Ocean‐scale prediction of whale shark distribution

Aim Predicting distribution patterns of whale sharks (Rhincodon typus, Smith 1828) in the open ocean remains elusive owing to few pelagic records. We developed multivariate distribution models of seasonally variant whale shark distributions derived from tuna purse‐seine fishery data. We tested the hypotheses that whale sharks use a narrow temperature range, are more abundant in productive waters and select sites closer to continents than the open ocean. Location Indian Ocean. Methods We compared a 17‐year time series of observations of whale sharks associated with tuna purse‐seine sets with chlorophyll a concentration and sea surface temperature data extracted from satellite images. Different sets of pseudo‐absences based on random distributions, distance to shark locations and tuna catch were generated to account for spatiotemporal variation in sampling effort and probability of detection. We applied generalized linear, spatial mixed‐effects and Maximum Entropy models to predict seasonal variation in habitat suitability and produced maps of distribution. Results The saturated generalized linear models including bathymetric slope, depth, distance to shore, the quadratic of mean sea surface temperature, sea surface temperature variance and chlorophyll a had the highest relative statistical support, with the highest percent deviance explained when using random pseudo‐absences with fixed effect‐only models and the tuna pseudo‐absences with mixed‐effects models (e.g. 58% and 26% in autumn, respectively). Maximum Entropy results suggested that whale sharks responded mainly to variation in depth, chlorophyll a and temperature in all seasons. Bathymetric slope had only a minor influence on the presence. Main conclusions Whale shark habitat suitability in the Indian Ocean is mainly correlated with spatial variation in sea surface temperature. The relative influence of this predictor provides a basis for predicting habitat suitability in the open ocean, possibly giving insights into the migratory behaviour of the world’s largest fish. Our results also provide a baseline for temperature‐dependent predictions of distributional changes in the future.     

Higher spring temperatures increase food scarcity and limit the current and future distributions of crossbills

Aim

Understanding how climate affects species distributions remains a major challenge, with the relative importance of direct physiological effects versus biotic interactions still poorly understood. We focus on three species of resource specialists (crossbill Loxia finches) to assess the role of climate in determining the seasonal availability of their food, the importance of climate and the occurrence of their food plants for explaining their current distributions, and to predict changes in their distributions under future climate change scenarios.

Location

Europe.

Methods

We used datasets on the timing of seed fall in European Scots pine Pinus sylvestris forests (where different crossbill species occur) to estimate seed fall phenology and climate data to determine its influence on spatial and temporal variation in the timing of seed fall to provide a link between climate and seed scarcity for crossbills. We used large‐scale datasets on crossbill distribution, cover of the conifers relied on by the three crossbill species and climate variables associated with timing of seed fall, to assess their relative importance for predicting crossbill distributions. We used species distribution modelling to predict changes in their distributions under climate change projections for 2070.

Results

We found that seed fall occurred 1.5–2 months earlier in southern Europe than in Sweden and Scotland and was associated with variation in spring maximum temperatures and precipitation. These climate variables and area covered with conifers relied on by the crossbills explained much of their observed distributions. Projections under global change scenarios revealed reductions in potential crossbill distributions, especially for parrot crossbills.

Main conclusions

Ranges of resource specialists are directly influenced by the presence of their food plants, with climate conditions further affecting resource availability and the window of food scarcity indirectly. Future distributions will be determined by tree responses to changing climatic conditions and the impact of climate on seed fall phenology.

     

Distributional migrations,expansions, and contractions of tropical plant species as revealed in dated herbarium records

Species are predicted to respond to global warming through ‘cold‐ward’ shifts in their geographic distributions due to encroachment into newly suitable habitats and/or dieback in areas that become climatically unsuitable. I conduct one of the first‐ever tests of this hypothesis for tropical plant species. I test for changes in the thermal distributions of 239 South American tropical plant species using dated herbarium records for specimens collected between 1970 and 2009. Supporting a priori predictions, many species (59%) exhibit some evidence of significant cold‐ward range shifts even after correcting for collection biases. Over 1/3 of species (35%) show significant cold‐ward movement in their hot thermal limits (mean rate of change = 0.022 °C yr^?1). Most of these species (85%; 30% of all study species) show no corresponding shift in their cold thermal limits. These unbalanced changes in the species’ thermal range limits may indicate species that are experiencing dieback due to their intolerance of rising temperatures coupled with an inability to expand into newly climatically suitable habitats. On the other hand, 25% of species show significant cold‐ward shifts in their cold thermal range limits (mean rate of change = 0.003 °C yr^?1), but 80% of these species (20% of all study species) show no corresponding shift in their hot thermal range limits. In these cases, the unbalanced shifts may indicate species that are able to ‘benefit’ under global warming, at least temporally, by both tolerating rising temperatures and expanding into new suitable habitat. An important ancillary result of this study is that the number of species exhibiting significant range shifts was greatly influenced by shifting collector biases. This highlights the need to account for biases when analyzing natural history records or other long‐term records.     

Mechanistic variables can enhance predictive models of endotherm distributions: the American pika under current,past, and future climates

How climate constrains species’ distributions through time and space is an important question in the context of conservation planning for climate change. Despite increasing awareness of the need to incorporate mechanism into species distribution models (SDMs), mechanistic modeling of endotherm distributions remains limited in this literature. Using the American pika (Ochotona princeps) as an example, we present a framework whereby mechanism can be incorporated into endotherm SDMs. Pika distribution has repeatedly been found to be constrained by warm temperatures, so we used Niche Mapper, a mechanistic heat‐balance model, to convert macroclimate data to pika‐specific surface activity time in summer across the western United States. We then explored the difference between using a macroclimate predictor (summer temperature) and using a mechanistic predictor (predicted surface activity time) in SDMs. Both approaches accurately predicted pika presences in current and past climate regimes. However, the activity models predicted 8–19% less habitat loss in response to annual temperature increases of ~3–5 °C predicted in the region by 2070, suggesting that pikas may be able to buffer some climate change effects through behavioral thermoregulation that can be captured by mechanistic modeling. Incorporating mechanism added value to the modeling by providing increased confidence in areas where different modeling approaches agreed and providing a range of outcomes in areas of disagreement. It also provided a more proximate variable relating animal distribution to climate, allowing investigations into how unique habitat characteristics and intraspecific phenotypic variation may allow pikas to exist in areas outside those predicted by generic SDMs. Only a small number of easily obtainable data are required to parameterize this mechanistic model for any endotherm, and its use can improve SDM predictions by explicitly modeling a widely applicable direct physiological effect: climate‐imposed restrictions on activity. This more complete understanding is necessary to inform climate adaptation actions, management strategies, and conservation plans.     

Meta‐analysis reveals enhanced growth of marine harmful algae from temperate regions with warming and elevated CO2 levels

Elevated pCO₂ and warming may promote algal growth and toxin production, and thereby possibly support the proliferation and toxicity of harmful algal blooms (HABs). Here, we tested whether empirical data support this hypothesis using a meta‐analytic approach and investigated the responses of growth rate and toxin content or toxicity of numerous marine and estuarine HAB species to elevated pCO₂ and warming. Most of the available data on HAB responses towards the two tested climate change variables concern dinoflagellates, as many members of this phytoplankton group are known to cause HAB outbreaks. Toxin content and toxicity did not reveal a consistent response towards both tested climate change variables, while growth rate increased consistently with elevated pCO₂. Warming also led to higher growth rates, but only for species isolated at higher latitudes. The observed gradient in temperature growth responses shows the potential for enhanced development of HABs at higher latitudes. Increases in growth rates with more CO₂ may present an additional competitive advantage for HAB species, particularly as CO₂ was not shown to enhance growth rate of other non‐HAB phytoplankton species. However, this may also be related to the difference in representation of dinoflagellate and diatom species in the respective HAB and non‐HAB phytoplankton groups. Since the proliferation of HAB species may strongly depend on their growth rates, our results warn for a greater potential of dinoflagellate HAB development in future coastal waters, particularly in temperate regions.     

Amazon Basin climate under global warming: the role of the sea surface temperature

The Hadley Centre coupled climate-carbon cycle model (HadCM3LC) predicts loss of the Amazon rainforest in response to future anthropogenic greenhouse gas emissions. In this study, the atmospheric component of HadCM3LC is used to assess the role of simulated changes in mid-twenty-first century sea surface temperature (SST) in Amazon Basin climate change. When the full HadCM3LC SST anomalies (SSTAs) are used, the atmosphere model reproduces the Amazon Basin climate change exhibited by HadCM3LC, including much of the reduction in Amazon Basin rainfall. This rainfall change is shown to be the combined effect of SSTAs in both the tropical Atlantic and the Pacific, with roughly equal contributions from each basin. The greatest rainfall reduction occurs from May to October, outside of the mature South American monsoon (SAM) season. This dry season response is the combined effect of a more rapid warming of the tropical North Atlantic relative to the south, and warm SSTAs in the tropical east Pacific. Conversely, a weak enhancement of mature SAM season rainfall in response to Atlantic SST change is suppressed by the atmospheric response to Pacific SST. This net wet season response is sufficient to prevent dry season soil moisture deficits from being recharged through the SAM season, leading to a perennial soil moisture reduction and an associated 30% reduction in annual Amazon Basin net primary productivity (NPP). A further 23% NPP reduction occurs in response to a 3.5 degrees C warmer air temperature associated with a global mean SST warming.     

Incorporating adaptive responses into future projections of coral bleaching

Climate warming threatens to increase mass coral bleaching events, and several studies have projected the demise of tropical coral reefs this century. However, recent evidence indicates corals may be able to respond to thermal stress though adaptive processes (e.g., genetic adaptation, acclimatization, and symbiont shuffling). How these mechanisms might influence warming‐induced bleaching remains largely unknown. This study compared how different adaptive processes could affect coral bleaching projections. We used the latest bias‐corrected global sea surface temperature (SST) output from the NOAA/GFDL Earth System Model 2 (ESM2M) for the preindustrial period through 2100 to project coral bleaching trajectories. Initial results showed that, in the absence of adaptive processes, application of a preindustrial climatology to the NOAA Coral Reef Watch bleaching prediction method overpredicts the present‐day bleaching frequency. This suggests that corals may have already responded adaptively to some warming over the industrial period. We then modified the prediction method so that the bleaching threshold either permanently increased in response to thermal history (e.g., simulating directional genetic selection) or temporarily increased for 2–10 years in response to a bleaching event (e.g., simulating symbiont shuffling). A bleaching threshold that changes relative to the preceding 60 years of thermal history reduced the frequency of mass bleaching events by 20–80% compared with the ‘no adaptive response’ prediction model by 2100, depending on the emissions scenario. When both types of adaptive responses were applied, up to 14% more reef cells avoided high‐frequency bleaching by 2100. However, temporary increases in bleaching thresholds alone only delayed the occurrence of high‐frequency bleaching by ca. 10 years in all but the lowest emissions scenario. Future research should test the rate and limit of different adaptive responses for coral species across latitudes and ocean basins to determine if and how much corals can respond to increasing thermal stress.     

Identifying species at extinction risk using global models of anthropogenic impact

The International Union for Conservation of Nature Red List of Endangered Species employs a robust, standardized approach to assess extinction threat focussed on taxa approaching an end‐point in population decline. Used alone, we argue this enforces a reactive approach to conservation. Species not assessed as threatened but which occur predominantly in areas with high levels of anthropogenic impact may require proactive conservation management to prevent loss. We matched distribution and bathymetric range data from the global Red List assessment of 632 species of marine cone snails with human impacts and projected ocean thermal stress and aragonite saturation (a proxy for ocean acidification). Our results show 67 species categorized as ‘Least Concern’ have 70% or more of their occupancy in places subject to high and very high levels of human impact with 18 highly restricted species (range <100 km²) living exclusively in such places. Using a range‐rarity scoring method we identified where clusters of endemic species are subject to all three stressors: high human impact, declining aragonite saturation levels and elevated thermal stress. Our approach reinforces Red List threatened status, highlights candidate species for reassessment, contributes important evidential data to minimize data deficiency and identifies regions and species for proactive conservation.     

气候速度影响下中国周边海域鲨鱼保护优先区识别

鲨鱼在气候变化和人类活动等因素的影响下面临着种群衰退的风险,开展鲨鱼保护优先区研究是鲨鱼保护行动的重要工作.将气候速度引入鲨鱼保护优先区的识别过程,旨在阐明中国周边海域鲨鱼现状保护成效和保护空缺,并预测气候速度影响下的鲨鱼保护优先区空间格局及其变化趋势.以集成物种分布模型模拟的146种鲨鱼栖息地作为保护对象,以2015年至2100年两种气候变化情景下的气候速度作为保护的机会成本,基于系统保护规划理论模拟现状和未来情景下的鲨鱼保护优先区选址方案.研究结果表明：（1）长江口以南至台湾海峡和北部湾近岸海域为鲨鱼多样性分布的主要区域,台湾海峡区域亦为珍稀濒危物种的重要分布区;（2）在两种气候情景下,南海中南部将面临较高的气候变化风险,而长江口以南至珠江口的近岸海域气候速度均相对较低,提示了这些区域或能成为气候变化影响下的生物避难所;（3）现有保护区仅保护了1.33%的海域和不到4%的鲨鱼物种,尚存在较大的保护空缺.当保护海域比例提升至10%时,可覆盖绝大多数鲨鱼物种.而当比例提升至30%时,珍稀濒危物种的栖息地将得到有效保护;（4）气候变化影响下保护优先区选址将发生不同程度的变化,尤其是在中国南海区域,如在保护规划时兼顾气候速度,可在满足相似保护目标的前提下减少保护优先区内25%以上的气候压力,以使其具有较强的应对气候变化潜力。     

Warming off southwestern Japan linked to distributional shifts of subtidal canopy‐forming seaweeds

To assess distributional shifts of species in response to recent warming, historical distribution records are the most requisite information. The surface seawater temperature (SST) of Kochi Prefecture, southwestern Japan on the western North Pacific, has significantly risen, being warmed by the Kuroshio Current. Past distributional records of subtidal canopy‐forming seaweeds (Laminariales and Fucales) exist at about 10‐year intervals from the 1970s, along with detailed SST datasets at several sites along Kochi's >700 km coastline. In order to provide a clear picture of distributional shifts of coastal marine organisms in response to warming SST, we observed the present distribution of seaweeds and analyzed the SST datasets to estimate spatiotemporal SST trends in this coastal region. We present a large increase of 0.3°C/decade in the annual mean SST of this area over the past 40 years. Furthermore, a comparison of the previous and present distributions clearly showed the contraction of temperate species' distributional ranges and expansion of tropical species' distributional ranges in the seaweeds. Although the main temperate kelp Ecklonia (Laminariales) had expanded their distribution during periods of cooler SST, they subsequently declined as the SST warmed. Notably, the warmest SST of the 1997–98 El Niño Southern Oscillation event was the most likely cause of a widespread destruction of the kelp populations; no recovery was found even in the present survey at the formerly habitable sites where warm SSTs have been maintained. Temperate Sargassum spp. (Fucales) that dominated widely in the 1970s also declined in accordance with recent warming SSTs. In contrast, the tropical species, S. ilicifolium, has gradually expanded its distribution to become the most conspicuously dominant among the present observations. Thermal gradients, mainly driven by the warming Kuroshio Current, are presented as an explanation for the successive changes in both temperate and tropical species' distributions.     

Climate change and the future distributions of aquatic macrophytes across boreal catchments

Aim Aquatic–terrestrial ecotones are vulnerable to climate change, and degradation of the emergent aquatic macrophyte zone would have severe ecological consequences for freshwater, wetland and terrestrial ecosystems. Our aim was to uncover future changes in boreal emergent aquatic macrophyte zones by modelling the occurrence and percentage cover of emergent aquatic vegetation under different climate scenarios in Finland by the 2050s. Location Finland, northern Europe. Methods Data derived from different GIS sources were used to estimate future emergent aquatic macrophyte distributions in all catchments in Finland (848 in total). We used generalized additive models (GAM) with a full stepwise selection algorithm and Akaike information criterion to explore the main environmental determinates (climate and geomorphology) of emergent aquatic macrophyte distributions, which were derived from the national subclass of CORINE land‐cover classification. The accuracy of the distribution models (GAMs) was cross‐validated, using percentage of explained deviance and the area under the curve derived from the receiver‐operating characteristic plots. Results Our results indicated that emergent aquatic macrophytes will expand their distributions northwards from the current catchments and percentage cover will increase in all of the catchments in all climate scenarios. Growing degree‐days was the primary determinant affecting distributions of emergent aquatic macrophytes. Inclusion of geomorphological variables clearly improved model performance in both model exercises compared with pure climate variables. Main conclusions Emergent aquatic macrophyte distributions will expand due to climate change. Many emergent aquatic plant species have already expanded their distributions during the past decades, and this process will continue in the years 2051–80. Emergent aquatic macrophytes pose an increasing overgrowth risk for sensitive macrophyte species in boreal freshwater ecosystems, which should be acknowledged in management and conservation actions. We conclude that predictions based on GIS data can provide useful ‘first‐filter’ estimates of changes in aquatic–terrestrial ecotones.     

Potential effects of future climate change on global reptile distributions and diversity

Aim

Until recently, complete information on global reptile distributions has not been widely available. Here, we provide the first comprehensive climate impact assessment for reptiles on a global scale.

Location

Global, excluding Antarctica.

Time period

1995, 2050 and 2080.

Major taxa studied

Reptiles.

Methods

We modelled the distribution of 6296 reptile species and assessed potential global and realm-specific changes in species richness, the change in global species richness across climate space, and species-specific changes in range extent, overlap and position under future climate change. To assess the future climatic impact on 3768 range-restricted species, which could not be modelled, we compared the future change in climatic conditions between both modelled and non-modelled species.

Results

Reptile richness was projected to decline significantly over time, globally but also for most zoogeographical realms, with the greatest decreases in Brazil, Australia and South Africa. Species richness was highest in warm and moist regions, with these regions being projected to shift further towards climate extremes in the future. Range extents were projected to decline considerably in the future, with a low overlap between current and future ranges. Shifts in range centroids differed among realms and taxa, with a dominant global poleward shift. Non-modelled species were significantly stronger affected by projected climatic changes than modelled species.

Main conclusions

With ongoing future climate change, reptile richness is likely to decrease significantly across most parts of the world. This effect, in addition to considerable impacts on species range extent, overlap and position, was visible across lizards, snakes and turtles alike. Together with other anthropogenic impacts, such as habitat loss and harvesting of species, this is a cause for concern. Given the historical lack of global reptile distributions, this calls for a re-assessment of global reptile conservation efforts, with a specific focus on anticipated future climate change.     

Climate change alters stability and species potential interactions in a large marine ecosystem

We have little empirical evidence of how large‐scale overlaps between large numbers of marine species may have altered in response to human impacts. Here, we synthesized all available distribution data (>1 million records) since 1992 for 61 species of the East Australian marine ecosystem, a global hot spot of ocean warming and continuing fisheries exploitation. Using a novel approach, we constructed networks of the annual changes in geographical overlaps between species. Using indices of changes in species overlap, we quantified changes in the ecosystem stability, species robustness, species sensitivity and structural keystone species. We then compared the species overlap indices with environmental and fisheries data to identify potential factors leading to the changes in distributional overlaps between species. We found that the structure of the ecosystem has changed with a decrease in asymmetrical geographical overlaps between species. This suggests that the ecosystem has become less stable and potentially more susceptible to environmental perturbations. Most species have shown a decrease in overlaps with other species. The greatest decrease in species overlap robustness and sensitivity to the loss of other species has occurred in the pelagic community. Some demersal species have become more robust and less sensitive. Pelagic structural keystone species, predominately the tunas and billfish, have been replaced by demersal fish species. The changes in species overlap were strongly correlated with regional oceanographic changes, in particular increasing ocean warming and the southward transport of warmer and saltier water with the East Australian Current, but less correlated with fisheries catch. Our study illustrates how large‐scale multispecies distribution changes can help identify structural changes in marine ecosystems associated with climate change.     

Cetacean range and climate in the eastern North Atlantic: future predictions and implications for conservation

There is increasing evidence that the distributions of a large number of species are shifting with global climate change as they track changing surface temperatures that define their thermal niche. Modelling efforts to predict species distributions under future climates have increased with concern about the overall impact of these distribution shifts on species ecology, and especially where barriers to dispersal exist. Here we apply a bio‐climatic envelope modelling technique to investigate the impacts of climate change on the geographic range of ten cetacean species in the eastern North Atlantic and to assess how such modelling can be used to inform conservation and management. The modelling process integrates elements of a species' habitat and thermal niche, and employs “hindcasting” of historical distribution changes in order to verify the accuracy of the modelled relationship between temperature and species range. If this ability is not verified, there is a risk that inappropriate or inaccurate models will be used to make future predictions of species distributions. Of the ten species investigated, we found that while the models for nine could successfully explain current spatial distribution, only four had a good ability to predict distribution changes over time in response to changes in water temperature. Applied to future climate scenarios, the four species‐specific models with good predictive abilities indicated range expansion in one species and range contraction in three others, including the potential loss of up to 80% of suitable white‐beaked dolphin habitat. Model predictions allow identification of affected areas and the likely time‐scales over which impacts will occur. Thus, this work provides important information on both our ability to predict how individual species will respond to future climate change and the applicability of predictive distribution models as a tool to help construct viable conservation and management strategies.     

Predicting the potential global distribution of Ageratina adenophora under current and future climate change scenarios

AimInvasive alien species (IAS) threaten ecosystems and humans worldwide, and future climate change may accelerate the expansion of IAS. Predicting the suitable areas of IAS can prevent their further expansion. Ageratina adenophora is an invasive weed over 30 countries in tropical and subtropical regions. However, the potential suitable areas of A. adenophora remain unclear along with its response to climate change. This study explored and mapped the current and future potential suitable areas of Ageratina adenophora.LocationGlobal.TaxaAsteraceae A. adenophora (Spreng.) R.M.King & H.Rob. Commonly known as Crofton weed.MethodsBased on A. adenophora occurrence data and climate data, we predicted its suitable areas of this weed under current and future (four RCPs in 2050 and 2070) by MaxEnt model. We used ArcGIS 10.4 to explore the potential suitable area distribution characteristics of this weed and the “ecospat” package in R to analyze its altitudinal distribution changes.ResultsThe area under the curve (AUC) value (>0.9) and true skill statistics (TSS) value (>0.8) indicated excelled model performance. Among environment factors, mean temperature of coldest quarter contributed most to the model. Globally, the suitable areas for A. adenophora invasion decreased under climate change scenarios, although regional increases were observed, including in six biodiversity hotspot regions. The potential suitable areas of A. adenophora under climate change would expand in regions with higher elevation (3,000–3,500 m).Main conclusionsMean temperature of coldest quarter was the most important variable influencing the potential suitable area of A. Adenophora. Under the background of a warming climate, the potential suitable area of A. adenophora will shrink globally but increase in six biodiversity hotspot regions. The potential suitable area of A. adenophora would expand at higher elevation (3,000–3,500 m) under climate change. Mountain ecosystems are of special concern as they are rich in biodiversity and sensitive to climate change, and increasing human activities provide more opportunities for IAS invasion.     

Predicting the distributions of Pouteria adolfi-friederici and Prunus africana tree species under current and future climate change scenarios in Ethiopia

Distributions of potential ranges of plant species are not yet fully known in Ethiopia where high climatic variability and vegetation types are found. This study was undertaken to predict distributions of suitable habitats of Pouteria adolfi-friederici and Prunus africana under current and two future climate scenarios (RCP 4.5 and RCP 8.5 in 2050 and 2070) in Ethiopia. Eleven environmental variables with less correlation coefficients (r < 0.7) were used to make the prediction. Shifting in extents of habitat suitability and effects of elevation, solar radiation and topographic position in relation to the current and future climatic scenarios were statistically analysed using independent t-test and linear model. We found decreasing area of highly suitable habitat from 0.51% to 0.46%, 0.36% and 0.33%, 0.24% for Prunus africana and 1.13% to 1.02%, 0.77% and 0.76%, 0.60% for Pouteria adolfi-friederici, under RCP 4.5 and RCP 8.5 by 2050 and 2070 respectively. Moist and dry afromontane forests are identified as the most suitable habitat for both species. Overall, our results suggest that climate change can promote dynamic suitable habitat niches under different future climate scenarios. Therefore, biodiversity conservation strategies should take into account habitat suitability dynamics issues and identify where to conserve species before implementing conservation practices.     

Tackling intraspecific genetic structure in distribution models better reflects species geographical range

Genetic diversity provides insight into heterogeneous demographic and adaptive history across organisms’ distribution ranges. For this reason, decomposing single species into genetic units may represent a powerful tool to better understand biogeographical patterns as well as improve predictions of the effects of GCC (global climate change) on biodiversity loss. Using 279 georeferenced Iberian accessions, we used classes of three intraspecific genetic units of the annual plant Arabidopsis thaliana obtained from the genetic analyses of nuclear SNPs (single nucleotide polymorphisms), chloroplast SNPs, and the vernalization requirement for flowering. We used SDM (species distribution models), including climate, vegetation, and soil data, at the whole‐species and genetic‐unit levels. We compared model outputs for present environmental conditions and with a particularly severe GCC scenario. SDM accuracy was high for genetic units with smaller distribution ranges. Kernel density plots identified the environmental variables underpinning potential distribution ranges of genetic units. Combinations of environmental variables accounted for potential distribution ranges of genetic units, which shrank dramatically with GCC at almost all levels. Only two genetic clusters increased their potential distribution ranges with GCC. The application of SDM to intraspecific genetic units provides a detailed picture on the biogeographical patterns of distinct genetic groups based on different genetic criteria. Our approach also allowed us to pinpoint the genetic changes, in terms of genetic background and physiological requirements for flowering, that Iberian A. thaliana may experience with a GCC scenario applying SDM to intraspecific genetic units.