Latitudinal Patterns Research Articles

Macroscale spatiotemporal variability of Beryllium-7 and Lead-212 in surface air driven by meteorological factors.

Abstract Vegetation greening, primarily driven by climate change and land management, has been widely reported globally, with China experiencing one of the most pronounced instances of greening in recent decades. Current studies have mainly focused on the temperature effects of changes in land cover types; however, the impacts of vegetation self‐greening, characterized by natural physiological processes such as aging and canopy structure development, on land surface temperature (LST) remain unclear. Here, we employed a space‐for‐time approach to quantify the biophysical effects of vegetation greening on LST (i.e., ΔLST) across China from 2000 to 2018 using multi‐year satellite observations. We found that vegetation greening caused significant daytime cooling (−0.36 K), surpassing that of nighttime (−0.07 K) over the study period. Spatially, pronounced cooling dominated lower latitudes, contrasting with slight warming in mid‐to‐high latitudes, with this warming phenomenon being more evident at nighttime. The latitudinal transition of LST from cooling to warming occurred at around 47°N for daytime, nighttime, and daily mean values. This latitudinal pattern was season‐dependent, shifting to its northernmost extent in summer and southward to around 40°N in winter. Data‐driven methods revealed that albedo decreased by −0.0035 ± 0.009 in total, contributing to warming in Northeastern China, while evapotranspiration (ET) increased by 37.3 ± 33.9 mm across China, driving cooling in other regions. Our findings highlight the importance of vegetation greening in shaping local climate and advance understanding of vegetation feedback on climate, providing valuable insights for developing targeted land management strategies.

Climate has shaped green leaf nitrogen (N) and phosphorus (P) patterns through its direct physiological effects (Temperature–Plant Physiology hypothesis), indirect pathways involving soil nutrients (Soil Substrate Age hypothesis), or vegetation composition (Species Composition hypothesis). However, the efficiencies of these hypotheses and the relative importance of the factors involved in predicting leaf litter N and P remain unresolved. We evaluated these hypotheses by analyzing 4657 global observations of leaf litter N and P concentrations and N/P ratios, demonstrating that litter stoichiometries diverged in plant functional types, and that litter N and N/P ratios declined with latitude, while P increased. The validity of each hypothesis in predicting latitudinal patterns of leaf litter P was confirmed, with the Species Composition hypothesis being the most effective model; however, all hypotheses failed to predict the litter N. Environmental and biological factors collectively explained over 40% of the variations in litter stoichiometries, with plant functional type, soil pH, and climatic factors being the most important drivers of litter N, P, and N/P ratio, respectively. The fundamentally different control mechanisms of litter stoichiometry patterns compared with those of green leaves challenge the idea that common hypotheses can predict biogeographic patterns across all leaf stages; thus, current litter element biogeochemical models and plant nutrition paradigms require revision.

Eukaryotic microalgae are key organisms in marine environments, contributing to essential nutrient and biogeochemical cycles. Climate change is already causing shifts in the composition and diversity of microalgal assemblages, with coastal ecosystems experiencing increased pressure. Molecular techniques, such as environmental DNA (eDNA) metabarcoding, have allowed eukaryotic microalgal communities (EMCs) to be characterised more rapidly than traditional methods, addressing some data gaps. Many geographic regions still lack comprehensive baseline assessments of entire EMCs, often focusing on specific taxonomic or functional groups. In this study, we used eDNA metabarcoding of the 18S V9 gene region to characterise EMCs across a latitudinal gradient spanning five ecoregions from the South Pacific to the Ross Sea. Temperate sites had the highest alpha diversity and the most distinct EMCs across all ecoregions. Community composition showed clear latitudinal gradients, with a shift from dinoflagellate-dominant EMCs at lower latitudes to diatom-dominant EMCs at higher latitudes. The formation of EMCs was influenced by similar habitats/conditions (homogeneous selection) and proximity (homogenising dispersal) within ecoregions, while variable conditions (variable selection) and limited interconnectivity (dispersal limitation) were more prevalent between ecoregions. This snapshot of coastal EMC diversity across five ecoregions highlights distinct latitudinal patterns in community composition, with temperate regions showing higher diversity compared to polar areas. These findings provide a useful baseline for future monitoring and can help guide assessments of potential changes in microalgal communities due to climate change.

Intraspecific trait variation (ITV) drives plant species performance in natural communities and can have substantial influences on multiple ecological processes. However, current studies on plant belowground (root) ITV are limited in trait coverage, spatial scale and biome type. Here, by conducting in-situ measurements of root traits in three forests from temperate to subtropics and compiling a large-scale dataset of root traits, we explore the latitudinal pattern of root ITV among species within natural plant community, its drivers and implications. Our results show that intraspecific variation constitute a substantial component of the total variation in root traits, and the physiological trait, root exudation, exhibit the highest ITV among traits. The extent of root ITV tends to increase with root diameter across species, with thick-root species having higher root ITV than thin-root species. We also find a significant latitudinal gradient for species' intraspecific root trait variation in natural communities, with increasing ITV towards the equator. These findings can simplify the incorporation of root ITV in trait-based ecology, and contribute to understanding of plant species performance and community assembly under environmental changes.

Abstract Many plants are responding to increases in spring temperatures by advancing their leaf‐out and flowering times in temperate regions around the world. The magnitudes of species' sensitivities to temperature vary widely, and patterns within that variation can illuminate underlying phenological drivers related to species' life histories and local‐scale adaptations. The USA National Phenology Network (USA‐NPN) and the National Ecological Observatory Network (NEON) are two rapidly growing, taxonomically and geographically extensive phenology data resources in the USA that offer opportunities to explore emergent properties of spring phenology. Using observations of leaf‐out and flowering in temperate deciduous plant species from USA‐NPN (2009–2024) and NEON (2014–2022), we estimated species‐level flowering (n = 164) and leaf‐out (n = 136) sensitivities to temperatures of the preceding months, obtained through PRISM. We used the results to assess differences in sensitivities between the two datasets and among life history traits (e.g. introduced or native status, seasonal timing and growth habit) and to explore latitudinal patterns in sensitivity among and within species. We found significant relationships between temperature and leaf‐out phenology (2009–2024 for 109 (80%) species, ranging from −7.4 to −1.3 days/°C, and between temperature and flowering phenology for 140 (85%) species, ranging from −8.0 to −1.1 days/°C. Plant sensitivities were highly consistent among the USA‐NPN and NEON datasets, suggesting these datasets can be reasonably combined to expand the coverage of publicly available phenological data across the USA. Introduced species showed stronger sensitivity to temperature than native species for both leaf‐out (−0.8 days/°C difference) and flowering (−0.7 days/°C difference). The strongest (i.e. most negative) leaf‐out sensitivities to temperature were associated with earlier leaf‐out dates and strong flowering sensitivities. Latitudinal analyses within and across species indicate that flowering and leaf‐out sensitivities are both stronger at lower latitudes. Synthesis. Phenological ‘big data’ encompassing over 100 species across the eastern USA shows that leaf‐out and flowering occur earlier with warmer temperatures and that native species and individuals at high latitudes tend to have weaker temperature sensitivities than introduced species and more southern plants; these findings suggest adaptations within and across species to avoid leafing out and flowering under harsh environmental conditions.

ABSTRACTArgentina has a complex and diverse landscape of honeybee (Apis mellifera sp.) populations shaped by historic introductions and hybridization between Africanized (AHB) and European (EHB) lineages. While a latitudinal cline of Africanization has been documented, the adaptive consequences of this genetic admixture and its implications for local beekeeping practices remain poorly understood. In this study, we provide a more in‐depth analysis of Argentine honeybee populations using recently published data from a panel of 272 SNP markers across five ecoregions to: (1) quantify how ancestry proportion (African A, European C/M) varies along geographic gradients, (2) assess whether ecoregion boundaries influence population structure, and (3) evaluate the potential trade‐offs between AHB and EHB ancestry in hybrid genomes. Our results confirm a strong latitudinal pattern of Africanization but reveal novel complexity, with C‐lineage ancestry inversely correlated with A‐lineage contributions while M‐lineage ancestry remains independent. We also detected trace contributions from the O lineage (Middle Eastern), highlighting Argentina's complex admixture history. Despite Argentina's diverse ecoregions, we find limited evidence for ecotype‐specific differentiation, suggesting gene flow may outweigh local adaptation—though sampling limitations warrant caution. By linking genetic patterns to apicultural relevance (e.g., AHB's northward expansion and hybridization zones), this study provides a framework for conserving genetic diversity and managing hive productivity across environmental gradients. Further genome‐wide analyses are needed to disentangle adaptive traits in this understudied yet economically critical pollinator system.

The accurate assessment and management of Blue Mackerel (Scomber australasicus) and Chub Mackerel (Scomber japonicus) resources in the high seas of the Northwest Pacific are constrained by the persistent issue of data misreporting in catch records, which arises from their high morphological similarity. This study integrates fishery logbooks and field sampling data from Chinese purse seine fleets (2014-2023), along with key oceanographic factors-six of which were finally selected after correlation analysis. We introduce, for the first time, a Zero-One Inflated Beta Model (ZOIBM) to analyze the spatiotemporal distribution of the relative abundance of these two mackerel species. Furthermore, a Generalized Additive Model (GAM) was employed to reveal the environmental mechanisms driving their niche differentiation. The results show that the ZOIBM demonstrates excellent performance (R2 = 0.63, RMSE = 0.305), effectively quantifying the proportional composition of the two species in mixed catches. Spatially, high-abundance areas of Blue Mackerel were concentrated within 35-44° N, 145-160° E, with its proportion decreasing at higher latitudes. In contrast, Chub Mackerel exhibited an opposite latitudinal pattern, with its high-abundance areas covering a broader latitudinal range (35-47.5° N). The analysis of environmental drivers indicated that SST was the most critical factor for differentiation, while Chla and VO further amplified the divergence in resource utilization strategies between the species. From 2014 to 2023, the distribution centroids of both mackerel species showed significant northward and eastward shifts, and their spatial overlap has been continuously increasing. This research provides a methodological reference for the fine-scale assessment of co-occurring fish resources and offers a scientific basis for the sustainable management of the North Pacific mackerel fishery.

ABSTRACT This study investigates the latitudinal patterns of species richness in tropical forests of Togo, focusing on the roles of species abundance distribution (SAD), total abundance (N) and spatial aggregation (AGG). By analysing biodiversity metrics along a latitudinal gradient, we aim to elucidate the key factors influencing species diversity in this region. Our findings reveal distinct differences between tree and herbaceous species, with tree species exhibiting a positive correlation between richness and total abundance, while herbaceous species show a negative relationship, indicating higher sensitivity to sampling effort. The study highlights the importance of SAD and AGG in shaping biodiversity patterns, with tree species benefiting from a more balanced abundance distribution compared to herbaceous species. Additionally, the research underscores the need for a comprehensive understanding of biodiversity dynamics, considering both ecological and anthropogenic influences. Despite limitations related to geographical scope and sampling methodologies, this study contributes valuable insights into the mechanisms driving biodiversity in tropical ecosystems. The results have significant implications for conservation strategies, emphasising the necessity of preserving diverse habitats to maintain ecological balance and resilience in the face of climate change and human impacts.

The latitudinal variations in sedimentary molecular markers reveal broad-scale spatial patterns in organic matter sources and anthropogenic pressure across Norwegian fjords, NE Atlantic.

The return of natural lead to the Northeast Atlantic Ocean captured by brown algae.

Exposure characteristics and health risk differences of airborne viable microorganisms across different climate zones: Insights from eight typical cities in China.

ABSTRACTAimSilicon (Si) enhances plants' resistance to environmental stress. Forests absorb much more Si than other vegetation types, making it crucial to comprehend the factors influencing Si concentration in woody plants for studying global terrestrial Si cycling, especially under significant environmental changes. Here, we analyze the latitudinal pattern of leaf Si concentration in woody plants and identify its main environmental drivers.LocationWorldwide; covering six continents except Antarctica.Time Period1945–2023.Major Taxa StudiedTerrestrial woody plants.MethodsWe compiled a dataset of leaf Si concentration for wild terrestrial woody plants and analysed the latitudinal patterns of leaf Si concentration and their environmental drivers.ResultsWe revealed a significant unimodal latitudinal pattern of leaf Si concentration in woody plants, peaking in subtropical high‐pressure regions. Solar radiation and water stress are the main environmental drivers of this pattern. Additionally, different plant functional groups with distinct concentrations but similar latitudinal trends of leaf Si, together with their latitudinal distribution shifts, intensify this pattern.Main ConclusionsHigh leaf Si concentration is an important adaptive strategy for woody plants to mitigate the adverse effects of intense solar radiation and water stress in subtropical high‐pressure regions. The biogeography of leaf Si in woody plants revealed here provides insight into the macro‐evolution of Si in plant stress resistance and highlights its important role in sustaining forest productivity under global climate change.

Latitudinal patterns in fitness-related traits within species are receiving increased attention as these inform how high-latitude populations may evolve in response to global warming. The underlying mechanisms for these latitudinal trait patterns remain poorly understood, and recently the gut microbiome has been suggested to be a potentially important proximate driver of these patterns. We investigated the novel idea of whether the gut microbiome drives latitudinal differences in immune function and pathogen load. To test this idea, we performed a reciprocal gut microbiome transplant between slow-paced, high-latitude (southern Sweden) and fast-paced, low-latitude (southern France) populations of Ischnura elegans damselflies. The transplants were conducted in the laboratory between high- and low-latitude larvae, at both a colder and warmer thermal regime, whereafter larvae were exposed to Escherichia coli, a widespread pathogenic bacterium in aquatic ecosystems. During the experiment, larval mortality, growth rate, phenoloxidase (PO) level (a measure of immune function), E. coli burden (a measure of pathogen load) and the gut microbiome diversity (α-diversity) and community compositions (β-diversity) were analysed. Exposure to the pathogen increased mortality, especially under warming. Our results confirmed latitude-associated thermal adaptation and a faster pace of life of the low-latitude larvae, which was associated with a lower immune function (lower activity of PO), consistent with previous findings and now showed this to be linked to a higher pathogen load (higher E. coli body burden). Moreover, our results provided the first experimental evidence that the gut microbiome causally contributed to latitudinal differences in the host's immune function and pathogen load. As latitudinal patterns in the microbiome are widespread, this may be an important yet ignored proximate driver of the latitudinal patterns in immune function and pathogen load.

This study examines the production of polyunsaturated fatty acids (PUFAs) and carotenoids in Labyrinthulomycetes isolated along a thermal gradient on the Chilean coast. Phylogenetic analysis revealed clades corresponding to Oblongichytrium, Schizochytrium, and Thraustochytrium aggregatum. Strains of Oblongichytrium sp. from colder, higher pH sites (9°C, pH 8.64) produced up to 34 times more DHA in laboratory conditions than those from warmer, lower pH areas (13°C, pH 7.30), suggesting an influence of native environmental conditions on biosynthetic capacity. In contrast, DHA production by Schizochytrium sp. and T. aggregatum was limited to specific isolates, without a clear latitudinal pattern. Polyunsaturated fatty acids were detected in all strains, although no relationship with environmental variables was found. All strains produced astaxanthin, while β-carotene was detected in some, with no consistent pattern; canthaxanthin was absent. The results highlight the high biotechnological potential of Oblongichytrium strains from colder, alkaline coastal environments, emphasizing the importance of exploring diverse natural habitats for organisms with valuable lipid production profiles. This study supports the value of targeted bioprospecting to identify strains with promising applications in lipid-based industries.

Observed richness has long been the basis for studies of species distribution patterns and community ecology, but dark diversity (i.e. the group of species in the regional pool that can live under the specific local environmental conditions but which are not part of the local species richness) has recently gained prominence for providing complementary ecological information. In this study we aim to determine the role of latitude on shaping ant dark diversity in Europe, with special attention to the effects of elevation and biotic pressure. We computed dark diversity from observed and expected richness in 415 ant communities distributed through Europe. We found that ant dark diversity in Europe shows a negative latitudinal pattern (with greater values where there are more favourable environmental conditions), and this trend is more pronounced at higher elevations. Moreover, dark diversity increases more strongly with decreasing latitude than observed richness, suggesting the existence of a larger species reservoir at southern latitudes. Our results also show that dark diversity tends to increase with biotic pressure (i.e. abundance of dominant species). This suggests an effect of behaviourally dominant ants in structuring ant communities, an effect that is hardly detected in classical studies of ant community structure. Despite the fact that different mechanisms might shape the latitudinal pattern of dark diversity, our results suggest that in southern latitudes the important role of interspecific competition is prominent, while in northern latitudes the environmental filter is more important. At the local level, biotic pressure tends to increase dark diversity, although small‐scale species dispersal limitation and habitat quality may also play important roles. The analysis of dark diversity patterns in ants allowed us to better understand the mechanisms that shape ant diversity, which might not be detectable only by analyzing observed richness.

Biogeography has traditionally relied on species-based measures of biodiversity, partially reflecting the processes shaping spatial patterns. Incorporating the evolutionary relationships among taxa can provide a greater understanding of how distinct processes define different regional patterns over time. Here, we describe the biogeography of marine ray-finned fishes (Actinopterygii) in Aotearoa New Zealand and adjacent areas of the Southwest Pacific using phylogenetic measures of richness and endemism. Defining a geographic area of 30° latitude by 20° longitude that encompasses New Zealand’s main and offshore islands, we compiled distributional maps for 313 taxa occurring in 0–500 m waters using AquaMaps, a web-based tool that generates occurrence probability maps based on environmental and occurrence data. We describe spatial patterns of biodiversity with species and phylogenetic metrics of richness and endemism, including phylogenetic diversity and phylogenetic endemism, using a comprehensive molecular phylogeny of New Zealand’s marine fishes. To identify endemism centres, we employ the “categorical analysis of neo- and paleoendemism” (CANAPE) method which distinguishes locations with an over-representation of spatially rare short phylogenetic branches (neoendemism) and spatially rare long phylogenetic branches (paleoendemism). Latitudinal patterns of richness and endemism differ, with richness peaking at 35°S along the North Island, while endemism reaches maximum values in the northernmost oceanic islands where neoendemism dominates. Significant paleoendemism clusters around two coastal areas of mainland New Zealand. Our study shows that richness and endemism hotspots are geographically distinct for New Zealand’s marine fishes, likely the result of distinct acting processes. The richness maximum appears to be the result of a range overlap between distantly related tropical taxa shifting towards high latitudes and a lower number of older temperate taxa. Neoendemism is likely driven by the isolation of young volcanic islands, and coastal paleoendemism might be the legacy of locally stable environmental conditions that served as a refuge for relict lineages over time. We identify areas where evolutionary processes have left a signal unnoticed by species richness alone. Northern subtropical marine fish assemblages are composed of a heterogeneous mixture of distantly related taxa. Southern temperate and subantarctic areas are characterized by the presence of a low number of old lineages as well as the absence of extremely young and old taxa. We generate a phylogenetic landscape from which future biogeographic research can test hypotheses to unveil underlying evolutionary and ecological processes.

Benthic foraminifera play crucial roles in marine ecosystems and serve as valuable bioindicators of ecological conditions and environmental changes. Despite their importance, comprehensive basin-wide assessments of their diversity patterns remain scarce, particularly in complex environments like the Arabian Gulf. This study reveals the variation of benthic foraminiferal diversity within the gulf and provides insights into its distribution patterns and relationships with environmental gradients. We compiled a comprehensive dataset of benthic foraminiferal occurrences from published literature and public databases, encompassing more than 492 species from nine orders, 39 superfamilies, 89 families, and 150 genera. Using an ensemble of species distribution models, we modelled the spatial patterns of individual species and stack these predictions to estimate foraminiferal species richness across the basin. We documented a pronounced north-south diversity gradient that differs from typical latitudinal patterns observed in larger marine systems. Our methodological framework identifies bathymetry and dissolved oxygen as primary drivers of foraminiferal distributions when averaged across all species, with significant influence from iron concentration and salinity. However, individual species showed diverse environmental responses, with variables of lower mean importance often exerting primary control on specific taxa, highlighting the ecological specialization that enables such high diversity in this extreme environment. The east-west diversity gradient reveals the impact of basin-scale circulation patterns on foraminiferal assemblage composition, a phenomenon relevant to other semi-enclosed seas worldwide. The models show high performance (mean AUC > 0.94, TSS > 0.8, Kappa > 0.82), demonstrating the potential of this approach in capturing complex species-environment relationships. Additionally, model predictions align well with known foraminiferal distributions and diversity patterns reported in previous studies across the gulf. This study provides the first basin-wide assessment of benthic foraminiferal diversity in the Arabian Gulf, revealing complex spatial patterns and environmental relationships. Most significantly, our delineation of species-specific ecological niches provides a valuable framework for forecasting foraminiferal responses to climate-driven environmental changes, particularly thermal stress, which our models identify as more influential in its extreme rather than mean values.

ABSTRACTThe latitudinal diversity gradient (LDG) is one of the general ecological patterns and has been extensively studied in plant and microbial communities. However, whether plant–microbe networks follow latitudinal trends and the underlying mechanisms driving such patterns remain largely unknown. In this study, we used an ecological survey dataset with simultaneously investigated plant species and microbial data from 26 forests at a continental scale and constructed the plant–microbe networks for each forest across the latitude gradients. We observed clear latitudinal patterns in plant–microbe networks, consistent with the LDG. Specifically, both the richness of networked species and the nestedness of the network architecture declined from tropical to temperate forests. Moreover, the plant‐level network robustness decreased with increasing latitude, and positive biodiversity‐robustness relationships were observed for plants and microbes. Mean annual temperature (MAT) was the most important factor for the observed latitudinal patterns, especially for plant–microbe network stability, evidenced by the robustness index. Additionally, MAT had a stronger effect on plant robustness than soil pH, primarily through its influence on plant diversity. Overall, this study demonstrated the latitudinal distribution patterns of the plant–microbe networks in natural forests and highlighted the positive relationship between biodiversity and robustness through plant–microbe interaction processes.

Latitudinal patterns of microplastic contamination in remote areas.