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Aim: Climate change poses a challenge to the Azores' biodiversity, with consequences that remain unexplored. To shed light on the potential impacts of climate change, we have developed a large ensemble of species distribution models (SDMs) for species found in the coastal marine environments and examined their spatiotemporal turnover and stability. Location: The Azorean archipelago. Taxon: Coastal marine species (mammals, fish, turtles, seabirds, kelp forest and corals). Methods: SDMs were fitted a large ensemble comprising 10 machine learning algorithms and a fivefold cross‐validation resampling procedure, thus yielding a maximum number of 50 models fitted per species. These models were then utilised for projecting species distribution under different future scenarios. The projected distributions of the species were employed to assess changes in the stability of their ranges throughout the entire modelled period (2030–2100) and in their community compositions by examining changes in alpha diversity and beta diversity over 10‐year periods. Results: We show that under our model assumptions over 12% of the modelled units could lose suitable climate by the end of the century, with this number increasing up to 25% under a high carbon emissions scenario. Climate change refugia, which are areas of long‐term species range stability, are expected to be mainly located in the coastal areas in the northernmost part of the archipelago. A substantial loss of suitable climate is anticipated for mammals and birds, which is likely to trigger a major loss of species on the islands of Santa Maria, São Miguel, Pico and Faial. For fish, the loss of suitable climates is less pronounced. However, climate change is expected to cause a major reshuffling of the pelagic fish assemblage, with important consequences for local fisheries on each island. Main Conclusions: Our models provide insights into how climate change may alter the distribution of Azorean marine coastal species, offering important guidance for conservation and management efforts in these important North Atlantic ecosystems. [ABSTRACT FROM AUTHOR]

Arctic vegetation is crucial for fauna and the livelihoods of Northern peoples and is tightly linked to climate, permafrost soils, and water. Yet, a comprehensive understanding of climate change effects on Arctic vegetation is lacking. Protected areas cannot halt climate change but could reduce future pressure from additional drivers, like land use change and local industrial pollution. Therefore, it is crucial to understand the contribution of protected areas in safeguarding threatened Arctic vegetation types. We compare the present baseline with 2050 predictions of circumpolar Arctic vegetation type distributions and demonstrate an overrepresentation of dominant vegetation types and an underrepresentation of declining vegetation types within protected areas. Our study predicts five of eight assessed tundra vegetation types to be threatened by 2050, following International Union for Conservation of Nature criteria. Further, we mapped potential climate change refugia, areas with the highest potential for safeguarding threatened vegetation types. This study provides an essential first step assessing vegetation type vulnerability based on predictions covering 42 percent of Arctic landscapes. The co-development of new protective measures by policymakers and Indigenous peoples at a pan-Arctic scale requires more robust and spatially complete vegetation predictions, as increasing pressures from resource exploration and infrastructure development threaten the sustainable development of the rapidly thawing and greening Arctic.

Understory vascular plant species play a key role in natural ecosystems by maintaining nutrient balances and providing both food for wildlife and non-wood forest products. However, some such species are facing potential extirpation due to human interventions such as forest harvesting practices, land use change, and climate change. Despite their ecological and societal importance, the influence of different environmental variables on the distribution of vascular plant communities remains unclear. This study evaluated how several Acadian understory rare plant species (categorized as S1-S2 species) in New Brunswick will respond to future climate scenarios. We used presence-only occurrence records of four S1-S2 rare plant species and eight bioclimatic variables to calibrate climate suitability models using maximum entropy algorithm (MaxEnt). The key bioclimatic predictor variables for the two S1 species (Canada Honewort and Furbish Lousewort) were maximum temperature of the warmest month and precipitation of the driest quarter. The predictor variables with significant contribution for the two S2 plant species were annual precipitation (35%) for Anticosti Aster and precipitation of wettest quarter (85.7%) for Parker's Pipewort. Our models predicted that the two S1 plant species are likely to gain more suitable climate space by 2070, while the two S2 plant species are likely to lose suitable climate space and may face extirpation risk from New Brunswick. The difficulty of projecting rare plant species is very scarce occurrence data, but analyses such as ours can help indicate current locations and in-situ and ex-situ climate change refugia areas for use in biodiversity conservation planning. [ABSTRACT FROM AUTHOR]

Arctic vegetation is crucial for fauna and the livelihoods of Northern peoples and is tightly linked to climate, permafrost soils, and water. Yet, a comprehensive understanding of climate change effects on Arctic vegetation is lacking. Protected areas cannot halt climate change but could reduce future pressure from additional drivers, like land use change and local industrial pollution. Therefore, it is crucial to understand the contribution of protected areas in safeguarding threatened Arctic vegetation types. We compare the present baseline with 2050 predictions of circumpolar Arctic vegetation type distributions and demonstrate an overrepresentation of dominant vegetation types and an underrepresentation of declining vegetation types within protected areas. Our study predicts five of eight assessed tundra vegetation types to be threatened by 2050, following International Union for Conservation of Nature criteria. Further, we mapped potential climate change refugia, areas with the highest potential for safeguarding threatened vegetation types. This study provides an essential first step assessing vegetation type vulnerability based on predictions covering 42 percent of Arctic landscapes. The co-development of new protective measures by policymakers and Indigenous peoples at a pan-Arctic scale requires more robust and spatially complete vegetation predictions, as increasing pressures from resource exploration and infrastructure development threaten the sustainable development of the rapidly thawing and greening Arctic. [ABSTRACT FROM AUTHOR]

Given the accelerating rate of biodiversity loss, the need to prioritize marine areas for protection represents a major conservation challenge. The three‐dimensionality of marine life and ecosystems is an inherent element of complexity for setting spatial conservation plans. Yet, the confidence of any recommendation largely depends on shifting climate, which triggers a global redistribution of biodiversity, suggesting the inclusion of time as a fourth dimension. Here, we developed a depth‐specific prioritization analysis to inform the design of protected areas, further including metrics of climate‐driven changes in the ocean. Climate change was captured in this analysis by considering the projected future distribution of >2000 benthic and pelagic species inhabiting the Mediterranean Sea, combined with climatic stability and heterogeneity metrics of the seascape. We identified important areas based on both biological and climatic criteria, where conservation focus should be given in priority when designing a three‐dimensional, climate‐smart protected area network. We detected spatially concise, conservation priority areas, distributed around the basin, that protected marine areas almost equally across all depth zones. Our approach highlights the importance of deep sea zones as priority areas to meet conservation targets for future marine biodiversity, while suggesting that spatial prioritization schemes, that focus on a static two‐dimensional distribution of biodiversity data, might fail to englobe both the vertical properties of species distributions and the fine and larger‐scale impacts associated with climate change. [ABSTRACT FROM AUTHOR]

For forest species, areas buffered from the rapidly increasing climate stressors and patterns of disturbance — i.e., climate change refugia — are important targets for conservation and protection. Here, we present a novel field survey and remote sensing approach to identification of fine-scale functional drought refugia for bigcone Douglas-fir (Pseudotsuga macrocarpa)-dominated forests. This rare species has been exposed to climate change-exacerbated drought conditions over the past two decades; yet, little is known about its responses to recent drought and how these drought responses vary across local environmental gradients and interact with recent record wildfire seasons. We combined a remote sensing analysis of vegetation condition with field surveys and physiological measurements to better understand bigcone Douglas-fir responses to recent climate trends. We also identified 444 stands exhibiting relatively low response and high resilience to drought — i.e., potential drought refugia. We found that low elevation stands and those in south-facing aspects generally experienced greater levels of seasonal and interannual drought stress. This trend was more pronounced for stands that experienced fire (2007 Zaca Fire) prior to the drought, suggesting that wildfire can increase the importance of topographic mediation of climate conditions in bigcone Douglas-fir forests. Elevation and aspect also interacted to affect physiological acclimation to seasonal drought conditions, with low elevation north-facing sites in particular experiencing a favorable combination of greater climate buffering and greater drought resilience, suggesting that these sites may be important refugia for bigcone Douglas-fir at low elevations. Furthermore, we found that the relationships between topography and drought response were weaker in more coastal sites, possibly due to maritime climate buffering in these sites. Altogether, these results illustrate how topographic mediation of regional drought conditions is critical for the persistence of this rare species in drought and fire-prone landscapes, and offer important insights for the conservation and restoration of this iconic species.

Peatlands perform many important ecosystem functions at both the local and global scale, including hydrologic and climatic regulation. Although peatlands often act as climatic microrefugia, they have rarely been the subject of long-term microclimatic studies. In this study, we aimed to compare the local climatic conditions of a mid-forest mire to that of an open area and examine the differences in microclimates within the mire based on plant community diversity, shading, and water table depths. The peatland studied in this work was significantly cooler than the reference site, mainly due to a higher decline in nighttime air temperatures. However, the daily maximum air temperature near the ground was often higher. We also noticed that microclimates significantly differed within the studied peatland. Wet and shaded microsites were cooler than the sites having a lower water level and receiving higher amounts of solar radiation. The results of the study suggest that peatlands have locally cooler climates, and thus can serve as climate change refugia. These findings can help us interpret reconstructed data from the peat archive, and, when combined with experiments, identify tipping points for peatland ecosystems. [ABSTRACT FROM AUTHOR]

The European ground squirrel (Spermophilus citellus) is an endangered semifossorial small mammal of grassland/agricultural ecosystems. In the last few decades, the species’ population has declined throughout its range in Europe. The Greek populations represent the southernmost limit of the species’ range and are notably small, scattered, and located mainly in human-modified areas. The goal of the present research is to understand the environmental and anthropogenic variables associated with its distribution in the Mediterranean habitats, assess possible drivers of observed local extinctions, and propose conservation and land-use management actions in light of near-future climate change scenarios. We used presence records since 2000 across all known populations (107 colonies) and maximum entropy conditional probability models (MaxEnt) to calculate both the habitat suitability (bioclimatic variables) and habitat availability (anthropogenic/land-use variables) within the European ground squirrel’s historical range in northern Greece. We report a projected 39% to 94.3% decrease in habitat suitability by 2040–2060 due to climate change. Based on our findings, we provide guidance by proposing nascent conservation actions to protect the few existing colonies in Greece via improved land management practices and identify in situ climate refugia that could be prioritized as sites for future reintroductions.

While climate change will have significant impacts on terrestrial organisms, microclimates offer potential refugia for vulnerable species when regional conditions become unsuitable and temperatures exceed physiological limits. The efficacy of microclimates as buffers to extreme events is determined not only by their availability, but also by the behavioral flexibility of individuals to access these unique environments during stressful periods. We characterized (i) how forest structure and topography shaped microclimates at roost sites used by California spotted owls (Strix occidentalis occidentalis), a climate-vulnerable species, and (ii) how owls outfitted with temperature sensors used microclimates during warm temperature events. Higher elevations, taller canopies, and greater canopy cover promoted cooler maximum temperatures in stands used for roosting. Within those stands, individuals roosted in cooler sites, especially when roosts were in forest stands on warmer slopes. Tall canopies created relatively cooler microclimates when temperatures were hot, and individuals actively used roost sites that minimized increases in operative temperature, suggesting spotted owls have an adaptive capacity to use cooler microclimates. However, roosts at low elevations consistently exceeded physiological thresholds when temperatures were warm, potentially explaining vacancies in low elevation territories with more open forest. For spotted owls to persist in warming environments, conserving tall, closed-canopy forests that promote cooler microclimates for roosting is critical. While a future climate promises heat events that approach and exceed thermal extremes for a suite of canopy-dwelling species, cooler microclimates provided by forest structure and topography could constitute important refugia in a rapidly changing system. [ABSTRACT FROM AUTHOR]

Climate and land-use changes are among the most important drivers of biodiversity loss and, moreover, their impacts on biodiversity are expected to increase further in the 21st century. In this study, the future impact of climate and land-use changes on Anatolian ground squirrels (Spermophilus xanthoprymnus) was assessed. Accordingly, a hierarchical approach with two steps was used. First, ecological niche modelling was used to assess the impact of climate change in areas accessible to Anatolian ground squirrels through dispersal (i.e. the impact of climate change). Second, based on the habitat preferences of ground squirrels, land-use data were used to assess the impact of land-use change in suitable bioclimatic areas for Anatolian ground squirrels under present and future conditions (i.e. the combined impact of both changes). Also, priority areas for the conservation of Anatolian ground squirrels were identified based on in-situ climate change refugia. This study represents a first attempt to combine niche modelling and land-use data for a species in Anatolia, one of the most vulnerable regions to the drivers of biodiversity loss, because it is the region where three of biodiversity hotspots meet, and interact. Habitat suitability (i.e. suitable habitats across suitable bioclimatic areas) was projected to decline by 19–69% in the future (depending on the scenario), mainly due to the loss of suitable bioclimatic areas (47–77%, depending on the scenario) at lower elevations and in the western part of the central Anatolia and in the eastern Anatolia, suggesting that Anatolian ground squirrels will contract their range in the future, mainly due to climate change. Thus, in-situ climate change refugia were projected mainly in the eastern and southeastern parts of the central Anatolia, suggesting these regions as priority areas for the conservation of Anatolian ground squirrels. • Anatolia is the region where three biodiversity hotspots meet, and interact • This study is the first to combine niche modelling and land-use data in Anatolia • The species will contract its range in the future, mainly due to climate change • In-situ climate change refugia were projected mainly in the central Anatolia • Future studies should focus on hotspots of in-situ climate change refugia in Anatolia [ABSTRACT FROM AUTHOR]

The European ground squirrel (Spermophilus citellus) is an endangered semifossorial small mammal of grassland/agricultural ecosystems. In the last few decades, the species' population has declined throughout its range in Europe. The Greek populations represent the southernmost limit of the species' range and are notably small, scattered, and located mainly in human-modified areas. The goal of the present research is to understand the environmental and anthropogenic variables associated with its distribution in the Mediterranean habitats, assess possible drivers of observed local extinctions, and propose conservation and land-use management actions in light of near-future climate change scenarios. We used presence records since 2000 across all known populations (107 colonies) and maximum entropy conditional probability models (MaxEnt) to calculate both the habitat suitability (bioclimatic variables) and habitat availability (anthropogenic/land-use variables) within the European ground squirrel's historical range in northern Greece. We report a projected 39% to 94.3% decrease in habitat suitability by 2040–2060 due to climate change. Based on our findings, we provide guidance by proposing nascent conservation actions to protect the few existing colonies in Greece via improved land management practices and identify in situ climate refugia that could be prioritized as sites for future reintroductions. [ABSTRACT FROM AUTHOR]