Erosion of Lizard Diversity by Climate Change and Altered Thermal Niches

Targeting research to underpin climate change adaptation for birds J. W. PEARCE-HIGGINS,* R. B. BRADBURY, D. E. CHAMBERLAIN, A. DREWITT, R. H. W. LANGSTON & S. G. WILLIS BTO, The Nunnery, Thetford, Norfolk IP24 2PU, UK RSPB, The Lodge, Sandy, Bedfordshire SG19 2DL, UK Dipartimento di Biologia Animale e dell’Uomo, Universita di Torino, Via Accademia Albertina 13, 10123 Turin, Italy English Nature, Northminster House, Peterborough PE1 1UA, UK Institute of Ecosystem Science, School of Biological Sciences, University of Durham, South Road, Durham DH1 3LE, UK

Climate change is expected to exert varying effects on different taxa and species, affecting both their abundance and distribution ranges. Previous studies have used climate niche models (CNMs) to estimate shifts in the distribution of insects, without considering whether the effects of climate change may vary depending on their functional traits (nesting strategy, body size, and period of activity). Dung beetles, a taxonomic group characterized by using mammalian dung as their primary source of food (coprophagy), respond differently to temperature fluctuations depending on their nesting strategy and body size. In this study, we used CNMs to estimate shifts in the distribution ranges of 33 species of dung beetles under climate change scenarios (the shared socioeconomic pathways from the IPCC’s Sixth Assessment Report) for the period 2041–2060 in North America and Central America (excluding Canada due to absence of data). Additionally, we analyzed whether the effects of climate change on the distribution ranges of the studied species are significantly different depending on their functional traits. Our results showed that climate change will negatively affect the distribution range of the majority of the studied species by the middle of this century, with contrasting effects depending on their nesting strategy and body size. The smallest species and dwellers showed an increase in their occurrence probabilities and percentage of highly suitable habitats, whereas larger-bodied species and tunnelers showed a decrease in both. We found no significant differences between diurnal and nocturnal species. Our results show that by incorporating key traits related to temperature response and ecosystem function, we can analyze shifts in species distribution ranges more precisely, enabling the identification of patterns across functional categories and predictions about their future.

Climate change has led to shifts in species distribution and become a crucial factor in the extinction of species. Increasing average temperatures, temperature extremes, and unpredictable weather events have all become a part of a perfect storm that is threatening ecosystems. Higher altitude habitats are disproportionately affected by climate change, and habitats for already threatened specialist species are shrinking. The Siberian ibex, Capra sibirica, is distributed across Central Asia and Southern Siberia and is the dominant ungulate in the Pamir plateau. To understand how climate change could affect the habitat of Siberian ibex in the Taxkorgan Nature Reserve (TNR), an ensemble species distribution model was built using 109 occurrence points from a four-year field survey. Fifteen environmental variables were used to simulate suitable habitat distribution under different climate change scenarios. Our results demonstrated that a stable, suitable habitat for Siberian ibex was mostly distributed in the northwest and northeast of the TNR. We found that climate change will further reduce the area of suitable habitat for this species. In the scenarios of RCP2.6 to 2070 and RCP8.5 to 2050, habitat loss would exceed 30%. In addition, suitable habitats for Siberian ibex will shift to higher latitudes under climate change. As a result, timely prediction of the distribution of endangered animals is conducive to the conservation of the biodiversity of mountain ecosystems, particularly in arid areas.

Amidst several global environmental challenges, climate change severely threatens biodiversity, leading to shifts in species distributions, and, in extreme cases, local or global extinctions. Here, we modeled the current and future distributions of biodiversity hotspots for terrestrial venomous snake species across India and evaluated shifts under two climate change scenarios that represent future greenhouse gas concentrations for the years 2050 and 2070. Additionally, to assess potential changes in human-snake conflict zones, we emphasized the four major species of medical importance (hereafter “big four”): Bungarus caeruleus, Naja naja, Daboia russelii, and Echis carinatus. We compiled 4966 occurrence records of 30 species obtained from citizen science platforms, open-access repositories, social media groups, and scientific literature, which were further thinned to 2931 unique locations. We developed species distribution models using MaxEnt by integrating species-specific sets of least-correlated bioclimatic variables. Species-specific distribution maps were overlaid to identify regional hotspots and their predicted spatial shifts. Our projections indicated that around ~ 3% of India’s land area could undergo hotspot turnover by 2070 (in worst-case scenario), including substantial contractions in the Western Ghats and northeast India, and expansions in central India. The consensus habitat suitability for the big four showed a significant positive effect on state-wide snakebite records (β = 1.15 ± 0.4, p < 0.01). Future scenarios suggest increasing snakebite risk in parts of northern India, including Himalaya and northeast India, and southern elevated ranges, such as the Western Ghats. Our study provides the first nationwide assessment of climate-driven distributional shifts in venomous snakes in India, highlighting the need to integrate climate-driven conservation planning with adaptive public health strategies to minimize biodiversity loss and human-snake conflict under future climate change scenarios.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-24731-z.

Quantifying responses of aquatic insects to environmental change

Global climate change has become one of the main drivers of the biodiversity crisis and the instability of natural ecosystems in various parts of the world. This study aims to systematically synthesize scientific findings related to the impact of climate change on biodiversity and ecosystem stability through a Systematic Literature Review (SLR) approach. The study was conducted on national and internationally reputable scientific articles published in the period 2010-2025, with an emphasis on the last five years. Literature searches were conducted through Google Scholar, Scopus, Web of Science, and PubMed databases using keywords related to climate change, biodiversity, and ecosystem stability. Study selection followed the PRISMA guidelines with strict inclusion and exclusion criteria to ensure the quality and relevance of the literature. The results of the synthesis indicate that climate change has a significant impact on biodiversity through shifts in species distribution, phenological disruption, habitat degradation, and increased extinction risks, especially for tropical and endemic species. This decline in biodiversity directly contributes to the weakening of ecosystem stability and resilience, both in terrestrial, freshwater, and marine ecosystems. The loss of keystone species and reduced functional redundancy have been shown to reduce the ability of ecosystems to maintain essential ecosystem functions and services, such as nutrient cycling, primary productivity, coastal protection, and climate regulation. This study confirms that biodiversity is a key foundation for ecosystem stability and that conservation efforts need to be closely integrated with climate change mitigation and adaptation strategies through an ecosystem-based approach.

Biodiversity indices often combine data from different species when used in monitoring programs. Heuristic properties can suggest preferred indices, but we lack objective ways to discriminate between indices with similar heuristics. Biodiversity indices can be evaluated by determining how well they reflect management objectives that a monitoring program aims to support. For example, the Convention on Biological Diversity requires reporting about extinction rates, so simple indices that reflect extinction risk would be valuable. We developed 3 biodiversity indices that are based on simple models of population viability that relate extinction risk to abundance. We based the first index on the geometric mean abundance of species and the second on a more general power mean. In a third index, we integrated the geometric mean abundance and trend. These indices require the same data as previous indices, but they also relate directly to extinction risk. Field data for butterflies and woodland plants and experimental studies of protozoan communities show that the indices correlate with local extinction rates. Applying the index based on the geometric mean to global data on changes in avian abundance suggested that the average extinction probability of birds has increased approximately 1% from 1970 to 2009.Conectando Índices para el Monitoreo de la Biodiversidad con la Teoría de Riesgo de ExtinciónResumenLos índices de biodiversidad combinan frecuentemente los datos de diferentes especies cuando se usan en los programas de monitoreo. Las propiedades heurísticas pueden sugerir índices preferidos, pero carecemos de medios objetivos para discriminar a los índices con propiedades heurísticas similares. Los índices de biodiversidad pueden evaluarse al determinar qué tan bien reflejan los objetivos de manejo que un programa de monitoreo busca apoyar. Por ejemplo, la Convención sobre la Diversidad Biológica requiere reportar las tasas de extinción, así que los índices que reflejan el riesgo de extinción serían valiosos. Desarrollamos 3 índices de biodiversidad que se basan en modelos sencillos de viabilidad de población y que relacionan el riesgo de extinción con la abundancia. Basamos el primer índice en la media geométrica de la abundancia de especies, y el segundo en una media de poder más general. En el tercer índice integramos la media geométrica y la tendencia. Estos índices requieren los mismos datos que índices previos, pero también se relacionan directamente con el riesgo de extinción. La información de campo sobre mariposas y plantas de bosque, y los estudios experimentales de comunidades protozoarias, muestran que los índices se correlacionan con las tasas locales de extinción. Al aplicar el índice basado en la media geométrica sobre los datos globales de los cambios en la abundancia de aves, sugirió que la probabilidad de extinción promedio de aves ha incrementado aproximadamente 1% desde 1970 hasta 2009.Palabras ClaveÍndice de biodiversidad, media geométrica, medida de la biodiversidad, riesgo de extinción

Assumptions about factors such as climate in shaping species' realized and potential distributions underlie much of conservation planning and wildlife management. Climate and climatic change lead to shifts in species distributions through both direct and indirect ecological pressures. Distributional shifts may be particularly important if range overlap is altered between interacting species, or between species and protected areas. The cattle family (Bovidae) represents a culturally, economically, and ecologically important taxon that occupies many of the world's rangelands. In contemporary North America, five wild bovid species inhabit deserts, prairies, mountains, and tundra from Mexico to Greenland. Here, we aim to understand how future climate change will modify environmental characteristics associated with North American bovid species relative to the distribution of extant protected areas. We fit species distribution models for each species to climate, topography, and land cover data using observations from a citizen science dataset. We then projected modeled distributions to the end of the 21st century for each bovid species under two scenarios of anticipated climate change. Modeling results suggest that suitable habitat will shift inconsistently across species and that such shifts will lead to species‐specific variation in overlap between potential habitat and existing protected areas. Furthermore, projected overlap with protected areas was sensitive to the warming scenario under consideration, with diminished realized protected area under greater warming. Conservation priorities and designation of new protected areas should account for ecological consequences of climate change.

Land-cover and climate change are two main drivers of changes in species ranges. Yet, the majority of studies investigating the impacts of global change on biodiversity focus on one global change driver and usually use simulations to project biodiversity responses to future conditions. We conduct an empirical test of the relative and combined effects of land-cover and climate change on species occurrence changes. Specifically, we examine whether observed local colonization and extinctions of North American birds between 1981-1985 and 2001-2005 are correlated with land-cover and climate change and whether bird life history and ecological traits explain interspecific variation in observed occurrence changes. We fit logistic regression models to test the impact of physical land-cover change, changes in net primary productivity, winter precipitation, mean summer temperature, and mean winter temperature on the probability of Ontario breeding bird local colonization and extinction. Models with climate change, land-cover change, and the combination of these two drivers were the top ranked models of local colonization for 30%, 27%, and 29% of species, respectively. Conversely, models with climate change, land-cover change, and the combination of these two drivers were the top ranked models of local extinction for 61%, 7%, and 9% of species, respectively. The quantitative impacts of land-cover and climate change variables also vary among bird species. We then fit linear regression models to test whether the variation in regional colonization and extinction rate could be explained by mean body mass, migratory strategy, and habitat preference of birds. Overall, species traits were weakly correlated with heterogeneity in species occurrence changes. We provide empirical evidence showing that land-cover change, climate change, and the combination of multiple global change drivers can differentially explain observed species local colonization and extinction.

news and update ISSN 1948-6596 thesis abstract Potential impacts of climate change on the distribution of fresh- water fishes in French streams and uncertainty of projections Laetitia Buisson PhD, Laboratoire Evolution et Diversite Biologique, Universite Paul Sabatier, Toulouse, and La- boratoire d’Ecologie Fonctionnelle, ENSAT, Castanet-Tolosan, France Current address: Laboratoire Evolution et Diversite Biologique, Universite Paul Sabatier, Tou- louse, France; E-mail: buisson@cict.fr; http://www.edb.ups-tlse.fr/ Climate change and its impact on biodiversity are receiving increasing attention from scientists and people managing natural ecosystems. Recent modifications of climate have induced diverse functional (e.g. phenology, physiology) and struc- tural (e.g. species distribution shifts, range con- traction, local extinctions) responses among or- ganisms (Walther et al. 2002). Given the projec- tions of future climate change, these responses are expected to continue throughout the 21st century and climate change could thus have major consequences on species and assemblages. A common approach to project the potential im- pacts of environmental changes on the distribu- tion of biodiversity is the use of species distribu- tion models (SDM) (e.g. Thuiller 2003). These cor- relative models first relate the present-day spe- cies distribution to a set of climate and other envi- ronmental descriptors. Then, the application of scenarios of future climate changes provides pre- dictions of the habitats potentially suitable in the future for the species. In spite of their widespread use, a growing concern has emerged for the vari- ability in the predicted impacts by such models due to the methodological decisions taken during the modeling process (Thuiller 2004). Improve- ments in the accuracy of predictions combined with an estimation of the uncertainty inherent to those predictions are thus urgently needed. Among freshwater ecosystems, stream fish have no physiological ability to regulate their body temperature and could therefore be very sensitive to climate warming, especially cold-stenotherm fish such as salmonid species. Stream fish also have to cope with hydrological variability of streams and strong anthropogenic pressures (e.g. habitat loss, stream fragmentation). In addition, they have limited dispersal ability within hydro- graphic networks in which they currently live. Yet their response to current and future climate change has been poorly documented and few studies have used SDM to assess the potential consequences of the on-going climate change on freshwater fish species distribution, especially in European streams. In that context, the aim of my PhD thesis was to assess the potential impacts of climate change on fish in French streams, mainly on spe- cies distribution and assemblages’ structure. I used fish data provided by the Office National de l’Eau et des Milieux Aquatiques (ONEMA), the in- stitution in charge of the protection and conserva- tion of freshwater ecosystems in France. These data were combined with climate and environ- mental descriptors through the use of correlative statistical modeling. As my goal was to provide reliable estimates of the future impacts of climate change on stream fish, I have considered recent criticisms (e.g. choice of statistical method, pure bioclimatic models) of species distribution models by justifying each step and optimizing the use of such models. In all, five papers are derived from my PhD work. The first three papers set the bases for the building of the models by considering the uncertainty in predictions, while the latest two assess the impacts of climate change on stream fish species and assemblages. In stream fish ecology, many studies have been conducted to identify the environmental drivers structuring fish assemblages (reviewed in Matthews 1998). It appears that fish species distri- bution and structure of fish assemblages are de- termined by a complex interplay of biotic, abiotic and spatial factors (Jackson et al. 2001). Disentan- © 2009 the authors; journal compilation © 2009 The International Biogeography Society — frontiers of biogeography 1.2, 2009

Summary1. A critical need in conservation biology is to determine which species are most vulnerable to extinction. Freshwater mussels (Bivalvia: Unionacea) are one of the most imperilled faunal groups globally. Freshwater mussel larvae are ectoparasites on fish and depend on the movement of their hosts to maintain connectivity among local populations in a metapopulation.2. I calculated local colonisation and extinction rates for 16 mussel species from 14 local populations in the Red River drainage of Oklahoma and Texas, U.S. I used general linear models and AIC comparisons to determine which mussel life history traits best predicted local colonisation and extinction rates.3. Traits related to larval dispersal ability (host infection mode, whether a mussel species was a host generalist or specialist) were the best predictors of local colonisation.4. Traits related to local population size (regional abundance, time spent brooding) were the best predictors of local extinction. The group of fish species used as hosts by mussels also predicted local extinction and was probably related to habitat fragmentation and host dispersal abilities.5. Overall, local extinction rates exceeded local colonisation rates, indicating that local populations are becoming increasingly isolated and suffering an ‘extinction debt’. This study demonstrates that analysis of species traits can be used to predict local colonisation and extinction patterns and provide insight into the long‐term persistence of populations.

Species distribution models (SDMs) are important tools to explore the effects of future global changes in biodiversity. Previous studies show that variability is introduced into projected distributions through alternative datasets and modelling procedures. However, a multi-model approach to assess biogeographic shifts at the global scale is still rarely applied, particularly in the marine environment. Here, we apply three commonly used SDMs (AquaMaps, Maxent, and the Dynamic Bioclimate Envelope Model) to assess the global patterns of change in species richness, invasion, and extinction intensity in the world oceans. We make species-specific projections of distribution shift using each SDM, subsequently aggregating them to calculate indices of change across a set of 802 species of exploited marine fish and invertebrates. Results indicate an average poleward latitudinal shift across species and SDMs at a rate of 15.5 and 25.6 km decade−1 for a low and high emissions climate change scenario, respectively. Predicted distribution shifts resulted in hotspots of local invasion intensity in high latitude regions, while local extinctions were concentrated near the equator. Specifically, between 10°N and 10°S, we predicted that, on average, 6.5 species would become locally extinct per 0.5° latitude under the climate change emissions scenario Representative Concentration Pathway 8.5. Average invasions were predicted to be 2.0 species per 0.5° latitude in the Arctic Ocean and 1.5 species per 0.5° latitude in the Southern Ocean. These averaged global hotspots of invasion and local extinction intensity are robust to the different SDM used and coincide with high levels of agreement.

AimClimate change causes major shifts in species distributions, reshuffling community composition and favouring warm‐adapted species (“thermophilization”). The tree community response is likely to be affected by major disturbances, such as fire and harvest. Here, we quantify the relative contributions of climate change and disturbances to temporal shifts in tree composition over the last decades and evaluate whether disturbances accelerate community thermophilization.LocationQuébec, Canada.Time period1970–2016.Taxa studiedTrees.MethodsUsing 6,281 forest inventory plots, we quantified temporal changes in species composition between a historical (1970–1980) and a contemporary period (2000–2016) by measuring temporal β‐diversity, gains and losses. The effects of climate and disturbances on temporal β‐diversity were quantified using multiple regressions and variation partitioning. We compared how community indices of species temperature preference (CTI) and shade tolerance (CSI) changed for forests that experienced different levels of disturbance. We quantified the contribution of species gains and losses to change in CTI.ResultsTemporal β‐diversity was mainly driven by disturbances, with historical harvesting as the most important predictor. Despite the prevailing influence of disturbances, we revealed a significant thermophilization (ΔCTI = +.03 °C/decade) throughout forests in Québec. However, this shift in community composition was weakly explained by climate change and considerably slower than the rate of warming (+.14 °C/decade). Importantly, thermophilization was amplified by moderate disturbances (+.044 °C/decade), almost a threefold increase compared with minor disturbances (+.015 °C/decade). The gains and losses of a few tree species contributed to this community‐level shift.ConclusionsOur study provides evidence that disturbances can strongly modify tree community responses to climate change. Moderate disturbances, such as harvesting, might reduce competition and facilitate gains of warm‐adapted species, which then accelerate thermophilization of tree communities under climate change. Although accelerated by disturbances, community thermophilization was driven by the gains and losses of a small number of species, notably gains of maples.

Climate change will lead to substantial shifts in species distributions. Most of the predictions of shifting distributions rely on modelling future distributions with ecological niche models. We used these models to investigate (i) the expected species turnover, loss and gain within bird communities of fourSouthAfrican biomes and (ii) the expected changes in the body mass frequency distributions of these communities. We used distributional data of theSouthernAfricanBirdAtlasProject, current climate data and two scenarios of future climate change for 2050 to build ensemble models of bird distributions. Our results indicate that future species loss, gain and turnover within the four biomes will be considerable. Climate change will also have statistically significant effects on body mass frequency distributions, and these effects differ substantially depending on the severity of future climate change. We discuss the possible ecological effects of these predicted changes on ecosystem interactions and functions.

The geographic range limits of many species are strongly affected by climate and are expected to change under global warming. For species that are able to track changing climate over broad geographic areas, we expect to see shifts in species distributions toward the poles and away from the equator. A number of ecological and evolutionary factors, however, could restrict this shifting or redistribution under climate change. These factors include restricted habitat availability, restricted capacity for or barriers to movement, or reduced abundance of colonists due the perturbation effect of climate change. This research project examined the last of these constraints - that climate change could perturb local conditions to which populations are adapted, reducing the likelihood that a species will shift its distribution by diminishing the number of potential colonists. In the most extreme cases, species ranges could collapse over a broad geographic area with no poleward migration and an increased risk of species extinction. Changes in individual species ranges are the processes that drive larger phenomena such as changes in land cover, ecosystem type, and even changes in carbon cycling. For example, consider the poleward range shift and population outbreaks of the mountain pine beetle that has decimated millions of acres of Douglas fir trees in the western US and Canada. Standing dead trees cause forest fires and release vast quantities of carbon to the atmosphere. The beetle likely shifted its range because it is not locally adapted across its range, and it appears to be limited by winter low temperatures that have steadily increased in the last decades. To understand range and abundance changes like the pine beetle, we must reveal the extent of adaptive variation across species ranges - and the physiological basis of that adaptation - to know if other species will change as readily as the pine beetle. Ecologists tend to assume that range shifts are the dominant response of species to climate change, but our experiments suggest that other processes may act in some species that reduce the likelihood of geographic range change. In the first part of our DOE grant (ending 2008) we argued that the process of local adaptation of populations within a species range, followed by climatic changes that occur too quickly for adaptive evolution, is an underappreciated mechanism by which climate change could affect biodiversity. When this process acts, species ranges may not shift readily toward the poles, slowing the rate of species and biome change. To test this claim, we performed an experiment comparing core and peripheral populations in a series of field observations, translocation experiments, and genetic analyses. The papers in Appendix A were generated from 2005-2008 funding. In the second part of the DOE grant (ending 2011) we studied which traits promote population differentiation and local adaptation by building genomic resources for our study species and using these resources to reveal differences in gene expression in peripheral and core populations. The papers in Appendix B were generated from 2008-2011 funding. This work was pursued with two butterfly species that have contrasting life history traits (body size and resource specialization) and occupy a common ecosystem and a latitudinal range. These species enabled us to test the following hypotheses using a single phylogenetic group.