An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 2: impacts on organisms and ecosystems

New information on the lethal and sublethal effects of neonicotinoids and fipronil on organisms is presented in this review, complementing the previous WIA in 2015. The high toxicity of these systemic insecticides to invertebrates has been confirmed and expanded to include more species and compounds. Most of the recent research has focused on bees and the sublethal and ecological impacts these insecticides have on pollinators. Toxic effects on other invertebrate taxa also covered predatory and parasitoid natural enemies and aquatic arthropods. Little, while not much new information has been gathered on soil organisms. The impact on marine coastal ecosystems is still largely uncharted. The chronic lethality of neonicotinoids to insects and crustaceans, and the strengthened evidence that these chemicals also impair the immune system and reproduction, highlights the dangers of this particular insecticidal classneonicotinoids and fipronil. , withContinued large scale – mostly prophylactic – use of these persistent organochlorine pesticides has the potential to greatly decreasecompletely eliminate populations of arthropods in both terrestrial and aquatic environments. Sublethal effects on fish, reptiles, frogs, birds and mammals are also reported, showing a better understanding of the mechanisms of toxicity of these insecticides in vertebrates, and their deleterious impacts on growth, reproduction and neurobehaviour of most of the species tested. This review concludes with a summary of impacts on the ecosystem services and functioning, particularly on pollination, soil biota and aquatic invertebrate communities, thus reinforcing the previous WIA conclusions (van der Sluijs et al. 2015)

The effect of soil type and ecosystems on the soil nematode and microbial communities

Integrated studies are required to better understand the relationships between groups of soil microfauna under the influence of various biotic and abiotic factors that drive and characterise ecosystems. We analysed soil nematode communities and microbial diversity and the properties of three soil types to assess the effect of these environmental variables on biological diversity in natural (forest), semi-natural (meadow), and managed (agriculture) habitats of the Slovak Republic. The type of ecosystem and soil and the interaction of both factors had considerable effects on most monitored abiotic and biotic soil properties. The forest with a Chernozem soil had the most nematode species, highest nematode diversity, highest abundance of nematode within functional guilds, best values of ecological and functional indices, highest microbial biomass, highest microbial richness and diversity, and the highest values of various soil properties, followed by meadows with a Cambisol soil. The agricultural ecosystem with a Stagnosol soil had the lowest biological diversity and values of the soil properties. Several nematode species were new for Slovak nematode fauna. Sampling date and the interaction of all three factors (ecosystem × soil × date) had minor or no effect on most of the parameters, except soil moisture content, microbial richness, nematode channel ratio, nematode maturity index, and plant parasitic index. Both the biological indicators and basic soil properties indicated that the natural forest with a Chernozem soil was the best habitat from an ecological point of view. This ecosystem is thus the most appropriate for ecological studies

Influence of invasion by Sosnowsky's hogweed on nematode communities and microbial activity in forest and grassland ecosystems

This study determined the effect of the invasive plant Heracleum sosnowskyi on selected soil microbial properties and the taxonomic and trophic composition of soil nematode communities in the Serpukhov district of Moscow region, Russia. We compared invaded by H. sosnowskyi (at least twenty years) and uninvaded plots in two ecosystems, forest and grassland. Soil was sampled and analysed in the autumn and spring. The forest and grassland ecosystems had substantially different soil microbial and nematode communities, but both were considerably altered by invasion. The soil microbial properties differed among the investigated plots and season, but the differences were observed to be non-significant between the invaded and the uninvaded plots. By contrast, invasion significantly negatively affected total nematode abundance and altered nematode numbers and the generic composition of two trophic groups, herbivores and omnivores, in both seasons, but significantly only in the spring. The numbers of bacterivorous, fungivorous, and predaceous nematodes were not affected by H. sosnowskyi invasion. The channel index indicated that bacteria strongly contributed to decomposition in all plots (grassland and forest), regardless of invasion status. Enrichment and structure indices suggested that resource availability and ecosystem disturbance were higher in the invaded than the uninvaded plots, but significantly only in the spring. Our results thus indicated that invasion by H. sosnowskyi influenced several nematode communities parameters while others remained unaffected, regardless of habitat were invasion take place. © 2019 The Author