No mycorrhizae on Schoenoplectus maritimus in the Camargue

It has been thought for a long time that wetland plants were devoid of mycorrhizae. In recent years, however, an increasing number of studies have reported the presence of vesicular-arbuscular mycorrhizae (or endomycorrhizae) on several marsh plants. These fungi are often beneficial for their hosts enhancing growth through better mineral and water nutrition as well as photosynthetic activity. Giving the importance of endomycorrhizae on resource allocation, we sought to determine whether these structures were present on S. maritimus growing in southern France. We sampled roots of 25 tubers collected at 5 sampling stations in 2 marshes for a total of 250 roots. Roots were stained and observed under a light microscope (400 X). No fungal structures (hyphae, vesicles, arbuscles, or spores) were observed on S. maritimus roots

Dynamique, apres perturbations, de peuplements de deux Ericacees (Arbutus unedo L. et Erica arborea L.), en Corse

CNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

The Cassaïre wetland restoration project: defining the reference ecosystem

International audienceDefining a reference ecosystem for ecological restoration project is an essential step. The reference can correspond to the historical ecosystem, can be defined to solve environmental issues or can correspond to a socioecosystem. For the restoration of the Cassaïre site in the Camargue delta in southern France, the reference ecosystems chosen are: Mediterranean temporary wetlands and Mediterranean meso-xeric grasslands. The choice of these two reference ecosystems appears logical considering their contribution to regional biodiversity. Temporary wetlands and meso-xeric grasslands are rare, adapted to the Mediterranean climate, seriously endangered and host a high species richness. They are potentially achievable restoration targets because patches of these ecosystems remain in the Camargue area and close to the Cassaïre site. Moreover, an ecological history approach reveals deep human imprints on ecosystems and ensures that historical restoration targets (the state prior to human impacts) cannot be reached, because they are associated with hydraulic functioning (flooding of the Rhône and Durance) that no longer exists. The restored site is planned to be suitable for livestock grazing, thus presenting a new agricultural opportunity, while simultaneously offering new services, such as hunting

Extensive horse grazing improves grassland vegetation diversity, seed bank and forage quality of artificial embankments (Rhône River - southern France)

International audienceGrazing by herds of herbivores modifies plant communities in different ways, depending on the herbivore species. Horse grazing is already known to be effective in increasing plant diversity and maintaining herbaceous vegetation, creating different types of patches and thus ensuring spatial heterogeneity. On an artificial embankment at the Donzère-Mondragon hydroelectric facility in the Rhône Valley, extensive grazing by a rustic horse (Konik-Polski) was introduced several years ago to control shrub encroachment and to enhance plant grassland diversity. Vegetation monitoring surveys over a five-year period (2014-2018) showed that horse grazing maintained patches of open and short grasslands and increased species-richness, in particular of annual species, some of which have heritage value. In contrast, overly-low grazing pressure led to the dominance of an unpalatable perennial grass (Brachypodium phoenicoides) at the expense of the annual species that significantly enhance the forage value of the most heavily grazed patches. Horse grazing also had a positive impact on the permanent seed bank of the soil, increasing its heterogeneity and the density of viable seeds. Extensive horse grazing thus appears to be a relevant management tool to preserve the diversity and the forage quality of the most open and short grasslands. Nevertheless, grazing pressure here remained too low to allow restoration of grasslands already colonised by woody species. Combining different livestock species might be a better alternative to pure horse grazing, to increase heterogeneity and diversity. Our results are discussed in relation to extensive horse grazing on artificial ecosystems, such as the embankments bordering rivers and canals

The Cassaïre wetland restoration project: defining the reference ecosystem

International audienceDefining a reference ecosystem for ecological restoration project is an essential step. The reference can correspond to the historical ecosystem, can be defined to solve environmental issues or can correspond to a socioecosystem. For the restoration of the Cassaïre site in the Camargue delta in southern France, the reference ecosystems chosen are: Mediterranean temporary wetlands and Mediterranean meso-xeric grasslands. The choice of these two reference ecosystems appears logical considering their contribution to regional biodiversity. Temporary wetlands and meso-xeric grasslands are rare, adapted to the Mediterranean climate, seriously endangered and host a high species richness. They are potentially achievable restoration targets because patches of these ecosystems remain in the Camargue area and close to the Cassaïre site. Moreover, an ecological history approach reveals deep human imprints on ecosystems and ensures that historical restoration targets (the state prior to human impacts) cannot be reached, because they are associated with hydraulic functioning (flooding of the Rhône and Durance) that no longer exists. The restored site is planned to be suitable for livestock grazing, thus presenting a new agricultural opportunity, while simultaneously offering new services, such as hunting

Impacts de l'éco-pastoralisme sur les communautés végétales

National audienc

Restaurer la nature, un travail de fourmis ?

National audienceLe 07 août 2009, la fuite accidentelle d’un oléoduc provoquait une marée noire terrestre sur plus de 5 hectares dans la plaine de la Crau, au cœur d’une réserve naturelle située dans le sud-est de la France. Devant l’ampleur de la pollution générée par les 4 700 m3 de pétrole brut épandu, 72 000 tonnes de sols pollués sont retirées l’année suivante sur une profondeur moyenne de 50 cm pour être ensuite stockées dans une décharge spécialisée. Depuis, plusieurs méthodes ont été testées pour restaurer les écosystèmes dans la zone. L’une d’entre elles est fondée sur l’introduction de fourmis moissonneuses dans les sols contaminés

Impacts de l'éco-pastoralisme sur les communautés végétales

National audienc

L’écopastoralisme comme outil de gestion des digues artificielles : le cas de la réserve de chasse et de faune sauvage de Donzère-Mondragon

International audienc