Search

We present the results of our 14th horizon scan of issues we expect to influence biological conservation in the future. From an initial set of 102 topics, our global panel of 30 scientists and practitioners identified 15 issues we consider most urgent for societies worldwide to address. Issues are novel within biological conservation or represent a substantial positive or negative step change at global or regional scales. Issues such as submerged artificial light fisheries and accelerating upper ocean currents could have profound negative impacts on marine or coastal ecosystems. We also identified potentially positive technological advances, including energy production and storage, improved fertilisation methods, and expansion of biodegradable materials. If effectively managed, these technologies could realise future benefits for biological diversity.

SummaryClimate change presents a particularly complex challenge in the context of flyway scale conservation of migratory bird species as it requires coordinated action by multiple countries along these species’ migratory routes. Coordinating conservation responses requires understanding the vulnerability of species and their habitats to climate change at the flyway scale throughout each species’ annual cycle. To contribute to such understanding, we used species distribution models to assess the exposure to climate change of waterbird species that are the focus of the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA). We found that the species with the smallest proportion of their current range projected to be climatically suitable by 2050 (those whose distributions respond to changes in water availability but that do not perform synchronised migration) are dispersive species in the Afrotropical biogeographic realm, and migratory species in their breeding season, particularly Arctic breeding waders. These species also have the most limited availability of newly suitable areas. Projections for most other Palearctic migratory waterbird species suggest that losses of suitable areas in their current passage and wintering ranges may be largely offset by new areas becoming climatically suitable. The majority of migratory Palearctic waterbirds in the breeding season and Afrotropical waterbirds are widely dispersed with only a small proportion of their populations currently supported by ‘Critical Sites’ (i.e. sites that are either important for Globally Threatened Species or support 1% of the bioregional population of any waterbird species). This makes it unlikely that climate change adaptation measures focusing only on key sites will be sufficient to counter the predicted range losses. Therefore, climate change adaptation responses should also be implemented at the landscape scale for Afrotropical waterbirds and for breeding populations of Palearctic migrant waterbirds.

Aim: Global declines in the populations of migratory species have been attributed largely to climate change and anthropogenic habitat change. However, the relative contribution of these factors on species’ breeding and non‐breeding ranges is unclear. Here, we present the first large‐scale assessment of the relative importance of climatic conditions and land cover on both the breeding and non‐breeding grounds in driving the long‐term population trends of migratory species. Location: Europe and Africa. Methods: We use data on the long‐term population trends of 61 short‐ and 39 long‐distance migratory species of European breeding birds. We analyse these population trends in relation to changes in climate and land cover across species’ breeding and non‐breeding ranges over a 36‐year period, along with species’ migratory behaviour. Results: The population trends of European migratory birds appear to be more closely related to changes in climate than changes in land cover on their breeding grounds, but the converse is true on their non‐breeding grounds. While improvements in climate suitability across the breeding ranges of short‐distance migrants led to increasing population trends, the same was not true for long‐distance migrants. The combined effects of changes in climate and land cover account for approximately 40% of the variation in migratory species’ population trends, suggesting that factors other than climate and land cover as we have measured them, such as habitat quality, also affect the population trends of migrant birds. Main Conclusions: Over recent decades, population trends of most migrant species are most strongly related to climatic conditions on the breeding grounds but land cover change on the non‐breeding grounds. This suggests that management to stem the declines of migrant birds requires an integrated approach that considers all processes affecting migrant birds across their dynamic distributions throughout the year.

There is considerable debate over the most appropriate method for surveying dragonflies and damselflies (odonates). Using data from 62 survey locations nested within 26 waterbodies at 15 sites (discrete parcels of common ownership) in West Suffolk, UK, we show that short (20 m line transects or 3 min duration point counts), monthly counts of adults are repeatable. Correlations between predictions from models accounting for variation in ambient conditions and time of day and 52 separate counts used for validation equalled r = 0.87 for total abundance and r = 0.75 for species richness. Correlation coefficients between observed and modelled abundance exceeded 0.5 for eight of fourteen species modelled individually. Ambient temperature was the most important weather variable that influenced survey results, affecting the abundance of nine species, total abundance and species’ richness. Most of the spatial variation in survey results was between waterbodies, rather than between sites or at individual survey locations, suggesting that adult counts may indicate aspects of waterbody quality, although differences in these patterns were observed between dragonflies (Anisoptera) and damselflies (Zygoptera). Encouraging relatively infrequent and rapid counts of flying adults may therefore be used to increase volunteer participation in citizen (community) science odonate monitoring schemes whilst also providing repeatable abundance and species richness data that can contribute to research and monitoring programmes.

Context: Climate change is a severe threat to biodiversity. Areas with a high variety of microclimates may provide opportunities for species to persist in a changing climate.\ud \ud Objectives: Test the extent to which microclimate is an important determinant of the distribution of a widespread upland passerine, the meadow pipit Anthus pratensis, and whether microclimate becomes an increasingly important determinant of distribution towards the warm edge of the species’ range.\ud \ud Methods: We used models of the occurrence of meadow pipits based on data from an extensive survey to identify macroclimate and topographic associations, the latter as proxies of microclimate. We assessed magnitude and direction of the effects of microclimate and whether the magnitude of microclimate effects increases as macroclimate suitability declines. \ud \ud Results: The probability of meadow pipit occurrence is significantly correlated with macroclimate and microclimate. Microclimate accounts for about a third of the variation in occupancy probability and has a stronger effect than macroclimate at all three spatial scales considered. Elevation and topographical wetness index are positively correlated with meadow pipit occurrence, while insolation is negatively correlated. Elevation and macroclimate suitability show a positive interaction, while insolation and macroclimate suitability show a negative interaction.\ud \ud Conclusions: Microclimate substantially influences the distribution of the meadow pipit. For high latitude and upland species such as this, suitable areas on cool slopes could form the focus for conservation protection, as these areas are likely to become increasingly utilised and may remain the only locations occupied in otherwise unsuitable climate.

Protected area (PA) networks have in the past been constructed to include all major habitats, but have often been developed through consideration of only a few indicator taxa or across restricted areas, and rarely account for global climate change. Systematic conservation planning (SCP) aims to improve the efficiency of biodiversity conservation, particularly when addressing internationally agreed protection targets. We apply SCP in Great Britain (GB) using the widest taxonomic coverage to date (4,447 species), compare spatial prioritisation results across 18 taxa and use projected future (2080) distributions to assess the potential impact of climate change on PA network effectiveness. Priority conservation areas were similar among multiple taxa, despite considerable differences in spatial species richness patterns; thus systematic prioritisations based on indicator taxa for which data are widely available are still useful for conservation planning. We found that increasing the number of protected hectads by 2% (to reach the 2020 17% Aichi target) could have a disproportionate positive effect on species protected, with an increase of up to 17% for some taxa. The PA network in GB currently under-represents priority species but, if the potential future distributions under climate change are realised, the proportion of species distributions protected by the current PA network may increase, because many PAs are in northern and higher altitude areas. Optimal locations for new PAs are particularly concentrated in southern and upland areas of GB. This application of SCP shows how a small addition to an existing PA network could have disproportionate benefits for species conservation.

Capsule: Population growth rates of one-third of 68 breeding bird species in England were significantly affected by climatic variables, leading to notable (>10%) population increases in 13 species,...

Land sparing has been proposed as a strategy to reconcile biodiversity conservation with agricultural production, with empirical studies on five continents indicating that most species would benefit if food demand was met through high‐yield farming combined with the protection or restoration of natural habitat. Most such studies come from landscapes covered by large areas of natural habitat and without a long history of intense human modification. However, much of Europe consists of human‐dominated landscapes, where biodiversity responses to land sparing may differ. To test this, we use estimates of bird population density in different (semi‐)natural habitats, and forecasts of population density in farmland habitat, to assess the future consequences for birds of land‐sparing scenarios in the United Kingdom. Our scenarios predict that whilst up to 18 of the 156 species assessed (predominantly farmland associated species) might decline in UK conservation status under land sparing, up to 35 UK bird species (mainly woodland and wetland species) might improve in status. This contrasts with a maximum of eight species likely to improve in conservation status without land sparing, with up to seven species deteriorating. Combining land sparing with demand management measures (reducing food waste and the consumption of animal products) led to more positive population changes under all scenarios. Synthesis and applications. Land sparing has the potential to benefit UK bird populations in aggregate but would likely have negative impacts on farmland bird species. These findings are likely to be applicable across human‐dominated landscapes beyond the UK, though effects on other taxa, implementation mechanisms and the sustainability of higher yields all require careful consideration.

Despite their importance for biodiversity and ecosystem services, wetlands are among the most threatened ecosystems globally. The conservation of many migratory waterbirds depends on the conservation of a network of key sites along their flyways. However, the suitability of these sites is changing under climate change, and it is important that management of individual sites in the network adapts to these changes. Using bioclimatic models that also account for changes in inundation, we found that projected climate change will reduce habitat suitability for waterbirds at 57.5% of existing Critical Sites within Africa-Eurasia, varying from 20.1% in Eastern Europe to 87.0% in Africa. African and Middle East sites are particularly threatened, comprising 71 of the 100 most vulnerable sites. By highlighting priority sites for conservation and classifying Critical Sites into Climate Change Adaptation Strategy (CCAS) classes, our results can be used to support the climate change adaptation of both individual sites and the entire site network.

There is in an ongoing expansion of powerlines as a result of an increasing global demand for energy. Powerlines have the potential to negatively impact wild bird populations through collisions and/or electrocution, and reducing bird powerline collision and electrocution risk is a priority for companies running high-voltage powerlines (known as Transmission System Operators (TSOs)). Most TSOs are legally required to assess any potentially significant impacts via Enivronmental Impact Assessments, and so potentially collect a significant amount of data on the presence of species, species behaviour, and observed mortality rates. The value of such data, if available, for reducing and preventing bird casualties could be enhanced by increasing availability across TSOs and other decision-makers. We review the extent to which the sharing of data is happening across Europe, and how the quality, scope and availability of bird data collected by European TSOs could be improved, through use of a questionnaire and workshop with TSOs, conservationists and academics. Sixteen European TSOs responded to the questionnaire and 30 stakeholders attended the workshop. There was wide recognition of the value of different types of data on birds at powerlines, and a positive attitude to working together to share and enhance data across stakeholders to achieve the shared goal of reducing bird mortalities. Key barriers to the sharing of data included a lack of a centralised database, the lack of standardised methods to collect bird data and concerns over the confidentiality of data and reports. In order to overcome these barriers and develop a collaborative approach to data sharing, and ultimately inform best practice to reduce significant negative impacts on bird populations, we suggest a stepwise approach that (1) develops guidance around the field methods and data to be collected for mitigation effectiveness and (2) shares meta-data/bibliography of studies of powerline impacts/mitigation effectiveness for birds. In time, a more structured approach to the sharing of data and information could be developed, to make data findable, accessible, interoperable and reusable.

Climate warming has caused the seasonal timing of many components of ecological food chains to advance (Thackeray et al. 2010, 2016). Differential shifts lead to phenological asynchrony, often referred to as trophic mismatch when it is detrimental for consumers (Cushing 1990). In the context of trophic interactions, it has been suggested that consumers will shift their phenology to adapt to shifts in the availability of their food source (Visser and Both 2005), but they rarely do so in practice (Thackeray et al. 2016; Kharouba et al. 2018). Whether such unequal shifts are detrimental or not is unresolved (Johansson and Jonzén 2012; Reed et al. 2013a; Samplonius et al. 2016; Radchuk et al. 2019; Visser and Gienapp 2019). At present there has been no consistent analysis of the links between temperature change, phenological asynchrony, and individual-to-population level impacts across taxa, trophic levels and biomes at a global scale. Instead, many of our insights into mismatch and its impacts stem from a handful of independent single-system studies, varying greatly in their conceptual basis and methodological approach. Here, we propose five criteria that all need to be met to demonstrate that temperature-mediated trophic mismatch poses a growing risk to consumers. These criteria are: 1) an ephemeral resource contributes a large proportion of the consumer’s diet; 2) asynchrony between phenology of consumer and resource is increasing over time; 3) interannual variation in asynchrony is driven by interannual variation in temperature; 4) asynchrony reduces consumer fitness, 5) mismatch impacts negatively on consumer population size or growth. We conduct a literature review of 109 papers studying 132 taxa, and find that for most taxa only two of the five criteria are met. Moreover, all five criteria are only assessed for two taxa. The most commonly-tested criteria are 1 and 2, and few studies further examined evidence for criteria 4 or 5. Furthermore, effects of mismatch are heavily skewed towards juvenile stages rather than adults. Crucially, nearly every study was conducted in Europe or North America, and most studies were on terrestrial secondary consumers. We thus lack a robust evidence base from which to draw general conclusions about the risk that climate-mediated trophic mismatch may pose to populations worldwide.

Climate change is an increasing threat to global biodiversity. Whilst there is growing evidence about the potential effectiveness of some aspects of climate change adaptation, the role for site-based management to increase the resilience of vulnerable populations to climate change has been little studied. Here, we test whether such management may reduce the negative effects of unfavourable weather upon a southern range margin Welsh black grouse Tetrao tetrix population that is vulnerable to climate change. The Welsh black grouse recovery programme funded a range of interventions that contributed to a 39% population increase over 10 years. One likely mechanism linking black grouse populations to climate change is the sensitivity of chicks to high June rainfall. We modelled the relationship between June rainfall and management interventions which aimed to increase breeding success (habitat management and lethal predator control) to test whether management could increase the resilience of black grouse populations to such unfavourable weather. Importantly, we found that the negative effect of June rainfall upon productivity was eliminated at sites where predator control occurred, and that productivity was maximised when predator and habitat management were combined. Active management therefore reduced the negative effects of June rainfall upon this vulnerable southern range margin black grouse population, although further work is required to quantify any limits to the success of such management. Active management should be considered as a tool for climate change adaptation in other vulnerable populations, particularly where there is limited potential for species to undergo climate-driven range changes.

Tick infestation increased with temperature and vegetation height, and was negatively correlated with Golden Plover Pluvialis apricaria chick survival, but not growth rates.To examine the factors a...

International audience; We present the results of our tenth annual horizon scan. We identified 15 emerging priority topics that may have major positive or negative effects on the future conservation of global biodiversity, but currently have low awareness within the conservation community. We hope to increase research and policy attention on these areas, improving the capacity of the community to mitigate impacts of potentially negative issues, and maximise the benefits of issues that provide opportunities. Topics include advances in crop breeding, which may affect insects and land use; manipulations of natural water flows and weather systems on the Tibetan Plateau; release of carbon and mercury from melting polar ice and thawing permafrost; new funding schemes and regulations; and land-use changes across Indo-Malaysia.

Farmland birds are among the most threatened bird species in Europe, largely as a result of agricultural intensification which has driven widespread biodiversity losses. Breeding waders associated with grassland and arable habitats are particularly vulnerable and a frequent focus of agri‐environment schemes (AES) designed to halt and reverse population declines. We review existing literature, providing a quantitative assessment of the effectiveness of policy and management interventions used throughout Europe to improve population and demographic metrics of grassland‐breeding waders. Targeted AES and site protection measures were more likely to be effective than less targeted AES and were ten times more likely to be effective than would be expected by chance, particularly for population trend and productivity metrics. Positive effects of AES and site protection did not appear synergistic. Management interventions which had the greatest chance of increasing population growth or productivity included modification of mowing regimes, increasing wet conditions, and the use of nest protection. Success rates varied according to the species and metric being evaluated. None of the policy or management interventions we evaluated were associated with a significant risk of negative impacts on breeding waders. Our findings support the use of agri‐environment schemes, site protection, and management measures for grassland‐breeding wader conservation in Europe. Due to publication bias, our findings are most applicable to intensively managed agricultural landscapes. More studies are needed to identify measures that increase chick survival. Despite broadly effective conservation measures already in use, grassland‐breeding waders in Europe continue to decline. More research is needed to improve the likelihood and magnitude of positive outcomes, coupled with wider implementation of effective measures to substantially increase favorable land management for these species.

Citizen science is increasingly recognised as one of the most cost-effective means of achieving large-scale and long-term biodiversity monitoring. Here we assess the potential for citizen scientists to contribute to the long-term monitoring of land cover, land use and habitat change through ongoing field data collection. Land cover monitoring is most commonly carried out via remote sensing or professional surveys but these can be costly, low detail or spatiotemporally limited. We used ongoing habitat data collection by citizen scientists participating in a structured survey of breeding birds to assess whether there is the potential for citizen scientists more broadly to play a role in the long-term monitoring of habitat extent and condition. Categorical habitat data has been collected annually by over 2500 volunteers as part of the UK Breeding Bird Survey since 1994 and we used this to quantify temporal variation in the reporting of different habitats in the British countryside. Where possible we validated our estimates of habitat cover and change using independent estimates from professional surveys and other datasets. We detected increases in woodland cover, in particular mixed woodland, and declines in farmland cover, particularly livestock farming. Our habitat cover estimates closely matched alternative land cover estimates but there was little correspondence in estimates of change between survey types and we discuss why discrepancies may occur. Although the data we used were not initially designed for this purpose, our results suggest that there is considerable potential to use citizen science for cost-effective identification of temporal patterns in land use, habitat-type and management in ways that could complement other methods.

1. Public data archiving (PDA) is widely advocated as a means of achieving open data standards, leading to improved data preservation, increased scientific reproducibility, and transparency, as well as additional data use. 2. Public data archiving was primarily conceived to archive data from short‐term, single‐purpose scientific studies. It is now more widely applied, including to large‐scale citizen science biodiversity recording and monitoring schemes which combine the efforts of volunteers with professional scientists. 3. This may affect the financial security of such schemes by reducing income from data and analytical services. Communication between scheme organizers and researchers may be disrupted, reducing scientific quality and impeding scheme development. It may also have an impact on the participation of some volunteers. 4. Synthesis and applications. In response to the challenges of public data archiving for citizen science biodiversity recording and monitoring schemes, the archive function of scheme organizations should be better recognized by those promoting open data principles. Increased financial support from the public sector or from commercial or academic data users may offset financial risk. Those in favour of public data archiving should do more to facilitate communication between nonscheme users and the originating schemes, while a more flexible approach to data archiving may be required to address potential impacts on volunteer participation.

Soil invertebrates play important roles in nutrient cycling, the development of soil structure, food webs and even climate regulation. It is likely that climate change will have far-reaching impacts on soil invertebrates but a lack of information about how soil invertebrate populations vary with soil characteristics and climate make projections difficult. To address this gap, we present the results of a large-scale citizen science project that examined the abundance of soil macro-invertebrates across the UK. The abundance and biomass of twelve invertebrate groups were recorded by school children using standardised protocols on six occasions over two years. Using these data, we examined the relative impact of local habitat and soil characteristics, and weather and climate, upon these taxa. The abundance of many soil invertebrate groups varied with season and small-scale habitat factors. We found that the abundance and biomass of earthworms was strongly correlated with soil moisture. There was, however, little evidence that large-scale variation in soil invertebrate abundance could be explained by spatial variation in climate. Given the importance of earthworms for soil processes, periods of dry weather may reduce their ability to undertake nutrient cycling and the provision of other services such as food for invertivorous species. Future analyses of the impacts of climate change on soil invertebrates may usefully consider variables such as frequency of rain, rather than monthly or seasonal averages more widely used. Our results were generally in accord with patterns expected from previous literature, providing important quality assurance. This indicates that this could be an effective scheme for long-term monitoring of soil invertebrates and that it is possible to utilise educational establishments as a forum for large-scale environmental data collection. Not only can this deliver valuable environmental data, but also it can engage school children in the collection of scientifically valuable data.

Projections of species’ distributions in future climates can aid adaptive conservation strategies. Although presence-absence or presence-only data have been extensively used for this purpose, modelling changes in spatial patterns of abundance provides a more sensitive tool for estimating species’ vulnerabilities to climate impacts. We used abundance data from citizen science bird surveys in the UK and France to predict spatial patterns of future climatic suitability throughout Great Britain for 124 breeding bird species. We project that climatic suitability of Great Britain will increase for 44% of species and decline for 9% of species by 2080. Of the latter group, most are already red-listed for their severe long-term population declines. If our suitability projections translate into population changes, by 2080, conservation listing status will worsen for 10 species and improve for 28 species. Projected changes in climatic suitability translate into net gains of species abundance in northern and western areas and high turnover in community composition throughout Britain, particularly under medium- and high-emission scenarios. In conclusion, community-wide projections of changes in climatic suitability based on abundance indicate that bird assemblages throughout Great Britain will be impacted by climate change and that species already of concern are likely to be impacted hardest. Of the species projected to benefit, the ability of currently red-listed species to respond positively to climate without other interventions is unclear.

Aim Time-lagged population synchrony, where spatially separated populations show similar fluctuations in abundance lagged over time, is thought to be driven by dispersal among populations. When dispersal is proportional to population density or positively density dependent, and individuals move readily from population A to population B, then as population A increases, the increased number of dispersers from population A to B will cause a subsequent increase in population B. If true, then time-lagged synchrony should be strongest at a species’ typical dispersal distance, because the rate of exchange between populations will be greatest at that distance. Location United Kingdom (U. K.). Time period 1994 – 2013. Major taxa studied Birds (class Aves). Methods We estimated the spatial scale of 1-year-lagged population synchrony for 76 U.K. bird species, using 20 years of bird count data collected at 2,415 locations by the British Breeding Bird Survey. We then compared these spatial scales with published mean natal and breeding dispersal distance estimates (ranging from 0.1 to 25.8 km) for the same species based on an independent, large-scale, mark–recapture dataset of 492,272 bird recaptures in Britain and Ireland. Results We found strong, positive cross-species relationships between the spatial scale of time-lagged synchrony and mean natal and breeding dispersal distance estimates from the mark–recapture study. However, average spatial scales of time-lagged synchrony were more than 60 km longer than those from mark–recapture data, with scales ranging from 5 to 185 km. Main conclusions Ours is the first study to show that the spatial scale of time-lagged synchrony increases with species dispersal distance. The scale of synchrony was larger than expected, probably because mark–recapture data underestimated the real dispersal distances, or because dispersal synchronizes populations at a larger spatial scale than that of dispersal (e.g., through formation of travelling waves), or both. Nevertheless, the strong relative concordance is consistent with the explanation that time-lagged synchrony results from dispersal among populations.

It is important for conservationists to be able to assess the risks that climate change poses to species, in order to inform decision making. Using standardised and repeatable methods, we present a national-scale assessment of the risks of range loss and opportunities for range expansion that climate change could pose for over 3000 plants and animals. Species were selected by their occurrence in England, the primary focus of the study, but climate change impacts were assessed across Great Britain, widening their geographical relevance. A basic risk assessment that compared projected future changes in potential range with recently observed changes classified 21% of species as being at high risk and 6% at medium risk of range loss under a B1 climate change scenario. A greater number of species were classified as having a medium (16%) or high (38%) opportunity to potentially expand their distribution. A more comprehensive assessment, incorporating additional ecological information, including potentially confounding and exacerbating factors (e.g. dispersal, habitat availability and other constraints), was applied to 402 species, of which 35% were at risk of range loss and 42% may expand their range extent. This study covers a temperate region with a significant proportion of species at their poleward range limit; the balance of risks and opportunities from climate change may be different elsewhere. The outcome of both risk assessments varied between taxonomic groups, with bryophytes and vascular plants containing the greatest proportion of species at risk from climate change. Upland habitats contained more species at risk than other habitats. Whilst the overall pattern was clear, confidence was generally low for individual assessments, with the exception of well-studied taxa such as birds. In response to climate change, nature conservation needs to plan for changing species distributions and an uncertain future.

Although the number of studies discerning the impact of climate change on ecological systems continues to increase, there has been relatively little sharing of the lessons learnt when accumulating this evidence. At a recent workshop entitled ‘Using climate data in ecological research’ held at the UK Met Office, ecologists and climate scientists came together to discuss the robust analysis of climate data in ecology. The discussions identified three common pitfalls encountered by ecologists: 1) selection of inappropriate spatial resolutions for analysis; 2) improper use of publically available data or code; and 3) insufficient representation of the uncertainties behind the adopted approach. Here, we discuss how these pitfalls can be avoided, before suggesting ways that both ecology and climate science can move forward. Our main recommendation is that ecologists and climate scientists collaborate more closely, on grant proposals and scientific publications, and informally through online media and workshops. More sharing of data and code (e.g. via online repositories), lessons and guidance would help to reconcile differing approaches to the robust handling of data. We call on ecologists to think critically about which aspects of the climate are relevant to their study system, and to acknowledge and actively explore uncertainty in all types of climate data. And we call on climate scientists to make simple estimates of uncertainty available to the wider research community. Through steps such as these, we will improve our ability to robustly attribute observed ecological changes to climate or other factors, while providing the sort of influential, comprehensive analyses that efforts to mitigate and adapt to climate change so urgently require.

Capsule: Across Britain, breeding Eurasian Curlew Numenius arquata are less numerous and have shown greater population declines in areas with more arable farming, woodland cover and higher generalist predator abundance.Aims: We present the first national-scale analysis of the potential drivers of Curlew population change in Britain, which is needed to guide conservation action for this globally near-threatened, declining species.Methods: Breeding Bird Survey data and environmental predictors were used to model variation in Curlew abundance in 1995–99 and 2007–11, and population change between these periods.Results: Arable farming and woodland cover were negatively associated with Curlew abundance and population declines. Curlew abundance was positively associated with extent of protected area coverage and gamebird numbers. Abundance and population change were positively associated with cooler temperatures and higher summer rainfall, but negatively associated with numbers of generalist predators.Co...

The BBS is undertaken by the British Trust for Ornithology (BTO) and jointly funded by the BTO, the Joint Nature Conservation Committee and the Royal Society for the Protection of Birds. 1. Modelling spatio-temporal changes in species abundance and attributing those changes to potential drivers such as climate, is an important but difficult problem. The standard approach for incorporating climatic variables into such models is to include each weather variable as a single covariate whose effect is expressed through a low-order polynomial or smoother in an additive model. This, however, confounds the spatial and temporal effects of the covariates. 2. We developed a novel approach to distinguish between three types of change in any particular weather covariate. We decomposed the weather covariate into three new covariates by separating out temporal variation in weather (averaging over space), spatial variation in weather (averaging over years) and a space-time anomaly term (residual variation). These three covariates were each fitted separately in the models. We illustrate the approach using generalized additive models applied to count data for a selection of species from the UK’s Breeding Bird Survey, 1994-2013. The weather covariates considered were the mean temperatures during the preceding winter and temperatures and rainfall during the preceding breeding season. We compare models that include these covariates directly with models including decomposed components of the same covariates, considering both linear and smooth relationships. 3. The lowest QAIC values were always associated with a decomposed weather covariate model. Different relationships between counts and the three new covariates provided strong evidence that the effects of changes in covariate values depended on whether changes took place in space, in time, or in the space-time anomaly. These results promote caution in predicting species distribution and abundance in future climate, based on relationships that are largely determined by environmental variation over space. 4. Our methods estimate the effect of temporal changes in weather, while accounting for spatial effects of long-term climate, improving inference on overall and/or localized effects of climate change. With increasing availability of large-scale data sets, need is growing for appropriate analytical tools. The proposed decomposition of the weather variables represents an important advance by eliminating the confounding issue often inherent in analyses of large-scale data sets. Postprint

UK moorlands are semi-natural habitats managed for a mix of livestock, game shooting and forestry, among other activities. An assessment of the importance of characteristics that correlate with moorland bird populations of high conservation importance can inform appropriate management at appropriate locations. We use hierarchical partitioning to assess the absolute and relative importance of climate, topography, soil, landscape management (wider scale habitat configuration of forestry and agriculture) and site-based management (indices of predator control, and vegetation characteristics) in determining the abundance of a suite of upland birds in four regions of the UK. Unmeasured region-specific effects often made the largest contribution to models. Physical characteristics (climate, topography, soil) were important and on average explained a similar amount of variation to site-based management. However, there was considerable interspecific variation in the importance of both. Landscape-scale variables were generally of low importance. An index of predator control was positively correlated with the abundance of Red Grouse Lagopus lagopus scotica and two waders. Vegetation characteristics (composition and structure) were, together, strong correlates of the abundance of passerine species. Vegetation characteristics were as important as indices of predator control for waders and grouse. The importance of regional effects, physical characteristics and variables relating to management suggest targeting site-based management (such as predator control or vegetation management) to the areas where physical characteristics are most favourable. The most beneficial management will vary between species, necessitating a mosaic of management options across upland areas to benefit all species.

SummaryThe breeding areas of the Critically Endangered Slender-billed CurlewNumenius tenuirostrisare all but unknown, with the only well-substantiated breeding records being from the Omsk province, western Siberia. The identification of any remaining breeding population is of the highest priority for the conservation of any remnant population. If it is extinct, the reliable identification of former breeding sites may help determine the causes of the species’ decline, in order to learn wider conservation lessons. We used stable isotope values in feather samples from juvenile Slender-billed Curlews to identify potential breeding areas. Modelled precipitationδ2H data were compared to feather samples of surrogate species from within the potential breeding range, to produce a calibration equation. Application of this calibration to samples from 35 Slender-billed Curlew museum skins suggested they could have originated from the steppes of northern Kazakhstan and part of southern Russia between 48°N and 56°N. The core of this area was around 50°N, some way to the south of the confirmed nesting sites in the forest steppes. Surveys for the species might be better targeted at the Kazakh steppes, rather than around the historically recognised nest sites of southern Russia which might have been atypical for the species. We consider whether agricultural expansion in this area may have contributed to declines of the Slender-billed Curlew population.

SummaryThe Numeniini is a tribe of 13 wader species (Scolopacidae, Charadriiformes) of which seven are Near Threatened or globally threatened, including two Critically Endangered. To help inform conservation management and policy responses, we present the results of an expert assessment of the threats that members of this taxonomic group face across migratory flyways. Most threats are increasing in intensity, particularly in non-breeding areas, where habitat loss resulting from residential and commercial development, aquaculture, mining, transport, disturbance, problematic invasive species, pollution and climate change were regarded as having the greatest detrimental impact. Fewer threats (mining, disturbance, problematic native species and climate change) were identified as widely affecting breeding areas. Numeniini populations face the greatest number of non-breeding threats in the East Asian-Australasian Flyway, especially those associated with coastal reclamation; related threats were also identified across the Central and Atlantic Americas, and East Atlantic flyways. Threats on the breeding grounds were greatest in Central and Atlantic Americas, East Atlantic and West Asian flyways. Three priority actions were associated with monitoring and research: to monitor breeding population trends (which for species breeding in remote areas may best be achieved through surveys at key non-breeding sites), to deploy tracking technologies to identify migratory connectivity, and to monitor land-cover change across breeding and non-breeding areas. Two priority actions were focused on conservation and policy responses: to identify and effectively protect key non-breeding sites across all flyways (particularly in the East Asian- Australasian Flyway), and to implement successful conservation interventions at a sufficient scale across human-dominated landscapes for species’ recovery to be achieved. If implemented urgently, these measures in combination have the potential to alter the current population declines of many Numeniini species and provide a template for the conservation of other groups of threatened species.

1. The intensity of pastoral management in areas of High Nature Value farming is declining in some regions of Europe but increasing in others. This affects open habitats of conservation concern, such as the British uplands, where bird species that benefit from low-intensity grazing may be most sensitive to such polarization. While experimental manipulations of livestock grazing intensities have improved our understanding of upland breeding bird responses in the short term, none have examined the long-term impacts of altered management on reproductive success. 2. Using a replicated landscape-scale experiment that started in 2003, we investigated the effects of four grazing treatments (intensive sheep; low-intensity sheep; low-intensity mixed sheep and cattle; and no grazing) on the breeding productivity of meadow pipits Anthus pratensis, the most common upland passerine. Surveys were carried out systematically during early (2003 and 2004) and late (2015 and 2016) sampling periods of the experiment to compare the short- and long-term effects of grazing treatments on breeding density and productivity of pipits specifically, but also on the overall bird community. 3. Pipit breeding density was lowest under low-intensity sheep grazing while the highest egg-stage nest survival was observed in the same treatment, although no significant treatment effects were detected on overall nest survival or fledgling output. There were no significant differences in treatment effects between the sampling periods on any breeding variable, but overall nest survival was lower in the later sampling period across all treatments. 4. Breeding bird species richness differed between treatments in the later sampling period, with highest species richness in the ungrazed treatment. 5. Synthesis and applications. Livestock grazing management can have different outcomes for different upland birds. Our results showed that, with time, meadow pipit breeding productivity tended to be higher when sheep grazing intensity was reduced and/or mixed with cattle, and lower when livestock were removed, but not significantly so. Removal of grazing, however, can significantly increase bird species richness. The long-term experiment showed an overall decline in fledglings regardless of grazing treatments, potentially a result of increased predator numbers harboured by nearby developing woodland, highlighting the importance of considering wider landscape processes in grazing management decisions.

In this horizon scan, we highlight 15 emerging issues of potential relevance to global conservation in 2020. Seven relate to potentially extensive changes in vegetation or ecological systems. These changes are either relatively new, for example, conversion of kelp forests to simpler macroalgal systems, or may occur in the future, for example, as a result of the derivation of nanocelluose from wood or the rapid expansion of small hydropower schemes. Other topics highlight potential changes in national legislation that may have global effect on international agreements. Our panel of 23 scientists and practitioners selected these issues using a modified version of the Delphi technique from a long-list of 89 potential topics. info:eu-repo/semantics/publishedVersion

BACKGROUND Responding effectively to climate change requires urgent action to halt net greenhouse gas (GHG) emissions and to adapt to changes that cannot be prevented. The Paris Agreement of the United Nations Framework Convention on Climate Change has committed governments to the following: keeping global temperature rise below 2°C, pursuing efforts to limit it to 1.5°C, and adapting to reduce the vulnerability of people and ecosystems to the damaging consequences of a changing climate. When protected, restored, or managed appropriately, natural and seminatural ecosystems make critical contributions to climate change mitigation and to helping people adapt to climate change. Ecosystems themselves are vulnerable to climate change, but by restoring natural ecosystem processes, resilience can be built, and a wide range of adaptation strategies can ameliorate the impacts. Both synergies and conflicts between different objectives can arise, and it is essential to have clarity about what constitutes success across the range of adaptation and mitigation outcomes and to track progress. The success of ecosystem-based mitigation can be measured in terms of falling net emissions and stabilization of atmospheric CO2 concentration. Although this is conceptually straightforward, it can be difficult to measure ecosystem fluxes accurately. Adaptation is more complicated because it encompasses a wide range of objectives, with respect to people and biodiversity, including both reducing vulnerability and managing unavoidable change. ADVANCES Many studies have investigated how nature-based solutions can contribute to climate change mitigation and adaptation. The evidence is now clear that protecting and restoring ecosystems is essential to holding global temperature rise to between 1.5° and 2°C. The value of different interventions for reducing GHG emissions and promoting carbon sequestration can be quantified with varying degrees of confidence. The evidence for the effectiveness, opportunities, and limitations of ecosystem-based adaptation in enabling people to cope with climate change is also growing, and these approaches are starting to be implemented. Adaptation to reduce the vulnerability of biodiversity and ecosystems themselves to climate change has been discussed over many years but proposed measures remain largely untested. This is starting to change, with recent studies gathering empirical evidence of the factors that influence the vulnerability of ecosystems and biodiversity. Nevertheless, evaluation and reporting of adaptation is currently focused on planning and implementation of actions rather than on assessment of whether these programs have successfully reduced vulnerability. OUTLOOK A picture is emerging of what successful adaptation and mitigation in terrestrial ecosystems looks like when it is built around protecting and restoring natural ecosystem processes. To realize the potential of ecosystems to ameliorate climate change requires integrated actions that are consistent with wider biodiversity and sustainable development goals. High-carbon ecosystems, particularly forests and peatlands, are essential, but other ecosystems, such as savannas, are also important elements of wider nature-based solutions and should be protected and restored. Pursuing mitigation objectives alone risks perverse outcomes that increase rather than reduce vulnerability. Further work is required to test the effectiveness of specific ecosystem-based mitigation and adaptation measures and what works best to support biodiversity in a changing climate. More-robust monitoring and evaluation are needed to drive progress. Measuring adaptation for biodiversity is particularly challenging, and monitoring and management will need to develop together as we learn from experience.

Anthropogenic climate change is already impacting ecological systems. Understanding how organisms respond to weather (short-term) and climate (long-term) variability, and the population and ecosystem-wide consequences of climate change, is a research priority. The appropriate use of information on past and potential future weather and climate conditions is crucial for such research, but uncertainties and biases in this information are seldom given full consideration, with important consequences for assessing the potential impacts of climate change on the conservation of biodiversity. Here, we highlight three important neglected issues pertaining to the major applications of weather and climate information in ecological and biogeographical studies. These are as follows: (1) the uncertainty associated with historical weather and climate information; (2) the selection of ensembles of simulated future climate conditions derived from general circulation models (GCM); and (3) the uncertainty and assumptions associated with downscaling GCM simulations to ecologically relevant spatial scales. Broadly, in order to improve the use of weather and climate information in ecological studies, we propose that ecologists must: (1) use weather and climate products that are appropriate for their intended purpose; (2) explore the consequences of uncertainty in these products for ecological conclusions; and (3) seek greater integration of ecological and climate research to create products that reflect both the requirements of ecologists and the limits of climatology. This will enable more effective research into the likely responses of ecological systems to future climate change.

Many factors may affect daily nest survival. We present a novel multi-state, multi-stage model to estimate daily survival for each nest stage, daily hatching probability and probability that a failed nest died during a specific stage when stage of failure is unknown. The model does not require that hatching date be known. We used data from a large citizen science dataset to demonstrate the application of this approach, exploring the impact of laying dates, weather conditions, conserved soil moisture, soil carbon, habitat type and urbanization on failure rates of common blackbird (Turdus merula) nests. Models selected and estimates of nest success were similar to those of the simpler logistic exposure method, but accounted for additional uncertainty. Simulations suggest the multi-state approach performs better when incubation mortality is affected by nest age, but not when incubation mortality is assumed constant. Both approaches worked best when date of incubation initiation was known for all nests first visited during the incubation stage. Daily blackbird survival probabilities were higher in human rural habitat than in urban or countryside habitats supporting the hypothesis that these intermediate habitats offer a better balance between low food availability in urban areas and high predation rates in the wider countryside. Nest success was influenced more by recent precipitation in urban habitats, but by a longer-term measure of water availability, soil moisture, in non-human dominated habitats, indicating that climatic change is likely to alter relationships between habitat and breeding success (and their temporal scale) by influencing the trade-off between food availability and predation rates. The multi-state, multi-stage model developed here may be helpful to other researchers modelling ecological processes in which transition probabilities between multiple stages are of interest.

Lepidoptera are sensitive to climate change, with documented impacts on their phenology, distribution and communities. However, there remains considerable uncertainty over which species are most vulnerable, and which have been most affected so far. To address this, we analyse 35-year UK or English population trends of 55 butterfly and 265 moth species to model the impacts of variation in temperature and precipitation upon population growth rates. We identify the weather variables and periods that species are most sensitive to, the long-term impacts of climate change, and the characteristics of species which show the greatest responses. Positive impacts of summer temperature on both butterflies and moths were partly offset by negative impacts of temperature in other seasons, particularly winter. Precipitation tended to have negative impacts on population growth rates, particularly for moths. Annual population fluctuations were strongly driven by inter-annual variation in weather conditions. Over 40% of a significant decline in mean moth abundance from the 1990s to 2000s was consistent with a weather-driven decline predicted by our models, which also explained up to 19% of the decadal variation in abundance between species. Species overwintering as larvae and multivoltine species were most sensitive to the effects of weather, whilst southerly-distributed species, species associated with woodland and unimproved grassland habitats, and pest species, showed the most positive long-term responses to climate change. Combined, these results show how climate change is already having significant impacts on the abundance of particular butterfly and moth species, with likely future consequences for ecosystem function and services.

The impacts of climate change on species and ecosystems are increasingly evident. While these tend to be clearest with respect to changes in phenology and distribution ranges, there are also important consequences for population sizes and community structure. There is an urgent need to develop ecological indicators that can be used to detect climate-driven changes in ecological communities, and identify how those impacts may vary spatially. Here we describe the development of a new community-based seasonal climate change indicator that uses national population and weather indices. We test this indicator using Lepidopteran and co-located weather data collected across a range of UK Environmental Change Network (ECN) sites. We compare our butterfly indicator with estimates derived from an alternative, previously published metric, the Community Temperature Index (CTI). First, we quantified the effect of temperature on population growth rates of moths and butterflies (Species Temperature Response, STR) by modelling annual variation in national population indices as a function of nationally averaged seasonal variation in temperature, using species and weather data independent of the ECN data. Then, we calculated average STRs for annually summarised species data from each ECN site, weighted by species’ abundance, to produce the Community Temperature Response (CTR). Finally, we tested the extent to which CTR correlated with spatial variation in temperature between sites and the extent to which temporal variation in CTR tracked both annual and seasonal warming trends. Mean site CTR was positively correlated with mean site temperature for moths but not butterflies. However, spatial variation in moth communities was well explained by mean site summer temperature and butterfly communities by winter temperature, respectively accounting for 74% and 63% of variation. Temporal variation in moth and butterfly CTR within sites did not vary with the mean annual temperature but responded to variation in the mean temperature of specific seasons. There were positive correlations between moth seasonal CTRs and seasonal temperatures in winter, spring and summer; and butterfly seasonal CTRs and seasonal temperatures in winter and summer. Butterfly CTR and CTI both correlated spatially and temporally with winter temperature. Our results highlight the need for seasonality to be considered when examining the impact of climate change on communities. Seasonal CTRs may be used to track the impact of changing temperatures on biodiversity and help identify potential mechanisms by which climate change is affecting communities. In the case of Lepidoptera, our results suggest that future warming may reassemble Lepidoptera communities.

The timing of migration is one of the key life-history parameters of migratory birds. It is expected to be under strong selection, to be sensitive to changing environmental conditions and to have implications for population dynamics. However, most phenological studies do not describe arrival and departure phenologies for a species in a way that is robust to potential biases, or that can be clearly related to breeding populations. This hampers our ability to understand more fully how climate change may affect species’ migratory strategies, their life histories and ultimately their population dynamics. Using generalized additive models (GAMs) and extensive large-scale data collected in the UK over a 40-year period, we present standardized measures of migration phenology for common migratory birds, and examine how the phenology of bird migration has changed in the UK since the 1960s. Arrival dates for 11 of 14 common migrants became significantly earlier, with six species advancing their arrival by more than 10 days. These comprised two species, Blackcap Sylvia atricapilla and Chiffchaff Phylloscopus collybita, which winter closest to Britain in southern Europe and the arid northern zone of Africa, Common Redstart Phoenicurus phoenicurus, which winters in the arid zone, and three hirundines (Sand Martin Riparia riparia, House Martin Delichon urbicum and Barn Swallow Hirundo rustica), which winter in different parts of Africa. Concurrently, departure dates became significantly later for four of the 14 species and included species that winter in southern Europe (Blackcap and Chiffchaff) and in humid zones of Africa (Garden Warbler Sylvia borin and Whinchat Saxicola rubetra). Common Swift Apus apus was the exception in departing significantly earlier. The net result of earlier arrival and later departure for most species was that length of stay has become significantly longer for nine of the 14 species. Species that have advanced their timing of arrival showed the most positive trends in abundance, in accordance with previous studies. Related in part to earlier arrival and the relationship above, we also show that species extending their stay in Great Britain have shown the most positive trends. Further applications of our modelling approach will provide opportunities for more robust tests of relationships between phenological change and population dynamics than have been possible previously.

Previous studies have shown negative associations between wind energy development and breeding birds, including species of conservation concern. However, the magnitude and causes of such associations remain uncertain, pending detailed ‘before-after-control-intervention’ (BACI) studies. We conducted one of the most detailed such studies to date, assessing the impacts of terrestrial wind energy development on the European Golden Plover Pluvialis apricaria, a species with enhanced protection under European environmental law. Disturbance activity during construction had no significant effect on Golden Plover breeding abundance or distribution. In contrast, once turbines were erected, Golden Plover abundance was significantly reduced within the wind farm (−79%) relative to the baseline, with no comparable changes in buffer or control areas. Golden Plovers were significantly displaced by up to 400 m from turbines during operation. Hatching and fledging success were not affected by proximity to turbine locations either during construction or operation. The marked decline in abundance within the wind farm during operation but not construction, together with the lack of evidence for changes in breeding success or habitat, strongly suggests the displacement of breeding adults through behavioural avoidance of turbines, rather than a response to disturbance alone. It is of critical importance that wind farms are appropriately sited to prevent negative wildlife impacts. We demonstrate the importance of detailed BACI designs for quantifying the impacts on birds, and recommend wider application of such studies to improve the evidence base surrounding wind farm impacts on birds.

Recently detected invertebrate population declines are likely to have far-reaching impacts for ecosystem function. However, very little large-scale monitoring of invertebrates, especially soil invertebrates, has taken place. To address this gap, we established a school-based citizen science project to collect data on soil invertebrate abundance and bird counts across the UK. We examined the association between earthworms (which comprised 93% of the total soil invertebrate biomass in the surface soil) and 15 bird species on school playing fields over three years. We also tested whether simple bird counts of species that rely on earthworms could be used to indicate the earthworm abundance in soil. We found a clear link between earthworm abundance and counts of robins (Erithacus rubecula), blackbirds (Turdus merula) and other thrushes (Turdus pilaris, Turdus viscivorus, Turdus philomelos and Turdus iliacus), all of which rely on earthworms as an important component of their diet. None of these relationships varied with season. There were no correlations found between earthworm abundance and bird counts for species that do not rely on earthworms. We found that the total thrush count (including blackbirds) could be used as a simple indicator of earthworm abundance, explaining up to 20% of the variation in earthworm counts. In spite of the uncertainties associated with the data, these results raise the possibility that existing, robust, long-term bird monitoring data could, with further research, be used to infer changes in soil invertebrates, such as earthworms, and therefore aspects of soil health. We conclude by identifying a series of criteria that would need to be fulfilled in order for such inference to be robust.

Global warming has advanced the timing of biological events, potentially leading to disruption across trophic levels. The potential importance of phenological change as a driver of population trends has been suggested. To fully understand the possible impacts, there is a need to quantify the scale of these changes spatially and according to habitat type. We studied the relationship between phenological trends, space and habitat type between 1965 and 2012 using an extensive UK dataset comprising 269 aphid, bird, butterfly and moth species. We modelled phenologies using generalized additive mixed models that included covariates for geographical (latitude, longitude, altitude), temporal (year, season) and habitat terms (woodland, scrub, grassland). Model selection showed that a baseline model with geographical and temporal components explained the variation in phenologies better than either a model in which space and time interacted or a habitat model without spatial terms. This baseline model showed strongly that phenologies shifted progressively earlier over time, that increasing altitude produced later phenologies and that a strong spatial component determined phenological timings, particularly latitude. The seasonal timing of a phenological event, in terms of whether it fell in the first or second half of the year, did not result in substantially different trends for butterflies. For moths, early season phenologies advanced more rapidly than those recorded later. Whilst temporal trends across all habitats resulted in earlier phenologies over time, agricultural habitats produced significantly later phenologies than most other habitats studied, probably because of nonclimatic drivers. A model with a significant habitat‐time interaction was the best‐fitting model for birds, moths and butterflies, emphasizing that the rates of phenological advance also differ among habitats for these groups. Our results suggest the presence of strong spatial gradients in mean seasonal timing and nonlinear trends towards earlier seasonal timing that varies in form and rate among habitat types.

Assessing species' vulnerability to climate change is a prerequisite for developing effective strategies to conserve them. The last three decades have seen exponential growth in the number of studies evaluating how, how much, why, when, and where species will be impacted by climate change. We provide an overview of the rapidly developing field of climate change vulnerability assessment (CCVA) and describe key concepts, terms, steps and considerations. We stress the importance of identifying the full range of pressures, impacts and their associated mechanisms that species face and using this as a basis for selecting the appropriate assessment approaches for quantifying vulnerability. We outline four CCVA assessment approaches, namely trait-based, correlative, mechanistic and combined approaches and discuss their use. Since any assessment can deliver unreliable or even misleading results when incorrect data and parameters are applied, we discuss finding, selecting, and applying input data and provide examples of open-access resources. Because rare, small-range, and declining-range species are often of particular conservation concern while also posing significant challenges for CCVA, we describe alternative ways to assess them. We also describe how CCVAs can be used to inform IUCN Red List assessments of extinction risk. Finally, we suggest future directions in this field and propose areas where research efforts may be particularly valuable.