ABSTRACT Aim Wildfires are the primary agents of disturbance in boreal forests. Under climate change, their frequency and size are expected to increase, raising concerns about the long‐term boreal forest resilience. Despite the importance and complexity of post‐fire recovery, large‐scale assessments of post‐fire vegetation composition remain limited for much of the boreal forest biome. Here, we characterised post‐fire vegetation across the forests of Eastern Siberia, one of the major wildfire hotspots. Location Eastern Siberia. Time Period 1990s to current time. Major Taxa Studied Boreal forests. Methods Based on historical Landsat satellite imagery, we identified 1863 wildfires in 1990–1994. We then mapped the current fractional cover of five key boreal vegetation types using regression‐based spectral unmixing of Sentinel‐2 satellite imagery. We quantified vegetation differences between burned and adjacent unburned areas, assessing the effects of burn severity, proximity to the fire edge and average annual air temperatures on post‐fire compositional changes. Results Thirty years following the fire, vegetation on more than 95% of burned area has recovered. Deciduous broadleaf forests maintained their composition even after high‐severity fires, while coniferous trees were commonly replaced by early successional broadleaf species, especially further from the fire edge and in warmer annual air temperatures. In colder mountainous areas and sites with high burn severity, shrubby and herbaceous vegetation outcompeted broadleaf trees in the recovery process. The fraction of evergreen coniferous species decreased even after low‐severity fires, whereas larch showed higher resilience; however, its recovery has been poorer in the southern parts of its range. Main Conclusions Post‐fire recovery of East Siberian boreal forests is slow and is characterised by compositional shifts. Increasing frequency and severity of wildfires may pave the way for a permanent shift from coniferous to broadleaf forests in the warmer parts of Eastern Siberia.
ABSTRACT Aim To test whether spatial trait–temperature relationships predicted by ecogeographic rules (Bergmann's rule and the thermal melanism hypothesis) can be used as space‐for‐time substitutions to anticipate temporal changes in community morphology under climate warming. Location Finland. Time Period 1993–2021. Major Taxa Studied Geometrid moths (Lepidoptera: Geometridae). Methods We analysed 29 years of standardised moth monitoring data spanning a 1200 km latitudinal gradient in Finland. For each moth community, we quantified mean wingspan and pigmentation as thermal morphological traits. We examined spatial relationships between community‐mean traits, latitude and temperature and assessed temporal trends in these traits in relation to long‐term changes in temperature. Results Across space, site‐level community‐mean trait composition over the study period showed that moth communities in colder northern regions were dominated by larger and darker species, whereas warmer southern communities comprised smaller and lighter‐coloured species, consistent with both ecogeographic rules. Through time, communities shifted towards smaller mean wingspan over the study period, consistent with the spatial expectations described by Bergmann's ecogeographic rule, while mean pigmentation exhibited no consistent directional change, contrary to expectations from the thermal melanism hypothesis. Main Conclusions Our results provide mixed support for space‐for‐time substitution in predicting climate‐driven changes in community morphology. While spatial patterns in wingspan successfully anticipated temporal shifts consistent with Bergmann's rule, spatial gradients in pigmentation did not translate into temporal change. These findings indicate that the predictive power of ecogeographic rules depends on the trait considered, and highlight both the promise and limitations of space‐for‐time approaches for forecasting climate‐driven reassembly of insect communities, particularly at high latitudes.
ABSTRACT Aim Natural disturbances are intensifying under global change, yet a global synthesis of their effects on forest structure and composition remains lacking. We aimed to assess the prevalence of structural versus compositional changes and to identify common post‐disturbance reorganisation pathways across forest biomes. Time Period 1980–2023. Location Global. Taxa Studied Forest tree species. Methods We conducted a systematic literature review of 159 studies reporting pre‐ and post‐disturbance forest structure and composition (i.e., mainly from fires, insect outbreaks and windthrow). We quantified structural and compositional changes by disturbance agent, biome, severity, study method and time since disturbance. We subsequently classified post‐disturbance trajectories into four pathways: self‐replacement, relay succession, novelty, and delayed regeneration. Results Most studies on post‐disturbance forest development focused on temperate forests and fire, with structural change being more common than compositional change. Knowledge of post‐disturbance trajectories is largely dominated by short‐term studies, revealing a critical gap in understanding long‐term post‐disturbance trajectories. Self‐replacement is common across biomes, suggesting that disturbances act as catalysts of change only under specific conditions. Relay succession is a prevalent post‐disturbance development pathway in boreal forests, delayed regeneration in temperate broadleaved and mixed forests, and post‐disturbance novelty occurs in temperate, Mediterranean and tropical regions. Main Conclusions As disturbances continue to change, the emerging novel disturbance regimes could alter prevailing reorganisation pathways. Understanding post‐disturbance forest reorganisation is thus critical for forest management and conservation in an era of global change.
ABSTRACT Aim Belowground biodiversity is key to ecosystem multifunctionality, yet the strength and taxonomic drivers of biodiversity–multifunctionality (BMF) relationships likely vary across ecosystems. Whether ecosystem type modulates these relationships, however, remains largely untested due to a lack of cross‐ecosystem evidence. Coastal ecosystems comprising mudflats, salt marshes and mangroves provide a natural gradient of aboveground plant coverage, offering an ideal opportunity to address this knowledge gap. Location Mudflats, salt marshes and mangroves along the entire coastline of China. Time Period Current. Major Taxa Studied Bacteria, fungi, protists and metazoa. Method We combined a large‐scale survey along China's coastline with a meta‐analytic synthesis of 43 datasets across six ecosystems. We quantified 17 functions underpinning four key ecosystem services: plant production, carbon storage, nutrient supply and soil organic matter decomposition, and assessed the contributions of bacteria, fungi, protists and metazoans in maintaining the functions. Using beta regression, piecewise structural equation models and multilevel meta‐regressions we examined BMF relationships both in coastal ecosystems and across six other ecosystems globally. Results Despite supporting the highest multifunctionality, mangroves exhibited relatively weak positive BMF coupling (59% of functions positively supported). In contrast, salt marshes and mudflats exhibited stronger positive relationships (75%–88% of functions). Fungal diversity was linked to the broadest range of functions, while bacterial diversity showed variable and often negative associations. Globally, we found that eukaryote‐dominated positive BMF relationships were more prevalent in ecosystems with limited vegetation cover (e.g., grasslands, drylands) than in dense forests, mirroring the patterns observed in coastal ecosystems. Main Conclusions Our findings demonstrate that the contribution of belowground biodiversity to ecosystem multifunctionality varies systematically across ecosystems, with eukaryotes dominating positive BMF relationships in coastal and multiple other ecosystems globally. This highlights the importance of conserving belowground eukaryotic diversity, especially in ecosystems with low vegetation cover, to sustain multifunctionality.
ABSTRACT Aim Extreme temperature fluctuations are becoming more frequent under climate change, altering the energy and water balance of organisms. Species from different climatic regions may differ in their metabolic responses to such temperature anomalies due to contrasting thermoregulatory adaptations. Here, we examine how short‐term temperature anomalies influence metabolic requirements of mammals across broad climatic gradients. Location Global. Time Period 1966–2007. Major Taxa Studied Mammals. Methods We compiled field metabolic rate (FMR) data from the literature, including 371 individuals representing 41 mammal species worldwide. For each measurement, we extracted monthly mean ambient temperature at the time and location of FMR collection using historical weather data and quantified temperature anomalies relative to long‐term monthly mean conditions. We modelled FMR as a function of temperature anomaly, long‐term mean temperature, and their interaction. Results Metabolic responses to temperature anomalies varied systematically across climatic regimes. Mammals from colder environments increased FMR during both negative (cold) and positive (heat) anomalies. In contrast, species from warmer environments showed increases in FMR during negative anomalies but no increase—or even decreases—in FMR during positive anomalies. Main Conclusions Mammalian metabolic responses to short‐term temperature anomalies are climate dependent, likely reflecting divergent adaptations to local thermal regimes. These findings highlight the importance of considering climatic context when predicting the energy consequences of increasing thermal extremes under climate change.
ABSTRACT Aim Marine species ranges are often large, contributing to relatively high community similarity over space, with decreased ranges expected among taxa that have lower dispersal and/or higher substrate requirements. We tested for a weakening of biogeographic structuring among dispersing abyssal taxa along the benthic to holoplanktonic habitat continuum by comparing geographic ranges and rates of community dissimilarity across the eastern North Pacific seafloor (spanning a total of 3700 km between sites). Location Abyssal Pacific Ocean, within the Clarion‐Clipperton Zone (CCZ). Time Period Present. Major Taxa Studied Benthic, benthopelagic and holoplanktonic invertebrates (18 phyla). Methods We sampled zooplankton in situ via dual pumps attached to a benthic lander and used bulk community metabarcoding (18S V1V2, 18S V7V8, mtCOI) to characterise a diverse suite of taxa and define habitat assemblages. We measured (i) minimum geographic range, (ii) distance‐decay rates and (iii) environmental structuring, with each measure grouped by habitat assemblage to test the effect of seafloor affinity in shaping biogeography. Patterns were also assessed within broad taxonomic groups to evaluate the degree of phylogenetic constraint. Results Distance‐decay rates increased with increasing affinity to the seafloor, and potential environmental drivers differed between benthic and pelagic assemblages. Unexpectedly, range size did not differ significantly by habitat occupancy and instead varied phylogenetically, with taxa that are sessile on polymetallic nodules (e.g., bryozoans, hydroids) having among the smallest observed ranges. Main Conclusions Our results indicate a significant role for habitat occupancy in shaping biogeographic community patterns in the abyss, though community dissimilarity is likely determined by habitat availability rather than by dispersal. In the context of deep‐sea biodiversity conservation planning, we demonstrate that dispersal ranges are insufficient to connect populations inhabiting impacted areas to protected areas for select taxonomic groups, indicative of potentially high extinction risk. We suggest that marine protected areas should capture a broad range of habitats and environmental variability to protect entire abyssal communities.
Aim Frugivorous birds provide crucial seed-dispersal functions in terrestrial ecosystems. However, the impact of climate change on plant-avian frugivore interactions remains unclear due to past methodological limitations. In this study, we address this by mapping these interactions across the Americas and projecting shifts in interaction diversity under future climate scenarios.Location North, South, and Central America.Time Period Present (1980-2010) and future (2070-2100).Major Taxa Studied Frugivorous birds and fleshy-fruited plants.Methods Using a trait-matching framework, we estimated interaction probabilities between frugivorous birds (n = 539 species) and fleshy-fruited plants (n = 3280 species) at the ecoregion level. To estimate climate impacts, we modeled how interaction probabilities will change under future scenarios based on the overlap between avian climate niches and ecoregion climates. From these probabilities, we calculated plant-frugivore interaction diversity as the effective number of avian partners for a given plant species in an ecoregion. We then used simulations to examine how avian dietary flexibility and dispersal may buffer future diversity of plant-frugivore interactions.Results Under future climate scenarios, our models projected a decline in interaction diversity across most ecoregions, especially in tropical and subtropical biomes. Simulations indicated that interaction rewiring through dietary flexibility and dispersal could partially mitigate losses of interaction diversity, particularly in tropical forests.Main Conclusions Our results suggest that the diversity of plant-frugivore interactions in the Americas will decline in response to climate change, potentially undermining the stability of seed-dispersal functions. We also show that the resilience of this function depends on the capacity of frugivorous birds to modify their geographic ranges or dietary preferences. However, the extent to which avian dispersal and adaptation will regulate future species interactions remains unknown, highlighting the importance of maintaining high plant-frugivore interaction diversity in current assemblages to buffer ecosystems against future climatic changes, especially in the tropics.
ABSTRACT Aim The first decade of the 21st century has marked a worsening of anthropogenic climate change which could induce a slowdown in tree growth. However, no consensus has emerged from studies published so far, as positive, negative, or no changes in long‐term tree growth in temperate and boreal forests were locally found. We conducted a meta‐analysis to reveal whether an overall change in tree growth trends has emerged in the last few decades and to determine which factors may have driven any such changes. Location Temperate and boreal forests worldwide. Time Period 1980–2009. Major Taxa Studied Angiosperm and gymnosperm tree species. Methods We performed statistical meta‐regression analyses on the growth of trees in 210 populations gleaned from 62 studies selected after a systematic review of more than 2300 published studies. We calculated effect size values at the population level to compare the slope of tree growth trends over time before and after a given year for each year between 1980 and 2009. We then statistically compared changes in growth among tree species, drought resistance classes, and the position of the species in their climatic niche. Results Estimated effect sizes were close to 0 throughout the end of the 20th century, then dropped from 2005 to 2008 and reached significant negative levels in 2008. Only drought resistance had a significant effect on the increased occurrence of negative effect size values. Main Conclusions Overall tree growth trends remained stable during the last two decades of the 20th century. However, a significant change in tree growth trends occurred during the first decade of the 21st century, with a negative trajectory. Europe most strongly displays this negative change in growth. Drought‐tolerant species were less negatively impacted.
ABSTRACT Aim Species richness of local communities may be regulated via negative diversity dependence of colonization or positive diversity dependence of extinction rate. We explore whether and how bird communities are regulated and what determines extinction and colonization rates across communities. Location North America, spanning the United States and Canada. Time Period 1995–2019. Major Taxa Studied Passerines. Methods We used long‐term community time‐series from the North American Breeding Bird Survey (BBS) to analyse spatial patterns in colonization and extinction rates across 646 survey routes. We linked these rates to community species richness, proportion of species pool represented in the local community, richness relative to resource level, mean population size and stability and environmental productivity and its seasonality (approximated by Normalized Difference Vegetation Index, NDVI). We used correlation analyses, generalized linear models, Random Forest and Structural Equation Modelling (SEM). Results Extinction and colonization rates are highly balanced across sites, supporting the idea of diversity regulation. Both rates are lower at sites with higher equilibrium species richness and especially at sites with a higher proportion of the species pool represented in the local community, supporting the diversity‐dependence of colonization rate. In contrast, we did not find any evidence for local diversity‐dependence of extinction rate. However, extinction rates increase with decreasing population sizes of species and are negatively affected by environmental productivity that influences population stability. Main Conclusions Local bird community richness appears regulated, but this regulation stems primarily from a progressive exhaustion of the number of potential colonists from a species pool as local species richness increases, not from a decreasing population size with increasing richness. Local bird diversity is then determined by the interaction of the size of the species pool with local population persistence modulated by environmental productivity. Diversity dynamics is thus essentially equilibrial, but regional and local diversity appear regulated by different mechanisms.
ABSTRACT Background Phylogenetic imputation—a method that replaces missing trait values with estimates based on evolutionary relationships—is increasingly used for handling data gaps. Although a powerful tool to leverage existing data, it is often treated as a substitute for empirical measurements. Problems and Risks A growing number of trait datasets report single‐value phylogenetic estimates, often without integrating uncertainty into the primary data products or rigorously evaluating whether the phylogenetic imputation model is informative. For many traits—especially those with weak phylogenetic signal and sparse empirical data—these estimates tend to perform no better than a trivial baseline such as the mean of the observed values. Even when phylogenetic signal is non‐negligible and overall imputation performance is acceptable, improvements at the level of individual estimates are often modest. When used uncritically, such estimates can distort ecological patterns, mislead conservation priorities, and propagate errors across a wide range of downstream applications. Guiding Principles for Imputation We propose two complementary strategies: (1) prioritising targeted empirical data collection, guided by tools such as phylogenetic ignorance maps to identify critical data gaps, and (2) adopting multiple phylogenetic imputation as a probabilistic framework that quantifies and propagates uncertainty into downstream analyses. We provide practical recommendations for implementing such an uncertainty‐aware workflow, including procedures for assessing how the expected accuracy of phylogenetic estimates varies across individual missing values. Conclusions Trait‐based science must move beyond the illusion of completeness. Reliable inference depends on clear distinctions between what is known, what is estimated, and how uncertainty influences conclusions. Without appropriate standards and transparency, imputation risks generating misleading results that may ultimately undermine the reliability of subsequent inferences.
ABSTRACT Aim To quantify the relative influence of climate, soil and land‐use on the distributions of terrestrial invertebrate species and to assess whether their importance is consistent among taxonomic/trophic groups, biogeographical regions and land‐use‐intensity gradients. Location Europe. Time Period Contemporary. Major Taxa Studied 6844 species in 13 invertebrate groups spanning decomposers (earthworms, springtails), herbivores (gastropods, grasshoppers, moths), predators (spiders, ground beetles, dragonflies), omnivores (ants), pollinators (bees, hoverflies, butterflies), and parasitoids (parasitoid wasps). Methods We aggregated > 18 million presence records to a 1‐km grid and fitted ensemble species‐distribution models with target‐group background sampling and spatial block cross‐validation. SHapley Additive exPlanations (SHAP) quantified the contribution of climatic, soil, land‐cover, and land‐use‐intensity variables to occurrence probabilities. Predictor importance, direction of effect, and land‐use‐mediated effects were compared across taxa, European biogeographical regions, and species niche characteristics. Results Climatic variables had the highest predictive importance for species distributions (mean ± SD = 44% ± 5% of weighted summed SHAP importance), followed by soil (30% ± 6%), with land cover and land‐use intensity each contributing ~13%. Although average variable hierarchies were similar among invertebrate groups, intra‐group variation was high, and the importance of soil increased with niche specialization. Limiting environmental variables shifted geographically: snow cover governed Arctic‐Alpine ranges, whereas precipitation seasonality and the number of growing degree days constrained species in the Mediterranean region. High land‐use intensity was negatively associated with species occurrence, especially in grasslands. Main Conclusions Continental‐scale invertebrate distribution patterns are mainly associated with climate and modulated by soil properties, but species‐specific niches and regional contexts generate diverse responses to land‐use change. Instead of relying on single‐taxon surrogates or uniform prescriptions, conservation strategies should better integrate soil management and habitat restoration in sensitive areas, such as the central Danube basin, and for sensitive species, such as grassland butterflies and hoverflies.
ABSTRACT Aims The latitudinal diversity gradient (LDG), a foundational pattern describing increasing biodiversity towards the Equator, has been extensively documented for aboveground organisms. However, whether this pattern holds for belowground biodiversity, the largest component of Earth's biodiversity remains unclear. Location Globe. Time Period Present. Major Taxa Studies Soil Archaea, Bacteria, Fungi, Protists, and Invertebrates. Methods We put together two data collections (amplicon and metagenomics) encompassing over 5,000 soil samples published online across multiple trophic levels, including archaea, bacteria, fungi, protists, and invertebrates. Results Our results demonstrate that multitrophic soil biodiversity deviates substantially from the classical LDG, with most taxa showing no decline in diversity with increasing latitude. We further found that local‐scale edaphic properties (e.g., soil carbon, nitrogen, and pH) and global‐scale climatic variables (e.g., rainfall and temperature), largely override latitude in explaining soil biodiversity variations. Multi‐group structural equation modelling indicated that local diversity was primarily governed by regional diversity and soil nitrogen availability, suggesting that nutrient supply mediates spatial variation in community assembly across regions. Conclusions Our findings challenge the universality of the classical LDG pattern and advance our understanding of the mechanisms shaping global soil biodiversity patterns.
ABSTRACT Aim Diet is a fundamental aspect of vertebrate life history, shaping survival, recruitment, and fitness. While spatial variation in avian dietary characteristics has been studied, seasonal dynamics at species and assemblage levels remain largely unexplored, hindering our understanding of biodiversity patterns and processes. We present the first global‐scale assessment of seasonal variation in avian dietary space and its environmental drivers. Location Global. Time Period Contemporary. Major Taxa Studied Birds. Methods We integrated seasonal species distributions for over 10,000 bird species with the SAviTraits 1.0 database, a compilation of intra‐annual variation in species‐specific dietary preferences. We summarized the avian dietary space using a Log Ratio Analysis and identified the dominant components of seasonal variation in avian dietary space using a Principal Component Analysis. To assess species contributions to the seasonality of assemblage‐level dietary space, we quantified species‐level annual variability in dietary characteristics. Finally, we examined correlations of assemblage‐level dietary variability with temperature, precipitation, and GPP seasonality as well as with predictability of seasonal changes using logistic quantile regressions. Results Strong seasonal variation in dietary space exists at both assemblage and species levels, and is most pronounced in temperate and boreal regions of the Northern Hemisphere. This seasonality arises from two key processes: (1) the seasonal redistribution of migratory species, which occupy distinct regions of dietary space, alters assemblage composition and thus dietary space, and (2) within‐species dietary shifts. We also find that temporal variation in avian diets is linked to different environmental drivers across latitudes, with temperature seasonality playing a dominant role in northern regions and precipitation seasonality being more influential in southern regions. Main Conclusions Viewing species' traits as dynamic systems provides a powerful framework to capture the temporal complexity of trait‐environment associations, understand factors shaping community structure, and advance conservation efforts.
Aim Comparison between islands and equivalent mainland areas to dissect the effect of area, isolation and species traits in determining island genetic endemicity and genetic differentiation.Location The Western Mediterranean region.Time Period Current.Major Taxa Studied Butterflies (Lepidoptera, Papilionoidea).Methods We analysed 10,367 COI sequences from 105 species, 34 islands and 47 sea straits, along with four functional species traits. We compared determinants of genetic diversity (nucleotide diversity, NucDiv), endemic mutations (EM) and the Dst fixation index between island populations and similarly sized mainland populations (Continental Area Equivalents, CAEs). Generalised linear mixed models tested fixed effects and interactions of island characteristics and species traits. We also evaluated whether population-level effects (individual species increasing differentiation with island size and isolation) or community-level effects (larger, less isolated islands hosting more genetically divergent species) better explain observed island patterns.Results CAEs and islands exhibited highly distinct genetic signatures. NucDiv was higher in CAEs while Dst was higher across sea straits than between land areas separating CAEs, particularly for larger islands and non-migratory species. EM increased with island area, especially in non-migratory and small species. Island communities were significantly nested. Widespread species also showed lower genetic variation, thus producing a strong community-level effect. The population-level effects showed a weaker effect. Counterintuitively, increasing isolation did not increase divergence, as both processes tended to reduce genetic differentiation in more isolated islands.Main Conclusions Comparing islands with CAEs reveals that even narrow sea barriers of a few kilometres greatly reduce gene flow in non-migratory butterflies, increasing genetic differentiation to a greater extent than similar mainland distances. After controlling for the presence of sea straits, island size predicts genetic divergence while increasing isolation does not. Overall, endemicity remains low, indicating that mainland-driven genetic turnover, rather than in situ evolution, dominates insular genetic patterns.
Aim The niche is a fundamental concept in theoretical and experimental ecology and is used to describe a wide range of ecological processes from species' interactions with the environment to community assemblies. A common way to represent the niche is through a multidimensional geometry known as the Hutchinsonian niche hypervolume. Ecological theory predicts that niche hypervolumes have properties such as holes with broader eco-evolutionary significance, but we lack a comprehensive empirical study of niche hypervolume properties and their evolutionary meaning.Location Global.Time Period Holocene.Major Taxa Studied Gymnosperms.Methods We conducted for the first time a systematic and comprehensive test of the evolution of Hutchinsonian climatic niche hypervolume properties (volume and holes) across 418 species, 65 genera, and 12 families of gymnosperms, which includes many species that are endangered or threatened. Using cutting-edge computational algorithms, we measured the evolution of geometric (i. e., volume) and topological (i. e., holes) properties of gymnosperm hypervolumes across a comprehensive calibrated phylogeny.Results Our comparative analysis revealed moderate evidence of the non-independent evolution of niche hypervolume and no evidence of the non-independent evolution of holey hypervolumes across gymnosperm species. We also found that species, genera and families with low hypervolume volume, such as monotypic groups like Gingko, likely experienced shifts in hypervolume evolutionary rates. However, our analysis of niche positioning showed that climatic distances between co-occurring species did not significantly depart from null expectations, suggesting that their spatial distribution within the climatic space is independent of limiting similarity.Main Conclusions Our results indicate that topological properties of gymnosperm climatic niche hypervolumes show little phylogenetic constraint and thus arise as emergent outcomes of species-environment interactions. In contrast, the breadth of environmental occupancy (hypervolume volume) retains a moderate evolutionary signal. These patterns suggest that while the capacity to occupy wider or narrower climatic conditions is moderately shared by evolutionary history, the actual realisation of these niches is not driven by significant climatic divergence.
Aim: Phylogenetic diversity (PD) and phylogenetic endemism (PE) offer biogeographical and conservation insights beyond taxonomic approaches, yet their environmental associations in freshwater ecosystems remain unclear. Using freshwater fish, we mapped PD and PE patterns, identified their environmental correlates, and compared them with taxonomic metrics (species richness [SR], weighted endemism [WE]), while assessing conservation gaps. Location: Qinghai-Tibetan Plateau (QTP) and surrounding regions. Time period: Mid-Pliocene to present. Major taxa studied: Schizothoracine fishes. Methods: We compiled species distribution and reconstructed a molecular-based phylogeny. PD, PE, SR, and WE were quantified at the subdrainage scale. Phylogenetic hotspots were categorised as 'cradles' (neo-endemism) or 'museums' (paleo-endemism). Linear mixed-effects models evaluated environmental correlates (climate, hydrology, topography, and geology). Hotspot overlap with protected areas was assessed. Results: Subdrainages exhibiting high values for both phylogenetic and taxonomic metrics were predominantly distributed along the southern margin of the QTP, particularly in the Hindu Kush-Himalaya-Hengduan mountains, yet showed substantial spatial incongruence between metrics (SR vs. PD: r = 0.67, p < 0.001; WE vs. PE: r = 0.29, p < 0.001). Both hotspot types were concentrated in these high-value subdrainages, covering 13.36% (phylogenetic) and 11.96% (taxonomic) of the study area, with limited spatial overlap (Jaccard index = 0.18). Notably, 65.89% of 'cradles' and 'museums' exhibited co-occurrence. Although most environmental factors, dominated by temperatures (annual mean and seasonality), showed generally consistent associations with both phylogenetic and taxonomic metrics, their contributions varied considerably. Conservation coverage remained inadequate for both hotspots (phylogenetic: 27.43%; taxonomic: 31.89%). Main Conclusions: We highlight substantial incongruence between phylogenetic and taxonomic diversity patterns and their environmental correlates in freshwater fishes. Our drainage-scale framework provides a template for analyzing freshwater phylogenetic diversity metrics, complementing taxonomic diversity in conservation planning, as protecting both is essential for maintaining ecosystem adaptive capacity under anthropogenic pressures.
Context: Ecogeographical rules such as Bergmann's and Allen's have long guided expectations about how organismal size and shape vary across temperature gradients. Yet these rules are typically tested independently despite sharing a common thermoregulatory basis. I synthesised recent empirical literature to evaluate how often Bergmann's and Allen's rules are analysed jointly and assess what is lost when size and shape are studied in isolation. A review of 86 studies published since 2021 reveals that less than half examine both rules together, and far fewer test for co-dependence between them. Linking Size and Shape: Isolated rule testing obscures several processes structuring thermoregulatory adaptation. These processes can generally be thought of as interactions-where temperature effects on one trait (size or shape) depend on the state of another, producing context-dependent or even inverse clines. One important class of interactions can be described broadly as trait & times; 'strength of constraint' interactions, providing a common conceptual foundation for the theories of trade-offs and complementarity. Both theories propose that stronger adherence to Bergmann's rule is linked with weaker adherence to Allen's rule, and vice versa, and that functional constraints are likely an important determinant in partitioning morphological change across size-shape axes. I argue that trade-offs are a boundary case of complementarity, rather than representing categorically different phenomena. Thermo-Morpho Framework: I propose a Thermo-Morpho framework that treats size and shape as complementary axes of thermoregulatory adaptation, explicitly linking ecogeographical rules to their shared biophysical basis. Beyond Morphology: These same principles extend to physiology, coloration, phenology, and behaviour, which frequently interact with morphology to shape thermoregulation. Focusing narrowly on single traits risks mischaracterising adaptive pathways and underestimating organismal flexibility under climate change. Conclusion: We must move beyond single-rule analyses toward integrative tests of organismal response to climatic warming.
Background: Ecological niches are commonly treated as species-level properties, assuming uniform responses to environmental and biotic gradients. However, empirical evidence increasingly shows that ecological differentiation often arises within species, as populations experience distinct environmental regimes, biotic interactions and evolutionary histories. These patterns highlight the need for a framework that captures how niche attributes emerge across levels of biological organization. Conceptual Framework: We develop a hierarchical framework for the Hutchinsonian niche in which ecological structure becomes most coherent at the population level, where local selection, demography and ecological interactions intersect. Within this framework, niche attributes such as position, breadth and functional organization arise from population-level processes and integrate non-additively into species-level niche envelopes, while remaining fully compatible with classical theory. Empirical Synthesis: Evidence from diverse taxa and ecosystems demonstrates consistent divergence among populations in climatic tolerances, resource use and functional traits. These divergences reflect localized ecological filtering, dispersal constraints and adaptive differentiation, and are supported by genetic, isotopic and trait-based studies. Together, these findings indicate that population-level structure is a pervasive component of ecological niches. Implications: A hierarchical niche framework improves the mechanistic basis for ecological modelling, biogeographic inference and conservation. Extending the classical Biotic-Abiotic-Mobility (BAM) framework to its population-structured formulation (BAMp) enables characterization of population-specific abiotic, biotic and mobility components. We outline operational approaches-including spatial stratification, hierarchical modelling and integration of functional and movement data-to incorporate population-level structure into ecological analyses. Conclusion: By making explicit the hierarchical organization through which ecological structure emerges, this framework provides a more biologically grounded basis for interpreting ecological niches and species' environmental responses under environmental change, and enables the identification of ecologically meaningful units for conservation.
Background: Many studies have tried to estimate the number of undescribed species based on the known diversity. These estimates often rely on extrapolation based on data from a limited number of species. Although statistical methods provide accurate inference when generalizing from a random sample, their predictions will be biased when based on a non-random sample unless the sampling process is explicitly accounted for. Problem: In this paper, we argue that this is a fundamental issue in many estimates of unrecorded biodiversity. We show that the sample of species used in biodiversity extrapolation represents disproportionately common and abundant taxa, which leads to an overestimation of extrapolated diversity. We discuss this issue in the context of three specific cases: estimates of plant-associated insect diversity, estimates of parasite diversity and estimates of cryptic species diversity.
Aim: Anthropogenic pollution is a pervasive driver of global change, yet its ecological impacts on wild plants remain relatively less synthesised, particularly for their regeneration. Quantifying how pollution, such as heavy metals, threatens seed-to-seedling transitions in wild plants is essential for understanding species persistence, community resilience, and vegetation dynamics under accelerating environmental pressures. However, the quantitative impacts of pollution on wild plant regeneration remain poorly understood at a broad scale. Location: Global. Time Period: 1990 to 2024. Major Taxa Studied: Wild plants. Methods: We conduct a global meta-analysis of 4476 experiments from 107 publications to quantify the effects of pollution on the earliest life stages of 162 wild plant species. Results: Pollution significantly inhibits wild plant seed-based regeneration by an average of one-third. Specifically, pollution reduces seed germination by 33%, prolongs germination speed by 29%, and suppresses seedling growth by 42%. Pollution also disproportionately suppresses below-ground growth of seedlings, altering root-to-shoot biomass allocation by 27%. While these inhibitory impacts are qualitatively consistent across species and pollutant types, pollutant type and concentration are more important quantitative predictors of these impacts than plant characteristics such as growth form and seed mass. Heavy metals exhibit a dual, concentration-dependent effect, with low concentrations (< 0.05 mg/L on average) facilitating regeneration and high concentrations severely impairing it. Main Conclusions: These findings suggest pollution acts as a powerful "regeneration filter", favouring pollution-tolerant, often invasive, "winner" species over sensitive native "losers", thereby reshaping community assembly and exacerbating biotic homogenisation. By quantifying this severe ecological bottleneck, our study provides quantitative evidence that pollution poses a pervasive threat to biodiversity, with impacts on a critical life stage rivalling other major drivers of global change. These findings underscore the urgent need to integrate pollution mitigation into conservation frameworks like the Kunming-Montreal Global Biodiversity Framework to safeguard ecosystem function and resilience.
