Dietary generalism accelerates arrival and persistence of coral‐reef fishes in their novel ranges under climate change

Climate change is redistributing marine and terrestrial species globally. Life‐history traits mediate the ability of species to cope with novel environmental conditions, and can be used to gauge the potential redistribution of taxa facing the challenges of a changing climate. However, it is unclear whether the same traits are important across different stages of range shifts (arrival, population increase, persistence). To test which life‐history traits most mediate the process of range extension, we used a 16‐year dataset of 35 range‐extending coral‐reef fish species and quantified the importance of various traits on the arrival time (earliness) and degree of persistence (prevalence and patchiness) at higher latitudes. We show that traits predisposing species to shift their range more rapidly (large body size, broad latitudinal range, long dispersal duration) did not drive the early stages of redistribution. Instead, we found that as diet breadth increased, the initial arrival and establishment (prevalence and patchiness) of climate migrant species in temperate locations occurred earlier. While the initial incursion of range‐shifting species depends on traits associated with dispersal potential, subsequent establishment hinges more on a species’ ability to exploit novel food resources locally. These results highlight that generalist species that can best adapt to novel food sources might be most successful in a future ocean.     

Climate change induced elevational range shifts of Himalayan tree species

Global warming may force montane species to shift upward to keep pace with their shifting climate niche. How species differences in such distribution shifts depend on their elevational positions, elevation-dependent warming rates, and other environmental constraints, or plant functional traits is poorly understood. Here, we analyzed for 137 Himalayan tree species how distribution shifts vary with elevational niche positions, environmental constraints, and their functional traits. We developed ecological niche models using MaxEnt by combining species survey and botanical collections data with 19 environmental predictors. Species distributions were projected to 1985 and 2050 conditions, and elevational range parameters and distribution areas were derived. Under the worst-case RCP 8.5 scenario, species are predicted to shift, on average, 3 m/year in optimum elevation, and have 33% increase in distribution area. Highland species showed faster predicted elevational shifts than lowland species. Lowland and highland species are predicted to expand in distribution area in contrast to mid-elevation species. Tree species for which species distribution models are driven by responses to temperature, aridity, or soil clay content showed the strongest predicted upslope shifts. Tree species with conservative trait values that enable them to survive resource poor conditions (i.e., narrow conduits) showed larger predicted upslope shifts than species with wide conduits. The predicted average upslope shift in maximum elevation (8 m/year) is >2 times faster than the current observations indicating that many species will not be able to track climate change and potentially go extinct, unless they are supported by active conservation measures, such as assisted migration.     

Are Plant Species Able to Keep Pace with the Rapidly Changing Climate?

Future climate change is predicted to advance faster than the postglacial warming. Migration may therefore become a key driver for future development of biodiversity and ecosystem functioning. For 140 European plant species we computed past range shifts since the last glacial maximum and future range shifts for a variety of Intergovernmental Panel on Climate Change (IPCC) scenarios and global circulation models (GCMs). Range shift rates were estimated by means of species distribution modelling (SDM). With process-based seed dispersal models we estimated species-specific migration rates for 27 dispersal modes addressing dispersal by wind (anemochory) for different wind conditions, as well as dispersal by mammals (dispersal on animal''s coat – epizoochory and dispersal by animals after feeding and digestion – endozoochory) considering different animal species. Our process-based modelled migration rates generally exceeded the postglacial range shift rates indicating that the process-based models we used are capable of predicting migration rates that are in accordance with realized past migration. For most of the considered species, the modelled migration rates were considerably lower than the expected future climate change induced range shift rates. This implies that most plant species will not entirely be able to follow future climate-change-induced range shifts due to dispersal limitation. Animals with large day- and home-ranges are highly important for achieving high migration rates for many plant species, whereas anemochory is relevant for only few species.     

How do steppe plants follow their optimal environmental conditions or persist under suboptimal conditions? The differing strategies of annuals and perennials

For a species to be able to respond to environmental change, it must either succeed in following its optimal environmental conditions or in persisting under suboptimal conditions, but we know very little about what controls these capacities. We parameterized species distribution models (SDMs) for 135 plant species from the Algerian steppes. We interpreted low false‐positive rates as reflecting a high capacity to follow optimal environmental conditions and high false‐negative rates as a high capacity to persist under suboptimal environmental conditions. We also measured functional traits in the field and built a unique plant trait database for the North‐African steppe. For both perennial and annual species, we explored how these two capacities can be explained by species traits and whether relevant trait values reflect species strategies or biases in SDMs. We found low false‐positive rates in species with small seeds, flowers attracting specialist pollinators, and specialized distributions (among annuals and perennials), low root:shoot ratios, wide root‐systems, and large leaves (perennials only) (R² = .52–58). We found high false‐negative rates in species with marginal environmental distribution (among annuals and perennials), small seeds, relatively deep roots, and specialized distributions (annuals) or large leaves, wide root‐systems, and monocarpic life cycle (perennials) (R² = .38 for annuals and 0.65 for perennials). Overall, relevant traits are rarely indicative of the possible biases of SDMs, but rather reflect the species' reproductive strategy, dispersal ability, stress tolerance, and pollination strategies. Our results suggest that wide undirected dispersal in annual species and efficient resource acquisition in perennial species favor both capacities, whereas short life spans in perennial species favor persistence in suboptimal environmental conditions and flowers attracting specialist pollinators in perennial and annual species favor following optimal environmental conditions. Species that neither follow nor persist will be at risk under future environmental change.     

Eco‐evolution on the edge during climate change

We urgently need to predict species responses to climate change to minimize future biodiversity loss and ensure we do not waste limited resources on ineffective conservation strategies. Currently, most predictions of species responses to climate change ignore the potential for evolution. However, evolution can alter species ecological responses, and different aspects of evolution and ecology can interact to produce complex eco‐evolutionary dynamics under climate change. Here we review how evolution could alter ecological responses to climate change on species warm and cool range margins, where evolution could be especially important. We discuss different aspects of evolution in isolation, and then synthesize results to consider how multiple evolutionary processes might interact and affect conservation strategies. On species cool range margins, the evolution of dispersal could increase range expansion rates and allow species to adapt to novel conditions in their new range. However, low genetic variation and genetic drift in small range‐front populations could also slow or halt range expansions. Together, these eco‐evolutionary effects could cause a three‐step, stop‐and‐go expansion pattern for many species. On warm range margins, isolation among populations could maintain high genetic variation that facilitates evolution to novel climates and allows species to persist longer than expected without evolution. This ‘evolutionary extinction debt’ could then prevent other species from shifting their ranges. However, as climate change increases isolation among populations, increasing dispersal mortality could select for decreased dispersal and cause rapid range contractions. Some of these eco‐evolutionary dynamics could explain why many species are not responding to climate change as predicted. We conclude by suggesting that resurveying historical studies that measured trait frequencies, the strength of selection, or heritabilities could be an efficient way to increase our eco‐evolutionary knowledge in climate change biology.     

Do species’ traits predict recent shifts at expanding range edges?

Although some organisms have moved to higher elevations and latitudes in response to recent climate change, there is little consensus regarding the capacity of different species to track rapid climate change via range shifts. Understanding species' abilities to shift ranges has important implications for assessing extinction risk and predicting future community structure. At an expanding front, colonization rates are determined jointly by rates of reproduction and dispersal. In addition, establishment of viable populations requires that individuals find suitable resources in novel habitats. Thus, species with greater dispersal ability, reproductive rate and ecological generalization should be more likely to expand into new regions under climate change. Here, we assess current evidence for the relationship between leading-edge range shifts and species' traits. We found expected relationships for several datasets, including diet breadth in North American Passeriformes and egg-laying habitat in British Odonata. However, models generally had low explanatory power. Thus, even statistically and biologically meaningful relationships are unlikely to be of predictive utility for conservation and management. Trait-based range shift forecasts face several challenges, including quantifying relevant natural history variation across large numbers of species and coupling these data with extrinsic factors such as habitat fragmentation and availability.     

Congener diversity,topographic heterogeneity and human‐assisted dispersal predict spread rates of alien herpetofauna at a global scale

Understanding the factors that determine rates of range expansion is not only crucial for developing risk assessment schemes and management strategies for invasive species, but also provides important insight into the ability of species to disperse in response to climate change. However, there is little knowledge on why some invasions spread faster than others at large spatiotemporal scales. Here, we examine the effects of human activities, species traits and characteristics of the invaded range on spread rates using a global sample of alien reptile and amphibian introductions. We show that spread rates vary remarkably among invaded locations within a species, and differ across biogeographical realms. Spread rates are positively related to the richness of native congeneric species and human‐assisted dispersal in the invaded range but are negatively correlated with topographic heterogeneity. Our findings highlight the importance of environmental characteristics and human‐assisted dispersal in developing robust frameworks for predicting species' range shifts.     

Drought and leaf herbivory influence floral volatiles and pollinator attraction

The effects of climate change on species interactions are poorly understood. Investigating the mechanisms by which species interactions may shift under altered environmental conditions will help form a more predictive understanding of such shifts. In particular, components of climate change have the potential to strongly influence floral volatile organic compounds (VOCs) and, in turn, plant–pollinator interactions. In this study, we experimentally manipulated drought and herbivory for four forb species to determine effects of these treatments and their interactions on (1) visual plant traits traditionally associated with pollinator attraction, (2) floral VOCs, and (3) the visitation rates and community composition of pollinators. For all forbs tested, experimental drought universally reduced flower size and floral display, but there were species‐specific effects of drought on volatile emissions per flower, the composition of compounds produced, and subsequent pollinator visitation rates. Moreover, the community of pollinating visitors was influenced by drought across forb species (i.e. some pollinator species were deterred by drought while others were attracted). Together, these results indicate that VOCs may provide more nuanced information to potential floral visitors and may be relatively more important than visual traits for pollinator attraction, particularly under shifting environmental conditions.     

Range shift promotes the formation of stable range edges

Aim I investigate the counter‐intuitive possibility that range shift promotes the formation of stable range edges. This might be expected because: (1) range‐shifting populations typically evolve increased dispersal on the expanding range edge; (2) increased dispersal steepens the relative slope of environmental gradients (gradients appear steeper to a more dispersive population); and (3) environmental gradients that are steep relative to dispersal encourage the formation of stable range edges (when gradients appear steep, adaptation on the range edge is swamped by maladapted genes). Methods I test the idea that populations take longer to evolve across an environmental gradient when those populations have already undergone a period of spread. I do this using an individual‐based coupled map lattice simulation, in which individuals carry heritable traits for dispersal probability and environment‐specific fitness. Results Numerous simulations across parameter space confirm that a period of range shift almost always results in a longer time to evolve through an environmental gradient. This occurs because of both the mechanism described above and the erosion of adaptive variation resulting from the serial foundering that occurs during range advance. Main conclusions This result suggests that species may often shift their range due to intrinsic changes in the population rather than extrinsic changes in the environment. The result also suggests a new mechanism regulating the speed of invasion, and sounds a cautionary note for climate change impacts: the longer a species tracks climate change, the less able it may be to track that change into the future.     

Geographic range velocity and its association with phylogeny and life history traits in North American woody plants

The geographic ranges of taxa change in response to environmental conditions. Yet whether rates of range movement (biotic velocities) are phylogenetically conserved is not well known. Phylogenetic conservatism of biotic velocities could reflect similarities among related lineages in climatic tolerances and dispersal‐associated traits. We assess whether late Quaternary biotic velocities were phylogenetically conserved and whether they correlate with climatic tolerances and dispersal‐associated traits. We used phylogenetic regression and nonparametric correlation to evaluate associations between biotic velocities, dispersal‐associated traits, and climatic tolerances for 28 woody plant genera and subgenera in North America. The velocities with which woody plant taxa shifted their core geographic range limits were positively correlated from time step to time step between 16 and 7 ka. The strength of this correlation weakened after 7 ka as the pace of climate change slowed. Dispersal‐associated traits and climatic tolerances were not associated with biotic velocities. Although the biotic velocities of some genera were consistently fast and others consistently slow, biotic velocities were not phylogenetically conserved. The rapid late Quaternary range shifts of plants lacking traits that facilitate frequent long‐distance dispersal has long been noted (i.e., Reid's Paradox). Our results are consistent with this paradox and show that it remains robust when phylogenetic information is taken into account. The lack of association between biotic velocities, dispersal‐associated traits, and climatic tolerances may reflect several, nonmutually exclusive processes, including rare long‐distance dispersal, biotic interactions, and cryptic refugia. Because late Quaternary biotic velocities were decoupled from dispersal‐associated traits, trait data for genera and subgenera cannot be used to predict longer‐term (millennial‐scale) floristic responses to climate change.     

Marine range shifts and species introductions: comparative spread rates and community impacts

Aim Shifts in species ranges are a predicted and realized effect of global climate change; however, few studies have addressed the rates and consequence of such shifts, particularly in marine systems. Given ecological similarities between shifting and introduced species, we examined how our understanding of range shifts may be informed by the more established study of non‐native species introductions. Location Marine systems world‐wide. Methods Database and citation searches were used to identify 129 marine species experiencing range shifts and to determine spread rates and impacts on recipient communities. Analyses of spread rates were based on studies for which post‐establishment spread was reported in linear distance. The sizes of the effects of community impacts of shifting species were compared with those of functionally similar introduced species having ecologically similar impacts. Results Our review and meta‐analyses revealed that: (1) 75% of the range shifts found through the database search were in the poleward direction, consistent with climate change scenarios, (2) spread rates of range shifts were lower than those of introductions, (3) shifting species spread over an order of magnitude faster in marine than in terrestrial systems, and (4) directions of community effects were largely negative and magnitudes were often similar for shifters and introduced species; however, this comparison was limited by few data for range‐shifting species. Main conclusions Although marine range shifts are likely to proceed more slowly than marine introductions, the community‐level effects could be as great, and in the same direction, as those of introduced species. Because it is well‐established that introduced species are a primary threat to global biodiversity, it follows that, just like introductions, range shifts have the potential to seriously affect biological systems. In addition, given that ranges shift faster in marine than terrestrial environments, marine communities might be affected faster than terrestrial ones as species shift with climate change. Regardless of habitat, consideration of range shifts in the context of invasion biology can improve our understanding of what to expect from climate change‐driven shifts as well as provide tools for formal assessment of risks to community structure and function.     

Illuminating geographical patterns in species' range shifts

Species' range shifts in response to ongoing climate change have been widely documented, but although complex spatial patterns in species' responses are expected to be common, comprehensive comparisons of species' ranges over time have undergone little investigation. Here, we outline a modeling framework based on historical and current species distribution records for disentangling different drivers (i.e. climatic vs. nonclimatic) and assessing distinct facets (i.e. colonization, extirpation, persistence, and lags) of species' range shifts. We used extensive monitoring data for stream fish assemblages throughout France to assess range shifts for 32 fish species between an initial period (1980–1992) and a contemporary one (2003–2009). Our results provide strong evidence that the responses of individual species varied considerably and exhibited complex mosaics of spatial rearrangements. By dissociating range shifts in climatically suitable and unsuitable habitats, we demonstrated that patterns in climate‐driven colonization and extirpation were less marked than those attributed to nonclimatic drivers, although this situation could rapidly shift in the near future. We also found evidence that range shifts could be related to some species' traits and that the traits involved varied depending on the facet of range shift considered. The persistence of populations in climatically unsuitable areas was greater for short‐lived species, whereas the extent of the lag behind climate change was greater for long‐lived, restricted‐range, and low‐elevation species. We further demonstrated that nonclimatic extirpations were primarily related to the size of the species' range, whereas climate‐driven extirpations were better explained by thermal tolerance. Thus, the proposed framework demonstrated its potential for markedly improving our understanding of the key processes involved in range shifting and also offers a template for informing management decisions. Conservation strategies would greatly benefit from identifying both the geographical patterns and the species' traits associated with complex modifications of species' distributions in response to global changes.     

Species traits and climate velocity explain geographic range shifts in an ocean‐warming hotspot

Species' ranges are shifting globally in response to climate warming, with substantial variability among taxa, even within regions. Relationships between range dynamics and intrinsic species traits may be particularly apparent in the ocean, where temperature more directly shapes species' distributions. Here, we test for a role of species traits and climate velocity in driving range extensions in the ocean‐warming hotspot of southeast Australia. Climate velocity explained some variation in range shifts, however, including species traits more than doubled the variation explained. Swimming ability, omnivory and latitudinal range size all had positive relationships with range extension rate, supporting hypotheses that increased dispersal capacity and ecological generalism promote extensions. We find independent support for the hypothesis that species with narrow latitudinal ranges are limited by factors other than climate. Our findings suggest that small‐ranging species are in double jeopardy, with limited ability to escape warming and greater intrinsic vulnerability to stochastic disturbances.     

Do ecological differences between taxonomic groups influence the relationship between species’ distributions and climate? A global meta‐analysis using species distribution models

Understanding whether and how ecological traits affect species’ geographic distributions is a fundamental issue that bridges ecology and biogeography. While climate is thought to be the major determinant of species’ distributions, there is considerable variation in the strength of species’ climate–distribution relationships. One potential explanation is that species with relatively low dispersal ability cannot reach all geographic areas where climatic conditions are suitable. We tested the hypothesis that species from different taxonomic groups varied in their climate–distribution relationships because of differences in life history strategies, in particular dispersal ability. We conducted a meta‐analysis by combining the discrimination ability (AUC values) from 4317 species distribution models (SDMs) using fit as an indication of the strength of the species’ climate–distribution relationship. We found significant differences in the strength of species’ climate–distribution relationships across taxonomic groups, however we did not find support for the dispersal hypothesis. Our results suggest that relevant ecological trait variation among broad taxonomic groups may be related to differences in species’ climate–distribution relationships, however which ecological traits are important remains unclear.     

Species’ traits as predictors of range shifts under contemporary climate change: A review and meta‐analysis

A growing body of literature seeks to explain variation in range shifts using species’ ecological and life‐history traits, with expectations that shifts should be greater in species with greater dispersal ability, reproductive potential, and ecological generalization. Despite strong theoretical support for species’ traits as predictors of range shifts, empirical evidence from contemporary range shift studies remains limited in extent and consensus. We conducted the first comprehensive review of species’ traits as predictors of range shifts, collecting results from 51 studies across multiple taxa encompassing over 11,000 species’ responses for 54 assemblages of taxonomically related species occurring together in space. We used studies of assemblages that directly compared geographic distributions sampled in the 20th century prior to climate change with resurveys of distributions after contemporary climate change and then tested whether species traits accounted for heterogeneity in range shifts. We performed a formal meta‐analysis on study‐level effects of body size, fecundity, diet breadth, habitat breadth, and historic range limit as predictors of range shifts for a subset of 21 studies of 26 assemblages with sufficient data. Range shifts were consistent with predictions based on habitat breadth and historic range limit. However, body size, fecundity, and diet breadth showed no significant effect on range shifts across studies, and multiple studies reported significant relationships that contradicted predictions. Current understanding of species’ traits as predictors of range shifts is limited, and standardized study is needed for traits to be valid indicators of vulnerability in assessments of climate change impacts.     

A comparative analysis of dispersal syndromes in terrestrial and semi‐terrestrial animals

Dispersal, the behaviour ensuring gene flow, tends to covary with a number of morphological, ecological and behavioural traits. While species‐specific dispersal behaviours are the product of each species’ unique evolutionary history, there may be distinct interspecific patterns of covariation between dispersal and other traits (‘dispersal syndromes’) due to their shared evolutionary history or shared environments. Using dispersal, phylogeny and trait data for 15 terrestrial and semi‐terrestrial animal Orders (> 700 species), we tested for the existence and consistency of dispersal syndromes across species. At this taxonomic scale, dispersal increased linearly with body size in omnivores, but decreased above a critical length in herbivores and carnivores. Species life history and ecology significantly influenced patterns of covariation, with higher phylogenetic signal of dispersal in aerial dispersers compared with ground dwellers and stronger evidence for dispersal syndromes in aerial dispersers and ectotherms, compared with ground dwellers and endotherms. Our results highlight the complex role of dispersal in the evolution of species life‐history strategies: good dispersal ability was consistently associated with high fecundity and survival, and in aerial dispersers it was associated with early maturation. We discuss the consequences of these findings for species evolution and range shifts in response to future climate change.     

Density‐dependent dispersal and the formation of range borders.

Knowledge about the mechanisms of range formation is crucial for scientifically based species conservation strategies in the face of ongoing global climate change. In recent years an increasing amount of studies have focused on the influences of density‐dependent dispersal on demographic and biogeographical patterns. However, it still remains unclear, to what extent and in what ways this strategy would affect the range formation of species. In order to fill this gap, we present a study using individual‐based simulations of a species with discrete generations living along a dispersal mortality gradient. We compare the evolution of range sizes for species following density‐dependent and density‐independent emigration. Furthermore we assess the influence of environmental stochasticity and Allee effects on range formation, as both processes are known to play an important role for dispersal evolution. We find that density‐dependent dispersal always results in much wider ranges than unconditional dispersal. Increasing environmental stochasticity, a predicted consequence of climate change, can remarkably expand the ranges of species living in such connectivity gradients if dispersal decisions are based on local population density. A strong Allee effect causes range contraction for both strategies, but the effect is considerably less dramatic under density‐dependent compared to density‐independent emigration. We strongly recommend accounting for these findings in future attempts to model species’ range shifts due to climate change.     

Evolved dispersal strategies at range margins

Dispersal is a key component of a species''s ecology and will be under different selection pressures in different parts of the range. For example, a long-distance dispersal strategy suitable for continuous habitat at the range core might not be favoured at the margin, where the habitat is sparse. Using a spatially explicit, individual-based, evolutionary simulation model, the dispersal strategies of an organism that has only one dispersal event in its lifetime, such as a plant or sessile animal, are considered. Within the model, removing habitat, increasing habitat turnover, increasing the cost of dispersal, reducing habitat quality or altering vital rates imposes range limits. In most cases, there is a clear change in the dispersal strategies across the range, although increasing death rate towards the margin has little impact on evolved dispersal strategy across the range. Habitat turnover, reduced birth rate and reduced habitat quality all increase evolved dispersal distances at the margin, while increased cost of dispersal and reduced habitat density lead to lower evolved dispersal distances at the margins. As climate change shifts suitable habitat poleward, species ranges will also start to shift, and it will be the dispersal capabilities of marginal populations, rather than core populations, that will influence the rate of range shifting.     

Joint effects of species traits and environmental preferences on range edge shifts of British birds

Aim

Despite the strong evidence of species range shifts as a response to environmental change, attempts to identify species traits that modulate those shifts have been equivocal. We investigate the role of species traits and environmental preferences on birds' range shifts in Great Britain, an island where dispersal is limited by the English Channel and the North Sea.

Location

Great Britain (England, Scotland and Wales).

Taxa

Birds (Aves).

Time Period

1968–2011.

Methods

Using 404,949 occurrence records from two time periods, we investigated the potential drivers of leading and rear range edge shifts of breeding birds using phylogenetic linear mixed models. We hypothesized that shifts are influenced by species' trophic and morphological traits, dispersal abilities and environmental preferences, but also by the geographical boundaries of Great Britain.

Results

Geographical boundaries—the distance from the northern or southern boundaries of Britain—accounted for most of the variability in range edge shifts. Species traits and environmental preferences emerged as relevant drivers of range shifts only for northern and Passeriform species. Northern habitat specialist, those with more predators and those sensitive to precipitation were more likely to shift their rear edge poleward. For Passeriformes, habitat generalists, species with smaller dispersal capabilities, under higher predatory pressure or associated with forest and grassland were more likely to shift their rear edge poleward.

Main Conclusions

While geographical boundaries impose constraints on range shifts in British birds, the subtle effects of species traits and environmental preferences emerge as relevant predictors for Northern and passeriform species' rear edge shifts. This highlights the importance of accounting for geographical boundaries when predicting species responses to global change. Differential range shifts of species across different trophic levels could result in the reorganization of biotic interactions, with consequences for ecosystem structure and stability.     

Individualistic species limitations of climate‐induced range expansions generated by meso‐scale dispersal barriers

Aim Evidence indicates that species are responding to climate change through distributional range shifts that track suitable climatic conditions. We aim to elucidate the role of meso‐scale dispersal barriers in climate‐tracking responses. Location South coast of England (the English Channel). Methods Historical distributional data of four intertidal invertebrate species were logistically regressed against sea surface temperature (SST) to determine a climate envelope. This envelope was used to estimate the expected climate‐tracking response since 1990 along the coast, which was compared with observed range expansions. A hydrodynamic modelling approach was used to identify dispersal barriers and explore disparities between expected and observed climate tracking. Results Range shifts detected by field survey over the past 20 years were less than those predicted by the changes that have occurred in SST. Hydrodynamic model simulations indicated that physical barriers produced by complex tidal currents have variably restricted dispersal of pelagic larvae amongst the four species. Main conclusions We provide the first evidence that meso‐scale hydrodynamic barriers have limited climate‐induced range shifts and demonstrate that life history traits affect the ability of species to overcome such barriers. This suggests that current forecasts may be flawed, both by overestimating range shifts and by underestimating climatic tolerances of species. This has implications for our understanding of climate change impacts on global biodiversity.