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Due to rapid technological innovations, the automated monitoring of insect assemblages comes within reach. However, this continuous innovation endangers the methodological continuity needed for calculating reliable biodiversity trends in the future. Maintaining methodological continuity over prolonged periods of time is not trivial, since technology improves, reference libraries grow and both the hard- and software used now may no longer be available in the future. Moreover, because data on many species are collected at the same time, there will be no simple way of calibrating the outputs of old and new devices. To ensure that reliable long-term biodiversity trends can be calculated using the collected data, I make four recommendations: (1) Construct devices to last for decades, and have a five-year overlap period when devices are replaced. (2) Construct new devices to resemble the old ones, especially when some kind of attractant (e.g. light) is used. Keep extremely detailed metadata on collection, detection and identification methods, including attractants, to enable this. (3) Store the raw data (sounds, images, DNA extracts, radar/lidar detections) for future reprocessing with updated classification systems. (4) Enable forward and backward compatibility of the processed data, for example by in-silico data 'degradation' to match the older data quality. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'. [ABSTRACT FROM AUTHOR]

Insects are the most diverse group of animals on Earth, yet our knowledge of their diversity, ecology and population trends remains abysmally poor. Four major technological approaches are coming to fruition for use in insect monitoring and ecological research—molecular methods, computer vision, autonomous acoustic monitoring and radar-based remote sensing—each of which has seen major advances over the past years. Together, they have the potential to revolutionize insect ecology, and to make all-taxa, fine-grained insect monitoring feasible across the globe. So far, advances within and among technologies have largely taken place in isolation, and parallel efforts among projects have led to redundancy and a methodological sprawl; yet, given the commonalities in their goals and approaches, increased collaboration among projects and integration across technologies could provide unprecedented improvements in taxonomic and spatio-temporal resolution and coverage. This theme issue showcases recent developments and state-of-the-art applications of these technologies, and outlines the way forward regarding data processing, cost-effectiveness, meaningful trend analysis, technological integration and open data requirements. Together, these papers set the stage for the future of automated insect monitoring. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'. [ABSTRACT FROM AUTHOR]

Insects are the most diverse group of animals on Earth, but their small size and high diversity have always made them challenging to study. Recent technological advances have the potential to revolutionise insect ecology and monitoring. We describe the state of the art of four technologies (computer vision, acoustic monitoring, radar, and molecular methods), and assess their advantages, current limitations, and future potential. We discuss how these technologies can adhere to modern standards of data curation and transparency, their implications for citizen science, and their potential for integration among different monitoring programmes and technologies. We argue that they provide unprecedented possibilities for insect ecology and monitoring, but it will be important to foster international standards via collaboration. Technological developments are opening new possibilities for biodiversity monitoring, but – especially for insects – they come with their own unique set of limitations. Due to the vast diversity of insects, of which at least 80% remain undescribed, traditional monitoring is unable to provide even basic knowledge of the state of most insect species in most places. We appraise four emerging tools and technologies (computer vision, acoustic monitoring, radar, and molecular methods) that provide unprecedented opportunities for insect ecology. These technologies can enhance spatial, temporal, and taxonomic coverage of monitoring, but none can monitor all insects at all scales, and each comes with a set of limitations. Technological integration, open data, and international standards are needed to harness the full potential of novel technologies for insect monitoring. [ABSTRACT FROM AUTHOR]

Recent case studies showing substantial declines of insect abundances have raised alarm, but how widespread such patterns are remains unclear. We compiled data from 166 long-term surveys of insect assemblages across 1676 sites to investigate trends in insect abundances over time. Overall, we found considerable variation in trends even among adjacent sites but an average decline of terrestrial insect abundance by ~9% per decade and an increase of freshwater insect abundance by ~11% per decade. Both patterns were largely driven by strong trends in North America and some European regions. We found some associations with potential drivers (e.g., land-use drivers), and trends in protected areas tended to be weaker. Our findings provide a more nuanced view of spatiotemporal patterns of insect abundance trends than previously suggested. [ABSTRACT FROM AUTHOR]

Carrion of large animals is an extremely nutrient rich, ephemeral resource that is essential for many species, but is scarce in the anthropogenic Western-European landscape due to legislative restrictions. Rewilding, a novel conservation strategy that aims at restoring natural processes with minimal human intervention, is increasing in popularity and could lead to increased carrion availability in the landscape. It is therefore important to understand the effects of carrion on biodiversity. We investigated the direct and delayed (five months) effects of red deer (Cervus elaphus) carcasses on plants and arthropods in the Oostvaardersplassen, the Netherlands, one of the oldest rewilding sites in Europe. Specifically, we tested whether carrion has a positive direct effect on the abundances and diversity of various arthropod functional groups, as well as a delayed effect on the vegetation and arthropods through the increased nutrient availability. During the active decomposition stage in spring, we, not surprisingly, observed higher abundances of carrion associated species (scavengers and their specialized predators) at the carrion sites than at control sites without carrion, but no higher abundances of predators or detritivores. In late summer, after near-complete decomposition, plant biomass was five times higher, and nutritional plant quality (C:N ratio) was higher at the carrion sites than at the control sites. Arthropod abundance and diversity were also manifold higher, owing to higher numbers of herbivorous and predatory species. Regression analysis showed that abundances of herbivores and detritivores were positively related to plant biomass, and predator abundances were positively related to abundances of herbivores and detritivores, suggesting bottom-up effects propagating through the food chain. Our results show that even in a naturally nutrient-rich ecosystem like the Oostvaardersplassen, carrion can have strong positive effects on local plant biomass and nutritional quality and arthropod abundances, lasting the whole growing season. We found evidence that these effects were first directly caused by the presence of carrion, and later by the enhanced nutrient availability in the soil. This highlights the importance of the indirect pathways by which carrion can structure arthropod communities. [ABSTRACT FROM AUTHOR]

• Abundance is an important property to assess change in ecological communities. • It's unclear if individual number or biomass is the best measure of community size. • We compared change in these measures in plant- and leafhopper communities. • We found strong changes in species and trait composition for both measures. • Neither measure of community size was clearly superior. Declines in insect biomass and individual numbers have been demonstrated in many parts of the world, including central European dry grasslands. It is, howver, unclear if biomass data or individual numbers are superior as measures of change in species composition, and in trait composition of insect communities. We revisited a former study of ours demonstrating severe losses in abundance of planthoppers and leafhoppers in Central European grasslands since the 1960s. We performed a series of univariate, multivariate and trait-based tests to investigate the relationship between biodiversity change and environment, and compared the results for number-weighted and biomass-weighted community data. While both individual numbers and biomass declined strongly over time, no changes in species diversity (Jost's D) were observed irrespective of the measure used for weighting. Surprisingly, metrics for trait diversity tended to increase over time in both the number-weighted and biomass-weighted data. For both measures, community composition changed strongly over time for species and trait data, and was also associated with landscape structure and mean annual precipitation. Of the tested traits, we only found associations between an early phenology and time, and a temporal increase of species over-wintering in a nymphal stage, but again there was no major difference between the measure used for weighting. Our study shows that declining assemblage size (regardless of the measure used) does not necessarily translate in concomitant changes in functional diversity or trait diversity. From a methodological perspective, no clear evidence emerged for either biomass or individual number as measure of assemblage size being more sensitive to environmental change. This implies that conversion of widely used data of individual numbers to biomass values is unlikely to bring much additional insights. With respect to the general scarcity of quantitative data on insect communities, the focus should be on using whatever data is available. [ABSTRACT FROM AUTHOR]

European coastal salt marshes are important for the conservation of numerous species of specialist plants, invertebrates, breeding and migratory birds. When these marshes are managed for nature conservation purposes, livestock grazing is often used to counter the dominance of the tall grass Elytrigia atherica , and the subsequent decline in plant species richness. However, it remains unclear what is the optimal choice of livestock species and stocking density to benefit biodiversity of various trophic levels. To fill this knowledge gap, we set up a triplicate, full factorial grazing experiment with cattle and horse grazing at low and high stocking densities (0.5 or 1 animal ha −1 ) at the mainland coast of the Dutch Wadden Sea. Here, we present the results after 4 years and integrate these with previously published results from the same experiment to assess effects of livestock grazing on various trophic groups. Stocking density affected almost all measured variables: high stocking densities favoured plant species richness and suppression of E. atherica , whereas low stocking densities favoured abundances of voles, pollinators and flowers. Densities of different functional groups of birds showed no significant response to the regimes, but tended to be somewhat higher under 0.5 horse and 1 cattle ha −1 . Choice of livestock species had fewer and smaller effects than stocking density. Horse grazing was detrimental to vole density, and showed an interactive effect with stocking density for Asteraceae flower abundance. Multidiversity, a synthetic whole-ecosystem biodiversity measure, did not differ among regimes. These results are discussed in the light of other results from the same experiment. Because of these contrasting effects on different trophic groups, we advise concurrent application of different grazing regimes within a spatial mosaic, with the inclusion of long-term abandonment. High density horse grazing, however, is detrimental to biodiversity. [ABSTRACT FROM AUTHOR]

Natural grazing refuges can contribute significantly to plant and animal diversity in grazed ecosystems, particularly when herbivore densities are high. When natural grazing refuges are absent, artificial refuges could be created, for example by means of fencing. It remains, however, unclear how grazing refuges affect the diversity of various taxa in their surroundings. Edge effects can be expected to be positive for biodiversity because at these edges minimal disturbance is combined with beneficial light conditions for plant diversity. This can be expected to decrease with increasing distance and to differ between matrix vegetation types. Here, we investigated the impact of herbivore exclusion through fencing on communities of plants and various invertebrate taxa in a rewilding area on very productive soil, the Oostvaardersplassen, The Netherlands. The area is grazed year round by Heck cattle, konik horses and red deer, at a combined density of approximately 2.4 animal ha −1 . Ten exclosures (13 × 12 m) were erected in 2010 and plant communities were monitored for three years. In the third year, pitfall trapping, earthworm counts and plant surveys were performed in the centre, at the edge, at 10 m and at 20 m distance from each exclosure. Plant species richness declined strongly at the centre of the exclosures, but remained high outside the exclosures and at their edges. Earthworm, isopod, myriapod and ground beetle diversity increased in the exclosures, but showed small or no differences in species composition, while weevils showed a decrease. Spider, true bug, and leafhopper diversity did not differ, but showed large changes in species composition. For leaf-, dung and click beetles, neither diversity nor species composition differed systematically between treatments. For all taxa, diversity at the exclosure edges was as high as in the most diverse treatments, thus, combining all taxa to calculate multidiversity showed species richness to peak at the edge of the exclosures, but this positive edge-effect extended less than 10 metres. We conclude that when natural grazing refuges are not present, the creation of grazing refuges may thus be an effective management tool to increase diversity. Because exclosure edges support the highest multidiversity, maximising the edge length will have most beneficial effects for grassland flora and fauna, which can be achieved by creating many small, rather than few large refuges, or by creating serrated rather than straight edges. Such positive effects can be expected to be beneficial to higher trophic levels such as birds and other vertebrates. [ABSTRACT FROM AUTHOR]

Desquilbet et al. take issue with our data inclusion criteria and make several other dubious claims regarding data processing, analysis, and interpretation. Most of their concerns stem from disagreement on data inclusion criteria and analysis, misunderstanding of our goals, and unrealistic expectations. We maintain that our synthesis provides a state-of-the-art analysis of patterns of trends in insect abundances. [ABSTRACT FROM AUTHOR]

It is commonly thought that the biodiversity crisis includes widespread declines in the spatial variation of species composition, called biotic homogenization. Using a typology relating homogenization and differentiation to local and regional diversity changes, we synthesize patterns across 461 metacommunities surveyed for 10 to 91 years, and 64 species checklists (13 to 500+ years). Across all datasets, we found that no change was the most common outcome, but with many instances of homogenization and differentiation. A weak homogenizing trend of a 0.3% increase in species shared among communities/year on average was driven by increased numbers of widespread (high occupancy) species and strongly associated with checklist data that have longer durations and large spatial scales. At smaller spatial and temporal scales, we show that homogenization and differentiation can be driven by changes in the number and spatial distributions of both rare and common species. The multiscale perspective introduced here can help identify scale-dependent drivers underpinning biotic differentiation and homogenization. [ABSTRACT FROM AUTHOR]

Biotic responses to global change include directional shifts in organismal traits. Body size, an integrative trait that determines demographic rates and ecosystem functions, is thought to be shrinking in the Anthropocene. Here, we assessed the prevalence of body size change in six taxon groups across 5025 assemblage time series spanning 1960 to 2020. Using the Price equation to partition this change into within-species body size versus compositional changes, we detected prevailing decreases in body size through time driven primarily by fish, with more variable patterns in other taxa. We found that change in assemblage composition contributes more to body size changes than within-species trends, but both components show substantial variation in magnitude and direction. The biomass of assemblages remains quite stable as decreases in body size trade off with increases in abundance. [ABSTRACT FROM AUTHOR]

Over the past decades, studies have observed strong declines in biomass and the abundance of flying insects. However, there are many locations where no surveys of insect biomass or abundance are available. Weather radars are known to provide quantitative estimates of flying insect biomass and abundance, and can therefore be used to fill knowledge gaps in space and time. In this study, we go beyond previous studies by combining a machine-learning approach with ground-truth observations from an aphid trap network. In this study, radar echoes from Level-II (Base) data of three Next Generation Weather Radar (NEXRAD) stations in the U.S. are classified using machine learning approaches. Weekly aphid counts from suction traps at Manhattan (Kansas), Morris (Illinois), and Rosemount (Minnesota) are used as validation data. Variability and distribution of the radar signals of four scatterer classes (insects, light rain, heavy rain, and plankton) are assessed. Probability density functions (PDF) of reflectivities of insects and plankton were found to be distinct from those of light- and heavy rain. Furthermore, the PDF of radar variables of the insect scatter class was also characterized by a broad distribution of spectrum width, cross-correlation ratio, and a broad range of differential reflectivity values. Decision trees, random forests, and support vector machine models were generated to distinguish three combinations of scatterers. A random forest classifier is found to be the best-performing model. [ABSTRACT FROM AUTHOR]

Abstract: Studies of grassland communities have demonstrated that increasing vertebrate grazing decreases the diversity of specialised herbivorous insects, while plant diversity is maintained or increased. However, we still have a limited understanding of the causal mechanisms underlying these contrasting observations of two tightly linked groups of organisms. We used spatially linked plant and moth observations from salt marshes, sampled for 3 years along an experimental sheep‐grazing gradient (0, 1–2, 3–4 and 10 sheep ha−1), to test whether the disruption of plant–insect interactions by large herbivores accounts for these contrasting grazing effects. Moths were caught using emergence traps, which were moved and repositioned every 3 weeks. Firstly, we quantified species turnover between the grazing regimes for both taxa (measured as Sørensen dissimilarity) using a null‐model approach. Secondly, we analysed the number of observed insect ̶ host associations under the different regimes. Species turnover between grazing regimes was significant (after correcting for rarefaction effects) for moth species, but not for plants, indicating very few and random effects of grazing on plant species composition. The percentage of realised plant–moth associations decreased from 37% in the absence of grazing to 6.5% under high stocking densities. We thus conclude that vertebrate grazing caused a disruption of plant–moth associations, probably by rendering the host‐plants unsuitable for most of the moth species. Our findings provide further mechanistic understanding on how large herbivores shape arthropod communities and illustrate the importance of host‐plant associations in explaining effects of natural or anthropogenic habitat modification. [ABSTRACT FROM AUTHOR]

Ecological thresholds comprise relatively fast changes in ecological conditions, with respect to time or external drivers, and are an attractive concept in both scientific and policy arenas. However, there is considerable debate concerning the existence, underlying mechanisms, and generalizability of ecological thresholds across a range of ecological subdisciplines. Here, we usethe general concept of scale as a unifying framework with which to systematically navigate the variability within ecological threshold research. We review the literature to show how the observational scale adopted in any one study, defined by its organizational level, spatiotemporal grain and extent, and analytical method, can influence threshold detection and magnitude. We highlight a need for nuance in synthetic studies of thresholds, which could improve our predictive understanding of thresholds. Nuance is also needed when translating threshold concepts into policies, including threshold contingencies and uncertainties. [ABSTRACT FROM AUTHOR]

Climate change and land-use intensification pose increasing threats to biodiversity, with climate change expected to eventually surpass other global environmental change drivers and become the greatest threat to biodiversity in the future. Understanding the combined ecological impacts of multiple global change drivers is crucial to predict future scenarios of biodiversity change. However, experimental evidence for the impacts of land-use intensification under current and future climate scenarios is lacking, even though this is imperative for understanding future trajectories of biodiversity in agricultural landscapes. We experimentally tested for the simultaneous effects of land-use intensification and climate change on arthropod biodiversity in a field-scale grassland experiment known as the Global Change Experimental Facility (GCEF). Specifically, we tested whether future scenarios of climate change are likely to exacerbate impacts of land-use intensification on arthropod diversity and abundance across different trophic levels by sampling aboveground arthropod communities in low and high land-use intensity grasslands under current and future climatic conditions. We found that climate change reduced total abundances of arthropods and increased evenness of the whole community, while only having trophic level-specific effects on detritivore abundance and evenness. Land-use intensification reduced abundance of the whole community, predators and detritivores, but only eroded species richness of the whole community and herbivores, with the magnitude of declines in predator and detritivore abundance depending on the climate scenario. Additionally, both land-use intensification and climate altered species composition of the whole community and within the predator, herbivore, and detritivore trophic levels. We show that climate change and land use intensification cause simultaneous shifts in arthropod abundance, species richness, and species composition across trophic levels. Changes in arthropod communities as a result of climate change and land-use intensification will likely have profound consequences for ecosystem functioning under future environmental conditions. • We experimentally test for combined land-use and climate change impacts on arthropod communities. • Land-use and climate change reduced total abundance and diversity, but increased arthropod evenness. • Climate change interactively reduced land-use impacts on predator and detritivore abundance. • Land-use intensity had more widespread impacts on arthropods across trophic groups than climate change. • Both drivers caused shifts in species composition, within and across trophic groups. [ABSTRACT FROM AUTHOR]

Rewilding is a novel nature management type that aims at restoring natural processes with minimal human intervention. It is increasingly employed on abandoned agricultural lands in Europe, but empirical studies are scarce. Rewilding may lead to formation of wood-pastures, arguably the primeval landscape in parts of Europe before Neolithic times. We investigated sapling establishment, a key process for wood-pasture formation, in the Oostvaardersplassen: Europe’s oldest large-scale rewilding area, with high densities of free-roaming large herbivores. We transplanted saplings of pioneers, spiny shrubs, and hardwood species and studied how herbivore accessibility (grazed control, partial and full exclosure), vegetation type (tall roughs; short lawns) and soil-tillage (mimicking wild boar rooting) affected sapling survival for four years. No single sapling survived in grazed controls, while survival in exclosures was 25%. Differences in survival between partial and full exclosures were minor, indicating that reduced herbivore access is sufficient for sapling survival. Survival was higher in lawn than in rough in both exclosure types and for all species, indicating positive effects of preceding grazing. Soil tillage initially benefitted all species, but effects lasted for pioneers only, suggesting that – once introduced – wild boar rooting may affect woody species composition. We conclude that rewilding with herbivores can successfully form wood-pasture landscapes on abandoned agricultural land as long as grazing refuges are present that allow for sapling establishment. As grazing refuges are generally lacking on abandoned agricultural lands, where most rewilding is foreseen, we recommend that future projects consider the presence – or creation – of grazing refuges. [ABSTRACT FROM AUTHOR]

National and local governments need to step up efforts to effectively implement the post‐2020 global biodiversity framework of the Convention on Biological Diversity to halt and reverse worsening biodiversity trends. Drawing on recent advances in interdisciplinary biodiversity science, we propose a framework for improved implementation by national and subnational governments. First, the identification of actions and the promotion of ownership across stakeholders need to recognize the multiple values of biodiversity and account for remote responsibility. Second, cross‐sectorial implementation and mainstreaming should adopt scalable and multifunctional ecosystem restoration approaches and target positive futures for nature and people. Third, assessment of progress and adaptive management can be informed by novel biodiversity monitoring and modeling approaches handling the multidimensionality of biodiversity change. [ABSTRACT FROM AUTHOR]

Reassembling ecological communities and rebuilding habitats through active restoration treatments require curating the selection of plant species to use in seeding and planting mixes. Ideally, these mixes should be assembled based on attributes that support ecosystem function and services, promote plant and animal species interactions and ecological networks in restoration while balancing project constraints. Despite these critical considerations, it is common for species mixes to be selected opportunistically. Reframing the selection of seed mixes for restoration around ecological objectives is essential for success but accessible methods and tools are needed to support this effort.We developed a framework to optimize species seed mixes based on prioritizing plant species attributes to best support different objectives for ecosystem functions, services and trophic relationships such as pollination, seed dispersal and herbivory. We compared results to approaches where plant species are selected to represent plant taxonomic richness, dominant species and at random. We tested our framework in European alpine grasslands by identifying 176 plant species characteristic of the species pool, and identified 163 associated attributes affiliated to trophic relationships, ecosystem functions and services.In all cases, trophic relationships, ecosystem functions and services can be captured more efficiently through objective‐based prioritization using the functional identity of plant species. Solutions (plant species lists) can be compared quantitatively, in terms of costs, species or objectives. We confirm that a random draw of plant species from the regional plant species pool cannot be assumed to support other trophic groups and ecosystem functions and services.Synthesis and Applications. Our framework is presented as a proof‐of‐concept to help restoration practitioners better apply quantitative decision support to plant species selection to efficiently meet ecological restoration outcomes. Our approach may be tailored to any restoration initiative, habitat or restoration targets where seeding or planting mixes will be applied in active treatments. As global priority and resources are increasingly placed into restoration, this approach could be advanced to help make efficient decisions for many stages of the restoration process. [ABSTRACT FROM AUTHOR]

1. Over the last decades, biodiversity in agricultural landscapes has declined drastically. Initiatives to enhance biodiversity, such as agri-environment schemes, often have little effect, especially in intensively farmed landscapes. The effectiveness of conservation management may be improved by scheme implementation near high-quality habitats that can act as a source of species. We evaluated up to what distance high-quality habitats (nature reserves and artificially created flower-rich patches) affect the diversity of forbs and pollinators in intensively farmed landscapes of the Netherlands. 2. We surveyed forbs, inflorescences, bees and hover flies and estimated pollination services in transects along ditch banks extending 300 m from four nature reserves forming small islands in landscapes dominated by agriculture. 3. In a separate experiment, we surveyed inflorescences, bees and hover flies in 1500 m long transects on farmland adjacent to five newly introduced flower-rich patches and in five control transects. 4. Species density of forbs declined over the first 75 m and species density and abundance of hover flies declined over the first 125 m beyond the nature reserves. Beyond these distances, no further declines were observed. The effects of flower-rich patches were spatially limited. The species density and abundance of bees and hover flies were significantly enhanced in the flower-rich patch, but only the abundance of hover flies was enhanced up to 50 m beyond the patch. 5. Synthesis and applications. In intensively farmed areas, remnant high-quality habitats sustain more abundant and diverse pollinator and forb communities than the surrounding countryside. They do enhance biodiversity on nearby farmland but increases are spatially restricted (< 150 m) and relatively small. These habitats may therefore function only as dispersal sources for ecological restoration sites or agricultural fields under extensification schemes that are located in close proximity. Habitat restoration in intensively used farmland should therefore be implemented preferentially in the immediate vicinity of high-quality habitats. In the short term, newly created flower-rich habitats are no alternative to pre-existing seminatural habitats for the promotion of pollinators on nearby farmland. [ABSTRACT FROM AUTHOR]

Identifying patterns in the effects of temperature on species' population abundances could help develop a general framework for predicting the consequences of climate change across different communities and realms. We used long-term population time series data from terrestrial, freshwater, and marine species communitieswithin central Europe to compare the effects of temperature on abundance across a broad range of taxonomic groups.We askedwhether there was anaverage relationship betweentemperatures in different seasons andannual abundances of species in a community, and whether species attributes (temperature range of distribution, range size, habitat breadth, dispersal ability, body size, and lifespan) explained interspecific variation in the relationship between temperature and abundance. We found that, on average, warmer winter temperatureswere associatedwith greater abundances in terrestrial communities (ground beetles, spiders, and birds) but not always in aquatic communities (freshwater and marine invertebrates and fish). The abundances of species with large geographical ranges, larger body sizes, and longer lifespans tended to be less related to temperature. Our results suggest that climate changemay have, in general, positive effects on species' abundanceswithinmany terrestrial communities in central Europe while the effects are less predictable in aquatic communities. [ABSTRACT FROM AUTHOR]

A summary is presented of an article published online at http://dx.doi.org/10.1126/science.aav5570 concerning challenges in rewilding complex natural ecosystems. It focuses on developing a guideline for rewilding efforts that are applicable for a variety of approaches to promote beneficial interaction between nature and society. It comments on structural restoration planning which involves managers, researchers, and stakeholders and includes adaptive management and ecosystem monitoring.