Global Change Biology

Climate warming is increasing mismatches between thermal phenotypes and habitat temperatures, driving range shifts and population extirpations. While within-species variation in heat tolerance and local warming rates can predict responses to climate warming, how these factors shape differences in vulnerability among taxa and ecosystems is uncertain. Here we combine climate and thermal trait data from 69 species across four ecosystem types to examine the effects of incorporating intraspecific variation in heat tolerance and local warming rates on projected vulnerability to climate warming. Because vulnerability to warming depends on existing phenotypic variation in thermal performance and relative rates of habitat warming, we develop a new metric that integrates localized rates of warming with spatial variation in thermal tolerances, termed the minimum trait velocity. Incorporating intraspecific variation in heat tolerance lowered estimates of warming tolerance (a measure of vulnerability) across most ecosystem types, with the strongest negative impact on marine taxa. Although intraspecific variation in heat tolerance could facilitate adaptation to climate change, our results suggest such variation is generally less than the projected near future warming. This suggests that opportunities for evolutionary rescue via gene flow between locally adapted populations are limited, adding to mounting concern as the climate warms.

In tundra ecosystems, moss-associated microbes are a major source of new nitrogen, yet the relative contributions of environment, host identity, and microbiome composition to variation in nitrogen-fixation rates are difficult to disentangle. To test how environmental change alters moss microbiomes and nitrogen-fixation rates, we used a one-year reciprocal transplant experiment between two Alaskan tundra sites that differ by 5{degrees}C in mean annual temperature. Intact moss cores containing one of three moss species, Hylocomium splendens, Aulacomnium turgidum, and Pleurozium schreberi, were transplanted between sites or returned to their home site. After one year, we quantified nitrogen-fixation rates using 15N incubation and characterized bacterial communities using 16S rRNA gene amplicon sequencing. H. splendens showed consistently low nitrogen-fixation rates with little transplant response, whereas P. schreberi and A. turgidum home and transplant tundra cores generally exhibited higher rates at the cooler, more northern site regardless of origin. In contrast, bacterial community structure changed little following transplantation, with composition driven primarily by moss species. Only in cyanobacteria and some heterotrophic bacterial lineages did we find subtle ASV-level changes. The absence of an association between microbial composition and nitrogen fixation, together with the heterogeneity among moss species, suggests that over short timescales, host physiology and microenvironment play a larger role in the variation of nitrogen-fixation rates than community turnover. The fact that short-term shifts in moss-associated nitrogen-fixation rate are driven primarily by host species identity, rather than microbiome restructuring, has important implications for near-term predictions of nitrogen inputs under Arctic climate change.

Mesic resources, the late-season herbaceous vegetation found in riparian areas and wet meadows, provide disproportionately important forage and habitat across western U.S. rangelands, yet their response to climatic variability and anthropogenic influences remains poorly understood. Using a 40-year Landsat time series (1984-2024), we quantified trends in late-season productivity (NDVI) across 4.5 million hectares of the sagebrush biome and applied random forest models to distinguish between temporal and spatial predictors of mesic resource productivity. We identified a fundamental shift in how mesic resources respond to drought: from 1984 to 2004, mesic productivity was strongly correlated with drought severity (Palmer Drought Severity Index, R{superscript 2} = 0.92), but this relationship weakened substantially in the next two decades (2005-2024; R{superscript 2} = 0.28), during which time productivity increased despite persistent aridity. Temporal modeling identified rising atmospheric CO2 concentrations as the strongest predictor of this shift, consistent with enhanced plant water-use efficiency under CO2 fertilization. Spatially, large agricultural valley floodplains act as anthropogenic refugia, sustaining productive mesic resources through flood irrigation and subsequent groundwater recharge into late summer. These findings suggest that human water management and physiological shifts in vegetation are currently buffering mesic systems against meteorological drought throughout U.S. rangelands. However, this apparent buffering is spatially heterogeneous and may mask vulnerability to groundwater depletion, shifts in precipitation regimes, and woody encroachment. Sustaining these vital ecosystems will require conservation approaches that go beyond climate monitoring to include balanced management considering both agricultural and ecological water needs and constraints.

O_LISubmerged macrophytes are central to freshwater ecosystems functioning but are declining globally under multiple anthropogenic stressors. We aimed to identify general patterns in physiological responses and interaction types, and to assess whether a mechanistic understanding of stressor interactions can be developed from published evidence. C_LIO_LIWe systematically reviewed 12,858 records, identified 172 relevant papers, and extracted effect sizes from 124 experiments included in the meta-analysis. C_LIO_LIMost studies examined combinations of nutrient enrichment, shading, toxic trace metals, warming, and emerging contaminants such as PFAS and microplastics, typically under simplified 2 x 2 factorial laboratory designs. Additive effects dominated (50%), while synergistic interactions were relatively infrequent (14%). Antagonistic interactions often reflected dominance of a single stressor or compensatory responses, whereas synergisms were most frequent with metals combined with co-stressors enhancing bioavailability. C_LIO_LIOur synthesis suggests that accumulated stressors cause negative, but not necessarily amplified, responses, although the limited number of experiments testing more than two stressors means synergistic effects may be underestimated. We propose Stuckenia pectinata as a model organism because of its cosmopolitan distribution, experimental tractability, and available genomic resources, and argue that expanding stressor complexity, duration, and taxonomic breadth will strengthen predictions of macrophyte responses and inform freshwater conservation under global change. C_LI

Invasive plants can reshape ecosystems by altering soil biogeochemistry and microbial functioning under global change. Competitive interactions between the invasive Conyza bonariensis and the native Helminthotheca echioides were evaluated under warming, nitrogen enrichment, and elevated CO2, together with rhizosphere microbial function in solitary versus competitive growth. Plants were grown alone or in interspecific competition under elevated temperature (27 vs 29 {degrees}C), ammonium-nitrate fertilization versus no fertilization, and ambient versus elevated CO2 (400 vs 720 ppm). Plant traits and relative growth rate (RGR) were measured alongside potential extracellular enzyme activities (EEA) of -D-glucosidase (C acquisition) and N-acetyl-{beta}-D-glucosaminidase (NAGase; N acquisition) and functional gene abundances (nirS and bacterial amoA). To relate enzyme signals to plant demand and microbial biomass, we calculated a growth-normalized rhizosphere investment metric (Specific Rhizosphere Index; SRI) and a biomass-normalized investment metric (Specific Enzyme Activity; SEA). Competition effects were summarized as {Delta}SRI and {Delta}Tax (change from alone to competition) to quantify how competition altered growth- and biomass-normalized investment. Plant responses were driver- and context-dependent. Elevated CO2 produced the largest changes in growth traits, especially for the invasive species. Warming effects were modest in solitary plants but became apparent under competition, where elevated temperature reduced competitive suppression via increased invasive leaf production and reduced constraints on native leaf expansion. Fertilization caused comparatively small shifts in plant endpoints. Microbial responses depended strongly on soil conditioning history. Potential EEA showed limited shifts with warming and fertilization, whereas elevated CO2 enhanced NAGase mainly in invasive-conditioned soils and increased nirS across soils. Despite overlap in ecoenzymatic stoichiometry, SRI and {Delta}Tax revealed treatment- and legacy-dependent patterns in how competition re-scaled microbial C and N acquisition relative to plant growth and microbial biomass. Together, these results indicate that global change can decouple plant growth from enzymatic investment and reconfigure invasive-native interactions through shifts in above-belowground coupling.

Climate change can affect salmon and steelhead (Oncorhynchus spp.) throughout their anadromous life cycles, yet there have been no assessments of which Canadian populations face the greatest exposure. We developed a framework to quantify relative climate change exposure of salmon and steelhead populations based on the spatial and temporal distribution of different life stages. Exposure was calculated from climate model projections for freshwater and marine climate variables considering unique impact thresholds for each population and life stage. We applied this framework to 60 Conservation Units of Pacific salmon and steelhead in the Fraser River basin, British Columbia. Lake-type sockeye had the highest exposure, driven by elevated stream temperatures during adult freshwater migration and spawning stages and relatively low thermal tolerance of marine stages. Chinook salmon were the next most exposed, while coho, pink, and chum salmon had relatively low exposure. Uniquely, steelhead exposure was driven by high stream temperatures during incubation. Our framework is broadly applicable, and our findings provide critical input for climate change vulnerability assessments and forward-looking resilience planning for Pacific salmon.

Timing of flowering is shifting with climate change. Although climate-driven shifts in phenology sometimes affect seed production, whether changing phenology will scale up to affect population dynamics of long-lived plants remains largely unknown, particularly under changing precipitation. Understanding how phenology affects persistence and extinction risk is a pressing need given contemporary biodiversity loss. We combined nearly a decade of demographic censuses and a four-year phenological survey in a rainfall manipulation experiment to examine the effects of experimental drought and irrigation on flowering phenology, vital rates (e.g., survival and individual growth), and population growth in the perennial herb Lomatium utriculatum. We found that drought advanced flowering by 3.3 days on average, and that earlier-flowering plants produced more seeds regardless of treatment. However, both rainfall treatments reduced seed production compared to controls. We quantified the phenology-mediated and direct, non-phenological effects of rainfall manipulation on population growth rates using integral projection models and a life table response experiment. Drought and irrigation increased {lambda} through increased individual growth, but these effects were partially negated by treatment-driven declines in seed output. In contrast, changes to seed production resulting from shifting flowering times had negligible effects on population growth. Our results suggest that climate-driven phenological shifts may only marginally impact population dynamics in perennial plants and highlight that assessing phenologys consequences for persistence under climate change must also account for direct demographic effects of the climate driver(s) themselves. SignificanceWill changing flowering times under climate change increase extinction risk in plant populations? Despite well-documented earlier flowering and its influence on the number of offspring produced, how changing flowering times will affect population growth or decline is still mostly unknown. We study this in a perennial wildflower subject to changes in rainfall. While we found that drought meant earlier flowering and that, all else equal, early flowering meant more seeds, these effects only marginally affected population growth. Instead, population growth was influenced mostly by rainfall-driven changes to individual plant growth. While shifting flowering times remain an important indicator of climate change, assessing extirpation in plants requires considering flowering times as only one of many life cycle processes changing with climate.

Marine protected areas (MPAs) are increasingly promoted as climate mitigation tools, yet guidance on their placement to maximize resilience against climate stressors like marine heatwaves remains limited. Here, we develop MPA placement guidelines that explicitly consider a mechanistic pathway through which MPAs could enhance kelp forest resilience to heatwaves: protecting fishery-targeted urchin predators to prevent kelp overgrazing. Using a spatially explicit, tri-trophic model of California kelp forests, we evaluate alternative MPA configurations across a hypothetical coastline where half the habitat experiences an increased probability of experiencing heatwaves. We found that effective MPA placement depends on whether MPAs are being newly established or reconfigured within an existing network, and that among-patch connectivity and spillover played vital roles in the relative effectiveness of different MPA configurations. Changes in resilience occurred primarily at the patch scale, with trade-offs between increased within-MPA resilience and decreased resilience in some fished areas, resulting in minimal coastwide population effects. For example, for new MPAs, large single MPAs within heatwave-prone areas maximized within-MPA resilience gains, while multiple small MPAs in heatwave refugia best supported whole-coast resilience. When reconfiguring established networks, expanding existing MPAs in refugia areas was most effective. We also demonstrate the importance of considering MPA recovery timescales: for example, relocating old MPAs to heatwave refugia yielded minimal short-term benefits due to the loss of rebuilt, previously fished, predator biomass. Our findings demonstrate that climate-adaptive marine planning should explicitly consider the spatiotemporal implications of trophic cascades, connectivity, and transient population dynamics to support ecosystem resilience.

O_LIAquatic algae are key primary producers in the Arctic and Antarctic, yet how cold-water species respond to environmental change is poorly understood. The Polar Regions are increasingly exposed to frequent heat waves, leading to declining ice cover, increased light availability, and decreasing salinity in polar waters. We compared three phylogenetically related but geographically distant polar Chlamydomonas species to test how habitat history shapes algal responses to light, salinity, and temperature stress. C_LIO_LIWe assessed the growth, morphology, and photochemistry of psychrophilic Chlamydomonas acclimated to native-like (lower light, higher salinity) and climate-shifted conditions (higher light, lower salinity). Next, we exposed acclimated cultures to a lethal heat shock and observed how acclimation affects algal temperature stress resilience. C_LIO_LIAll three species acclimated to climate-shifted conditions grew rapidly but showed the greatest sensitivity to temperature stress, with rapid loss of viability and photosynthetic efficiency. In contrast, slow-growing cultures acclimated to native-like conditions exhibited significantly greater resilience to temperature stress. C_LIO_LIOur work is the first to directly link light and salinity acclimation with temperature resilience in psychrophilic algae, suggesting that fast-growing polar green algae may be particularly vulnerable to increasingly frequent heat waves, with major implications for primary productivity in polar environments. C_LI

Kelp forests are widely distributed along temperate and polar coastlines worldwide and are among the worlds most productive and diverse marine ecosystems. Yet, due in part to ocean warming, they are declining and even disappearing in many parts of the world. While genomic tools can identify local adaptation and predict species responses to global change, these predictions have rarely been validated in the field, hampering their widespread use in conservation practice. Here, we applied a seascape genomics approach to investigate environmental adaptation in the two main canopy-forming species of the Northeast Pacific, Macrocystis tenuifolia and Nereocystis luetkeana. We leveraged whole-genome sequences of 598 individuals across 94 sites along the British Columbia and Washington coasts, together with 37 environmental variables. Both species showed genomic signatures of local adaptation, with distinct environmental drivers shaping adaptation in each species despite their co-occurrence across much of the studied area. Using gradient forests, we modelled the genetic turnover across environmental gradients and predicted populations vulnerability (genomic offset) under projected environmental conditions. Genomic offsets differed greatly among regions and were positively correlated with kelp declines observed to date, especially in Macrocystis, validating the link between genomic models and outcomes in the field and allowing us to translate genomic predictions into an ecologically meaningful metric: the risk of extirpation under global change. Our models predict that assisted migration could significantly attenuate kelps vulnerability to global change. Across environmentally heterogenous coastlines, short-distance migration can often substantially reduce future genomic-environmental mismatches, but in many cases, long-distance migration would be most beneficial. Our results highlight the potential of seascape genomics to predict vulnerability of populations to global change. Importantly, the validated link between our genomic models and ecological outcomes allows quantification of climate-driven extirpation risk and can inform conservation strategies to improve the resilience and sustainable management of these vulnerable ecosystems.

AimUnderstanding whether invasive species retain or shift their ecological niches has traditionally relied on scalar overlap metrics that quantify the magnitude of niche change, but not its structure. Here, we test whether biological invasions involve a reorganisation of the environmental axes along which native and invasive ranges are differentiated, and whether the dominant axes of this reorganisation are consistently associated with invasion pathway type (intercontinental vs. within-continent). LocationGlobal (North America, Europe, Africa, Asia, Australasia). Time periodContemporary (environmental variables representing long-term averages, 1980-2021). Major taxa studiedFreshwater crayfish (Decapoda: Astacidea): Procambarus clarkii, Faxonius limosus, Pacifastacus leniusculus, Faxonius virilis, Faxonius rusticus. MethodsWe analysed native and invasive occurrences for five globally important crayfish invaders using [~]400 hydrologically resolved environmental variables from the Global Crayfish Database of Geospatial Traits. Classification models were used to quantify environmental differentiation between native and invasive ranges, and feature contributions were aggregated by environmental domain (climate, topography, soil, land cover). Patterns were evaluated across intercontinental and within-continent invasion pathways and assessed for robustness using cross-validation, permutation tests, sample-size sensitivity, and comparisons with classical niche overlap metrics. ResultsNative and invasive occurrences were consistently distinguishable across all species (accuracy 96.5-99.9%). A pathway-dependent pattern emerged: intercontinental invaders were primarily differentiated along climatic dimensions (58-76% of model importance), whereas within-continent invaders showed a more balanced contribution of climatic and topographic variables ([~]42% each), including strong signals from river network position. This contrast was stable across cross-validation folds (SD < 1.6%), and supported by permutation tests (P = 0.001). Classical niche overlap metrics (Schoeners D = 0.30-0.62) did not capture this qualitative distinction. Main conclusionsBiological invasions involve not only changes in niche position but a reorganisation of the environmental axes that distinguish species distributions. Our results suggest that the dominant axes of this reorganisation differ systematically with invasion pathway, reflecting whether species encounter novel climatic regimes or primarily shift within existing climatic space along topographic and network-position gradients. By resolving which environmental dimensions underpin native-invasive differentiation, this approach provides a complementary perspective to scalar overlap metrics and a basis for more mechanistic interpretations of invasion processes.

Probiotics can enhance coral thermal tolerance, yet their ecosystem-level effects remain unknown. Here, we present the first long-term in-situ test of whether coral-targeted probiotics influence adjacent cryptobenthic reef communities during a record marine heatwave. Probiotics were applied to Pocillopora favosa and Acropora spp. coral colonies for 18 months, spanning the fourth global bleaching event. Cryptobenthic communities were assessed using biomimetic monitoring structures integrating biodiversity surveys, molecular profiling, microbial network analyses, and metabolic assays. Before the heatwave, probiotic and control patches were comparable across structural, microbial, and functional metrics. Following thermal stress, control patches exhibited pronounced losses of cryptobenthic invertebrate abundance and taxonomic breadth, microbial network fragmentation, and net carbonate dissolution. In contrast, probiotic-treated patches retained higher biodiversity, cohesive microbial interaction architectures, and positive calcification. These findings demonstrate that coral-targeted probiotics can scale from host-level intervention to buffer adjacent ecosystem-level responses to extreme marine heatwaves under accelerating climate change. TeaserA coral-targeted probiotic strategy enhances multi-trophic resilience under heat stress.

Extreme climatic events are reshaping ecosystems worldwide as individual organisms vary markedly in their ability to withstand these disturbances. Deciphering patterns of persistence on local scales is therefore critical for predicting biodiversity trajectories under intensifying climate extremes. In this study, we examined variation in thermal stress responses among individuals of the coral Stylophora pistillata species complex during a heatwave at Heron Island Reef, Australia. More than half of the focal coral colonies died on the reef, and survival of coral fragments maintained under ex situ common thermal stress conditions was significantly correlated with the survival of their source colony. This demonstrates that survival differences result largely from biological factors rather than differential thermal exposure across reef habitats. Under common garden conditions, we observed striking differences in bleaching severity and survival times among three sympatric cryptic taxa and their highly host-specific symbiont community. Within the most locally common taxon, corals from historically warmer and more seasonally variable reef habitats seem more susceptible to bleaching, contrary to expectations. Together, these results reveal how biological differences among cryptic taxa and among individuals can shape coral responses during a heatwave and advance our understanding of coral vulnerability in a rapidly warming world.

Arctic winters are long and cold and have traditionally been considered a period of limited biological activity. However, the seasonal dynamics of microbial community composition and functional potential during winter remain poorly understood. Here, we investigated taxonomic (bacteria, fungi, archaea) and functional (fungal guilds and nitrogen cycling genes) dynamics throughout a full year at two Arctic tundra heath sites with contrasting snow regimes. A steep drop in microbial abundances in early to mid-winter, likely linked to freeze-thaw events, coincided with shifts in soil pH and elevated community turnover. Saprotrophic and root-associated fungi were more abundant in the cold-season, while inorganic nitrogen cycling groups were more abundant in summer and declined toward winter despite high bacterial abundance. This indicates sustained organic matter cycling during the winter and expanded inorganic nitrogen cycling in the summer. Functional gene ratios further suggested a higher early-winter nitrogen loss potential via nitrous oxide and greater late-winter nitrogen retention. Site-specific differences in snow regime altered the timing and magnitude of these dynamics. Together, our results demonstrate that winter represents a critical and dynamic period for microbial community restructuring with important implications for nitrogen turnover in Arctic tundra soils.

Accurately predicting species responses to climate change requires an understanding of the drivers of their thermal limits. Despite rapid warming of freshwater ecosystems worldwide, we still lack a global perspective on how upper thermal limits (UTLs) vary among aquatic insects, what constrains these limits, and how they contribute to species vulnerability. Here, we compiled a global dataset encompassing 423 aquatic insect species to test the effects of environmental conditions, organismal traits, acclimation history, and phylogenic relationships on patterns of heat tolerance. Maximum habitat temperatures were positively correlated with UTLs supporting the Climate Extremes Hypothesis, and insects relying exclusively on dissolved oxygen had the lowest UTLs supporting the Oxygen- and Capacity-Limited Thermal Tolerance hypothesis. Functional traits also explained substantial variation in UTLs; those that feed via scraping and shredding exhibited some of the lowest UTLs. Laboratory acclimation methods further influenced UTL estimates. Short-term exposure to higher acclimation temperatures increased UTLs, but longer exposure led to decreased heat tolerance. Finally, warming tolerance, i.e., the difference between UTL and the maximum habitat temperature) varied with breathing mode. Across latitude, warming tolerances were lowest for obligate dissolved oxygen-breathers but increased more rapidly in insects that can access terrestrial air. Collectively, these patterns indicate that oxygen is a key mechanism shaping thermal vulnerability in aquatic insects.

Urbanization and human-induced environmental changes create unique and unprecedented thermal landscapes, yet the extent to which species respond to these changes remains poorly understood. One major challenge in studying these responses is the spatial mismatch between the small scale at which organisms experience their environment and the broader scale at which climate data are typically collected. We use Infrared Thermography (IRT) to quantify the fine scale microclimate in urban and rural habitats used by two tropical agamid lizards, Calotes versicolor and Psammophilus dorsalis. By combining field-based body temperatures and lab-based measures of thermal limits (CTmax, CTmin)and preferences (Tpref), we assess how the thermal heterogeneity of these fine mosaics of microhabitats influence the degree of thermoregulation (k) of these species. We find that thermal responses to urbanization are shaped by species-specific thermal traits and patterns of microhabitat use. Between the species, urban individuals did not differ markedly in habitat thermal heterogeneity, substrate temperature used or degree of thermoconformity. However, within species, P. dorsalis experiences warmer and more heterogeneous conditions in rural habitats, whereas C. versicolor experiences similar thermal conditions across habitats. Calotes versicolor also exhibits broader thermal tolerance and preferred temperature ranges than P. dorsalis. Collectively, our results suggest that P. dorsalis may be more susceptible to the thermal constraints imposed by human-modified landscapes. Overall, we demonstrate the critical need to account for microclimatic conditions and species-specific thermal traits when determining how animals respond to changes in the thermal environment expected from climate change.

Low dispersal ability might limit a species capacity to track its climate preferences across the landscape, yet evidence that low dispersal slows species range shifts under contemporary climate change remains contentious. Here we develop a new hypothesis under which we expect variation in dispersal ability to affect range expansion rates only when climate velocity exceeds dispersal rates, which is logical yet rarely applied because it requires a common yardstick to compare rates. We test this hypothesis using empirical relationships between dispersal ability, local range expansion rate, and the velocity of isotherm shifts in terrestrial plants and birds, all estimated in km/yr. In 370 range shifts, we found that range expansion rates were best explained by the slower of either a species dispersal rate or the velocity of isotherm shifts, as predicted under our hypothesis. Furthermore, when species dispersal rates were slower than the velocity of isotherm shifts, we found that dispersal ability positively affects range shift rates. Substantial variation in range expansion rates remained unexplained, indicating that additional factors influence range shift dynamics. Our results provide new clarity when understanding the role of dispersal ability on variation in range shift rates and emphasize the importance of evaluating dispersal capacity relative to climatic change exposure when testing hypotheses about species responses to ongoing environmental change. Significance StatementSpecies dispersal ability is widely thought to limit biodiversity redistribution in response to climate change, but we still lack a clear understanding of when or for which species dispersal limitations matter. Using hundreds of range expansion rates documented over the 10 last decades for terrestrial birds and plants together with their dispersal rates, in common units of km/yr, we show that dispersal ability slows climate-mediated range expansion, but that dispersal limitations occur only when the rates of climate change are faster than the ability of species to redistribute. So far, many species display dispersal rates higher than the velocity of climate change but dispersal limitations may become more pronounced in the future.

Mesophotic coral ecosystems have been proposed as climate refugia for shallow reefs, yet the capacity of mesophotic corals to persist across depth gradients remains unresolved. We conducted a long-term reciprocal transplantation of the Caribbean coral Porites astreoides between shallow (10 m) and mesophotic (40 m) reefs to assess physiological, skeletal, and transcriptomic plasticity. Depth, rather than season, was the primary driver of coral performance. Shallow colonies exhibited higher metabolic activity and calcification, whereas mesophotic colonies showed reduced protein content, slower skeletal extension, and elevated expression of skeletal organic matrix genes. Transplant responses were asymmetric: shallow-to-deep corals acclimated through coordinated physiological and transcriptional adjustments, while deep-to-shallow transplants experienced mortality and limited transcriptional reprogramming. Moderate genetic connectivity across depths suggests that performance differences arise primarily from phenotypic plasticity rather than fixed genetic divergence. Our findings indicate that shallow populations harbor greater acclimatory capacity, whereas mesophotic corals show constrained upward resilience, challenging the generality of deep reefs as refugia under rapid environmental change. TeaserAsymmetric plasticity limits the capacity of mesophotic corals to rejuvenate shallow reefs under climate change.

The yellownose skate (Dipturus chilensis) is an endangered skate with a narrow distribution in the southeastern Pacific, facing intense fishing pressure and potential climate threats. Using a species distribution model, we projected the current and future distribution of D. chilensis under contrasting climate change scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5) for mid-century (2050) and end-of-century (2100). Our models, which demonstrated robust predictive performance significantly better than random expectations, identified maximum temperature and minimum oxygen as the primary environmental drivers of habitat suitability. Projections revealed a consistent poleward range shift towards the Channels and Fjords of Southern Chile ecoregion across all scenarios. While localized habitat loss was projected in Central Chile and Araucanian ecoregions, particularly under high emissions (SSP5-8.5), these losses were outweighed by southern expansions, leading to a net increase in total suitable habitat by 2100. These findings underscore the critical need for climate-adaptive management strategies, including the protection of emerging southern refugia and dynamic fisheries regulations, to ensure the long-term persistence of D. chilensis.

Microbial communities can shift under drought in ways that enhance plant performance during drought ("microbe-mediated acclimation"). However, it is also possible for microbial communities to shift in ways that worsen the effects of drought ("mal-acclimation"). It is unclear how and where microbe-mediated acclimation vs. mal-acclimation occurs, or if there are types of soils or microbial communities that are more likely to harbor microbes that enhance plant acclimation and limit mal-acclimation. We tested for microbe-mediated plant acclimation/mal-acclimation to drought in soils from 21 maize farms in the midwestern United States, spanning a range of climate, soil types, and management practices. We first conditioned soil microbial communities to drought vs. well-watered conditions in a greenhouse and then tested for microbe-mediated acclimation by growing maize in soils inoculated with the conditioned microbial communities under drought and well-watered conditions. Drought-conditioned soils did not enhance plant performance under drought. In fact, one third of the farms exhibited mal-acclimation, especially under well-watered conditions where wet-conditioned soils reduced plant performance in well-watered contemporary conditions. Farm management practices, climate, soil texture, and microbial diversity generally did not predict when this microbe-mediated mal-acclimation occurred. Overall, these results suggest that in agricultural soils, microbes may frequently impede-rather than facilitate-plant acclimation to soil moisture levels. Open research statementThe plant and soil data used in this study are available via the Environmental Data Initiative repository at https://doi.org/10.6073/pasta/f4a0db3a076cf6d8cef908947f82736e. The bacterial and fungal amplicon sequence data are available via the European Nucleotide Archive under accessions PRJEB110071 and PRJEB109827, respectively.