• Energy Research

AbstractClimate change has been associated with both latitudinal and elevational shifts in species’ ranges. The extent, however, to which climate change has driven recent range shifts alongside other putative drivers remains uncertain. Here, we use the changing distributions of 378 European breeding bird species over 30 years to explore the putative drivers of recent range dynamics, considering the effects of climate, land cover, other environmental variables, and species’ traits on the probability of local colonisation and extinction. On average, species shifted their ranges by 2.4 km/year. These shifts, however, were significantly different from expectations due to changing climate and land cover. We found that local colonisation and extinction events were influenced primarily by initial climate conditions and by species’ range traits. By contrast, changes in climate suitability over the period were less important. This highlights the limitations of using only climate and land cover when projecting future changes in species’ ranges and emphasises the need for integrative, multi-predictor approaches for more robust forecasting.

Birds populations allied in abundance Changes in climate can cause populations of species to decline, to increase, or to remain steady. Stephens et al. looked across species of common birds in Europe and the United States. Despite many differences between the two regions, expectations about how a species might respond to climate change did predict actual responses. Species predicted to benefit from increasing temperatures, or their associated effects, tended to increase, whereas those predicted to be negatively affected declined. Thus, even across widely varying ecological conditions and communities, climate change can be expected to alter population sizes. Science , this issue p. 84

AbstractGlobal change in climate and land use has profound effects on species' geographic and elevational distributions. In European birds, while species are predicted to track their climatic niches upslope, lowland agricultural intensification and high‐elevation land abandonment can drive elevational shifts. Species traits that can predict response to change in climate and land use can inform conservation, but a thorough examination of their relationships with elevational shifts in European birds is lacking. We estimate the change in the elevational distributions of 71 species from 1996 to 2016 in a region of the western Palearctic with wide elevational gradients (approximately 3000 m) and large changes in temperature. We model the relationships between elevational shifts and species traits associated with resource preference and adaptive capacity at five reference points including the cool edge, warm edge, and the core of species' elevational distributions. When intermediate reference points were removed, changes to the results were negligible, indicating that three reference points are likely sufficient. We found significant upslope and downslope shifts in 56% and 23% of our study species, respectively. Asymmetric rates of shifts in the cool and warm edges caused significant contractions in elevational extent in 30% of our study species. The effect of elevational preference (i.e., midpoint elevation) was habitat dependent. Movement in alpine birds was unidirectionally upslope, with nearly half displaying significant or apparent elevational range contractions. In woodland birds, asymmetries of shifts in reference points led to expansions in extent in low‐elevation species and contractions in high‐elevation species. Generally, migrants, species with smaller mass, smaller relative brain size, smaller hand‐wing index, and generalists in diet, habitat, and elevation had greater upslope shifts. While elevational shifts in European birds were heterogenous and species‐specific, many were rapid, and species traits associated with resource preference and adaptive capacity were associated with common patterns of elevation.

Le fichier de données source contient des données pour tracer les figures 1,2 et 3 et les figures supplémentaires S1, S3 à S12 et le tableau supplémentaire S1. Les données supplémentaires contiennent les données sur les caractères de l'espèce. Des références pour les sources de données peuvent être trouvées dans la feuille séparée. Les traits à noter ont été rassemblés pour 378 espèces d'oiseaux nicheurs européens, mais les données sur l'étendue de l'habitat n'étaient disponibles que pour 336 espèces. Les sources de données sur les espèces se trouvent dans l'onglet Références. El archivo de datos de origen contiene datos para trazar las Figuras 1,2 y 3, y las Figuras Complementarias S1, S3 -S12 y la Tabla Complementaria S1. Los datos complementarios contienen datos de rasgos de las especies. Las referencias de las fuentes de datos se pueden encontrar en la hoja separada. Los rasgos de la nota se recopilaron para 378 especies de aves reproductoras europeas, pero los datos de amplitud del hábitat solo estaban disponibles para 336 especies. Las fuentes de datos de especies se pueden encontrar en la pestaña Referencias. Source data file contains data for plotting Figures 1,2, and 3, and Supplementary Figures S1, S3 -S12, and Supplementary Table S1. Supplementary data contains species' trait data. References for data sources can be found in the separate sheet. Note traits were collated for 378 species of European breeding bird, but habitat breadth data were only available for 336 species. Sources of species data can be found in the References tab. يحتوي ملف البيانات المصدر على بيانات لرسم الأشكال 1 و 2 و 3 والأشكال التكميلية S1 و S3 - S12 والجدول التكميلي S1. تحتوي البيانات التكميلية على بيانات سمات الأنواع. يمكن العثور على مراجع لمصادر البيانات في الورقة المنفصلة. تم جمع سمات الملاحظة لـ 378 نوعًا من طيور التكاثر الأوروبية، لكن بيانات اتساع الموائل كانت متاحة فقط لـ 336 نوعًا. يمكن العثور على مصادر بيانات الأنواع في علامة التبويب المراجع.

AbstractMountain areas often hold special species communities, and they are high on the list of conservation concern. Global warming and changes in human land use, such as grazing pressure and afforestation, have been suggested to be major threats for biodiversity in the mountain areas, affecting species abundance and causing distribution shifts towards mountaintops. Population shifts towards poles and mountaintops have been documented in several areas, indicating that climate change is one of the key drivers of species’ distribution changes. Despite the high conservation concern, relatively little is known about the population trends of species in mountain areas due to low accessibility and difficult working conditions. Thanks to the recent improvement of bird monitoring schemes around Europe, we can here report a first account of population trends of 44 bird species from four major European mountain regions: Fennoscandia, UK upland, south‐western (Iberia) and south‐central mountains (Alps), covering 12 countries. Overall, the mountain bird species declined significantly (−7%) during 2002–2014, which is similar to the declining rate in common birds in Europe during the same period. Mountain specialists showed a significant −10% decline in population numbers. The slope for mountain generalists was also negative, but not significantly so. The slopes of specialists and generalists did not differ from each other. Fennoscandian and Iberian populations were on average declining, while in United Kingdom and Alps, trends were nonsignificant. Temperature change or migratory behaviour was not significantly associated with regional population trends of species. Alpine habitats are highly vulnerable to climate change, and this is certainly one of the main drivers of mountain bird population trends. However, observed declines can also be partly linked with local land use practices. More efforts should be undertaken to identify the causes of decline and to increase conservation efforts for these populations.

Species respond dynamically to climate change and exhibit time lags. Consequently, species may not occupy their full climatic niche during range shifting. Here, we assessed climate niche tracking during recent range shifts of European and United States (US) birds. Using data from two European bird atlases and from the North American Breeding Bird Survey between the 1980s and 2010s, we analysed range overlap and climate niche overlap based on kernel density estimation. Phylogenetic multiple regression was used to assess the effect of species morphological, ecological and biogeographic traits on range and niche metrics. European birds shifted their ranges north and north-eastwards, US birds westwards. Range unfilling was lower than expected by null models, and niche expansion was more common than niche unfilling. Also, climate niche tracking was generally lower in US birds and poorly explained by species traits. Overall, our results suggest that dispersal limitations were minor in range shifting birds in Europe and the USA while delayed extinctions from unfavourable areas seem more important. Regional differences could be related to differences in land use history and monitoring schemes. Comparative analyses of range and niche shifts provide a useful screening approach for identifying the importance of transient dynamics and time-lagged responses to climate change. This article is part of the theme issue ‘Ecological novelty and planetary stewardship: biodiversity dynamics in a transforming biosphere’.