This session will bring together researchers, conservationists, and policymakers to present the latest findings on insect population trends across biomes and taxa. We welcome advances in long-term monitoring, meta-analyses, and novel data sources that close geographical and taxonomic gaps, and studies examining drivers of decline, such as land-use or climate change. We also invite research quantifying insects’ ecological and societal importance, showing how their diversity and abundance underpin ecosystem functioning, resilience, and service delivery.
In addition to diagnosing decline, this session emphasizes solutions. We welcome contributions presenting evidence for insect conservation and restoration, evaluating what works, where, and at what scale. We also welcome studies on the enabling conditions for success, such as policy interventions or governance approaches. By integrating knowledge on drivers, impacts, and solutions, this session aims to chart a path to halt and reverse insect biodiversity loss, securing resilient ecosystems and their benefits for future generations.
Insects are declining in abundance, diversity, and biomass across ecosystems worldwide, raising concerns not only for biodiversity but also for the many ecosystem services—also described as Nature’s Contributions to People - that support human well-being. Public alarm over these declines reflects the cultural and emotional value that society places on insects, yet their importance extends far beyond charismatic pollinators. Insects contribute directly and indirectly to a broad suite of ecosystem services, but these contributions remain under-recognized and insufficiently quantified. Comparative studies suggest that herbivorous insects, in particular, are among the groups most consistently linked to beneficial service proxies, underscoring their central role in ecosystem multifunctionality. However, major knowledge gaps persist regarding how different insect groups jointly shape ecosystem functions and how restoring insect populations might rebuild multiple ecosystem services across environmental contexts.
In this talk, we will synthesize current understanding of the diverse pathways through which insects provide ecosystem services and support human well-being. Direct contributions include culturally valued interactions with butterflies, grasshoppers or bees, which foster connection to nature and enhance psychological well-being. Indirect contributions arise for example through insects’ pervasive influence on ecosystem processes: herbivores regulate plant community composition, promote plant diversity, and shape soil carbon and nutrient cycling; decomposer insects accelerate litter breakdown and support soil fertility; and predatory insects and spiders deliver natural pest control with cascading benefits for crop production and reduced pesticide use.
The talk will also highlight key gaps that limit our ability to predict how insect loss will influence ecosystem service provision. For example, we lack experimental tests linking insect abundance to multiple services under varying environmental conditions, and little is known about trade-offs among services when certain insect groups increase. We will outline promising approaches—including coordinated multi-site experiments, trait-based frameworks, and integrated monitoring that links multiple insect groups to multiple ecosystem functions— that can help close these gaps. In summary, this talk will clarify the central role of insects in sustaining ecosystem services and chart a path toward understanding how their recovery can contribute to resilient, multifunctional landscapes.
How to cite: Kempel, A. and Allan, E.: Insects and Ecosystem Services: What We Know, What We Miss, and How to Find Out, World Biodiversity Forum 2026, Davos, Switzerland, 14–19 Jun 2026, WBF2026-836, https://doi.org/10.5194/wbf2026-836, 2026.
In-depth knowledge about insects is largely limited to a few conspicuous taxa such as butterflies, bees and dragonflies. Worse still, less than 20% of all insects on Earth have been described, and we have comprehensive distribution data and population trends for an even lower fraction. This means the vast majority of insects are basically unknown, even in well-studied countries like Sweden or Germany. Malaise traps, combined with recent advances in DNA metabarcoding, could be an effective and inexpensive tool for closing these enormous knowledge gaps. Here, we provide examples of how combining these methods has proven useful in addressing a broad variety of key questions, including biomass trends, filling taxonomic gaps, identifying habitat and driver relationships, evaluating the effectiveness of protected areas, and monitoring pollinators. Our examples are based on first results from the German Malaise Trap Program, a nation-wide long-term insect monitoring project launched in 2019. Today, 83 monitoring sites are included covering a wide range of land use types and protection categories. In particular, we relate our recent data to long-term trends in German insect biomass reported by Hallmann et al. (2017, 2025), and discuss strengths and weaknesses of trend estimates, considering potential limitations in monitoring design and data. Additionally, we outline what biomass trends may tell us about changes in overall insect biodiversity, and detail the vast number of new taxa that combining Malaise traps with metabarcoding can identify (including important pollinators), offering new insights into often unmonitored taxa. We also show how we have used Malaise traps and metabarcoding to determine the effect of land use, climate, and protected areas on insect diversity. Finally, we will provide an outlook on how insects will be monitored in the European research infrastructure eLTER in the coming years, and what additional tools are needed given common limitations in this methodology, and the necessity to further deepen our knowledge of insects to develop targeted and more effective mitigation measures.
How to cite: Haase, P. and Sinclair, J.: Malaise traps as tool for insect monitoring, World Biodiversity Forum 2026, Davos, Switzerland, 14–19 Jun 2026, WBF2026-233, https://doi.org/10.5194/wbf2026-233, 2026.
Global concern over insect declines contrasts with persistent blind spots in taxonomic knowledge. “Dark taxa” such as parasitoid wasps and nematoceran flies dominate insect biodiversity and underpin ecosystem functioning and resilience, yet remain underrepresented in monitoring and conservation. The cause is a taxonomic impediment, marked by considerable gaps in taxonomic knowledge, limited identification resources, and a shortage of specialists.
We address this challenge using the parasitoid wasp superfamily Ceraphronoidea as a model taxon, drawing on samples from the state-wide insect biodiversity monitoring programme of Baden-Württemberg (south-western Germany). To illuminate Ceraphronoidea diversity, we combine DNA barcodes with morphology, host associations, and high-resolution imaging. Our findings reveal a sixfold increase in the number of Ceraphronoidea species recorded in Germany, including a highly distinctive new species characterised by a trait not previously documented in wasps. A synthesis of biological associations reveals that most described Ceraphronoidea species lack host records, which constrains their use in biocontrol and conservation planning. By developing accessible identification tools and enhancing barcode reference libraries, we lay the groundwork to incorporate Ceraphronoidea into biomonitoring and further research. Overall, this integrative taxonomic workflow helps address longstanding gaps in Ceraphronoidea taxonomy.
Looking ahead, the challenges exposed in this case study can be tackled through methodological innovation and capacity-building. Diversity scanners that detect and prepare specimens from bulk samples for DNA barcoding are already under trial. Open-source photomicroscopes that produce focus-stacked images for AI-assisted classification further reduce the handling effort of large samples. Recent advances in micro-computed tomography enable complementary 3D mass digitisation of specimen morphology. In parallel, BioBlitz events and accessible, interactive identification tools that connect experts with volunteer citizen scientists can significantly boost taxonomic capacity.
Ultimately, overcoming the taxonomic impediment is essential for bringing dark taxa into scope for monitoring, policy and practice. Such integrative biomonitoring will not only accelerate species discovery but also provide the evidence base to measure and track actions that support the recovery of insect biodiversity.
How to cite: Moser, M. and Krogmann, L.: Barcoding the Blind Spots: Integrative Taxonomy of Dark Taxa to Counteract Insect Declines, World Biodiversity Forum 2026, Davos, Switzerland, 14–19 Jun 2026, WBF2026-196, https://doi.org/10.5194/wbf2026-196, 2026.
Biodiversity monitoring is a fundamental tool allowing researchers and land managers to understand the trends of indicator populations, with extension to the state of entire ecosystems. Scientific evidence points to a precipitous decline of insect abundance in recent decades. Due to insects’ great functional diversity, significant difficulty lies in teasing out the exact drivers of insect population decline. In response to management actions, measurement of recovery rates will rely on standardized monitoring strategies in the future, underpinned by sound baseline data and analytical approaches. Systematic documentation of insect traits should further improve data collection and guide effective management practices that can then be applied elsewhere, ideally allowing recovery of insect species diversity. Such breakthroughs will result in improvement of biodiversity at scale.
Our current contribution focuses on potential solutions for monitoring pollinator communities in agricultural landscapes. Strategies include implementation of modern and experimental technology-based insect monitoring techniques used as stand-alone approaches or in combination. We present recent findings from research trials on monitoring insect biodiversity using environmental DNA (eDNA) collection, camera trapping (CT), and artificial intelligence (AI) algorithms for identification, focusing on their use-cases, potential benefits, and current limitations. Specifically, we study the use of eDNA-derived community composition as contextual information to inform and constrain AI-based classification and quantification of insects, effectively providing site-specific ecological priors for visual inference. This multimodal-based approach should reduce misclassification for non-native taxa and enhance abundance estimates compared to image data alone.
We further discuss methodological combinations that more comprehensively document the insect community at individual sites - with an objective of mitigating method-specific detection biases. Trait-based digital repositories of insect species should accelerate the access to data on interactions of insects in the environment, improving knowledge on conserving them. As documentation requires appropriate deposition of voucher materials, we consider how input of trait-based data into the Global Repository of Insect Traits (GRIT) can support conservation efforts. We present preliminary findings as a proof-of-concept of a workflow combining insect eDNA collection with CT/AI.
How to cite: Kirse, A., Bdeir, A., Berger, V., Dalton, D., Landwehr, N., and Svetnik, I.: Next generation pollinator monitoring in agroecosystems: eDNA meets camera traps and AI, World Biodiversity Forum 2026, Davos, Switzerland, 14–19 Jun 2026, WBF2026-954, https://doi.org/10.5194/wbf2026-954, 2026.
Growing concern about insect declines has spurred increasing research into temporal trends in insect communities. Most studies, however, focus only on the past few decades. Yet many anthropogenic drivers of insect trends – such as land-use change and climate change – have been affecting insect communities for much longer. As a result, major shifts in insect diversity probably occurred earlier. Consequently, the baseline for studies based on time series starting in the late 20th century or even later might have shifted. This risks leading to misleading conclusions or poor conservation decisions.
To address this, we extended insect trends back nine decades by analysing 1.2 million records of 595 saproxylic beetle and 216 butterfly species. Using occupancy-detection models, we reconstructed continuous trends in species richness in Switzerland from 1930 to 2021 and related these trends to land-use change, climate change, and to species traits.
From the 1930s to the 1960s, the species richness of both studied insect groups declined. While the richness of saproxylic beetles stabilised and subsequently recovered, the richness of butterflies continued to decline until the 1980s and has not recovered since. As a consequence, the average richness of butterflies today is 12% lower than in 1930. The strong mid-century decreases were linked to increases in agricultural mechanisation, while the subsequent increases were linked to climate warming. Across the full 90-year period, declines disproportionately affected specialist and cold-adapted insect species. Since the acceleration of climate warming in the 1980s, warm-adapted species have increased in both saproxylic beetles and butterflies. Recent gains in saproxylic beetle richness may also reflect increased deadwood availability from windthrow and biodiversity-friendly forest management.
Our unprecedented long-term analyses reveal the strongest insect declines in the mid-20th century, with only partial recovery since. Our findings highlight the importance of accounting for shifted baselines when interpreting short-term evaluations of insect trends.
How to cite: Neff, F., Bollmann, K., Chittaro, Y., Gossner, M. M., Herzog, F., Korner-Nievergelt, F., Litsios, G., Martínez-Núñez, C., Moretti, M., Rey, E., Sanchez, A., and Knop, E.: Ninety-year trends reveal sharpest insect declines mid-20th century, World Biodiversity Forum 2026, Davos, Switzerland, 14–19 Jun 2026, WBF2026-494, https://doi.org/10.5194/wbf2026-494, 2026.
The vast majority of insect species are believed to be undescribed, yet they exhibit some of the largest reported losses in biomass, even in protected areas. As such, they exemplify the idea of an unknown, “hidden” group. We do not know to what extent declines in biomass correlate with declines in species richness, how these changes might affect ecosystem functioning, or which landscapes show higher losses of insect biodiversity. The project “unknown Germany” addresses this gap by re-analyzing the valuable Krefeld collection, which used standardized Malaise trapping to sample flying insect diversity across a variety of ecosystem types in Germany over the last 30 years. In this project, a total of around 400.000 specimens will be analyzed by sequencing the CO1 barcoding gene in applying high-throughput methods on material from two time points showing a significant decrease in biomass. This allows us exploring the links between biomass and biodiversity and identifying changes in several levels of species diversity, phylogenetic diversity, and community composition. Traits and ecological roles (such as pollinator, predator, etc.) from well-known species will be imputed to assess how changes over time within different functional groups may impact overall ecosystem functioning. Functional diversity and composition will be studied to
compare specialists with generalists, examine the presence of non-native species, and analyze alterations in food web structure. This sampling scheme will enable the detection of shifts at the community level, either through actual species loss or phenological changes—when shifts in the timing of species activity alter ecosystem service provision. In particular, the first quantification of trends in species-level diversity and their connection to ecosystem services will be provided by this project—an area that, until now, has only been hypothesized based on biomass changes and remains untested. The results will advise conservation legislators on how to support biodiversity resilience and ecosystem services in addressing diversity besides “iconic” species conservation methods are usually focusing.
How to cite: Müller, S., Pereira, R., Vasilita, C., and Orr, M.: Trends in hidden taxa and habitats – understanding the extent and impact of the biodiversity crisis, World Biodiversity Forum 2026, Davos, Switzerland, 14–19 Jun 2026, WBF2026-994, https://doi.org/10.5194/wbf2026-994, 2026.
In recent years much has been written about insect declines in response to global anthropogenic drivers. Aphids are a widespread and often abundant component of insect communities; due to their biology and life cycle, they provide an excellent indicator of changing environmental conditions. The UK suction trap network has been operating for several decades now and is used to monitor aphid flights and virus risk to agricultural crops. Previous analysis has shown temporal changes in aphid pesticide resistance and aphid phenology, and declines in individual aphid taxa, but the datasets have not yet been used to examine insect biodiversity trends and drivers at a regional scale. Using these long-term datasets of flying aphids from suction trap sites in eastern and southern Scotland, we examine the temporal trends in aphid diversity, composition and abundance and their relation to several environmental conditions.
Our analysis of Scottish suction trap data shows that flying aphid diversity (Shannon Index) and abundance has increased over recent decades, particularly in May–June, correlating with increasing temperatures. More detailed examination shows this diversity increase results from accelerated aphid first flight in spring, which is driven by warmer over-wintering temperatures. Principal co-ordinates analysis reveals the seasonality of aphid abundance and highlights the aphid taxa associated with high diversity in May–June. The application of time-varying autoregressive models to aphid abundance data highlights that year-to-year autocorrelation increases with aphid abundance, while distributed-lag modelling reveals this autocorrelation is strengthened under warmer winter temperatures.
Further work is planned to understand the role of land use change in these trends. Ultimately, we aim to determine whether specific taxa or groups of taxa act as indicators of environmental change. Wider ecosystem impacts will be informed by in-depth knowledge of the ecology of aphids, aiding predictions about how biodiversity will responses to future climatic conditions and land use scenarios.
How to cite: Addy, J., Karley, A., Zuta, A., Verrall, S., Malloch, G., Highet, F., and Preedy, K.: Has the diversity of flying aphids changed over the past 70 years? An analysis of Scottish suction trap data., World Biodiversity Forum 2026, Davos, Switzerland, 14–19 Jun 2026, WBF2026-988, https://doi.org/10.5194/wbf2026-988, 2026.
Anthropogenic pressures such as land-use intensification in grasslands increasingly threaten biodiversity by altering habitat structure. Particularly arthropods show highly variable responses to these pressures depending on the species, its traits and its habitat requirements.
For this study, we used quantitative niche models (a randomization method based on a null model) to assess species-specific responses and their abundance-weighted means (AWM) of the arthropods to mowing, fertilizing, and grazing. Species with observed AWM lower than 95% of the AWMnull values (p < 0.05) were treated as ‘loser', while those with AWM higher than 95% of the AWMnull values (p < 0.05) were identified as ‘winner'. We therefore analysed 1,352 arthropod species of four arthropod orders (Araneae, Coleoptera, Hemiptera, Orthoptera) across three regions in Germany (150 grassland plots) between 2008 and 2018.
The results reveal three times as many species were categorized as losers compared to winners and that fertilizing had the most detrimental effects, since fertilizing produced the fewest winners and the most losers. Grazing, however, yielded the highest proportion of winners and the fewest losers. Yet, neutral species still predominate as most species are generalists to human pressure and results may vary depending on the traits a specific species possesses. For example, grazing favored smaller species, whereas mowing and fertilizing favored larger ones, and herbivores were particularly sensitive to fertilizing. A further comparison of the results with the protection and conservation status of the German Red List showed that intensive management practices affect the already most vulnerable species. Especially, species negatively affected by mowing were overrepresented in higher-risk Red List categories, as well reflected by declining population trends.
This study demonstrates that arthropod responses to land-use are highly heterogeneous, but underline niche modeling as a robust tool for analyzing species-specific responses to land-use and management practices, which can be used as a basis with the Red List to develop targeted conservation strategies tailored to the ecological requirements of vulnerable species.
How to cite: Hartlieb, M.: Losers and winners: responses of grassland arthropods to land-use components, World Biodiversity Forum 2026, Davos, Switzerland, 14–19 Jun 2026, WBF2026-871, https://doi.org/10.5194/wbf2026-871, 2026.
How to cite: Millard, J.: Integrating expert opinion, spatial comparisons, and meta-analyses for the robust prediction of global insect biodiversity change, World Biodiversity Forum 2026, Davos, Switzerland, 14–19 Jun 2026, WBF2026-982, https://doi.org/10.5194/wbf2026-982, 2026.
Insect populations have declined dramatically over recent decades, yet the relative importance of the underlying drivers remains poorly understood. These declines are commonly attributed to habitat loss, climate change, agricultural intensification, and pesticide use. However, we hypothesize that road traffic represents an additional, largely overlooked driver of insect decline. Local research shows that road traffic contributes to insect mortality not only through direct collisions with vehicles but also via traffic-related pollutants and habitat disturbance. Roads and vehicles are now pervasive across landscapes worldwide, and traffic volumes have increased considerably over the past half-century. Despite this, the ecological consequences of road traffic for insects have received surprisingly little attention compared to other anthropogenic pressures.
To address this gap, we conducted a global analysis of the potential impact of road traffic on insect populations. Our spatial assessment reveals that agricultural and peri-urban landscapes—areas already identified as hotspots for insect declines—are disproportionately affected by high traffic densities.
Although a few studies have estimated insect mortality along specific road segments, little is known about the cumulative impact at regional or global scales. We extrapolate such local mortality estimates using global traffic data to approximate the worldwide impact of road traffic on insects. Our preliminary results indicate very high impacts of road traffic on insects. These findings underscore the urgent need to integrate road ecology into insect conservation frameworks and to develop mitigation strategies that address this overlooked threat.
However, mitigating the impact of road traffic on insects poses significant challenges. Roads and traffic may act as magnets for insects due to night-time lighting from streetlamps and vehicles, increasing collision risk. Traffic flows are constant throughout the year and extremely difficult to reduce without major societal changes. Moreover, road traffic introduces numerous additional stressors—such as chemical pollutants, noise, and microclimatic alterations—that compound its ecological footprint. We discuss these complexities alongside potential solutions, such as infrastructure design and lighting management, aiming to reduce the ecological impact of roads and safeguard insect biodiversity.
How to cite: van Strien, M. and Grêt-Regamey, A.: Is road traffic an important driver of global insect decline?, World Biodiversity Forum 2026, Davos, Switzerland, 14–19 Jun 2026, WBF2026-220, https://doi.org/10.5194/wbf2026-220, 2026.
The biodiversity of semi-natural grasslands has dramatically declined over the past century, largely due to the intensification of management practices. In this study we experimentally tested the efficacy of different assisted (active) restoration methods to increase plant and invertebrate biodiversity in relatively species-poor extensively managed Swiss lowland meadows. Four restoration treatments and a control were randomly established in 2019: 1) hay transfer from a species-rich donor meadow to a harrowed receiver meadow; 2) the same as 1), but to a ploughed meadow; 3) sowing a directly harvested native seed mixture originating from a species-rich donor meadow to a ploughed meadow; 4) sowing a propagated native mixture on a ploughed meadow; 5) control, with no soil disturbance and no reseeding. The experiment was conducted at field scale and replicated 12 times across the Swiss Plateau. Vegetation surveys were performed before (2018) and after the restoration (2021–2024). Pollinators were sampled in 2022 (wild bees and hoverflies) and 2024 (butterflies). After a marked increase in 2021, plant species richness stabilised in 2023 in most treatments with on average 29% more species compared to 2018 and 16% more species in restored compared to control meadows in 2023. Regional differences (beta diversity) were more pronounced in the hay transfer treatments. Harrowing before sowing proved to be as effective as ploughing. Importantly, in 2023, 90% of the restored meadows qualified for the result-based payment scheme, whereas none qualified before restoration. Wild bees and butterflies responded positively to the restoration treatments, though not consistently across all treatments. Hoverflies, as well as other invertebrate groups, showed no response. This real-scale study provides evidence-based recommendations for restoring grasslands through practical and financially viable methods. The results-based payment scheme acts as a strong legislative incentive, encouraging farmers to implement management measures that deliver higher biodiversity outcomes and, in turn, secure higher financial income.
How to cite: Humbert, J.-Y., Forgione, L., Slodowicz, D., and Arlettaz, R.: Restoring plant and pollinator diversity in lowland grasslands using different seed addition methods, World Biodiversity Forum 2026, Davos, Switzerland, 14–19 Jun 2026, WBF2026-516, https://doi.org/10.5194/wbf2026-516, 2026.
Land-use intensity, and hence farming intensity, is discussed as one of the major drivers of insect biodiversity change. However, working against insect declines requires action from key stakeholders such as farmers.
Collaborating with several networks of farmers across multiple years across a range of European countries, we measured biomass, abundance and species composition of insects in response to (i) pesticide reduction (insecticides and herbicides) (ii) on-farm biodiversity enhancement measures (such as in field or adjacent flowering strips) and (iii) crop identity under real-world farming conditions. Farmers, farmer associations and industry stakeholders were included in the design and implementation of biodiversity assessments and crop fields were managed according to conventional or organic practices. Insects were sampled using a range of methods, such as vane traps, pitfall traps, trap-nests for wild bees and antagonists, and soil cores for sampling of soil mesofauna.
We find that pesticide reduction and biodiversity enhancement measures (such as various flowering strip arrangements) consistently increase insect richness and biomass compared to controls, with largely additive effects of crop identity. Similar effects were found for belowground mesofauna that was, for example, enhanced in presence of flowering strips. Notably, our insect conservation measures were tailored to not compromise yield and to work under real-world everyday farming conditions.
In conclusion, farmers can contribute to "bending the curve" towards increasing insect diversity in farmland, for example by replacing insecticides or herbicides with measures of biodiversity conservation, without yield losses. Our findings pave the way for future policy development to arrive at more insect-friendly farming systems, with potential benefits in the heart of European high-intensity agriculture. One important component of such a strategy will be reduced pesticide use, for which mechanical weed control can be an economicaly viable strategy. If paired with other conservation efforts, e.g. on grassland or in nature reserves, a holistic approach to insect biodiversity protection in European agriculture can be achieved.
How to cite: Scherber, C., Kirse, A., Ott, D., Bohacz, C., Prenzel, V., Glock, I., and Hartke, T.: Bending the curve against insect declines - what can farmers do?, World Biodiversity Forum 2026, Davos, Switzerland, 14–19 Jun 2026, WBF2026-560, https://doi.org/10.5194/wbf2026-560, 2026.
