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1,813 result(s) for "Gregory, Richard D."
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Global effects of land-use intensity on local pollinator biodiversity
Pollinating species are in decline globally, with land use an important driver. However, most of the evidence on which these claims are made is patchy, based on studies with low taxonomic and geographic representativeness. Here, we model the effect of land-use type and intensity on global pollinator biodiversity, using a local-scale database covering 303 studies, 12,170 sites, and 4502 pollinating species. Relative to a primary vegetation baseline, we show that low levels of intensity can have beneficial effects on pollinator biodiversity. Within most anthropogenic land-use types however, increasing intensity is associated with significant reductions, particularly in urban (43% richness and 62% abundance reduction compared to the least intensive urban sites), and pasture (75% abundance reduction) areas. We further show that on cropland, the strongly negative response to intensity is restricted to tropical areas, and that the direction and magnitude of response differs among taxonomic groups. Our findings confirm widespread effects of land-use intensity on pollinators, most significantly in the tropics, where land use is predicted to change rapidly. Anthropogenic losses of animal pollinators threaten ecosystem functioning. Here the authors report a global analysis showing geographically varied yet widespread declines of pollinator diversity and abundance with land use intensification, particularly in tropical biomes.
Abundance decline in the avifauna of the European Union reveals cross‐continental similarities in biodiversity change
Although global assessments provide evidence of biodiversity decline, some have questioned the strength of the evidence, with local assemblage studies often showing a more balanced picture of biodiversity change. The multifaceted nature of biodiversity and imperfect monitoring datasets may partially explain these findings. Here, using an extensive dataset, we find significant biodiversity loss in the native avifauna of the European Union (EU). We estimate a decline of 17–19% in the overall breeding bird abundance since 1980: a loss of 560–620 million individual birds. Both total and proportional declines in bird numbers are high among species associated with agricultural land. The distribution of species’ population growth rates (ln) is centered close to zero, with numerical decline driven by substantial losses in abundant species. Our work supports previous assessments indicating substantial recent biodiversity loss and calls to reduce the threat of extinctions and restore species’ abundances, for the sake of nature and people. Using an extensive high‐quality dataset, we estimate a decline of 17%–19% in overall native breeding bird abundance in the European Union since 1980: a loss of 560–620 million individual birds. The distribution of species’ population growth rates (ln) is centred close to zero with numerical decline driven by substantial losses in abundant species. Our work supports previous assessments indicating recent biodiversity loss and calls to reduce the threat of extinctions and restore species’ abundances, for the sake of nature and people.
Disentangling the relative roles of climate and land cover change in driving the long-term population trends of European migratory birds
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.
Agricultural Management and Climatic Change Are the Major Drivers of Biodiversity Change in the UK
Action to reduce anthropogenic impact on the environment and species within it will be most effective when targeted towards activities that have the greatest impact on biodiversity. To do this effectively we need to better understand the relative importance of different activities and how they drive changes in species' populations. Here, we present a novel, flexible framework that reviews evidence for the relative importance of these drivers of change and uses it to explain recent alterations in species' populations. We review drivers of change across four hundred species sampled from a broad range of taxonomic groups in the UK. We found that species' population change (~1970-2012) has been most strongly impacted by intensive management of agricultural land and by climatic change. The impact of the former was primarily deleterious, whereas the impact of climatic change to date has been more mixed. Findings were similar across the three major taxonomic groups assessed (insects, vascular plants and vertebrates). In general, the way a habitat was managed had a greater impact than changes in its extent, which accords with the relatively small changes in the areas occupied by different habitats during our study period, compared to substantial changes in habitat management. Of the drivers classified as conservation measures, low-intensity management of agricultural land and habitat creation had the greatest impact. Our framework could be used to assess the relative importance of drivers at a range of scales to better inform our policy and management decisions. Furthermore, by scoring the quality of evidence, this framework helps us identify research gaps and needs.
Relating characteristics of global biodiversity targets to reported progress
To inform governmental discussions on the nature of a revised Strategic Plan for Biodiversity of the Convention on Biological Diversity (CBD), we reviewed the relevant literature and assessed the framing of the 20 Aichi Biodiversity Targets in the current strategic plan. We asked international experts from nongovernmental organizations, academia, government agencies, international organizations, research institutes, and the CBD to score the Aichi Targets and their constituent elements against a set of specific, measurable, ambitious, realistic, unambiguous, scalable, and comprehensive criteria (SMART based, excluding time bound because all targets are bound to 2015 or 2020). We then investigated the relationship between these expert scores and reported progress toward the target elements by using the findings from 2 global progress assessments (Global Biodiversity Outlook and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services). We analyzed the data with ordinal logistic regressions. We found significant positive relationships (p < 0.05) between progress and the extent to which the target elements were perceived to be measurable, realistic, unambiguous, and scalable. There was some evidence of a relationship between progress and specificity of the target elements, but no relationship between progress and ambition. We are the first to show associations between progress and the extent to which the Aichi Targets meet certain SMART criteria. As negotiations around the post-2020 biodiversity framework proceed, decision makers should strive to ensure that new or revised targets are effectively structured and clearly worded to allow the translation of targets into actionable policies that can be successfully implemented nationally, regionally, and globally. Para informar las discusiones gubernamentales sobre la naturaleza de una revisión del Plan Estratégico para la Biodiversidad del Convenio sobre la Diversidad Biológica (CBD, en inglés), revisamos la literatura relevante y evaluamos el marco de 20 Objetivos de Biodiversidad de Aichi en el plan estratégico actual. Le pedimos a expertos internacionales de organizaciones no gubernamentales, de la academia, de agencias gubernamentales, organizaciones internacionales, de institutos de investigación y de la CBD que puntuaran los Objetivos de Aichi y sus elementos constituyentes frente a un conjunto de criterios específicos, medibles, ambiciosos, realistas (basados en SMART [las iniciales en inglés] y excluyendo aquellos limitados por el tiempo, pues todos los objetivos están limitados al 2015 o al 2020), inequívocos, expansibles y completos (excluyendo aquellos limitados por el tiempo). Después investigamos la relación entre los puntajes de estos expertos y el progreso reportado hacia los elementos objetivo usando los resultados de dos valoraciones mundiales del progreso (el Pronóstico Mundial de la Biodiversidad y la Plataforma Intergubernamental de Ciencia y Política sobre la Biodiversidad y los Servicios Ambientales). Analizamos los datos con regresiones logísticas ordinales. Encontramos relaciones positivas significativas (p < 0.05) entre el progreso y el alcance al que fueron percibidos como medibles, realistas, inequívocos y expansibles los elementos objetivo. Hubo algo de evidencia de la relación entre el progreso y la ambición. Somos los primeros en mostrar las asociaciones entre el progreso y la extensión hasta la que los Objetivos de Aichi cumplen con ciertos criterios SMART. Conforme proceden las negociaciones en torno al marco de trabajo de biodiversidad post-2020, quienes toman las decisiones deberían esforzarse por asegurar que los objetivos nuevos o revisados estén estructurados efectivamente y redactados claramente para permitir la traducción de los objetivos hacia políticas factibles que puedan implementarse exitosamente a nivel nacional, regional y mundial.
An Indicator of the Impact of Climatic Change on European Bird Populations
Rapid climatic change poses a threat to global biodiversity. There is extensive evidence that recent climatic change has affected animal and plant populations, but no indicators exist that summarise impacts over many species and large areas. We use data on long-term population trends of European birds to develop such an indicator. We find a significant relationship between interspecific variation in population trend and the change in potential range extent between the late 20(th) and late 21(st) centuries, forecasted by climatic envelope models. Our indicator measures divergence in population trend between bird species predicted by climatic envelope models to be favourably affected by climatic change and those adversely affected. The indicator shows a rapid increase in the past twenty years, coinciding with a period of rapid warming.
Aiming Higher to Test a Bend in the Curve of Biodiversity Loss: The Challenge of Halt‐The‐Loss Targets
Efforts to ‘bend the curve’ of biodiversity loss involve setting targets to halt declines. Here, we propose an empirical test of such targets. This test states the probability that the rate of change in a biodiversity indicator is greater than or equal to zero. We used a combination of real and simulated data to explore factors affecting test performance. We found that while smoothing had a minimal effect, the outcome depends heavily on the variability and number of species in a dataset. This suggests that thresholds for target acceptance should be set on a case‐by‐case basis. Adding data for subsequent years could retrospectively change the outcome in a target year. Assessments made with data only up until the target year should therefore be regarded as interim, with the assessment of the target only finalised once subsequent data are also included. We recommend that simulations are used a priori to choose smoothing levels and to set thresholds for accepting a target has been met. We present a test to evaluate targets to ‘halt the loss’ of biodiversity. We use simulations to explore the accuracy of this test with different datasets. We recommend that thresholds for target assessments are set on a case‐by‐case basis using simulations, and that assessments are regarded as interim until data following the target year can be included.
What is the role of scientists in meeting the environmental challenges of the twenty-first century?
We live at a time of rapid and accelerating biodiversity loss and climate change that pose an existential risk to the environment, humanity, and social justice and stability. Governmental responses are seen by many citizens, including scientists, as inadequate, leading to an increase in civil protests and activism by those calling for urgent action to effect change. Here we consider the role(s) of scientists in responding to those challenges and engaging with policy given that when a scientist moves into political advocacy, reflecting their values and preferences, their objectivity and the value of scientific opinion may be seen as compromised. We then consider whether institutional setting and career stage may affect decisions to engage with policy or activism. Against this backcloth, we ask whether it is sufficient for scientists to act as impartial ‘brokers’ in societal decisions, arguing they should consider acting as ‘ Honest Advocates ’ in policy formation in some circumstances. Such advocacy can contribute to decision-making in a purposeful, well-informed manner, doing societal good without damaging the reputation of science. We encourage scientists to each reflect on their multiple roles in addressing the environmental challenges of our time.
Developing indicators for European birds
The global pledge to deliver 'a significant reduction in the current rate of biodiversity loss by 2010' is echoed in a number of regional and national level targets. There is broad consensus, however, that in the absence of conservation action, biodiversity will continue to be lost at a rate unprecedented in the recent era. Remarkably, we lack a basic system to measure progress towards these targets and, in particular, we lack standard measures of biodiversity and procedures to construct and assess summary statistics. Here, we develop a simple classification of biodiversity indicators to assist their development and clarify purpose. We use European birds, as example taxa, to show how robust indicators can be constructed and how they can be interpreted. We have developed statistical methods to calculate supranational, multi-species indices using population data from national annual breeding bird surveys in Europe. Skilled volunteers using standardized field methods undertake data collection where methods and survey designs differ slightly across countries. Survey plots tend to be widely distributed at a national level, covering many bird species and habitats with reasonable representation. National species' indices are calculated using log-linear regression, which allows for plot turnover. Supranational species' indices are constructed by combining the national species' indices weighted by national population sizes of each species. Supranational, multi-species indicators are calculated by averaging the resulting indices. We show that common farmland birds in Europe have declined steeply over the last two decades, whereas woodland birds have not. Evidence elsewhere shows that the main driver of farmland bird declines is increased agricultural intensification. We argue that the farmland bird indicator is a useful surrogate for trends in other elements of biodiversity in this habitat.
International Conservation Policy Delivers Benefits for Birds in Europe
Conservation of the planet's biodiversity will depend on international policy intervention, yet evidence-based assessment of the success of such intervention is lacking. Poor understanding of the effectiveness of international policy instruments exposes them to criticism or abandonment and reduces opportunities to improve them. Comparative analyses of population trends provide strong evidence for a positive impact of one such instrument, the European Union's Birds Directive, and we identify positive associations between the rate of provision of certain conservation measures through the directive and the response of bird populations. The results suggest that supranational conservation policy can bring measurable conservation benefits, although future assessments will require the setting of quantitative objectives and an increase in the availability of data from monitoring schemes.