Density-dependent predatory impacts of an invasive beetle across a subantarctic archipelago

Abstract Biological invasions represent a major threat to biodiversity, especially in cold insular environments characterized by high levels of endemism and low species diversity which are heavily impacted by global warming. Terrestrial invertebrates are very responsive to environmental changes, and native terrestrial invertebrates from cold islands tend to be naive to novel predators. Therefore, understanding the relationships between predators and prey in the context of global changes is essential for the management of these areas, particularly in the case of non-native predators. Merizodus soledadinus (Guérin-Méneville, 1830) is an invasive non-native insect species present on two subantarctic archipelagos, where it has extensive distribution and increasing impacts. While the biology of M. soledadinus has recently received attention, its trophic interactions have been less examined. We investigated how characteristics of M. soledadinus, its density, as well as prey density influence its predation rate on the Kerguelen Islands where the temporal evolution of its geographic distribution is precisely known. Our results show that M. soledadinus can have high ecological impacts on insect communities when present in high densities regardless of its residence time, consistent with the observed decline of the native fauna of the Kerguelen Islands in other studies. Special attention should be paid to limiting factors enhancing its dispersal and improving biosecurity for invasive insect species

How grassland introduction into annual crop rotation (maize/wheat/barley) affects earthworm communities and forage production?

International audienc

Effects of temporary grassland introduction into annual crop rotations and nitrogen fertilisation on earthworm communities and forage production

International audienceEarthworms contribute to a wide range of ecosystem services in agriculture. Most studies focusing on impacts of annual crop management on earthworm communities are related to soil tillage, fertilisation or pesticides, while the effect of introducing temporary grassland into an annual crop rotation remains largely unknown. In this context, the aims of the present study were to evaluate effects of (i) introducing grassland into a crop rotation, (ii) grassland duration and (iii) grassland fertilisation on earthworm communities and grassland forage production in a long-term experimental station in western France. Three years of highly fertilised (230 kg ha(-1) yr(-1) of mineral nitrogen) grassland preceded by three years of annual crop rotation was compared to an annual crop rotation without grassland and to six years of grassland either lightly (30 kg ha(-1) yr(-1) of mineral nitrogen) or highly (230 kg ha(-1) yr(-1) of mineral nitrogen) fertilised. Grassland introduction into a crop rotation significantly increased earthworm abundance, biomass, and diversity, especially for anecic species, and improved the functional structure of the earthworm community. Grassland duration and fertilisation increased earthworm abundance and biomass, especially for anecics, without affecting endogeic species and earthworm diversity. Grassland duration did not increase forage production, but the increase in fertilisation did. Three years of highly fertilised grassland significantly increased earthworm abundance and biomass, improved the functional structure of the earthworm community and produced as much forage per year as six years of highly fertilised grassland. Overall, the introduction of grassland into annual crop rotations appears an effective way to rapidly increase earthworm community parameters and, given the important role of earthworms in soils, enhance soil functioning

Can quarantine plant-parasitic nematodes within wastes be managed by useful tools in a circular economy approach?

International audienceSeen as an integral part of sustainable development, circular economy represents a model of production and consumption notably based on the limitation of both resource wastage and environmental impact. Laboratories and commercial companies working on plant pathogens, in particular quarantine species, must effectively disinfect their waste to avoid disseminating these organisms. The methods used for waste disinfection can however incur high energy costs or pose environmental and human health hazards. Here, we tested the effectiveness of five disinfection methods - chlorination, heat treatment, composting, mesophilic methanation and waste stabilization ponds - on plant-parasitic nematodes belonging to the genera Globodera and Meloidogyne. For the widely used chlorination and heat treatment methods, we showed that they can be very effective in inactivating nematodes at relatively low chlorine doses and temperatures (60 °C-3 min and 50 °C-30 min), respectively. For the three other disinfection methods tested, initially designed for waste recycling, we obtained different levels of efficiency. Composting and mesophilic methanation (based on cattle or pig slurry) both led to the complete elimination of nematodes, even for short treatment durations. However, waste stabilization ponds showed contrasting results, ranging from virtually no effect to high levels of inactivation of nematodes. Our study demonstrates that it is possible to use more environmentally friendly disinfection methods to control plant-parasitic nematodes. In particular, this finding paves the way towards the treatment of infected plant materials using composting or methanation, providing that disinfection is still reached under other (real-life) treatment conditions, especially with other kinds of waste. Both composting and methanation recycle and thus valorize infected waste; they are viable alternatives to landfilling or incineration, thereby demonstrating the usefulness of a circular economy approach

When citizens and scientists work together: a French collaborative science network on earthworms communities distribution

International audienc

When citizens and scientists work together: A French collaborative science network on earthworms communities (the OPVT)

International audienc

When citizens and scientists work together: a French collaborative science network on earthworms communities distribution

International audienc

When citizens and scientists work together: a French collaborative science network on earthworms communities distribution

International audienc

French national long-term monitoring program to assess earthworms’ response to the agricultural practices in farmlands

International audienc