• Energy Research

AbstractGeographic range size is the manifestation of complex interactions between intrinsic species traits and extrinsic environmental conditions. It is also a fundamental ecological attribute of species and a key extinction risk correlate. Past research has primarily focused on the role of biological and environmental predictors of range size, but macroecological patterns can also be distorted by human activities. Here, we analyse the role of extrinsic (biogeography, habitat state, climate, human pressure) and intrinsic (biology) variables in predicting range size of the world's terrestrial mammals. In particular, our aim is to compare the predictive ability of human pressure vs. species biology. We evaluated the ability of 19 intrinsic and extrinsic variables in predicting range size for 4867 terrestrial mammals. We repeated the analyses after excluding restricted‐range species and performed separate analyses for species in different biogeographic realms and taxonomic groups. Our model had high predictive ability and showed that climatic variables and human pressures are the most influential predictors of range size. Interestingly, human pressures predict current geographic range size better than biological traits. These findings were confirmed when repeating the analyses on large‐ranged species, individual biogeographic regions and individual taxonomic groups. Climatic and human impacts have determined the extinction of mammal species in the past and are the main factors shaping the present distribution of mammals. These factors also affect other vertebrate groups globally, and their influence on range size may be similar as well. Measuring climatic and human variables can allow to obtain approximate range size estimations for data‐deficient and newly discovered species (e.g. hundreds of mammal species worldwide). Our results support the need for a more careful consideration of the role of climate change and human impact – as opposed to species biological characteristics – in shaping species distribution ranges.

Pour faire face à la crise mondiale actuelle de la biodiversité, les gouvernements ont fixé des objectifs stratégiques et adopté des indicateurs pour suivre les progrès vers leur réalisation. La projection des impacts probables sur la biodiversité de différentes décisions politiques permet aux décideurs de comprendre si et comment ces objectifs peuvent être atteints. Nous avons projeté les tendances de deux indicateurs largement utilisés de l'abondance de la population : l'abondance moyenne géométrique, équivalente à l'indice de la planète vivante et le risque d'extinction (l'indice de la liste rouge) dans différents scénarios de changement climatique et d'utilisation des terres. En les testant sur des espèces terrestres de carnivores et d'ongulés, nous avons constaté que les deux indicateurs diminuent régulièrement et que, d'ici 2050, dans un scénario de statu quo, l'abondance moyenne géométrique des populations diminue de 18 à 35 %, tandis que le risque d'extinction augmente pour 8 à 23 % des espèces, en fonction des hypothèses sur les réponses des espèces au changement climatique. BAU ne parviendra donc pas à atteindre l'objectif 12 de la Convention sur la diversité biologique consistant à améliorer l'état de conservation des espèces menacées connues. Un scénario de développement durable alternatif réduit à la fois le risque d'extinction et les pertes de population par rapport au BAU et pourrait entraîner une augmentation de la population. Notre approche des réponses des espèces modèles aux changements mondiaux met l'accent sur les scénarios directement au niveau des espèces, prenant ainsi en compte une dimension supplémentaire de la biodiversité et ouvrant la voie à l'inclusion de fondations écologiques plus solides dans les futures évaluations des scénarios de biodiversité. Para abordar la actual crisis mundial de biodiversidad, los gobiernos han establecido objetivos estratégicos y han adoptado indicadores para monitorear el progreso hacia su logro. La proyección de los posibles impactos en la biodiversidad de las diferentes decisiones políticas permite a los responsables de la toma de decisiones comprender si se pueden cumplir estos objetivos y cómo. Proyectamos tendencias en dos indicadores ampliamente utilizados de abundancia poblacional, la Abundancia Media Geométrica, equivalente al Índice de Planeta Vivo y el riesgo de extinción (el Índice de la Lista Roja) bajo diferentes escenarios de cambio climático y de uso de la tierra. Probando estos en especies de carnívoros y ungulados terrestres, encontramos que ambos indicadores disminuyen constantemente y, para 2050, en un escenario de negocios como de costumbre (BAU), la abundancia de la población media geométrica disminuye en un 18–35%, mientras que el riesgo de extinción aumenta para el 8–23% de las especies, dependiendo de los supuestos sobre las respuestas de las especies al cambio climático. Por lo tanto, BAU no cumplirá con la meta 12 del Convenio sobre la Diversidad Biológica de mejorar el estado de conservación de las especies amenazadas conocidas. Un escenario alternativo de desarrollo sostenible reduce tanto el riesgo de extinción como las pérdidas de población en comparación con BAU y podría conducir a un aumento de la población. Nuestro enfoque para modelar las respuestas de las especies a los cambios globales lleva el enfoque de los escenarios directamente al nivel de las especies, teniendo en cuenta así una dimensión adicional de la biodiversidad y allanando el camino para incluir fundamentos ecológicos más sólidos en futuras evaluaciones de escenarios de biodiversidad. To address the ongoing global biodiversity crisis, governments have set strategic objectives and have adopted indicators to monitor progress toward their achievement. Projecting the likely impacts on biodiversity of different policy decisions allows decision makers to understand if and how these targets can be met. We projected trends in two widely used indicators of population abundance Geometric Mean Abundance, equivalent to the Living Planet Index and extinction risk (the Red List Index) under different climate and land-use change scenarios. Testing these on terrestrial carnivore and ungulate species, we found that both indicators decline steadily, and by 2050, under a Business-as-usual (BAU) scenario, geometric mean population abundance declines by 18–35% while extinction risk increases for 8–23% of the species, depending on assumptions about species responses to climate change. BAU will therefore fail Convention on Biological Diversity target 12 of improving the conservation status of known threatened species. An alternative sustainable development scenario reduces both extinction risk and population losses compared with BAU and could lead to population increases. Our approach to model species responses to global changes brings the focus of scenarios directly to the species level, thus taking into account an additional dimension of biodiversity and paving the way for including stronger ecological foundations into future biodiversity scenario assessments. ولمعالجة أزمة التنوع البيولوجي العالمية المستمرة، وضعت الحكومات أهدافاً استراتيجية واعتمدت مؤشرات لرصد التقدم المحرز نحو تحقيقها. إن توقع التأثيرات المحتملة على التنوع البيولوجي لقرارات السياسة المختلفة يسمح لصانعي القرار بفهم ما إذا كان يمكن تحقيق هذه الأهداف وكيفية تحقيقها. توقعنا اتجاهات في مؤشرين يستخدمان على نطاق واسع لوفرة السكان متوسط الوفرة الهندسية، أي ما يعادل مؤشر الكوكب الحي ومخاطر الانقراض (مؤشر القائمة الحمراء) في ظل سيناريوهات مختلفة لتغير المناخ واستخدام الأراضي. عند اختبارها على الأنواع آكلة اللحوم البرية وذوات الحوافر، وجدنا أن كلا المؤشرين ينخفضان بشكل مطرد، وبحلول عام 2050، في ظل سيناريو العمل كالمعتاد (BAU)، ينخفض متوسط وفرة السكان الهندسي بنسبة 18-35 ٪ بينما تزداد مخاطر الانقراض لـ 8-23 ٪ من الأنواع، اعتمادًا على الافتراضات حول استجابات الأنواع لتغير المناخ. وبالتالي، ستفشل جامعة البلقاء التطبيقية في تحقيق الهدف 12 من اتفاقية التنوع البيولوجي المتمثل في تحسين حالة حفظ الأنواع المعروفة المهددة بالانقراض. يقلل سيناريو التنمية المستدامة البديلة من خطر الانقراض والخسائر السكانية مقارنةً بوحدات العمل الاعتيادية ويمكن أن يؤدي إلى زيادة عدد السكان. إن نهجنا في استجابات الأنواع النموذجية للتغيرات العالمية يجلب تركيز السيناريوهات مباشرة إلى مستوى الأنواع، وبالتالي يأخذ في الاعتبار بُعدًا إضافيًا للتنوع البيولوجي ويمهد الطريق لإدراج أسس بيئية أقوى في تقييمات سيناريوهات التنوع البيولوجي المستقبلية.

AbstractEstimating population spread rates across multiple species is vital for projecting biodiversity responses to climate change. A major challenge is to parameterise spread models for many species. We introduce an approach that addresses this challenge, coupling a trait‐based analysis with spatial population modelling to project spread rates for 15 000 virtual mammals with life histories that reflect those seen in the real world. Covariances among life‐history traits are estimated from an extensive terrestrial mammal data set using Bayesian inference. We elucidate the relative roles of different life‐history traits in driving modelled spread rates, demonstrating that any one alone will be a poor predictor. We also estimate that around 30% of mammal species have potential spread rates slower than the global mean velocity of climate change. This novel trait‐space‐demographic modelling approach has broad applicability for tackling many key ecological questions for which we have the models but are hindered by data availability.

AbstractThe International Union for Conservation of Nature (IUCN) Red List is a central tool for extinction risk monitoring and influences global biodiversity policy and action. But, to be effective, it is crucial that it consistently accounts for each driver of extinction. Climate change is rapidly becoming a key extinction driver, but consideration of climate change information remains challenging for the IUCN. Several methods can be used to predict species’ future decline, but they often fail to provide estimates of the symptoms of endangerment used by IUCN. We devised a standardized method to measure climate change impact in terms of change in habitat quality to inform criterion A3 on future population reduction. Using terrestrial nonvolant tetrapods as a case study, we measured this impact as the difference between the current and the future species climatic niche, defined based on current and future bioclimatic variables under alternative model algorithms, dispersal scenarios, emission scenarios, and climate models. Our models identified 171 species (13% out of those analyzed) for which their current red‐list category could worsen under criterion A3 if they cannot disperse beyond their current range in the future. Categories for 14 species (1.5%) could worsen if maximum dispersal is possible. Although ours is a simulation exercise and not a formal red‐list assessment, our results suggest that considering climate change impacts may reduce misclassification and strengthen consistency and comprehensiveness of IUCN Red List assessments.

According to Bergmann's and Allen's rules, climate change may drive morphological shifts in species, affecting body size and appendage length. These rules predict that species in colder climates tend to be larger and have shorter appendages to improve thermoregulation. Bats are thought to be sensitive to climate and are therefore expected to respond to climatic changes across space and time. We conducted a phylogenetic meta‐analysis on > 27 000 forearm length (FAL) and body mass (BM) measurements from 20 sedentary European bat species to examine body size patterns. We assessed the relationships between body size and environmental variables (winter and summer temperatures, and summer precipitation) across geographic locations, and also analysed temporal trends in body size. We found sex‐specific morphological shifts in the body size of European bats in response to temperature and precipitation patterns across space, but no clear temporal changes due to high interspecific variability. Across Europe, male FAL decreased with increasing summer and winter temperatures, and BM increased with greater precipitation. In contrast, both FAL and BM of female bats increased with summer precipitation and decreased with winter temperatures. Our data can confirm Bergmann's rule for both males and females, while females' BM variations are also related to summer precipitation, suggesting a potential link to resource availability. Allen's rule is confirmed only in males in relation to summer temperature, while in females FAL and BM decrease proportionally with increasing temperature, maintaining a constant allometric relationship incompatible with Allen's rule. This study provides new insights into sex and species‐dependent morphological changes in bat body size in response to temperature and precipitation patterns. It highlights how body size variation reflects adaptations to temperature and precipitation patterns, thus providing insights into potential species‐level morphological responses to climate change across Europe.

ABSTRACTUnderstanding how species respond to climate change is key to informing vulnerability assessments and designing effective conservation strategies, yet research efforts on wildlife responses to climate change fail to deliver a representative overview due to inherent biases. Bats are a species‐rich, globally distributed group of organisms that are thought to be particularly sensitive to the effects of climate change because of their high surface‐to‐volume ratios and low reproductive rates. We systematically reviewed the literature on bat responses to climate change to provide an overview of the current state of knowledge, identify research gaps and biases and highlight future research needs. We found that studies are geographically biased towards Europe, North America and Australia, and temperate and Mediterranean biomes, thus missing a substantial proportion of bat diversity and thermal responses. Less than half of the published studies provide concrete evidence for bat responses to climate change. For over a third of studied bat species, response evidence is only based on predictive species distribution models. Consequently, the most frequently reported responses involve range shifts (57% of species) and changes in patterns of species diversity (26%). Bats showed a variety of responses, including both positive (e.g. range expansion and population increase) and negative responses (range contraction and population decrease), although responses to extreme events were always negative or neutral. Spatial responses varied in their outcome and across families, with almost all taxonomic groups featuring both range expansions and contractions, while demographic responses were strongly biased towards negative outcomes, particularly among Pteropodidae and Molossidae. The commonly used correlative modelling approaches can be applied to many species, but do not provide mechanistic insight into behavioural, physiological, phenological or genetic responses. There was a paucity of experimental studies (26%), and only a small proportion of the 396 bat species covered in the examined studies were studied using long‐term and/or experimental approaches (11%), even though they are more informative about the effects of climate change. We emphasise the need for more empirical studies to unravel the multifaceted nature of bats' responses to climate change and the need for standardised study designs that will enable synthesis and meta‐analysis of the literature. Finally, we stress the importance of overcoming geographic and taxonomic disparities through strengthening research capacity in the Global South to provide a more comprehensive view of terrestrial biodiversity responses to climate change.