Moderation is best: Effects of grazing intensity on plant-flower visitor networks in Mediterranean communities

The structure of pollination networks is an important indicator of ecosystem stability and functioning. Livestock grazing is a frequent land use practice that directly affects the abundance and diversity of flowers and pollinators and, therefore, may indirectly affect the structure of pollination networks. We studied how grazing intensity affected the structure of plant-flower visitor networks along a wide range of grazing intensities by sheep and goats, using data from 11 Mediterranean plant-flower visitor communities from Lesvos Island, Greece. We hypothesized that intermediate grazing might result in higher diversity as predicted by the Intermediate Disturbance Hypothesis, which could in turn confer more stability to the networks. Indeed, we found that networks at intermediate grazing intensities were larger, more generalized, more modular, and contained more diverse and even interactions. Despite general responses at the network level, the number of interactions and selectiveness of particular flower visitor and plant taxa in the networks responded differently to grazing intensity, presumably as a consequence of variation in the abundance of different taxa with grazing. Our results highlight the benefit of maintaining moderate levels of livestock grazing by sheep and goats to preserve the complexity and biodiversity of the rich Mediterranean communities, which have a long history of grazing by these domestic animals.The research has been co-financed by the European Union (European Social Fund—ESF) and Greek National funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF)—Research Funding Program: THALES: Investing in knowledge society through the European Social FundPeer Reviewe

Risk to pollinators from anthropogenic electro-magnetic radiation (EMR): evidence and knowledge gaps

Worldwide urbanisation and use of mobile and wireless technologies (5G, Internet of Things) is leading to the proliferation of anthropogenic electromagnetic radiation (EMR) and campaigning voices continue to call for the risk to human health and wildlife to be recognised. Pollinators provide many benefits to nature and humankind, but face multiple anthropogenic threats. Here, we assess whether artificial light at night (ALAN) and anthropogenic radiofrequency electromagnetic radiation (AREMR), such as used in wireless technologies (4G, 5G) or emitted from power lines, represent an additional and growing threat to pollinators. A lack of high quality scientific studies means that knowledge of the risk to pollinators from anthropogenic EMR is either inconclusive, unresolved, or only partly established. A handful of studies provide evidence that ALAN can alter pollinator communities, pollination and fruit set. Laboratory experiments provide some, albeit variable, evidence that the honey bee Apis mellifera and other invertebrates can detect EMR, potentially using it for orientation or navigation, but they do not provide evidence that AREMR affects insect behaviour in ecosystems. Scientifically robust evidence of AREMR impacts on abundance or diversity of pollinators (or other invertebrates) are limited to a single study reporting positive and negative effects depending on the pollinator group and geographical location. Therefore, whether anthropogenic EMR (ALAN or AREMR) poses a significant threat to insect pollinators and the benefits they provide to ecosystems and humanity remains to be established

The effects of shrub encroachment on arthropod communities depend on grazing history

Unsustainable grazing is a major driver of biodiversity loss worldwide. Conservation actions such as grazing exclusion are effective strategies for halting such decline. However, we still know little how the long-term impact of grazing exclusion depends on plant–animal interactions such as those between encroaching unpalatable shrubs and ground arthropods. Here, we assessed how encroaching, unpalatable shrub species (Sarcopoterium spinosum) mediates the effects of grazing exclusion on the recovery of arthropod communities. We used a large-scale, long-term (15–25 years) grazing exclusion experiment complemented with local-scale treatments that consider the presence or absence of shrubs. We found that halting overgrazing supported the recovery of biodiversity in the long-term. Notably, the impacts of shrubs on arthropod diversity vary with grazing history. Shrubs decreased arthropod abundance by three folds, affecting particularly flies, butterflies, hymenopteran, and beetles in protected areas. Yet, shrubs had positive effects on animal diversity, particularly centipedes and millipeds in grazed areas. On the one hand, shrubs may enhance biodiversity recovery in overgrazed systems; on the other hand, shrubs may be detrimental in protected areas, in the absence of grazing. Understanding how plant–animal interactions vary with historical land-use change is key for biodiversity conservation and recovery and for integrated management of agroecosystems

Habitat protection and removal of encroaching shrubs support the recovery of biodiversity and ecosystem functioning

Livestock overgrazing causes environmental degradation, species invasion, biodiversity loss, and productivity decline, with profound consequences for ecological sustainability and human livelihoods. Habitat protection can mitigate such impacts, but we know little about how the long-term recovery of plant communities from livestock overgrazing depends on the presence of encroaching shrubs. Here, we explored how shrub encroachment mediates the effects of habitat protection (i.e., livestock exclusion and creation of UNESCO protected areas) on biodiversity recovery and ecosystem functioning (i.e., biomass productivity). We leveraged a long-term (15–25 years) experiment of livestock exclusion and complemented it with the removal of an encroaching shrub species in pasture areas and protected areas. We reveal that habitat protection has positive effects on patterns of recovery. Yet, the effects of habitat protection are mediated by shrub encroachment. Encroaching shrubs have net positive effects on plant diversity in pasture areas but inhibit biodiversity recovery in protected areas. The combination of habitat protection and the removal of encroaching shrubs best enhances the recovery of plant diversity and biomass productivity. A potential underlying mechanism is the shift in plant interactions from facilitation for recruitment and associated resistance to competition for water. Understanding species interactions is key to guiding conservation and restoration actions which can turn degraded ecosystems back into functional, species-rich communities

Understorey biodiversity management in olive groves for integrated management of natural enemies

The management of natural enemies of perennial tree crops and especially insects is usually performed with pesticides, which can negatively impact the quality of products, natural resources, and biodiversity as well as the health of producers and consumers. An emerging trend focuses alternatively on the use of less or no chemicals and the management of crop pests with natural means. This trend is being promoted by the European Union through the new Common Agricultural Policy. Olive cultivation is one of the most important permanent crops in the Mediterranean area. The most important pest in olive groves is the olive fly [Bactrocera oleae (Rossi) (Diptera: Tephritidae)]. In this study we investigate the relationship between the fly population and plant and insect diversity in the understorey of 15 fields on Lesvos Island during 2021 and 2022. The results suggest that maintaining the plant cover undisturbed significantly improves the biodiversity of the olive groves and by extension the ecosystem services, such as pollination, pest control and soil health

Linking farmer and beekeeper preferences with ecological knowledge to improve crop pollination

1. Pollination by insects is a key input into many crops, with managed honeybees often being hired to support pollination services. Despite substantial research into pollination management, no European studies have yet explored how and why farmers managed pollination services and few have explored why beekeepers use certain crops. 2. Using paired surveys of beekeepers and farmers in 10 European countries, this study examines beekeeper and farmer perceptions and motivations surrounding crop pollination. 3. Almost half of the farmers surveyed believed they had pollination service deficits in one or more of their crops. 4. Less than a third of farmers hired managed pollinators, however most undertook at least one form of agri-environment management known to benefit pollinators, although few did so to promote pollinators. 5. Beekeepers were ambivalent towards many mass flowering crops, with some beekeepers using crops for their honey that other beekeepers avoid because of perceived pesticide risks. 6. The findings highlight a number of largely overlooked knowledge gaps that will affect knowledge exchange and co-operation between the two groups

Using Image-based AI for insect monitoring and conservation - InsectAI COST Action

The InsectAI COST action will support insect monitoring and conservation at the national and continental scale in order to understand and counteract widespread insect declines. The Action will bring together a critical mass of researchers and stakeholders in image-based insect AI technologies to direct and drive the research agenda, build research capacity across Europe and support innovation and application. There is mounting evidence that populations of insects around the world are in sharp decline. Understanding trends in species and their drivers is key to knowing the size of the challenge, its causes and how to address it. To identify solutions that lead to sustainable biodiversity alongside economic prosperity, insect monitoring should be efficient and provide standardised and frequently updated status indicators to guide conservation actions. The EU Biodiversity Strategy 2030 identifies the critical challenge of delivering standardised information about the state of nature and image-based insect AI can contribute to this. Specifically, the EU Nature Restoration Law will likely set binding targets for the high resolution data that cameras can provide. Thus, outputs of the Action will contribute directly to EU policies implementation, where biodiversity monitoring is considered a key component. The InsectAI COST Action will organise workshops, conferences, short-term scientific missions, hackathons, design-sprints and much more, across four Working Groups. These groups will address how image-based insect AI technologies can best address Societal Needs, support innovation in Image Collection hardware, create standardised approaches for Image Processing and develop novel Data Analysis and Integration methods for turning data into actionable insights