversity due to more intensive production methods. In order to increase species diversity, agri-environment schemes provide subsidies to farmers who devote a fraction of their land to ecological compensation areas (ECAs). Several studies have shown that invertebrate biodiversity is actually higher in ECAs than in nearby intensively cultivated farmland. It remains poorly understood, however, to what extent ECAs also favour vertebrates, such as small mammals and their predators, which would contribute to restoring functional food chains within revitalised agricultural matrices. We studied small mammal populations among eight habitat types—including wildflower areas, a specific ECA in Switzerland—and habitat selection (radiotracking) by the Barn Owl Tyto alba, one of their principal predators. Our prediction was that habitats with higher abundances of small mammals would be more visited by foraging Barn Owls during the period of chicks' provisioning. Small mammal abundance tended to be higher in wildflower areas than in any other habitat type. Barn Owls, however, preferred to forage in cereal fields and grassland. They avoided all types of crops other than cereals, as well as wildflower areas, which suggests that they do not select their hunting habitat primarily with respect to prey density. Instead of prey abundance, prey accessibility may play a more crucial role: wildflower areas have a dense vegetation cover, which may impede access to prey for foraging owls. The exploitation of wildflower areas by the owls might be enhanced by creating open foraging corridors within or around wildflower areas. Wildflower areas managed in that way might contribute to restore functional links in food webs within agro-ecosystem

Unravelling migration connectivity reveals unsustainable hunting of the declining ortolan bunting

In France, illegal hunting of the endangered ortolan bunting Emberiza hortulana has been defended for the sake of tradition and gastronomy. Hunters argued that ortolan buntings trapped in southwest France originate from large and stable populations across the whole of Europe. Yet, the European Commission referred France to the Court of Justice of the European Union (EU) in December 2016 for infringements to legislation (IP/16/4213). To better assess the impact of hunting in France, we combined Pan-European data from archival light loggers, stable isotopes, and genetics to determine the migration strategy of the species across continents. Ortolan buntings migrating through France come from northern and western populations, which are small, fragmented and declining. Population viability modeling further revealed that harvesting in southwest France is far from sustainable and increases extinction risk. These results provide the sufficient scientific evidence for justifying the ban on ortolan harvesting in France.Peer reviewe

Modeling Habitat Suitability for Complex Species Distributions by Environmental-Distance Geometric Mean

This paper presents a new habitat suitability modeling method whose main properties are as follows: (1) It is based on the density of observation points in the environmental space, which enables it to fit complex distributions (e.g. nongaussian, bimodal, asymmetrical, etc.). (2) This density is modeled by computing the geometric mean to all observation points, which we show to be a good trade-off between goodness of fit and prediction power. (3) It does not need any absence information, which is generally difficult to collect and of dubious reliability. (4) The environmental space is represented either by an expert-selection of standardized variables or the axes of a factor analysis [in this paper we used the Ecological Niche Factor Analysis (ENFA)].We first explain the details of the geometric mean algorithm and then we apply it to the bearded vulture (Gypaetus barbatus) habitat in the Swiss Alps. The results are compared to those obtained by the "median algorithm” and tested by jack-knife cross-validation. We also discuss other related algorithms (BIOCLIM, HABITAT, and DOMAIN). All these analyses were implemented into and performed with the ecology-oriented GIS software BIOMAPPER 2.0.The results show the geometric mean to perform better than the median algorithm, as it produces a tighter fit to the bimodal distribution of the bearded vulture in the environmental space. However, the "median algorithm” being quicker, it could be preferred when modeling more usual distributio

Effets d'une prise de glucocorticoïdes sur la performance (répercussions hormonales et métaboliques)

Si la prise de glucocorticoïdes par les sportifs, bien qu interdite par administration systémique, semble relativement fréquente, il n existe à l heure actuelle quasiment aucun travail scientifique étudiant les éventuels effets ergogéniques liés à la prise de ces substances. C est pourquoi nous nous sommes intéressés tout d abord aux effets d une prise aiguë de glucocorticoïdes sur la performance lors d un exercice sous-maximal intense. Aucune amélioration de performance n a été observée. Par la suite, nous avons étudié les effets d une prise aiguë de glucocorticoïdes sur l utilisation des substrats énergétiques au cours d un exercice sous-maximal, ce travail ayant mis en évidence une augmentation de l oxydation des lipides sous corticoïdes. Enfin, notre troisième étude a montré qu une prise de courte durée de glucocorticoïdes (7 jours) améliore significativement la performance lors d un exercice sous-maximal en modifiant parallèlement un grand nombre de paramètres métaboliques et hormonaux. A la vue de ces résultats, il apparaît clairement qu une prise thérapeutique de courte durée de glucocorticoïdes peut être utilisée à visée dopante par les sportifs. Néanmoins, d autres investigations sont nécessaires, le(s) mécanisme(s) impliqués dans cette amélioration de performance restant à être élucidés.ORLEANS-BU Sciences (452342104) / SudocSudocFranceF

Effets du tennis sur les tissus musculaires et osseux : cas particulier du membre supérieur

Ducher Gaële, Jaffré Christelle, Arlettaz Alexandre, Courteix Daniel. Effets du tennis sur les tissus musculaires et osseux : cas particulier du membre supérieur. In: Les Cahiers de l'INSEP, n°35, 2005. Les sports de raquette. Données scientifiques et méthodologiques. Applications pour l'entraînement. pp. 227-228

Effects of long-term tennis playing on the muscle-bone relationship in the dominant and non-dominant forearms

The relationship between muscle strength and bone mineral density illustrates the positive effect of mechanical loading on bone. But local and systemic factors may affect both muscle and bone tissues. This study investigated the effects of long-term tennis playing on the relationship between lean tissue mass and bone mineral content in the forearms, taking the body dimensions into account. Fifty-two tennis players (age 24.2 +/- 5.8 yrs, 16.2 +/- 6.1 yrs of practice) were recruited. Lean tissue mass (LTM), bone area, bone mineral content (BMC), and bone mineral density were measured at the forearms from a DXA whole-body scan. Grip strength was assessed with a dynamometer. A marked side-to-side difference (p &lt; 0.0001) was found in favor of the dominant forearm in all parameters. Bone area and BMC correlated with grip strength on both sides (r = 0.81 - 0.84, p &lt; 0.0001). The correlations were still significant after adjusting for whole-body BMC body height, or forearm length. This result reinforced the putative role of the muscles in the mechanical loading on bones. In addition, forearm BMC adjusted to LTM or grip strength was higher on the dominant side, suggesting that tennis playing exerts a direct effect on bone.<br /