Virome release of an invasive exotic plant species in southern France.

The increase in human-mediated introduction of plant species to new regions has resulted in a rise of invasive exotic plant species (IEPS) that has had significant effects on biodiversity and ecosystem processes. One commonly accepted mechanism of invasions is that proposed by the enemy release hypothesis (ERH), which states that IEPS free from their native herbivores and natural enemies in new environments can outcompete indigenous species and become invasive. We here propose the virome release hypothesis (VRH) as a virus-centered variant of the conventional ERH that is only focused on enemies.

Geometagenomics illuminates the impact of agriculture on the distribution and prevalence of plant viruses at the ecosystem scale.

Disease emergence events regularly result from human activities such as agriculture, which frequently brings large populations of genetically uniform hosts into contact with potential pathogens. Although viruses cause nearly 50% of emerging plant diseases, there is little systematic information about virus distribution across agro-ecological interfaces and large gaps in understanding of virus diversity in nature. Here we applied a novel landscape-scale geometagenomics approach to examine relationships between agricultural land use and distributions of plant-associated viruses in two Mediterranean-climate biodiversity hotspots (Western Cape region of South Africa and Rhône river delta region of France).

High Stocking Density Controls Phillyrea Angustifolia in Mediterranean Grasslands.

Extensive grazing applied in the form of low instantaneous pressure over a long period is a widespread management practice in protected areas. However this kind of stocking method does not always achieve the expected results, in particular because it fails to limit colonization by woody plants.This is the case in the relict xero-halophytic grasslands of the northern Mediterranean coastal region, subjected to widespread colonization by the shrub Phillyrea angustifolia despite the presence of extensive grazing.

Using Different Grazing Practices for Increasing Plant Biodiversity in the Dykes and Embankments Along the Rhône River (Southern France).

Extensive grazing by domestic herbivores is a widespread management practice used since the 80s in many European agro-ecosystems such as semi-natural grasslands to maintain open habitats and to enhance biodiversity. Such grazing systems have principally been tested in cultural ecosystems of high nature value threatened by grazing abandonment. However, there have been few case studies of grazing management in very anthropized ecosystems, such as the new ecosystems created by urban or industrial conversions.

Impact of the insecticide Alphacypermetrine and herbicide Oxadiazon, used singly or in combination, on the most abundant frog in French rice fields, Pelophylax perezi.

The potential impact of agricultural pesticides is a major concern with regard to biodiversity conservation. Pesticides are considered as one of the main causes of the worldwide decline of Amphibians. They are rarely used singly, but their cumulative impact and interaction are often neglected, as is the importance of the age or stage of the animal on which the impact of the molecules is assessed.

Alfalfa Leaf Curl Virus: an Aphid-Transmitted Geminivirus.

The family Geminiviridae comprises seven genera differentiated by genome organization, sequence similarity, and insect vector. Capulavirus, an eighth genus, has been proposed to accommodate two newly discovered highly divergent geminiviruses that presently have no known vector. Alfalfa leaf curl virus, identified here as a third capulavirus, is shown to be transmitted by Aphis craccivora.

Competition Is a Strong Driving Factor in Wetlands, Peaking during Drying Out Periods.

The aim of the study is to investigate the relative importance of plant-plant interactions with regard to flooding and drought effect on perennial plant performances in wetlands. Flooding is expected to be the major driver and, accordingly, the importance of drought is hardly if ever taken into account. Focusing on five widespread species, the growth, the survival and the competitive ability of plants were monitored on permanent plots spread along two elevation gradients.

Using Shrub Clearing, Draining, and Herbivory to Control Bramble Invasion in Mediterranean Dry Grasslands.

For centuries, the dry grassland of the plain of La Crau (south-eastern France) has been subjected to numerous disturbances resulting in the destruction and the fragmentation of this emblematic rangeland ecosystem of the Mediterranean. Today, this ecosystem is facing a new threat from a proliferating native species, the bramble (Rubus ulmifolius Schott), which preferentially colonizes areas that were formerly cultivated and/or exposed to water infiltration. To identify a strategy for effective control of this colonization, in situ experiments testing disturbance regimes (shrub clearing and/or mixed grazing by sheep and goats) combined with the control of access to water resources (with or without drainage trenches) were undertaken between 2010 and 2013.

Identification of novel Bromus- and Trifolium-associated circular DNA viruses.

The genomes of a large number of highly diverse novel circular DNA viruses from a wide range of sources have been characterised in recent years, including circular single-stranded DNA (ssDNA) viruses that share similarities with plant-infecting ssDNA viruses of the family Geminiviridae. Here, we describe six novel circular DNA viral genomes that encode replication-associated (Rep) proteins that are most closely related to those of either geminiviruses or gemycircularviruses (a new group of ssDNA viruses that are closely related to geminiviruses). Four possible viral genomes were recovered from Bromus hordeaceus sampled in New Zealand, and two were recovered from B.

Annual use of man-made wetlands by the mute swan (Cygnus olor).

This is essential to understand habitat selection by wildlife to manage habitats and populations. Studying the annual use of aquatic habitats provides information on how to manage wetlands for waterfowl, and to predict possible detrimental effects associated with extended usage by these birds. This is particularly important for species like the mute swan (Cygnus olor Gmelin), given its recent dramatic demographic expansion, causing concern in both Europe and America.

Impact of grazing on the species richness of plant communities in Mediterranean temporary pools (western Morocco).

The impact of grazing on the vegetation of Moroccan temporary pools has been studied at 2 scales: regional (inter-pools) and local (intra-pools). Half of the 16 forest pools studied is located in a reserve and ungrazed. The other half, located within public forest, is grazed.

Size-related consumption of Scirpus maritimus tubers by greylag geese Anser anser explained by their functional response.

To explain the preference of wintering greylag geese Anser anser for small Scirpus maritimus tubers (<10mm) over larger ones, our hypothesis was that the former would provide higher intake rates. This 'consumption rate hypothesis' was tested experimentally by deriving the functional responses of geese feeding on tubers of three contrasting sizes. Goose consumption rates were measured as: (i) feeding rate (tubers/min) and (ii) instantaneous intake rate (g fresh weight/min) on various tuber densities (5-200 tubers/tray).

Uselessness and indirect negative effects of an insecticide on rice field invertebrates.

Macro-invertebrate assemblages on organic and conventional rice fields were quantitatively compared in the Camargue (Rhone delta, France). There was no major difference in family richness, but significant differences as regard to abundance. Fipronil, the insecticide used to control chironomid larvae, was one of the main factors explaining those differences.

Competition between an introduced and an indigenous species: the case of Paspalum paspalodes (Michx) Schribner and Aeluropus littoralis (Gouan) in the Camargue (southern France).

Paspalum paspalodes, an introduced grass species, and Aeluropus littoralis, an indigenous species, develop abundantly in seasonally-flooded marshes in the Camargue (Rhône Delta, France). Although they occur together in many multispecies communities, neither species occurs when the other is dominat. The cultivation of cuttings of P.