AimBiodiversity is rapidly disappearing at local and global scales also affecting the functional diversity of ecosystems. We aimed to assess whether functional diversity was correlated with species diversity and whether both were affected by similar land use and vegetation structure drivers. Better understanding of these relationships will allow us to improve our predictions regarding the effects of future changes in land use on ecosystem functions and services. LocationThe Netherlands. MethodsWe compiled a dataset of c.3 million observations of 66 out of 106 known Dutch butterfly species collected across 6,075 sampling locations during a period of 7 years, together with very high-resolution maps of land use and countrywide vegetation structure data. Using a mixed-effects modelling framework, we investigated the relationship between functional and species diversity and their main land use and vegetation structure drivers. ResultsWe found that high species diversity does not translate into high functional diversity, as shown by their different spatial distribution patterns in the landscape. Functional and species diversity are mainly driven by different sets of structural and land use parameters (especially average vegetation height, amount of vegetation between 0.5 and 2m, natural grassland, sandy soils vegetation, marsh vegetation and urban areas). We showed that it is a combination of both vegetation structural characteristics and land use variables that defines functional and species diversity. Main conclusionsFunctional diversity and species diversity of butterflies are not consistently correlated and must therefore be treated separately. High functional diversity levels occurred even in areas with low species diversity. Thus, conservation actions may differ depending on whether the focus is on conservation of high functional diversity or high species diversity. A more integrative analysis of biodiversity at both species and trait levels is needed to infer the full effects of environmental change on ecosystem functioning.

Changes in climate and land use can have important impacts on biodiversity. Species respond to such environmental modifications by adapting to new conditions or by shifting their geographic distributions towards more suitable areas. The latter might be constrained by species’ functional traits that influence their ability to move, reproduce or establish. Here, we show that functional traits related to dispersal, reproduction, habitat use and diet have influenced how three pollinator groups (bees, butterflies and hoverflies) responded to changes in climate and land-use in the Netherlands since 1950. Across the three pollinator groups, we found pronounced areal range expansions (>53%) and modelled range shifts towards the north (all taxa: 17–22 km), west (bees: 14 km) and east (butterflies: 11 km). The importance of specific functional traits for explaining distributional changes varied among pollinator groups. Larval diet preferences (i.e. carnivorous vs. herbivorous/detritivorous and nitrogen values of host plants, respectively) were important for hoverflies and butterflies, adult body size for hoverflies, and flight period length for all groups. Moreover, interactions among multiple traits were important to explain species’ geographic range shifts, suggesting that taxon-specific multi-trait analyses are needed to predict how global change will affect biodiversity and ecosystem services.

Simple Summary There has been a widespread decline of many plants and animals driven at least partly by climate change. This pattern is not universal, and certain taxa are increasing in abundance and distribution. A better understanding of population dynamics and range expansions in different areas and how different taxa respond to changing temperatures is therefore important, as we are facing a warmer and more fluctuating climate in the future. In this study, we show that range-expanding moths in southeastern Sweden have increased their species richness over time and that abundance and population growth increase during years with higher temperatures. We also show that population growth in range-expanding moths is fastest in the first years after establishment in an area. These shifts in distribution and abundance of moths may lead to rapid and dramatic changes in community compositions, with potentially widespread consequences for species interactions and ecosystem functioning. Parallel to the widespread decline of plants and animals, there is also an ongoing expansion of many species, which is especially pronounced in certain taxonomic groups and in northern latitudes. In order to inform an improved understanding of population dynamics in range-expanding taxa, we studied species richness, abundance and population growth in a sample of 25,138 individuals representing 107 range-expanding moth species at three light-trap sites in southeastern Sweden over 16 years (from 2005 to 2020) in relation to temperature and years since colonisation. Species richness and average abundance across range-expanding moths increased significantly over time, indicating a continuous influx of species expanding their ranges northward. Furthermore, average abundance and population growth increased significantly with increasing average ambient air temperature during the recording year, and average abundance also increased significantly with increasing temperature during the previous year. In general, population growth increased between years (growth rate > 1), although the population growth rate decreased significantly in association with years since colonisation. These findings highlight that, in contrast to several other studies in different parts of the world, species richness and abundance have increased in southeastern Sweden, partly because the warming climate enables range-expanding moths to realise their capacity for rapid distribution shifts and population growth. This may lead to fast and dramatic changes in community composition, with consequences for species interactions and the functioning of ecosystems. These findings are also of applied relevance for agriculture and forestry in that they can help to forecast the impacts of future invasive pest species.

Environmental and climatic changes are inducing population declines in numerous species. However, certain species demonstrate remarkable resilience, exhibiting both population growth and range expansion. This longitudinal study in Sweden carried out over two decades (2004–2023) examines the noctuid moths Mythimna albipuncta and Hoplodrina ambigua. Abundance and phenology data were gathered from three light traps in southeastern Sweden and integrated with distribution and phenology data from the Global Biodiversity Information Facility. In M. albipuncta, the distribution area expanded from 7 to 76 occupied grids (60 km2) and the abundance increased from 7 to 6136 individuals, while in H. ambigua, the distribution area expanded from 1 to 87 occupied grids and the abundance increased from 0 to 6937 individuals, during the course of the study. Furthermore, a positive yearly association was observed between the number of occupied grids and light trap abundance for each species. We also found significant extensions in the adult flight periods of more than 100 days in both species. Light traps emerged as an effective monitoring tool, with light trap abundance as a reliable proxy for distribution changes. Our findings demonstrate that the studied species cope very well with environmental and climatic changes. Given their role as dominant links between primary producers and higher trophic levels, abundance and distribution shifts of these ecological engineers have the potential to cascade up and down in the ecosystem.

A high capacity for long‐distance dispersal is a key to success for species confronted with environmental heterogeneity, habitat modification, fragmentation and loss. However, dispersal capacity is difficult to quantify and therefore poorly known in most taxa. Here, we report on a test for an association of variation in dispersal capacity with variable colouration of noctuid moths. First, using data from 12 experienced lepidopterologists, we showed that despite variation among experts in average assessments, different species are consistently classified as having non‐variable, variable or highly variable colour patterns when assessed by different experts. We then compared the incidence of non‐resident species with high inter‐individual variation in colour patterns recorded on the isolated island Utklippan (n = 47), with that in a species pool of potential long‐distance dispersers from the nearest mainland (n = 295). Species with high inter‐individual colour pattern variation were over‐represented on the island compared with species having non‐variable colouration. This finding constitutes rare evidence from the wild of long‐distance dispersal, measured on a spatial scale relevant for moths when tracking habitats in fragmented and changing landscapes or when keeping pace with environmental challenges associated with climate change. Finally, we showed that Swedish noctuid moths classified as agricultural pests (n = 28) had more variable colour patterns compared with non‐pests (n = 368). The majority of agricultural pests were also recorded on the isolated island, an outcome that is indicative of pest species having high dispersal capacity. Data on colour pattern variation may thus offer a simple and cost‐effective proxy to estimate dispersal capacity and can also help identify potential pest species. Our findings are potentially useful when modelling and predicting population and range dynamics of species in spatiotemporally heterogeneous environments, with direct implications for conservation biology and pest management.

Mobility is an important factor influencing the range and persistence of local populations. However, mobility is very difficult to measure empirically and thus is poorly known in most taxa. Since ecological characteristics have been suggested as good estimators of mobility, we here explore the association between ecological characteristics and mobility. We surveyed night-active moths on a Swedish island, situated 16 km from the mainland, and compared ecological characteristics of the non-resident moths found on the island with those of a species pool of assumed potential vagrants from the neighbouring mainland. Species associated with high mobility were characterised by a large range, a high population density, an activity period during warm temperatures and by being habitat generalists or preferring open habitats. The generally assumed view of poly- and oligophagous species being more mobile than monophagous species was obscured by the effect of population density. Poly- and oligophagous species had higher population densities than did monophagous species, which probably explain their higher mobility found in this study. Our result highlights the need to consider the influence of ecological characteristics on mobility. This in turn will have implications for an increased understanding of distribution patterns, population persistence and how to prioritise conservation actions, especially since habitats and climate are under dramatic changes. In taxa where data on mobility are poor, ecological characteristics can be used as a proxy for mobility.

Abstract. 1. Mobility is important for the understanding of how species survive infragmented landscapes and cope with increasing rates of habitat and climate change.However, mobility is a difficult trait to explore and is poorly known in most taxa.Species traits have been studied in relation to range shifts, extinction risks, andresponses to habitat area and isolation, and have also been suggested as good estimatorsof mobility. Here we explore the relation between mobility and species traits in noctuidmoths.2. We sampled noctuid moths by an automatic light-trap on an island far out in theBaltic Sea. We compared traits of the non-resident species on the island with traits ofa species pool of assumed potential migrants from the Swedish mainland.3. Mobility was significantly related to adult activity period, length of flightperiod, and the interaction between host-plant specificity and distribution area. Widelydistributed host-plant generalists were more mobile than host-plant specialists withmore restricted distribution, and species with an adult activity period in August toSeptember moved to the island to a higher extent than species with an adult activityperiod in May to July. Our results remained qualitatively robust in additional analyses,after controlling for phylogeny and including all species recorded on the island, exceptfor the trait ‘length of flight period’.4. Our results highlight the importance of the relation between mobility and speciestraits. Noctuid moths with certain traits move over longer distances than earlier known.This finding is important to include when predicting range dynamics in fragmentedand changing landscapes, and when conservation measures of species are devised.

Theory posits that species with inter-individual variation in colour patterns should beless vulnerable to extinction, compared with species that do not vary in colour. Toevaluate this prediction, we explored whether differences in colour pattern diversitywas associated with extinction risk, using red-list status for more than 350 species ofnoctuid moths in Sweden. We also evaluated six other species characteristics thathave been proposed to influence extinction risk namely: host plant niche breadth,habitat type, area of occupancy, body size, overwintering life-history stage and lengthof flight activity period. We found that species with variable colour patterns hadreduced extinction risk overall compared with species having non-variable colourpatterns, and that this difference was pronounced more strongly among species havingsmaller areas of occupancy. There were also significant associations with hostplant niche breadth and habitat type, extinction risk being lower on average in polyphagousspecies and in generalist species that occupied different habitat types. Thesefindings represent the first evidence for insects that variable colouration is associatedwith reduced extinction risks. Information on colour pattern variation is readily availablefor many taxa and may be used as a cost-effective proxy for endangerment inthe work of halting national and global biodiversity loss.

Recent global change has had a substantial influence on the distribution of organisms, and many species are currently expanding their ranges. To evaluate the underlying processes, long-term data with good geographic resolution are essential. One important but generally overlooked data source is offered by the taxon-specific national catalogues of first provincial records that are kept in many countries. Here, we use such data to quantify trait-based influences on range expansion in Swedish butterflies and moths between 1973 and 2010. Of 282 species meeting pre-defined quality criteria, 170 expanded their northern range margin, with a mean expansion rate of 2.7 km per year. The analyses demonstrate that habitat and diet generalists, forest species and species active during warm conditions have expanded their ranges more rapidly than other species. Notably, range expansion in diet specialists was positively related to a nitrogen-favoured larval diet, an effect not found among oligo- or polyphagous species. In contrast to the general view, this shows that specialist species can undergo rapid range expansion. We suggest that increased areas of nitrogen-rich habitat, and increased availability of a nitrogen-favoured diet, are among the most important drivers of range expansions, potentially having far-reaching consequences for a wide variety of organisms.

Atmospheric nitrogen deposition and other sources of environmental eutrophication have increased substantially over the past century worldwide, notwithstanding the recent declining trends in Europe. Despite the recognized susceptibility of plants to eutrophication, few studies evaluated how impacts propagate to consumers, such as pollinators. Here we aim to test if soil eutrophication contributes to the temporal dynamics of pollinators and their larval resources. We used a temporally and spatially explicit historical dataset with information on species occurrences to test if soil eutrophication, and more specifically nitrogen deposition, contributes to the patterns of change of plant and pollinator richness in the Netherlands over an 80 yr period. We focus on bees and butterflies, two groups for which we have good knowledge of larval resources that allowed us to define groups of species with different nitrogen related diet preferences. For each group we estimated richness changes between different 20-yr periods at local, regional and national scale, using analytical methods developed for analyzing richness changes based on collection data. Our findings suggest that the impacts of soil eutrophication on plant communities propagate to higher trophic levels, but with a time-lag. Pollinators with nitrogen-related diet preferences were particularly affected, in turn potentially impairing the performance of pollinator-dependent plants. Pollinator declines continued even after their focal plants started to recover. In addition, our results suggest that current levels of nitrogen deposition still have a negative impact on most groups here analyzed, constraining richness recoveries and accentuating declines. Our results indicate that the global increase in nitrogen availability plays an important role in the ongoing pollinator decline. Consequently, species tolerances to soil nitrogen levels should be considered across all trophic levels in management plans that aim to halt biodiversity loss and enhance ecosystems services worldwide.

Land-use change and intensification threaten bee populations worldwide, imperilling pollination services. Global models are needed to better characterise, project, and mitigate bees' responses to these human impacts. The available data are, however, geographically and taxonomically unrepresentative; most data are from North America and Western Europe, overrepresenting bumblebees and raising concerns that model results may not be generalizable to other regions and taxa. To assess whether the geographic and taxonomic biases of data could undermine effectiveness of models for conservation policy, we have collated from the published literature a global dataset of bee diversity at sites facing land-use change and intensification, and assess whether bee responses to these pressures vary across 11 regions (Western, Northern, Eastern and Southern Europe; North, Central and South America; Australia and New Zealand; South East Asia; Middle and Southern Africa) and between bumblebees and other bees. Our analyses highlight strong regionally-based responses of total abundance, species richness and Simpson's diversity to land use, caused by variation in the sensitivity of species and potentially in the nature of threats. These results suggest that global extrapolation of models based on geographically and taxonomically restricted data may underestimate the true uncertainty, increasing the risk of ecological surprises.

Range shifts have been documented in many organisms, and climate change has been implicated asa contributing driver of latitudinal and altitudinal range modifications. However, little is known aboutwhat species trait(s) allow for faster environmental tracking and improved capacity for distributionexpansions. We used data for 416 species of moths, and show that range limits in Sweden have shifted tothe north by on average 52.4 km per decade between 1973 and 2014. When also including non-expandingspecies, average expansion rate was 23.2 km per decade. The rate of boundary shifts increased withincreasing levels of inter-individual variation in colour patterns and decreased with increasing latitude. Theassociation with colour patterns indicate that variation in this functionally important trait enables speciesto cope with novel and changing conditions. Northern range limits also increased with average abundanceand decreased with increasing year-to-year abundance fluctuations, implicating production of dispersersas a driver of range dynamics. Studies of terrestrial animals show that rates of poleward shifts differbetween taxonomic groups, increase over time, and depend on study duration and latitude. Knowledge ofhow distribution shifts change with time, location, and species characteristics may improve projections ofresponses to climate change and aid the protection of biodiversity

Theory and recent reviews state that greater genetic and phenotypic variation should be beneficial for population abundance and stability. Experimental evaluations of this prediction are rare, of short duration and conducted under controlled environmental settings. The question whether greater diversity in functionally important traits stabilizes populations under more complex ecological conditions in the wild has not been systematically evaluated. Moths are mainly nocturnal, with a large variation in colour patterns among species, and constitute an important food source for many types of organisms. Here, we report the results of a long-term (2003-2013) monitoring study of 115 100 noctuid moths from 246 species. Analysis of time-series data provide rare evidence that species with higher levels of inter-individual variation in colour pattern have higher average abundances and undergo smaller between-year fluctuations compared with species having less variable colour patterns. The signature of interspecific temporal synchronization of abundance fluctuations was weak, suggesting that the dynamics were driven by species-specific biotic interactions rather than by some common, density-independent factor(s). We condude that individual variation in colour patterns dampens population abundance fluctuations, and suggest that this may partly reflect that colour pattern polymorphism provides protection from visually oriented predators and parasitoids.

Forests are pivotal for biodiversity, food webs, and human economies, and as carbon sinks their climate change mitigation potential is undisputed. However, whether trees continue to efficiently accumulate biomass at an increasing rate with age, how growth trajectories respond to climate change, and vary with latitude at species range margins is under debate. Here, we combine tree-ring data with biometric equation modeling to analyze how annual biomass increment varies according to tree age, species, latitude, and germination year. We generated 26,225 estimates of annual biomass increments for 136 individual trees, representing two evergreen gymnosperm conifer species ( Picea abies (L.) H.Karst., and Pinus sylvestris L.) and two deciduous angiosperm species ( Quercus spp. L. and Fagus sylvatica L.). Our dataset includes some old trees (range 150- 405 years), and samples from locations spanning >10 degrees latitude (55.0- 66.3 degrees N) in Sweden. Annual biomass increments varied considerably between species, years and among individual trees within stands. On average, biomass increment remained positive throughout the lifespan across trees, species, and latitudes. Age-specific biomass increment was higher in the deciduous than in the evergreen species and declined with increasing latitude within species. For spruce and beech, biomass increment increased significantly with germination year, possibly reflecting faster growth in recent times in response to a warmer climate. The findings have implications for forestry practices aimed at productivity, biodiversity conservation, and climate change mitigation.

Animal colour patterns long have provided information about key processes that drive the ecological and evolutionary dynamics of biological diversity. Theory and empirical evidence indicate that variation in colour patterns and other traits among individuals generally improves the performance of populations and species, for example by reducing predation risk, increasing establishment success, improving resilience to environmental change, and decreasing risk of extinction. However, little is known about whether and how variation in colour pattern among species is associated with variation in other phenotypic dimensions. To address this issue, we analysed associations of colour pattern with morphological, behavioural and life-history traits on the basis of data for nearly 400 species of noctuid moths. We found that moths with more variable colour patterns had longer flight activity periods, more diverse habitats and a greater number of host plant species than species with less variable colour patterns. Variable coloration in adult noctuid moths therefore can be considered as indicative of broader niches and generalist diets. Colour pattern variability was not significantly associated with overwintering stage or body size (wing span), and it was independent of whether the colour pattern of the larvae was non-variable, variable or highly variable. Colour pattern variation during the larval stage tended to increase as the duration of the flight activity period increased, but was independent of the length of the larval period, diet breadth and habitat use. The realization that information on colour pattern variation in adult moths, and possibly other organisms, offers a proxy for niche breadth and dietary generalization can inform management and conservation biology.

Adaptive governance of areas set aside for future protection of biodiversity, sustainable production, and recreation requires knowledge about whether and how effects of area protection are modulated by climate change and redistribution of species. To investigate this, we compare biodiversity of plants (assessed using vegetation plots) and arthropods (collected with Malaise traps, analyzed using metabarcoding) and productivity (tree growth, determined using dendrochronology) in protected and non-protected oak ( Quercus spp.) forests along a latitudinal gradient (55.6 degrees N- 60.8 degrees N) in Sweden. We also compare historical, recent and projected future climate in the region. In contrast to established global latitudinal diversity gradients, species richness of plants and arthropods increased northwards, possibly reflecting recent climate-induced community redistributions, but neither was higher in protected than in non-protected areas, nor associated with contemporary ground temperature. Species composition of arthropods also did not differ between protected and non-protected areas. Arthropod biomass increased with latitude, suggesting that the magnitude of cascading effects mediated via their roles as pollinators, herbivores, and prey for other trophic levels, varies geographically and will change with a moving climate. Annual growth rate of oaks (an ecosystem service in the form of biomass increase and carbon sequestration) was independent of latitude and did not differ between protected and non-protected areas. Our findings question the efficacy of contemporary designation and management of protected oak forests, and emphasize that development and implementation of modified climate smart conservation strategies is needed to safeguard ecosystem functioning, biodiversity, and recreational values of protected forest areas against future challenges.

The diversity of herbivorous insects may arise from colonization and subsequent specialization on different hostplants. Such specialization requires changes in several insect traits, which may lead to host race formation if they reducegene flow among populations that feed on different plants. Behavioural changes may play a relevant role in host race formation,for example if different races evolve distinct sexual communication signals or adult phenology. Previous research hasrevealed differences in larval phenology in different host-associated populations of the browntail moth, Euproctis chrysorrhoea(Lepidoptera: Erebidae). Here, sex pheromones among populations of this species are compared, and pheromonetrapping data obtained is used in the field to build a phenological model that tests whether populations that feed on differentplants differ in their adult flight period. The chemical and electrophysiological analyses revealed that two E. chrysorrhoeapopulations (on Prunus and on Arbutus unedo) use the same sex pheromone component for mate finding. Our trapping data,however, showed that males fly on average 25 days earlier in populations whose larvae feed on A. unedo compared to thosewhose larvae feed on Quercus species. Although the shifted phenology described here may underlie host-plant specializationin E. chrysorrhoea, and adults of this species are short-lived, the use of a common sexual pheromone and a largeoverlap in flight periods suggest that host race formation via allochronic isolation is unlikely in this moth.

Context Conservation of endangered species necessitates an in-depth understanding of their ecological requirements. Particularly in landscape ecology, the behavioural tendencies of threatened butterfly species in Gotland, a biodiversity-rich island in the Baltic Sea, become crucial.

Objectives The primary aim of this study was to elucidate the movement patterns of three threatened butterfly species-Euphydryas aurinia, Parnassius apollo, and Phengaris arion-in Gotland and to identify the influence of specific land characteristics on these patterns.

Methods Our study, conducted from 2017 to 2020 across 60 km2 in Gotland, involved detailed capture-mark-recapture (CMR) efforts of 29,584 captures including 16,223 unique butterflies. We investigate the departure and arrival events of butterflies, specifically focusing on the associations between movements when individuals leave or enter a hectare grid different from their previously recorded location and key landscape features: open vegetated land, ground moisture, and forest cover. We model landscape features to examine the interplay between these and butterfly movement patterns, providing insights into preferred landscape features and conservation strategies.

Results Among the 4821 arrivals and 5083 departures documented, the species exhibited differential responses to the evaluated habitat features. Both E. aurinia and P. apollo displayed a positive density-dependent dispersal, while P. arion's movements were not significantly associated with any of the examined habitat features. Landscape properties like open vegetated land and ground moisture index statistically influenced the likelihood of arrival and departure.

Conclusions The study accentuates the relationship between land cover and the behavioural tendencies of the subject butterfly species. It has broader implications for the targeted habitat management strategies that would benefit threatened butterfly populations in Gotland.

Knowing how species’ traits relate to processes that underlie occupancy patterns such as colonisation and population persistence, is important for our understanding of how species survive in fragmented and changing landscapes. We used automatic UV light-traps to sample noctuidmoths on two remote islands, and compared traits of island occupants with those of a species pool from mainland southeast Sweden. Widely distributed species, generalist species, species with a long adult activity period and species active late in the summer had higher probability of occupancy on the remote islands. The results were consistent between islands. The traits of host plant specificity and species with an adult activity period during late summer remained robust and were statistically significant after controlling for any possible phylogenetic bias. This indicates that species exhibiting those traits survive better when habitat and climate changes. It is crucial to includeour results in; (1) conservation planning, e.g. when devising conservation measures in fragmented landscapes; (2) for predictions of future occupancy patterns; and (3) ecosystem impact assessments, e.g. the importance of moths as pollinators, herbivores and being the functional link between parasitoids, plants, consumers and predators.

Biodiversity is challenged worldwide by exploitation, global warming, changes in land use and increasing urbanization. It is hypothesized that communities in urban areas should consist primarily of generalist species with broad niches that are able to cope with novel, variable, fragmented, warmer and unpredictable environments shaped by human pressures. We surveyed moth communities in three cities in northern Europe and compared them with neighbouring moth assemblages constituting species pools of potential colonizers. We found that urban moth communities consisted of multi-dimensional generalist species that had larger distribution ranges, more variable colour patterns, longer reproductive seasons, broader diets, were more likely to overwinter as an egg, more thermophilic, and occupied more habitat types compared with moth communities in surrounding areas. When body size was analysed separately, results indicated that city occupancy was associated with larger size, but this effect disappeared when body size was analysed together with the other traits. Our findings indicate that urbanization imposes a spatial filtering process in favour of thermophilic species characterized by high intraspecific diversity and multi-dimensional generalist lifestyles over specialized species with narrow niches.

Recently developed glacier forelands provide valuable insights into vegetation dynamics. We studied the vascular plants in the glacier forelands of the Almajallojekna glacier in comparison to the plants in the surrounding area. The glacier is retreating rapidly at an average rate of 0.17 km(2) per year from 1898 to 2012. In the newly emerged glacier forelands, we found that 32 percent of the 381 plant taxa occurred in the surrounding region. Sixty-eight plant species were present on the youngest terrain (0-31 y), an additional thirteen species occurred on terrain aged 32-53 years, and an additional forty-two species were detected on terrain aged 54-114 years. Of the surrounding species pool, plant species that had successfully established in recently deglaciated terrains were characterized by high regional abundance and low seed weight, and they were more likely to be members of the plant families Saxifragaceae, Salicaceae, and Asteraceae. Woody plant species with a preference for well-drained soils were more likely to be present in the youngest terrain. Our results show that the vegetation of glacier forelands is developing rapidly depending on the plant species in the surrounding area and the species' life-history traits.

It has been hypothesized that species with more variable color patterns should have higher establishment success and be less sensitive to environmental changes and local extinction compared with species that do not vary in color. This difference in colonization/extinction balance should manifest as larger continental range distributions and modulate the species-area relationship on true islands. We evaluated these predictions using data for 1216 species of butterflies and moths that differed with regard to inter-individual variation in color pattern. We show that species with more variable color patterns have larger continental range sizes in Europe compared with non-variable species. We also provide rare evidence that the slope of the species-area relationship on islands is steeper for species having non-variable color patterns, suggesting that to preserve 60% of non-variable species would require an area twice as large compared to what would be needed to preserve 60% of variable species. Our findings suggest that combining information on ecological characteristics with presence/absence data from small and medium sized islands can help identify traits that drive species range patterns at the continental scale, and that individual variation in color pattern can be used as a proxy for ecological generalization and the ability to cope with environmental change.

As moths are vital components of ecosystems and serve as important bioindicators, understanding the dynamics of their communities and the factors influencing these dynamics, such as anthropogenic impacts, is crucial to understand the ecological processes. Our study focuses on two provinces in southern Sweden, V & auml;sterg & ouml;tland and Sm & aring;land, where we used province records from 1974 to 2019 in combination with light traps (in 2020) to record the presence and abundance of moth species, subsequently assessing species traits to determine potential associations with their presence in anthropogenically modified landscapes. This study design provides a unique opportunity to assess temporal changes in moth communities and their responses to shifts in environmental conditions, including anthropogenic impacts. Across the V & auml;sterg & ouml;tland and Sm & aring;land provinces in Sweden, we recorded 776 moth taxa belonging to fourteen different taxonomic families of mainly Macroheterocera. We captured 44% and 28% of the total moth species known from these provinces in our traps in Bor & aring;s (V & auml;sterg & ouml;tland) and Kalmar (Sm & aring;land), respectively. In 2020, the species richness and abundance were higher in Bor & aring;s than in Kalmar, while the Shannon and Simpson diversity indices revealed a higher species diversity in Kalmar. Between 1974 and 2019, the colonisation rates of the provinces increased faster in Sm & aring;land. Ninety-three species were found to have colonised these provinces since 1974, showing that species richness increased over the study period. We reveal significant associations between the probability of a species being present in the traps and distinct traits compared to a provincial species pool. Traits over-represented in the traps included species with a high variation in colour patterns, generalist habitat preferences, extended flight periods, lower host plant specificity, and overwintering primarily as eggs. Our findings underscore the ongoing ecological filtering that favours certain species-specific traits. This study sheds light on the roles of climate change and anthropogenic impacts in shaping moth biodiversity, offers key insights into the ecological processes involved, and can guide future conservation efforts.

We used observational data collected during a mark-recapture study that generated a total of 7503 captures of 6108 unique individuals representing three endangered butterfly species to quantify inter-and intraindividual variation in temperature utilization and examine how activity patterns vary according to season, time of day, and ambient temperature. The Marsh Fritillary, the Apollo, and the Large Blue differed in utilized temperatures and phenology. Their daily activity patterns responded differently to temperature, in part depending on whether they were active in the beginning, middle or end of the season, in part reflecting interindividual variation and intraindividual flexibility, and in part owing to differences in ecology, morphology, and colouration. Activity temperatures varied over the season, and the Apollo and the Large Blue were primarily active at the highest available ambient temperatures (on the warmest days and during the warmest part of the day). The Marsh Fritillary was active early in the season and decreased activity during the highest temperatures. The relationship between individual lifespan and the average temperature was qualitatively different in the three species pointing to species-specific selection. Lifespan increased with an increasing range of utilized temperatures in all species, possibly reflecting that intra-individual flexibility comes with a general survival benefit.

It remains unclear to what extent yearly weather variation and spatial variation in microclimate influences the outcome of interacting plant-animal species and whether responses differ between life stages. We collected data over several years on 46 ha on File Hajdar, Gotland, Sweden, and executed a complete mapping of larva nests (n = 776) and imago (n = 5,952) of the marsh fritillary butterfly Euphydryas aurinia and its host plant Succisa pratensis. The phenology of the butterflies and the major nectar plants visited varied among years. The duration of the adult flight period decreased with increasing ambient air temperatures. The density of butterflies, host plants, and host plant leaf size increased between years with increasing precipitation in the preceding year, and decreased with increasing average ambient air temperature in the preceding year. In 2021-2022 we deployed a unmanned aerial vehicle (UAV) with a high-resolution thermal sensor to measure spatial variation in surface temperatures in the study area. We found that survival from the egg to the larva stage increased with increasing surface temperature and host plant density. Host plants and larva nests generally occupied warmer microhabitats compared to imago butterflies. The results further suggested that the relationships linking surface temperature to the densities of imago, larva, host plants, and leaf size differed qualitatively between years. In 2017, larva nests and host plant density increased with increasing surface temperatures, and butterflies showed a non-linear response with a density peak at intermediate temperatures. As a result of the extreme drought in 2018 there was a reduction in maximum leaf size, and in the densities of plants, larvae, and butterflies. Moreover, the slopes of the relationships linking the density of larvae, butterflies, and plants to temperature shifted from linear positive to negative or curvilinear. Our findings demonstrate how yearly weather variation and heterogeneous surface temperatures can drive the spatiotemporal distribution and dynamics of butterflies and their host plants. The context specificity of the responses indicated by our results makes it challenging to project how climate change will affect the dynamics of ecological communities.

While some species rapidly decline, compromising vital ecosystem services, others are stable or even increasing in abundance. We studied shifts in species richness and abundance of moths over five decades in Central Sweden and examined whether and how changes were associated with phenotypic traits. We combined information from captures in a light trap in historical time (the 1970s) and contemporarily (2019) with provincial colonisation records. Both community species richness and the abundance of moths increased between the time periods. A large fraction (38%) of the 410 species were not present in both periods, 101 species had colonised the area (an estimated influx of about 2.5 new species per year), and 51 species had disappeared (an estimated local extinction rate of about 1.16 species per year). Abundance increased with an increasing number of host plants and with increasing colour pattern variation. The composition of the community shifted towards species characterised by smaller wingspan and larger ranges. The functional trait variability of the moth community was homogenised from the historical to the contemporary period, in line with reports from other species communities in modern landscapes. However, our finding of a concomitant increase in species richness and total abundance differs from the results of many recent studies of insect communities in other geographic regions.Implication for insect conservationWe conclude that the entire boreal moth fauna is undergoing a substantial biogeographical shift, changing to the moth species historically occurring at more southern latitudes. The alterations in species composition, overall abundance, and community-wide trait distribution described here may cascade up and down in the ecosystem because moths are important pollinators, herbivores, and prey.

Oak species worldwide face substantial challenges in natural recruitment, significantly affecting biodiversity and ecosystem services. Oaks are a keystone species in northern temperate zones, influencing ecosystem dynamics. This study analysed oak regeneration patterns from 29 oak stands ( Quercus spp.) across southern Sweden up to the species ' northern range limit. The study focused on two native species, Q. robur and Q. petraea , and one introduced species, Q. rubra , used in Swedish forestry. We aimed to evaluate whether and how oak regeneration was i) associated with latitude, ii) influenced by ground moisture and nitrogen levels, and iii) correlated with stand age, as well as to iv) compare regeneration rates among the species. Contrary to the hypothesis that oak regeneration should decline towards the range margin, our results did not indicate any latitudinal association. This finding raises the possibility of a future northward range expansion for oaks. We also observed that oak regeneration was positively correlated with stand age, while increasing nitrogen and ground moisture levels were inversely related to regeneration. The positive age-dependent effect on recruitment also indicates that species recruitment dynamics within forests may be modified via age-dependent effects within the tree community, with implications for forestry and conservation management. Notably, the natural regeneration of the introduced Q. rubra indicates its successful adaptation to Swedish climate and forests. This study represents Sweden 's first large-scale analysis of oak regeneration across multiple oak species. Future research should prioritise longitudinal monitoring, particularly at the northern range limits, and further investigate the expansion of the potentially invasive Q. rubra .

Human pressures on the environment are changing spatially and temporally, with profound implications for the planet's biodiversity. Butterflies are important indicators for environmental change and are a suitable group to detect areas of high conservation concern and prioritize conservation efforts. To obtain data to support urgently-needed conservation measures, we surveyed the butterfly fauna in a mountainous region of northern Vietnam, using transect counts over 8 months (121 survey days) from June 2014 to April 2015. In total, we recorded > 26,000 butterflies belonging to 231 species, including at least two species new to Vietnam, three red-listed and protected species listed by CITES. Most species were rare: we recorded members of 100 species ae<currency>5 times and 52 species just once. Males dominated the sample, accounting for 81% of all observed butterflies and all members of 84 observed species. Species richness and abundance were highest in July, and there were surprisingly large changes in species composition between months. Species richness curves reached saturation, indicating that we detected most species present in the area, except for members of two families (Lycaenidae and Hesperiidae). Our results highlight the importance of thorough studies using standardized methods, capable of detecting most species in an area, over a whole season. There are urgent needs to integrate butterflies into conservation programs and use their potential as indicator species of habitat degradation and land use intensity.

The species-area relationship (SAR) is one of the most thoroughly investigated empirical relationships in ecology. Two theories have been proposed to explain SARs: classical island biogeography theory and niche theory. Classical island biogeography theory considers the processes of persistence, extinction, and colonization, whereas niche theory focuses on species requirements, such as habitat and resource use. Recent studies have called for the unification of these two theories to better explain the underlying mechanisms that generates SARs. In this context, species traits that can be related to each theory seem promising. Here we analyzed the SARs of butterfly and moth assemblages on islands differing in size and isolation. We tested whether species traits modify the SAR and the response to isolation. In addition to the expected overall effects on the area, traits related to each of the two theories increased the model fit, from 69% up to 90%. Steeper slopes have been shown to have a particularly higher sensitivity to area, which was indicated by species with restricted range (slope  = 0.82), narrow dietary niche (slope  = 0.59), low abundance (slope  = 0.52), and low reproductive potential (slope  = 0.51). We concluded that considering species traits by analyzing SARs yields considerable potential for unifying island biogeography theory and niche theory, and that the systematic and predictable effects observed when considering traits can help to guide conservation and management actions.

Monitoring pollinator populations is crucial for understanding biodiversity trends and ensuring the health of ecosystems, especially in agricultural landscapes. This study introduces the "Knautia Pollinator Walk" as a new method for tracking pollinator diversity and abundance. By observing pollinators visiting the inflorescence of Knautia arvensis, we found significant correlations between pollinators and land use, and there were significant differences in pollinator communities between regions. Our findings highlight the importance of habitat type in influencing pollinator populations, offering a valuable tool for conservation efforts. Declining populations of native pollinators, especially wild bees, underline the urgent need for effective monitoring within agricultural ecosystems. This study aims to (i) establish the 'Knautia Pollinator Walk' as an innovative pollinator monitoring method, (ii) examine the link between pollinator richness/density and land cover, and (iii) assess if specialist solitary bees indicate pollinator abundance and morphogroup richness. The approach involves surveying 500 Knautia arvensis inflorescences per site thrice per season. Observations of 11,567 pollinators across 203 taxa showed significant correlations between pollinator diversity and land use. Pollinator populations fluctuated with land cover type, increasing in open areas but decreasing or stabilising in forested and shrubby regions. Noteworthy differences in pollinator types were seen between Russia (solitary bees, small Diptera, Lepidoptera) and Sweden (bumblebees, beetles, furry Diptera). The "Knautia Pollinator Walk" shows promising signs of being an effective tool for monitoring spatiotemporal biodiversity trends. The method offers a scalable approach to pollinator monitoring, which is essential for developing conservation strategies and supporting pollinator populations.

Body size latitudinal clines have been widley explained by the Bergmann's rule in homeothermic vertebrates. However, there is no general consensus in poikilotherms organisms in particular in insects that represent the large majority of wildlife. Among them, bees are a highly diverse pollinators group with high economic and ecological value. Nevertheless, no comprehensive studies of species assemblages at a phylogenetically larger scale have been carried out even if they could identify the traits and the ecological conditions that generate different patterns of latitudinal size variation. We aimed to test Bergmann's rule for wild bees by assessing relationships between body size and latitude at continental and community levels. We tested our hypotheses for bees showing different life history traits (i.e. sociality and nesting behaviour). We used 142 008 distribution records of 615 bee species at 50 x 50 km (CGRS) grids across the West Palearctic. We then applied generalized least squares fitted linear model (GLS) to assess the relationship between latitude and mean body size of bees, taking into account spatial autocorrelation. For all bee species grouped, mean body size increased with higher latitudes, and so followed Bergmann's rule. However, considering bee genera separately, four genera were consistent with Bergmann's rule, while three showed a converse trend, and three showed no significant cline. All life history traits used here (i.e. solitary, social and parasitic behaviour; ground and stem nesting behaviour) displayed a Bergmann's cline. In general there is a main trend for larger bees in colder habitats, which is likely to be related to their thermoregulatory abilities and partial endothermy, even if a 'season length effect' (i.e. shorter foraging season) is a potential driver of the converse Bergmann's cline particularly in bumblebees.

Climate change will cause alterations in tree species ranges. Non-native tree species are likely to be increasingly used in production forests, due to their often better adaptation to a warmer climate and their lower susceptibility to pests and pathogens. Trees form an important habitat for numerous species, many of which are more or less specialised regarding tree species. Thus, the tree-associated flora and fauna may be heavily impacted if nonnative trees replace native ones. Risk assessments from the introduction of non-native trees must rest on a solid knowledge base, including insights into the potential of such trees to function as biodiversity substitutes, i. e. to host similar biodiversity as closely related native tree species. In a study in temperate Sweden, we inventoried epiphytic lichens and bryophytes on ten random trees in each of 28 stands (14 stands of North American red oak Quercus rubra and 14 stands of native oak Q. robur/petraea), to compare species richness and composition. Overall, 101 lichen taxa and 35 bryophyte taxa were identified, and we found a generally higher diversity for native oak. The regional species richness (gamma diversity) for both lichens and bryophytes was higher in native oak than in red oak, and the lichen species richness at stand level (alpha diversity) was nearly significantly higher. Lichen composition differed between the two oak species, while there was no difference for bryophytes. More lichens were strongly associated with native oak than red oak, while most bryophyte species were generalists with no specific preference for either oak taxa. Bark structure was an important explanatory variable separating the lichen epiphytes, with species preferring smooth bark largely confined to red oak. In conclusion, our study suggests that substituting native oak with red oak could have adverse consequences for epiphytic lichen populations associated with native oak, resulting in a decline of several species. However, certain lichen and bryophyte species were exclusively found on Q. rubra, implying that incorporating a proportion of red oak stands in southern Swedish landscapes may enhance diversity. Further research is needed to explore the overlap between species associated with Q. rubra and other deciduous tree species that possess similar smooth bark. Our findings indicate that red oak may not be an appropriate alternative host tree for epiphytic lichens typically found on native oak, while the implications for bryophytes remain less clear.

The PREDICTS project-Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)-has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.

Extreme weather events can be expected to increase in frequency in the future. Our knowledge on how this may affect species persistence is, however, very limited. For reliable projections of future persistence we need to understand how extreme weather affects species' population dynamics.We analysed the effect of extreme droughts on the host plant Succisa pratensis, colonization-extinction dynamics, and future persistence of the threatened marsh fritillary Euphydryas aurinia. Specifically, we studied a metapopulation inhabiting a network of 256 patches on Gotland (Sweden), where the summer of 2018 was the driest ever recorded. We analysed how the frequency and leaf size of host plants changed between 2017 and 2019, based on 6,833 records in 0.5-m(2) sample plots. Using turnover data on the butterfly from 2018 to 2019 we modelled local extinction and colonization probabilities. Moreover, we projected future population dynamics with an increasing frequency of extreme years under three different management strategies that regulate the grazing regime.Our results show a substantial decrease in both frequency (46%) and size (20%) of host plants due to the drought, which taken together may constitute a 57% loss of food resources. The butterfly occupancy decreased by over 30% between 2018 and 2019 (from 0.36 to 0.27). The extinction probability increased with increasing 'effective area' of the patch (taking quality reduction due to grazing into account), and the colonization probability increased with increasing connectivity and ground moisture.Projections of future dynamics showed an increasing risk of metapopulation extinction with increasing frequency of years with extreme droughts. The risk, however, clearly differed between management strategies. Less grazing in years with droughts decreased the extinction risk considerably.Synthesis and applications. Extreme weather events can have profound negative impacts on butterflies and their host plants. For the marsh fritillary, an increased frequency of extreme droughts can lead to extinction of the entire metapopulation, even in a large and seemingly viable metapopulation. Increased grazing, due to fodder deficiency in dry years, may lead to cascading negative effects, while active management that reduce grazing in years with droughts can almost completely mitigate these effects.

Grazing generally benefits grassland biodiversity as it prevents shrub and tree succession. However, too intense grazing may have negative effects for example many grassland insects. EU-subsidies for grazing of some habitats, aimed at promoting biodiversity, still require a relatively intense grazing, and could therefore have negative consequences for some species. We quantified how such grazing affects habitat quality for the marsh fritillary butterfly, and how this influence its colonization-extinction dynamics and persistence. Specifically, we studied a metapopulation on Gotland (Sweden), where the marsh fritillary occupies unfertilized calcareous grassland with a naturally slow succession. We quantified the difference in larvae autumn nests between grazed and ungrazed habitat, and used this difference to adjust the 'effective area' of 256 habitat patches in a 50 km(2) landscape. We then parameterized a metapopulation model based on the occurrence pattern of the adult butterfly, and simulated future population development under different grazing regimes. The results showed that ungrazed habitat harbored 4.8 times more nests than grazed habitat. Reducing the 'effective area' of grazed patches accordingly increased the local extinction probability and decreased colonization. Grazing all suitable habitat reduced the occupancy by over 80%, while no grazing increased the occupancy by up to 40%, based on projections of future dynamics. Current grazing is clearly too intense, and EU-subsidies are here, thus, a conservation measure with negative consequences for a threatened butterfly. To prevent this, subsidies for grazing need to be more flexible and better adapted to the prevailing soil conditions and requirements of the target species.

Extreme weather events are becoming more frequent due to climate change. We therefore need to understand how species respond to these events. In 2018, the worst drought ever recorded hit the island of Gotland in the Baltic Sea, which led to a major decline of the threatened marsh fritillary (Euphydryas aurinia) the succeeding summer. We compared yearly occupancy among 256 habitat patches between 2018 and 2020 and analysed the colonisation-extinction dynamics between 2019 and 2020 in relation to patch area, connectivity, and habitat quality. Moreover, using capture-mark-release data in two patch clusters differing in connectivity, we also compared population sizes before and after the drought and analysed 'population growth rates'. We also compared yearly abundance of host plants (Succisa pratensis) over time. Results show a remarkable recovery of the marsh fritillary. Both patch occupancy in 2020 and the number of individuals in the well-connected patch cluster were higher than before the drought. In contrast, host plants were fewer and smaller, which taken together suggest that the amount of food resources was roughly half in 2020 compared to the pre-drought conditions. Moreover, the butterfly population in the less connected patch cluster was eight times smaller compared to the population size before the drought. Local colonisations, extinctions, and population growth rates were explained by connectivity. The ability to quickly recover after extreme droughts is promising in times of climate change. The significance of connectivity for the population dynamics during recovery highlights the importance of maintaining well-connected patch networks.

We investigated the population dynamics and future persistence of the last remaining Clouded Apollo butterfly metapopulation in southern Scandinavia. Based on three decades of surveys (1984-2015), we modelled colonization-extinction dynamics and local population sizes using habitat patch characteristics and connectivity, while accounting for imperfect detection and uncertainty in the local population sizes. The colonization probability increased with increasing connectivity and the local extinction probability decreased with increasing local population size in accordance with metapopulation theory. The local population size increased with increasing patch area, and was also affected by grazing intensity. Light grazing resulted in larger local populations compared to heavy grazing or no grazing at all. The butterfly population has decreased considerably during the study period and according to projections of future dynamics the estimated extinction risk within the coming 10 years is 17%. However, it is possible to change the negative trends and decrease the extinction risk considerably by conservation actions. By optimizing the grazing pressure in existing patches the extinction risk was reduced to 11% (a reduction with 35% compared to the scenario with no conservation action). If a few new patches are created close to the occupied ones the extinction risk can be reduced further. In conclusion, there is a large risk that the Clouded Apollo butterfly will go extinct from southern Scandinavia within the coming decade. However, conservation measures that are focused to the core area of the current distribution and applied soon can considerably improve the situation for the butterfly. (C) 2016 Elsevier Ltd. All rights reserved.

Species-rich semi-natural grasslands have been lost during the last century due to agricultural intensification. This has had large negative consequences for many specialised species, including grassland butterflies. To prevent further loss, management regimes in the remaining grasslands must maintain habitat quality over time, and we therefore need to understand the habitat preferences of specialised species and how different management regimes affect their survival. We studied the egg-laying preferences of the threatened marsh fritillary butterfly in relation to host plant properties, microclimate and management (grazing) on Gotland, Sweden. Moreover, we followed the survival of eggs and larvae from 27 egg batches during a period of 8 months (from June 2020 to March 2021) in grazed and ungrazed areas. We found 92 egg batches in total and the average number of eggs was 184.5. Egg-laying probability increased with increasing host plant size and abundance, and environmental variables associated with a warm microclimate (low grass cover, low vegetation height and south-facing edges). The 27 egg batches that were followed over time had on average 203 eggs in June. Roughly 28% of the eggs developed into larvae, and about 17% of these survived over the entire study period, resulting in an overall 4.7% survival. Egg survival was higher in ungrazed habitats compared with grazed; in March (post-hibernation), there were almost nine times more eggs in ungrazed habitats. This study highlights the complex habitat ecology of specialised butterflies and underscores the detrimental impact of intense grazing, advocating for rotational grazing or mowing regimes. We study oviposition preferences and survival of both eggs and larvae (post-hibernation) for the marsh fritillary, in relation to host plant availability, microclimate conditions and grazing management Egg-laying probability increased with increasing host plant size and abundance, and environmental variables associated with a warm microclimate (low grass cover, low vegetation height and south-facing edges) Egg survival was clearly higher in ungrazed habitats compared with grazed; in March (post-hibernation), there were almost nine times more eggs in ungrazed habitats. image

Light trapping is an ideal method for surveying nocturnal moths, but in the absence of standardised survey methods effects of confounding factors may impede interpretation of the acquired data. We explored the influence of weather, time of year, and light source on nightly catches of macro moths in light traps, and compared four strategies for sampling by estimating observed species richness using rarefaction. We operated two traps with different light sources for 225 consecutive nights from mid-March to the end of October in eastern Germany in 2011. In total, 49 472 individuals of 372 species were recorded. Species richness and abundance per night were mainly influenced by night temperature, humidity and lamp type. With a limited sample size (<10 nights) it was slightly better to concentrate sampling on the warmest summer nights, but with more sampling nights it was slightly better to sample during the warmest nights in each month (March to October). By exploiting the higher moth activity during warm nights and an understanding of the species' phenology, it is possible to increase the number of species caught and reduce effects of confounding abiotic factors.

In Europe, Natura 2000 sites should protect threatened target species and networks of habitats. The management of Natura 2000 grasslands is often financed by subsidized grazing as part of the Common Agricultural Policy (CAP). We studied the extent of CAP grazing for Natura 2000 management and how this affects a butterfly target species (the marsh fritillary) and floral resources. Based on extensive capture-mark-release studies from 2 years in >550 ha grid cells in a 225 km(2) landscape in Sweden that includes 15 Natura 2000 sites, we compared marsh fritillary occurrence probabilities and population densities in ungrazed and CAP-grazed habitats. Moreover, we analyzed how nectar resources and orchids were affected by CAP grazing based on plants records from 2347 sample plots. We estimated the proportion of butterfly habitats that were CAP-grazed within and outside Natura 2000 sites. In total, 10 453 and 4417 butterflies were marked in 2017 and 2019, respectively. The grid cell occurrence probability was 1.8 times higher and the population density was 2.3 times higher in ungrazed compared with CAP-grazed habitats in 2017, and the corresponding numbers for 2019 were 10 and 5.3 times higher, respectively. The number of flowering plants were on average 6.9 times higher and the density of orchids was 12.3 times higher in ungrazed habitats. Roughly, 30% (130 ha) of the marsh fritillary habitat was CAP grazed, and 97% of this grazing occurred within protected areas, of which 111 ha was situated within Natura 2000 area where the marsh fritillary is the target species. Alarmingly, we show that intense yearly CAP grazing, which is the dominant management strategy in all Natura 2000 sites, has devastating consequences for the target species and other aspects of biodiversity. Less intense management, which would benefit biodiversity, requires changes in the CAP, to allow more flexible payments for habitat management objectives and conservation of target species.

1. Established butterfly survey methods that are useful for monitoring species that are widely distributed and numerous may be less accurate for more rare species. We therefore need new monitoring approaches.2. We describe a plot-based survey method, where butterflies or larvae nests are counted within 1-ha grid cells. The aim was to compare this grid method with more traditional transect counts and evaluate both methods in relation to high-quality capture-mark-release (CMR) population estimates (reflecting the 'true' population). We do this using data from a large population of the marsh fritillary butterfly in Sweden. Moreover, we followed the overall population trend from 2017 to 2021 for both adult butterflies and larvae.3. Results showed a higher detection probability using the grid method compared with transect counts, which for adult butterflies seem to be explained by time effort. Moreover, grid surveys of adult butterflies showed a clear significant relationship with the estimated 'true' population size from CMR, while transect counts did not. For larvae, both methods showed significant relationships with the estimated adult population size, but the grid method found 5.7 times more larvae. The overall popu-lation fluctuated significantly across years. In years with low densities, the transect method largely failed to detect the species.4. The grid method seems more reliable for detecting the marsh fritillary and for estimating its population size, and thus, tracking the population trend. We propose this novel method to be integrated into surveys and monitoring of biodiversity, especially when focusing on rare habitat specialists that are normally underrepre-sented in monitoring based on volunteer counts.

Mobility may affect species' distribution patterns in heterogeneous landscapes, and it might impact fitness by influencing mating success, predation avoidance, and foraging success. Here, we studied causes and consequences of mobility patterns in butterflies: Argynnis adippe, a specialist constrained to warm microhabitats within woodland landscapes, and A. aglaja, a relative generalist that also inhabits grasslands, and tolerates lower temperatures. We explored associations of movement and occurrence patterns, population size and density, niche breadth, wing size, and different types of behaviour prior to capture by conducting a mark-release-recapture study on the Swedish island oland. We marked 1 935 A. aglaja and 123 A. adippe and achieved recapture rates of 9.5% (A. aglaja), and 8.9% (A. adippe). Estimated population densities were 5 066 and 814 individuals per km(2), for A. aglaja and A. adippe, respectively. Argynnis aglaja was less likely to perform long-distance flights according to estimated dispersal kernels, hinting at negative density-dependent dispersal in these species. Although we detected the longest flight distances ever in these species in MRR studies (11.9 km for A. aglaja and 3.7 km for A. adippe), most butterflies were recaptured within 200 meters (60-80%). Low recapture rates along with low estimated residence times and the potential for long movement might indicate that many individuals left the study area, and that the species form open populations, stretching over large areas. Despite significant differences in wing size and behaviour types, mean observed flight distances were similar in these species.

Understanding which factors and processes are associated with genetic differentiation within and among species remains a major goal in evolutionary biology. To explore differences and similarities in genetic structure and its association with geographical and climatic factors in sympatric sister species, we conducted a large-scale (>32 degrees latitude and >36 degrees longitude) comparative phylogeographical study on three Argynnini butterfly species (Speyeria aglaja, Fabriciana adippe and F. niobe) that have similar life histories, but differ in ecological generalism and dispersal abilities. Analyses of nuclear (ddRAD-sequencing derived SNP markers) and mitochondrial (COI sequences) data revealed differences between species in genetic structure and how genetic differentiation was associated with climatic factors (temperature, solar radiation, precipitation, wind speed). Geographical proximity accounted for much of the variation in nuclear and mitochondrial structure and evolutionary relationships in F. adippe and F. niobe, but only explained the pattern observed in the nuclear data in S. aglaja, for which mitonuclear discordance was documented. In all species, Iberian and Balkan individuals formed genetic clusters, suggesting isolation in glacial refugia and limited postglacial expansion. Solar radiation and precipitation were associated with the genetic structure on a regional scale in all species, but the specific combinations of environmental and geographical factors linked to variation within species were unique, pointing to species-specific responses to common environments. Our findings show that the species share similar colonization histories, and that the same ecological factors, such as niche breadth and dispersal capacity, covary with genetic differentiation within these species to some extent, thereby highlighting the importance of comparative phylogeographical studies in sympatric sister species.

Colour polymorphisms have long served as model systems in evolutionary studies and continue to inform about processes involved in the origin and dynamics of biodiversity. Modern sequencing tools allow for evaluating whether phenotypic differences between morphs reflect genetic differentiation rather than developmental plasticity, and for investigating whether polymorphisms represent intermediate stages of diversification towards speciation. We investigated phenotypic and genetic differentiation between two colour morphs of the butterfly Fabriciana adippe using a combination of ddRAD-sequencing and comparisons of body size, colour patterns and optical properties of bright wing spots. The silvery-spotted adippe form had larger and darker wings and reflected UV light, while the yellow cleodoxa form displayed more green scales and reflected very little UV, showcasing that they constitute distinct and alternative integrated phenotypes. Genomic analyses revealed genetic structuring according to source population, and to colour morph, suggesting that the phenotypic differentiation reflects evolutionary modifications. We report 17 outlier loci associated with colour morph, including ultraviolet-sensitive visual pigment (UVRh1), which is associated with intraspecific communication and mate choice in butterflies. Together with the demonstration that the wings of the adippe (but essentially not the cleodoxa) morph reflect UV light, that UV reflectance is higher in females than males and that morphs differ in wing size, this suggests that these colour morphs might represent genetically integrated phenotypes, possibly adapted to different microhabitats. We propose that non-random mating might contribute to the differentiation and maintenance of the polymorphism.

Understanding how large-scale environmental variability may shape the distribution of phenotypic variation remains central to evolutionary biology. Across-species comparisons of trait variation alongside environmental gradients may offer valuable insights into how different species may respond to similar selective pressures. We conducted a comparative morphological study (>32° latitude and >47° longitude) on three closely related Argynnini butterfly species, Speyeria aglaja, Fabriciana adippe, and F. niobe. We measured wing size and coloration to assess (1) whether they respond similarly or differently to environmental factors (longitude, latitude, altitude, temperature, precipitation, solar radiation, wind speed); (2) if these factors correspond with those associated with the species’ genetic structure based on a previous study; and (3) whether correlations between phenotypic traits within individuals are species-specific. We found common and species-specific associations of climatic (precipitation, wind speed) and geographic (longitude, altitude) factors with the composite phenotypic variation. Wing size was associated with different variables in the studied species, while melanisation mainly increased in cooler regions in all species, suggesting that the need for temperature regulation is a strong selective pressure on melanisation. Wing size was associated with the genetic structure in all species, highlighting the functional importance of this trait. The environmental drivers associated with the phenotypic variation in S. aglaja and F. adippe were largely the same as those associated with their genetic structure, hinting at a genetic underpinning of the observed morphological variation due to local adaption. We report some distinct intraspecific trait correlations in S. aglaja and F. adippe, indicative of independent phenotypic integration. These phenotypes seem to be associated with protection against predators and thermal regulation in the respective habitats of both species, suggesting that similar selective pressures have resulted in the evolution of different trait combinations. Some of the inter-specific differences could be related to diverging niche breadths and dispersal capacities, exemplifying that the evolution of trait integration and spatial phenotypic differentiation may differ between closely related species with overlapping distribution ranges. Our findings highlight the importance of comparative assessments of variation, and demonstrate that the relative effects of drivers of variability may vary between sister species.

Aim

Nitrogen deposition is a major global driver of change in plant communities, but its impacts on higher trophic levels are insufficiently understood. Here, we introduce and test a novel conceptual trait-based model describing how the effects of soil eutrophication cascade to higher trophic levels across differential plant–herbivore interactions.

Location

Northern Europe.

Methods

We synthesize previous literature on the effects of nitrogen on plants and herbivorous insects as well as relevant multispecies patterns of insect communities concerning species dietary breadth, body size, dispersal propensity and voltinism in order to derive the model. We empirically evaluate the proposed, hitherto untested, four main model pathways using statistical modelling and data on 1064 northern European butterfly and moth species, their life-history traits, phylogeny and population trends.

Results

We show that across all species: (1) larval dietary breadth and host plant foliar nitrogen content are positively and equally strongly related to insect body size, and that (2) multivoltinism, host plant preferences for soil nitrogen, body size and larval dietary breadth are positively related to population trends of butterflies and moths as predicted by the model. Positive relationships between plant foliar nitrogen content and body size as well as multivoltinism and population trends are the first multispecies demonstrations for these patterns.

Main conclusions

Soil nitrogen enrichment amplifies the diverging trends of herbivorous insects feeding on nitrophilous versus nitrophobous plants through differential plant–herbivore interactions, causing predictable changes in community composition at higher trophic levels. A positive foliar nitrogen–insect body size relationship, now empirically supported, is the integrating link within this cascade. As nitrogen deposition is a global driver, our model suggests that a major future trend may be an increased dominance of insects that are large, dispersive, multivoltine, dietary generalists or specialized on nitrophilous plant species at the expense of species preferring oligotrophic environments.