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Simple Summary: Northwest China is characterized by unique geological and historical dynamics and endemic biota, but the joint influence of geography and past climate changes on the evolutionary history of endemic animals is poorly understood. We used two mtDNA genes (ND4 and Cytb) and ecological niche modeling (ENM) to explore how the Quaternary climatic fluctuations and complex geography in Northwest China have shaped genetic diversity, genetic structure, and demographic history of the Alashan pit viper (Gloydius cognatus). Our results clearly show that the lineage diversification of G. cognatus is related to the expansions of deserts and/or the early Pleistocene integration of the Yellow River. The strong spatial genetic structure fits an isolation-by-distance model. The signature of demographic and range contractions during the last glacial maximum (LGM) is rejected by both mitochondrial evidence and ENM. In addition, the suitable habitat of G. cognatus is predicted to be decreased in the future, suggesting that conservation and management of evolutionary significant units (ESUs) should be a priority. Our findings provide the first insights on the evolutionary history of G. cognatus in arid Northwest China and adjacent areas throughout the Quaternary. The joint impacts of historical geological events and Quaternary climatic oscillations in Northwest China on species evolution have been examined extensively in plant under a phylogeographic perspective. However, animal phylogeographic analyses in this region are still limited. The Alashan pit viper, Gloydius cognatus, occurs primarily in arid Northwest China and adjacent areas. Based on variation at two mtDNA genes (ND4 and Cytb) in 27 individuals representing 24 populations, the spatial genetic structure and demographic history of G. cognatus were examined across its geographic range. Phylogenetic analyses revealed two well-supported allopatric clades (each with two distinct subclades/lineages), distributed across the southern (Qaidam Basin, Lanzhou Basin, and Zoige Basin [S1]; Loess Plateau [S2]) and northern (Ily Basin [N1]; Junggar Basin and Mongolian Plateau [N2]) regions. AMOVA analysis demonstrated that over 76% of the observed genetic variation was related to these lineage splits, indicating substantial genetic differentiation among the four lineages. A strong pattern of isolation-by-distance across the sampling populations suggested that geographic distance principally shaped the genetic structure. The four lineages diverged by 0.9–2.2% for the concatenated data, which were estimated to have coalesced ~1.17 million years ago (Mya), suggesting that the expansions of the Badain Jaran, Tengger, and Mu Us deserts during the Xixiabangma glaciation likely interrupted gene flow and triggered the observed divergence in the southern and northern regions. Subsequently, the early Pleistocene integration of the Yellow River and associated deserts expansion promoted the differentiation of S1 and S2 lineages (~0.9 Mya). Both mitochondrial evidence and ecological niche modeling (ENM) reject the signature of demographic and range contractions during the LGM for G. cognatus. In addition, ENM predicts that the suitable habitat of G. cognatus will contract in the future. As such, the conservation and management of ESUs should be a priority. Our findings provide the first insights on the lineage diversification and population dynamics of the Alashan pit viper in relation to geological history and Pleistocene climatic oscillations in arid Northwest China. [ABSTRACT FROM AUTHOR]

Aim: Pollination is an essential stage of angiosperm reproduction, and the mode of pollination plays a major role in driving evolutionary and ecological responses of plants to environmental changes. However, the effects of climate, evolutionary history and floral traits (i.e. plant sexual systems) on pollination mode variation remain unclear. Here, we explored the biogeographic patterns in pollination mode frequency and tested the hypothesis that insect pollination prevails in warm humid regions with old floras due to high pollinator dependence, whereas wind pollination is more frequent in arid regions with younger floras and is more strongly associated with dioecy. Location: China. Time period: Since the Last Glacial Maximum. Major taxa studied: Angiosperms. Methods: Using data on pollination modes and geographic ranges of 29,719 angiosperm species in China, we mapped the biogeographic pattern of pollination mode frequency. Phylogenetic logistic regressions and generalized linear mixed models were employed to evaluate the relative importance of climate, evolutionary history (represented by phylogenetic conservatism and grid‐level mean genus age) and sexual systems on variations in pollination modes across species and space. Results: Evolutionary history was the strongest correlate of pollination mode variation across species and space. The proportion of insect‐pollinated species was higher in humid regions with old floras, but lower in arid regions with young floras. Evolutionary history and temperature dominated variations in pollination mode frequency in humid areas, while precipitation dominated in arid areas. Climate influenced geographic pattern in pollination mode frequency both directly and indirectly via its effects on species richness and plant sexual systems. Main Conclusions: Our results showed that geographic pattern in angiosperm pollination mode frequency is dominated by evolutionary history followed by climate, which extended previous findings of climate‐driven mechanisms. Our findings demonstrate the importance to incorporate evolutionary history in understanding the mechanisms underlying the functional biogeography of plant traits. [ABSTRACT FROM AUTHOR]

In order to clarify the migration route and the source of white-backed planthopper (WBPH) (Sogatella furcifera) between Myanmar and Yunnan Province, China, we collected six populations throughout Myanmar and five populations around the border areas in Yunnan Province, China. A total of 790 base pairs in the mtDNA COI genes from 416 individuals were obtained. A total of 43 haplotypes were identified, among which 37 were unique haplotypes, and the remaining 6 were shared among different populations. Two common shared haplotypes (H_1 and H_2) had a widespread distribution in all populations and accounted for 88.8% of the total haplotype frequency, suggesting a high-level gene flow among the Myanmar and Yunnan populations. Bayesian skyline plot (BSP) analysis results indicated that the effective population size of WBPH expanded between about 10,000 and 7000 years ago, and S. furcifera might follow the post-LGM (Last Glacial Maximum) expansion pattern. Based on the total migrant (Nem) value, it can be deduced that north and northeast Myanmar were the primary migration sources for WBPH populations in the southwest and south Yunnan regions. This study aims to contribute to the sustainable regional management of this important rice pest and provide new insights into the genetic diversity of WBPH in Southeast Asia. [ABSTRACT FROM AUTHOR]

The prevailing paradigm about the Quaternary ecological and evolutionary history of Central European ecosystems is that they were repeatedly impoverished by regional extinctions of most species during the glacial periods, followed by massive recolonizations from southern and eastern refugia during interglacial periods. Recent literature partially contradicts this view and provides evidence to re‐evaluate this Postglacial Recolonization Hypothesis and develop an alternative one. We examined the long‐term history of the flora of the Carpathian (Pannonian) Basin by synthesising recent advances in ecological, phylogeographical, palaeoecological and palaeoclimatological research, and analysing the cold tolerance of the native flora of a test area (Hungary, the central part of the Carpathian Basin). We found that (1) many species have likely occurred there continuously since before the Last Glacial Maximum (LGM); (2) most of the present‐day native flora (1404 species, about 80%) can occur in climates as cold as or colder than the LGM (mean annual temperature ≤+3.5°C); and (3) grasslands and forests can be species‐rich under an LGM‐like cold climate. These arguments support an alternative hypothesis, which we call the Flora Continuity Hypothesis. It states that long‐term continuity of much of the flora in the Carpathian Basin is more plausible than regional extinctions during the LGM followed by massive postglacial recolonizations. The long‐term continuity of the region's flora may have fundamental implications not only for understanding local biogeography and ecology (e.g. the temporal scale of processes), but also for conservation strategies focusing on protecting ancient species‐rich ecosystems and local gene pools. [ABSTRACT FROM AUTHOR]

Premise: Phylogeographical studies are fundamental for understanding factors that influence the spatial distribution of genetic lineages within species. Population expansions and contractions, distribution shifts, and climate changes are among the most important factors shaping the genetic compositions of populations. Methods: We investigated the phylogeography of an endemic oak, Quercus mexicana (Fagaceae), which has a restricted distribution in northeastern Mexico along the Sierra Madre Oriental and adjacent areas. Nuclear and chloroplast DNA microsatellite markers were used to describe the genetic diversity and structure of 39 populations of Q. mexicana along its entire distribution area. We tested whether population expansion or contraction events influenced the genetic diversity and structure of the species. We also modeled the historical distributional range of Q. mexicana (for the Mid Holocene, the Last Glacial Maximum, and the Last Interglacial) to estimate the extent to which climate fluctuations have impacted the distribution of this oak species. Results: Our results revealed high genetic diversity and low genetic structure in Q. mexicana populations. Ecological niche models suggested historical fluctuations in the distributional range of Q. mexicana. Historical range changes, gene flow, and physical barriers seem to have played an important role in shaping the phylogeographic structure of Q. mexicana. Conclusions: Our study indicates that the genetic structure of Q. mexicana may have been the result of responses of oak trees not only to heterogeneous environments present in the Sierra Madre Oriental and adjacent areas, but also to elevational and latitudinal shifts in response to climate changes in the past. [ABSTRACT FROM AUTHOR]

Context: Environmental heterogeneity across species distributions creates diverse conditions that individual populations encounter. As a result, local selective pressures vary across a species range, leading to individual populations becoming locally adapted and therefore better suited to their environment. Recent advances in genomics and bioinformatics allow us to identify genetic signatures of selection. Objectives: We searched for genetic signals of selection in populations of the chisel-toothed kangaroo rat (Dipodomys microps), a species that occupies two distinct plant assemblages and a wide range of climatic conditions in the American southwest. Methods: We used double digest Restriction Site Associated DNA sequencing to generate a dataset of 42,890 single nucleotide polymorphisms from 180 individuals belonging to 30 populations. We used genome-environment association and gene ontology methods to identify genetic loci showing significant association with environmental variables, compare the strength of selection across the species distribution, and link loci under selection to genes and gene functions. Results: We identified over 2000 genetic loci that show correlation with climatic conditions (mean temperature of the warmest quarter, mean temperature of the wettest quarter, precipitation of the coldest quarter, and precipitation of the warmest quarter) and vegetation (represented by normalized difference vegetation index or a binary classification). Candidate loci were located within gene transcripts associated with development, thermal tolerance, and behavior. We detected the strongest signals of selection in populations that expanded into novel habitat after the Last Glacial Maximum. Our results corroborate the phenotypic differences among populations identified in previous studies. Conclusions: Our results show how environmental heterogeneity drives selection-driven intraspecific variation. This highlights the importance to consider local adaptation of individual populations in assessing conservation needs and developing species management plans. [ABSTRACT FROM AUTHOR]

Juglans regia is an important perennial crop cultivated for its high-quality nuts and wood. It is generally believed that J. regia survived and expanded in almost completely isolated stands in Asia after the last glaciation. Humans subsequently dispersed J. regia through cultural expansion and trade. We evaluated the spatial genetic structure and genetic diversity of 2,929 J. regia samples from 150 populations using 14 Simple Sequence Repeats (SSRs) markers. Our study revealed that regions with the highest genetic diversity included Southern Asia, Western Asia, Western Europe, and China, as illustrated using a Geostatistical Inverse Distance Weighting (IDW) interpolation of observed heterozygosity (HO), expected (HE) heterozygosity (HE), percentage of polymorphic loci (PPL), the total number of alleles (NA), and Allelic richness (RS) in Arc Geographic Information System (ArcGIS). The ecological Niche Model (ENM) showed J. regia had a high probability of association with Central Asian and Eastern Asian habitats. Population genetic structure, phylogeny, and Principal Coordinate Analysis (PCoA) identified three genetic groups corresponding to three geographic sources. Turkish and Georgian populations served as a bridge between Asian populations and Europe populations. We suggest that J. regia evolved in central Asian mountain ranges ~ 65 million years ago (Mya) and dispersed across Eurasia during climate shifts (~ 65 to 3Mya). The population contracted into multiple refugia during the Last Glacial Maximum. The current distribution of J. regia across Eurasia was shaped by the cumulative effects of contraction or expansion of different refugia and human exploitation after LGM. [ABSTRACT FROM AUTHOR]

Atmospheric CO2 variability on the glacial–interglacial (G–IG) timescale reflects a balance between oceanic and terrestrial processes involving carbon uptake and release. The Southern Ocean CO2 uptake is considered as an important modulator for the G–IG atmospheric CO2 variability, while the role of tropical ocean ventilation remains enigmatic. We present critical evidence for CO2 ventilation from the tropical Indian Ocean through the reconstruction of the Arabian Sea‐surface pCO2 for the past ∼136 ka utilizing boron isotope (δ11B) record of planktic foraminifera, Globigerinoides ruber. Our site in the Arabian Sea presently acts as a significant source of CO2. The reconstructed ΔpCO2 (ΔpCO2 = pCO2 Seawater − pCO2 Atmosphere) record shows an enhanced CO2 degassing up to ∼50 ppm during the major cooling events, such as the Last Glacial Maximum, Younger Dryas, and Heinrich‐Stadials. Our investigation based on multiproxy records of sea‐surface temperature, salinity, and productivity suggests that the northward invasion and shoaling of southern source CO2‐rich water, coupled with stronger upwelling, resulted in CO2 degassing during these cold intervals. This finding is in align with the tropical Atlantic which also demonstrated an enhanced CO2 degassing during the cold intervals; however, most of the upwelled CO2 was consumed as the water moved away from the upwelling sites. Therefore, our finding, when considered alongside tropical Atlantic records, suggests that tropical oceans played a minor role in reducing atmospheric CO2 levels during the cold intervals of the last glacial cycle, supporting the prevailing hypothesis. Key Points: Foraminifera δ11B‐based CO2 record of Arabian Sea surface for the past ∼136 kaEnhanced CO2 degassing during the cold climate events, that is, Heinrich‐Stadials, Younger Dryas, and Last Glacial MaximumThis degassing was caused by more export of southern‐sourced water and its upwelling [ABSTRACT FROM AUTHOR]

Geomorphological records of past ice sheet change offer the opportunity to examine their centennial‐scale response to changing boundary conditions, which are not adequately captured in the satellite record. Here, we present the first reconstruction of ice surface lowering at Byrd Glacier, the largest outlet glacier of the Transantarctic Mountains. Using surface exposure ages from glacial erratic cobbles collected in two vertical transects along the Lonewolf Nunataks, we find the initial emergence of this set of nunataks occurred at ~15 ka, with a rapid pulse of thinning at ~8 ka. We compare our glacier thinning profiles with modelled ice sheet thickness and grounding line histories from two model ensembles to identify key processes responsible for ice sheet change. All model runs from the two ensembles predict grounding line retreat and inland thinning to occur in one rapid step from Last Glacial Maximum to present, in line with marine geology records, our exposure age data and derived glacier thinning rates. Experiments best matching the glacial thickness constraints, reconstructed from the surface exposure data, have faster basal sliding (i.e., promote greater sliding rates resulting in thinner ice). However, experiments best matching the timing and rapid rate of ice thinning derived from the same surface exposure data have higher basal friction. This apparent change in the modelled basal sliding regime, from when the ice surface is at maximum thickness, to the rapid thinning at ~8 ka, occurs as the grounding line retreats towards the Byrd Glacier and Ross Ice Shelf forms during the Holocene. This past context has implications for the stability of the modern grounding line of Byrd Glacier, which is characterised by high basal melt rates at the terminus—a process that has the potential to propagate glacier thinning far inland, impacting the overall (in)stability of the Byrd Glacier and Ross Ice Shelf. [ABSTRACT FROM AUTHOR]

Glacial erosion rates on the Iceland landscape throughout the Pleistocene are not well quantified. Ice scour lakes provide an opportunity to investigate glacial erosive activity and relative intensity because they commonly form in areas beneath ice sheets due to intense quarrying. This study evaluates ice scour lake morphology and density as a potential proxy for paleo‐ice flow direction and basal thermal regime for parts of the Iceland Ice Sheet. Using GIS analysis, properties of ice scour lakes are examined in regions that experienced different rates of ice flow during and following the Last Glacial Maximum (LGM), as interpreted from streamlined subglacial landforms. The primary input datasets were topographic, hydrologic and bedrock data. Lake distribution and morphology were quantified for all natural lakes of Iceland (n = 30 169), with close examination of three 400 km2 sub‐regions in Vestfirðir (n = 904), Húnaflói (n = 69) and Bakkaheiði (n = 232). Lake distribution parameters include density, packing and centroid elevation. PolyMorph‐2D was used to quantify lake morphology including orientation, area and elongation ratio. Ice scour lake density, packing and elevation were all greatest on Vestfirðir. The high density and packing of lakes across Vestfirðir suggests unique ice dynamics relative to the other two sub‐regions, and multidirectional flow of lake axes supports the presence of an independent ice cap covering Vestfirðir. Differential intensity of glacial erosion interpreted from regions of high and low lake density on Bakkaheiði supports a proposed ice divide in Northeast Iceland. The orientation of lakes align with the flow directions of proposed LGM ice streams in Northern and Northeast Iceland. Ice scour lakes were most elongate on average on Bakkaheiði, which supports fast ice flow. Improving understanding of former ice sheet basal thermal regime and paleo‐ice flow velocity serves to inform modern controls on ice sheet stability and ice sheet basal processes. [ABSTRACT FROM AUTHOR]

While hybridization and introgression can have a strong adaptive importance, it can impede divergence of species. Quercus magnoliifolia and Q. resinosa are two endemic oak species distributed across the Mexican highlands. These species diverged ecological and morphologically; however, no nuclear genetic differentiation is evident. In this study, we determined the mechanisms that shape patterns of genetic variation and establish the role of migration and hybridization in the evolutionary history of these two oak species. To do this, Bayesian approaches were used for inference on migration rates and directionality and timing of divergence between species using chloroplast microsatellites. We then integrated species distribution models to infer the geographic distribution of Q. magnoliifolia and Q. resinosa during Last Interglacial, Last Glacial Maximum, and Mid-Holocene time frames. We failed in distinguishing a unique genetic composition for each species. Chloroplast differentiation was more congruent with geography than the taxonomic status of each species. Our study revealed that after the divergence (c. 10 Mya) of these two oak species, high rates of introgression took place at the end of the Pleistocene. Furthermore, past distribution models predicted that Q. magnoliifolia and Q. resinosa have likely been in sympatry presumable since Last Glacial Maximum and Q. resinosa probably expanded geographically towards its current distribution around Mid-Holocene. This expansion was supported by testing migration models, suggesting recent establishment of Q. resinosa to the north of Trans-Mexican Volcanic Belt. We hypothesized that after Q. magnoliifolia and Q. resinosa diverged, colonization events followed by hybridization between oaks and long-distance seed dispersal occurred, explaining the present-day patterns of distribution of chloroplast diversity. We propose that divergence of species remains mainly on loci under natural selection, providing evidence on the "porous" nature of species boundaries among oaks. [ABSTRACT FROM AUTHOR]

Abstract Quantitative constraints on past mean ocean temperature (MOT) critically inform our historical understanding of Earth's energy balance. A recently developed MOT proxy based on paleoatmospheric Xe, Kr, and N2 ratios in ice core air bubbles is a promising tool rooted in the temperature dependences of gas solubilities. However, these inert gases are systematically undersaturated in the modern ocean interior, and it remains unclear how air‐sea disequilibrium may have changed in the past. Here, we carry out 30 tracer‐enabled model simulations under varying circulation, sea ice cover, and wind stress regimes to evaluate air‐sea disequilibrium in the Last Glacial Maximum (LGM) ocean. We find that undersaturation of all three gases was likely reduced, primarily due to strengthened high‐latitude winds, biasing reconstructed MOT by −0.38 ± 0.37°C (1σ). Accounting for air‐sea disequilibrium, paleoatmospheric inert gases indicate that LGM MOT was 2.27 ± 0.46°C (1σ) colder than the pre‐industrial era.

Abstract We conducted two‐dimensional numerical simulations to investigate the mechanisms underlying the strong spatiotemporal correlation observed between submarine landslides and gas hydrate dissociation due to glacial sea‐level drops. Our results suggest that potential plastic deformation or slip could occur at localized and small scales in the shallow‐water portion of the gas hydrate stability zone (GHSZ). This shallow‐water portion of the GHSZ typically lies within the area enclosed by three points: the BGHSZ–seafloor intersection, the seafloor at ∼600 m below sea level (mbsl), and the base of the GHSZ (BGHSZ) at ∼1,050 mbsl in low‐latitude regions. The deep BGHSZ (>1,050 mbsl) could not slip; therefore, the entire BGHSZ was not a complete slip surface. Glacial hydrate dissociation alone is unlikely to cause large‐scale submarine landslides. Observed deep‐water (much greater than 600 mbsl) turbidites containing geochemical evidence of glacial hydrate dissociation potentially formed from erosion or detachment in the GHSZ pinch‐out zone.

Species distribution models (SDMs) are one of the most widely used approaches to predict changes in habitat suitability in response to climate change. However, as typically implemented, SDMs treat species as genetically uniform throughout their ranges and thereby ignore potentially important genetic differences between populations. While numerous studies have used SDMs to model genetically based subgroupings within species, the ability of such models to be transferred to new times has rarely been evaluated. Here, we used standard and genetically informed distribution models (gSDMs) to predict the future and past range of balsam poplar (Populus balsamifera L.). We then assessed model transferability of standard SDMs and gSDMs using balsam poplar fossil pollen and macrofossil occurrences. In general, standard and gSDMs performed similarly through time, with both predicting a northward expanding range from refugia as glaciers receded over the past 22 ky BP and declining suitable area in future climates. Both standard and gSDMs showed moderate abilities to distinguish balsam poplar fossils from pseudo-absences but tended to predict lower suitability at fossil sites during the Pleistocene-Holocene transition. Although gSDMs applied to balsam poplar did not prove more transferable than standard SDMs, they provided numerous unique insights, such as the change in suitable area of genetic clusters through time and potential refugial locations. We argue more research is needed to determine which species may benefit most from the gSDM approach and to test gSDMs with temporally or spatially independent occurrences, as is often recommended for standard SDMs.

This article explores the role of the westerly jet stream in shaping the climate of Central Asia, specifically focusing on the hydroclimate of the region throughout the Holocene. By analyzing speleothem proxy records, the study reveals a decline in precipitation in Western Central Asia compared to Eastern Central Asia, creating a hydroclimatic barrier between the two regions. The findings contribute to our understanding of the long-term relationship between regional hydroclimates and the westerly jet stream. The article also mentions the potential impact of global warming on the jet stream and the hydrological cycle. [Extracted from the article]

Under the background of global climate change, the evolution of climate in the future is the focus of geoscience. The Nanri Channel is an important passage connecting the Xinghua Bay and the Taiwan Strait, in China, and the study of its provenance and paleoenvironmental alternation is of great significance to the climate evolution in the eastern coast of China. The grain size and X-ray diffraction analyses of sediments from ZK1 in Nanri Channel and ZK5 in Xinghua Bay, were used to study the variation of grain size and clay mineral characteristics and to analyze the changes in hydrodynamic characteristics, provenance, and paleoenvironmental evolution in the regions since the Last Glacial Maximum. The results show that the sedimentary environment of ZK1 varies from the nearshore tidal flat facies with strong hydrodynamic conditions and the neighboring rivers as the main provenance, to the littoral facies with weak hydrodynamic conditions and the Yangtze River-like type sediments as the main provenance. The sedimentary environment of ZK5 is from the nearshore tidal flat facies with strong hydrodynamic conditions to the littoral facies with weak hydrodynamic conditions, and the provenance of both facies is mainly Yangtze River-like type sediments. The clay mineral characteristics of ZK1 show that the climate in the Nanri Channel has experienced a change from cool and wet, to mild and dry, to mild and wet since the Last Glacial Maximum, while the climate in the Xinghua Bay has experienced a change from warm and humid, to moderate and dry, to warm and humid since the early-middle Holocene, which provides scientific theoretical support for the provenance and paleoenvironment of sediments in the study area and neighboring areas.

Abstract The latitudinal position of the Intertropical Convergence Zone (ITCZ) reflects the energy imbalance between the hemispheres. Southward displacements of the ITCZ during the Last Glacial Maximum (LGM; 19–26.5 ka) and Heinrich Stadial 1 (HS1; 14.6–17.5 ka), are widely accepted, but their magnitude is controversial. Geochemistry of detrital fractions in down‐core sediments collected from 6°N to equator along the 131.5°W transect reveal a distinct shift in εNd, La/Yb, and La–Sc–Th composition from predominantly northern hemisphere‐sourced to mixed northern and southern hemisphere‐sourced signal at 3°N–4°N during the LGM and 3°N–6°N during HS1. These contrasting provenance signals point to the past ITCZ functioning as a dust barrier. Given that a comparable geochemical demarcation currently occurs at 6°N–7°N, our data suggest that the ITCZ migrated southward by ∼3° during the LGM and ∼1°–3° during HS1 relative to its modern position in the central Pacific.

Abstract Freshwater ecosystems are experiencing accelerating global biodiversity loss. Thus, knowing where these unique ecosystems' species richness reaches a peak can facilitate their conservation planning. By hosting more than 290 freshwater fishes, Iran is a major freshwater fish hotspot in the Middle East. Considering the accelerating rate of biodiversity loss, there is an urgent need to identify species‐rich areas and understand the mechanisms driving biodiversity distribution. In this study, we gathered distribution records of all endemic freshwater fishes of Iran (85 species) to develop their richness map and determine the most critical drivers of their richness patterns from an ecoregion approach. We performed a generalized linear model (GLM) with quasi‐Poisson distribution to identify contemporary and historical determinants of endemic freshwater fish richness. We also quantified endemic fish similarity among the 15 freshwater ecoregions of Iran. Results showed that endemic freshwater fish richness is highest in the Zagros Mountains while a moderate level of richness was observed between Zagros and Alborz Mountains. High, moderate, and low richness of endemic freshwater fish match with Upper Tigris & Euphrates, Namak, and Kavir & Lut Deserts ecoregions respectively. Kura – South Caspian Drainages and Caspian Highlands were the most similar ecoregions and Orumiyeh was the most unique ecoregion according to endemic fish presence. Precipitation and precipitation change velocity since the Last Glacial Maximum were the most important predictors of endemic freshwater fish richness. Areas identified to have the highest species richness have high priority for the conservation of freshwater fish in Iran, therefore, should be considered in future protected areas development.

In this comprehensive review, an extensive analysis has been conducted on paleoclimate datasets from climatically sensitive regions in the Indian Himalaya and Indo-Gangetic plain. Our main objective was to gain valuable insights into the broad palaeoclimatic variability during the Late Quaternary-Holocene period. To achieve this, careful categorization was focused for various archives from multi-proxy studies into three groups: glacial moraine, glacio-fluvial and lake records, and speleothems. The compilation of climate records from different geographical settings has revealed an overall coherence during warm and humid phases, with minor variations influenced by variable moisture sources and topographic changes. The analysis reveals that Indian Summer Monsoon (ISM) reached its peak during approximately 9-5 ka BP and subsequently weakened around the Mid-Holocene (ca. 4–5 ka BP). Notably, the Last Glacial Maximum (LGM) and early Holocene were characterized by significant glacial advances in the Himalayan region. Furthermore, the sedimentation rates derived from lacustrine records in different regions exhibit considerable variability. In conclusion, the compilation and comparisons of diverse palaeoclimate records have significantly improved our understanding of the regions palaeoclimate. These findings hold substantial value for planning future focused studies in the crucial climatic zone. By refining our understanding of past climate dynamics in the Indian Himalaya and Indo-Gangetic alluvium, a better comprehension of the regions susceptibility to climate change can be achieved. This, in turn, facilitates informed decisions for sustainable development and environmental management.

Abstract In this study, we differentiate wet processes from dry processes in shaping the extratropical thermal stratification during the Last Glacial Maximum. Our findings indicate that even during the dry glacial period the influence of wet processes on thermal stratification cannot be overlooked. The applicability of dry and wet baroclinic adjustment theory strongly depends on the seasonality rather than the glaciation as the warm season is characterized by a weaker meridional temperature gradient and increased precipitation than the cold season. Despite that the baroclinic adjustment theory based on effective static stability can be proficiently applied to all seasons, the classical dry baroclinic adjustment theory may be better suited for use during relatively cold seasons. These findings have important implications for understanding processes governing the extratropical thermal stratification, particularly in the context of cold climate.

During the Last Glacial Maximum (approximately 21 ka BP) the presence of large ice sheets over the Northern Hemisphere (NH) caused significant changes in the ocean–atmosphere interaction. Remarkable changes are noticed in NH both topography and atmospheric CO2 levels. This paper investigates the impact of the most recent paleotopography (ICE6G) in the Earth's climate and the oceanic carbonate system, based on a series of experiments conducted with the oceanic‐atmosphere‐vegetation‐ice‐carbon model, UVic ESCM. Results indicate enhanced cooling in northern North America in the ICE6G compared to the ICE4G simulation due to the lapse rate effect. The decrease of −24°C in the surface temperature in the ICE6G relative to the present day (PD) led to a modification of the atmospheric circulation in the Atlantic and North Pacific regions. Positive and negative anomalies vary widely for the E–P (evaporation–precipitation) flux pattern, but colder and drier atmosphere leads to a reduction in precipitation in the ICE6G experiment. Changes in wind stress between ICE6G and PD induce low temperatures in the Northern Hemisphere. These features are related changes of Ekman's transport and evaporative cooling resulting in positive anomalies of SST. Thus, changes in sea surface temperature and salinity (SST, SSS), and E–P flux led to modifications in the oceanic carbonate system, resulting in an overall increase of total alkalinity and a reduction in the concentrations of total carbon dioxide (TCO2) in the ICE6G with respect to the PD values. This is a consequence of the low concentration of glacial CO2 and increment in CO23− concentrations. The total alkalinity (TA) and TCO2 do not show a similar response to the SST and SSS, in the sense that larger departures from the PD are found in the Pacific equatorial region, which are affected by changes in water dilution as a result of precipitation and evaporation processes. [ABSTRACT FROM AUTHOR]

The evolutionary dynamics of mitochondrial DNA within the Thai population were comprehensively explored with a specific focus on the influence of South Asian admixture. A total of 166 samples were collected through randomized sampling, ensuring a diverse representation. Our findings unveil substantial genetic and haplogroup diversity within the Thai population. We have identified 164 haplotypes categorized into 97 haplogroups, with a notable inclusion of 20 novel haplogroups. The distribution of haplogroups exhibited variations across different populations and countries. The central Thai population displayed a high diversity of haplogroups from both the M and N clades. Maternal lineage affinities were discerned between several Mainland Southeast Asia (MSEA) and South Asian populations, implying ancestral genetic connections and a substantial influence of South Asian women in establishing these relationships. f4-statistics indicates the presence of a Tibeto-Burman genetic component within the Mon population from Thailand. New findings demonstrate two phases of population expansion occurring 22,000–26,000 and 2500–3800 years ago, coinciding with the Last Glacial Maximum, and Neolithic demographic transition, respectively. This research significantly enhances our understanding of the maternal genetic history of Thailand and MSEA, emphasizing the influence of South Asian admixture. Moreover, it underscores the critical role of prior information, such as mutation rates, within the Bayesian framework for accurate estimation of coalescence times and inferring demographic history. [ABSTRACT FROM AUTHOR]

The intertropical convergence zone (ITCZ) plays a key role in regulating tropical hydroclimate and global water cycle through changes in its convection strength, latitudinal position, and width. The long-term variability of the ITCZ, along with the corresponding driving mechanisms, however, remains obscure, mainly because it is difficult to separate different ITCZ variables in paleoclimate proxy records. Here, we report a speleothem oxygen isotope (d18O) record from southwestern Sulawesi, Indonesia, and compile it with other speleothem records from the Maritime Continent. Using the spatial gradient of speleothem d18O along a transect across the ITCZ, we constrain ITCZ variabilities over the Maritime Continent during the past 30,000 y. We find that ITCZ convection strength overall intensified from the last glacial period to the Holocene, following changes in climate boundary conditions. The mean position of the regional ITCZ has moved latitudinally no more than 3° in the past 30,000 y, consistent with the deduction from the atmospheric energy framework. However, different from modern observations and model simulations for future warming, the ITCZ appeared narrower during both the late Holocene and most part of the last glacial period, and its expansion occurred during Heinrich stadials and the early-to-mid Holocene. We also find that during the last glacial and deglacial period, prominent millennial-scale ITCZ changes were closely tied to the variability of the Atlantic meridional overturning circulation (AMOC), whereas during the Holocene, they were predominantly modulated by the long-term variability of the Walker circulation. [ABSTRACT FROM AUTHOR]

Relative sea level (local water depth) on the Antarctic continental shelf is changing by the complex interplay of processes associated with Glacial Isostatic Adjustment (GIA). This involves near-field visco-elastic bedrock displacement and self-gravitational effects in response to changes in Antarctic ice load, but also far-field interhemispheric effects on the sea-level pattern. On glacial time scales, these changes can be in the order of several hundred meters, modulating the access of ocean water masses at different depths to Antarctic grounding lines. Our study shows, that due to strong vertical gradients in ocean temperature and salinity at the continental shelf margin, basal melt rates of ice shelves can change significantly just by variations in relative sea level alone. Based on coupled ice sheet – GIA model experiments and the analysis of topographic features such as troughs and sills that regulate the access of open ocean water masses onto the continental shelf (oceanic gateways), we derive maximum estimates of Antarctic basal melt rate changes, solely driven by relative sea-level variations. Under Last Glacial Maximum sea-level conditions, this effect would lead to a substantial decrease of present-day sub-shelf melt rates in East Antarctica, while the strong subsidence of bedrock in West Antarctica can lead up to a doubling of basal melt rates. For a hypothetical globally ice-free sea-level scenario, which would lead to a global mean (barystatic) sea-level rise of around +70 m, sub-shelf melt rates for a present-day ice sheet geometry can more than double in East Antarctica, but can also decrease substantially, where bedrock uplift dominates. Also for projected sea-level changes at the year 2300 we find maximum possible changes of ±20 % in sub-shelf melt rates, as a consequence of relative sea-level changes only. [ABSTRACT FROM AUTHOR]

The family Rhinocerotidae is a key component of the Cenozoic European fauna. It reached its peak diversity during Miocene and began to decline in the Pliocene; the last representatives became extinct in Europe during the Quaternary. The present state-of-the-art review takes stock of the knowledge accumulated on Central and Eastern European Pleistocene rhinos to date. Eight species were present in Central and Eastern Europe in the Quaternary; five belonged to the genus Stephanorhinus (S. etruscus , S. jeanvireti , S. hundsheimensis , S. hemitoechus , and S. kirchbergensis), one was the woolly rhino Coelodonta antiquitatis , and two species were members of the genus Elasmotherium (E. peii and E. caucasicum). This review also offered the opportunity to critically reconsider some aspects of the systematics and stratigraphic location of the finds. Coelodonta antiquitatis is shown to have still been present as late as the Interplenivistulian and the Last Glacial Maximum; radiocarbon dating of its latest remains provided the timing of the final disappearance of the woolly rhino from the studied region. The Late Pleistocene distribution of Coelodonta antiquitatis in Central and Eastern Europe was found to largely overlap that of the woolly mammoth. [ABSTRACT FROM AUTHOR]

The newly developed paleo‐climate calibrated Community Earth System Model, version 2 (pCESM2) simulates a more realistic global temperature response to external forcing compared to the standard CESM2. Here we show that the code modifications in pCESM2 result in increased atmospheric convection and a northward shift of the Atlantic and eastern Pacific Intertropical Convergence Zones. These changes are exacerbated under Last Glacial Maximum forcing, resulting in tropical precipitation changes that are inconsistent with both proxy data evidence and simulations with other contemporary models. Similar model‐data disagreements are also present in the standard CESM2. Thus, more work is needed to improve the simulated Last Glacial Maximum hydroclimate response in CESM2. We further suggest that well‐constrained paleo climates should be given a larger emphasis in model development more broadly, as these climates can help identify issues with model parameterizations under altered forcing and thus improve the fidelity of simulations of past, present, and future climates. Plain Language Summary: Climate models are a central tool in modern climate science. The realism of any given model is however largely determined by a delicate calibration of the simulated physics in order to capture the observed features of the climate system. A recent study showed that the newly developed paleo‐climate calibrated Community Earth System Model, version 2 greatly improves the global temperature response in simulations of the Last Glacial Maximum compared to the standard model. This was achieved by altering properties of cloud processes in the model code. Here we show that the same changes that improve the overall model sensitivity help exaggerate issues with the distribution of tropical precipitation; similar precipitation issues are also present in the standard model. Understanding the connections between model sensitivity, cloud properties, and precipitation distribution is key for developing a model that can realistically simulate past, present, and future climates. Key Points: The Last Glacial Maximum climate simulated by the paleo‐climate calibrated Community Earth System Model, version 2 (CESM2) (pCESM2) is more realistic than the standard CESM2Both the pCESM2 and the standard CESM2 have large intertropical convergence zone precipitation biases under Last Glacial Maximum forcingSimulations of well‐constrained past climates can help inform model parameterizations and assess model performance [ABSTRACT FROM AUTHOR]

The Earth's polar regions are low rates of inter‐ and intraspecific diversification. An extreme mammalian example is the Arctic ringed seal (Pusa hispida hispida), which is assumed to be panmictic across its circumpolar Arctic range. Yet, local Inuit communities in Greenland and Canada recognize several regional variants; a finding supported by scientific studies of body size variation. It is however unclear whether this phenotypic variation reflects plasticity, morphs or distinct ecotypes. Here, we combine genomic, biologging and survey data, to document the existence of a unique ringed seal ecotype in the Ilulissat Icefjord (locally 'Kangia'), Greenland; a UNESCO World Heritage site, which is home to the most productive marine‐terminating glacier in the Arctic. Genomic analyses reveal a divergence of Kangia ringed seals from other Arctic ringed seals about 240 kya, followed by secondary contact since the Last Glacial Maximum. Despite ongoing gene flow, multiple genomic regions appear under strong selection in Kangia ringed seals, including candidate genes associated with pelage coloration, growth and osmoregulation, potentially explaining the Kangia seal's phenotypic and behavioural uniqueness. The description of 'hidden' diversity and adaptations in yet another Arctic species merits a reassessment of the evolutionary processes that have shaped Arctic diversity and the traditional view of this region as an evolutionary freezer. Our study highlights the value of indigenous knowledge in guiding science and calls for efforts to identify distinct populations or ecotypes to understand how these might respond differently to environmental change. [ABSTRACT FROM AUTHOR]

Determining recent Antarctic ice volume changes from satellite altimeter measurements of ice height requires a correction for contemporaneous vertical crustal deformation. This correction must consider two main sources of crustal deformation: (1) ongoing glacial isostatic adjustment (GIA), that is, the deformational, gravitational and rotational response to late Pleistocene and Holocene ice and ocean mass changes; and (2) modern ice mass flux. In this study, we seek to quantify the uncertainties associated with each of these corrections. Corrections of ice height changes for (1) have generally involved the adoption of global models of GIA defined by some preferred combination of ice history and mantle viscoelastic structure. We have computed the GIA correction generated from a coupled ice sheet – sea level model and a realistic earth model incorporating three-dimensional viscoelastic structure. Integrating the difference between this correction and those from recent GIA analyses widely adopted in the literature yields an uncertainty in total present-day ice volume change equivalent to approximately 10 % of Antarctic ice mass loss inferred for the previous decade. This reinforces earlier work indicating that ice histories characterized by relatively high excess ice volume at the Last Glacial Maximum may be introducing significant error in estimates of modern melt rates. Regarding correction (2), a spatially invariant scaling has commonly been used to convert GIA-corrected ice height changes obtained from satellite altimetry into ice volume estimates. We adopt modeling results based on a projection of Antarctic ice mass flux over the next 40 years to demonstrate a spatial variability in the scaling of up to 10 % across the ice sheet. Furthermore, using these calculations, we find an error in the projected net ice volume change of up to 4.5 mm GMSL equivalent forty years after present, with most of the difference arising in areas of West Antarctica above mantle zones of low viscosity. [ABSTRACT FROM AUTHOR]

Climatic conditions and its change shape the strength and extent of the oxygen minimum zone (OMZ). The presence and variability of the OMZ in the Arabian Sea is of importance for their ecosystem. The state of oxygenation has, for instance, an impact on the pelagic and benthic faunal community or the nitrogen and carbon cycles. The understanding of the dynamics of the OMZ, its marine environmental is of importance due to its climate feedbacks. In this study, we combined three independent proxies to reconstruct the oxygenation state of the water column and bottom water in the Gulf of Oman for the past about 43 ka for the first time. We used nitrogen isotopes (δ15N) as well as the alkane ratio (lycopane + n -C35)/ n -C31 and benthic foraminiferal faunal analysis to reconstruct the strength of the OMZ in the water column and bottom water oxygenation, respectively. Our results show that the Gulf of Oman experienced strong pronounced OMZ and bottom water deoxygenation during the Holocene. Contrary, during the Last Glacial Maximum (LGM)/ Marine Isotope Stage (MIS) 2 the Gulf of Oman was very well ventilated with a highly diverse benthic foraminiferal community. This may have been caused by stronger wind-induced mixing and better ventilation by oxygen-rich water masses. Our results also show moderate oxygenation during MIS 3 with deoxygenation events during most of the warmer Dansgaard-Oeschger (D/O) events. We propose two distinct oxygenation modes for the Gulf of Oman: 1) a stable period of either strongly pronounced water column OMZ and bottom water deoxygenation or well-oxygenated water column and bottom water conditions and 2) an unstable period of oscillating oxygenation states between moderately oxygenated (stadials) and deoxygenated (interstadial, D/O events) conditions. [ABSTRACT FROM AUTHOR]

The article offers information on the Andes Biodiversity and Ecosystem Research Group (ABERG) and its long-term field study of how an Amazon forest is responding to climate change. Topics include the project's development; its contributions to understanding climate change's effects on tropical ecosystems; its impact on Peru's scientific community; and the emerging threats and challenges it faces, such as drug trafficking and illegal mining affecting the region.

Paleoclimate proxy records from the North Atlantic region reveal substantially greater multicentennial temperature variability during the Last Glacial Maximum (LGM) compared to the current interglacial. As there was no obvious change in external forcing, causes for the increased variability remain unknown. Exploiting LGM simulations with a comprehensive coupled climate model along with high-resolution proxy records, we introduce an oscillatory mode of multicentennial variability, which is associated with moderate variations in the Atlantic meridional overturning circulation and depends on the large-scale salinity distribution. This self-sustained mode is amplified by sea-ice feedbacks and induces maximum surface temperature variability in the subpolar North Atlantic region. Characterized by a distinct climatic imprint and different dynamics, the multicentennial oscillation has to be distinguished from Dansgaard-Oeschger variability and emerges only under full LGM climate forcing. The potential of multicentennial modes of variability to emerge or disappear in response to changing climate forcing may have implications for future climate change. [ABSTRACT FROM AUTHOR]

The prehistoric human settlement of the Lakshadweep islands remains a mystery for various reasons. Uncertainty about the existence of indigenous tribes in these islands and the lack of folklore records present major obstacles to the reconstruction of Lakshadweep ancestry. However, with extant population data, we seek to understand the maternal ancestry of the Kavaratti islanders. Mitochondrial control region variation analysis of 80 individuals from this island shows maternal links with the populations in the northwestern region of the South Asian mainland. The founder clade R30b2, observed in the Kavaratti islanders, is so far present only in the Scheduled Castes from the Punjab region, Jat Sikhs and Nairs. All other mainland populations carry basal R30 or R30a subclades. The presence of a specific Uralic U4 lineage in our samples, in addition to the Indo-European affinity observed in the phylogeny tree, substantiates a northwestern maternal ancestry of the Kavaratti islanders and implies an ancestral admixture with early humans in the Near East at the time of the last glacial maximum (LGM). Based on our Bayesian analysis, we furthermore propose that a group bearing mostly R30b2 during the LGM recovery, moved eastward and southward, where they received Indian-specific M haplogroups. Hence, the maternal ancestry of the Kavaratti islanders is evidently a consequence of the demographic changes in the northwestern region of the Indian subcontinent caused by the Last Glacial Maximum. The haplogroup distribution pattern and nucleotide sequence data produced in this study will enrich the forensic database of the Lakshadweep islands. [ABSTRACT FROM AUTHOR]

During the Quaternary, Chaco Phytogeographic Domain (Chaco) flora in subtropical South America experienced temperature and humidity fluctuations, primarily driven by wind dynamics, leading to significant shifts in species distribution. The palm Butia yatay is endemic to the Chaco and thrives in areas characterized by a warm–rainy climate and mostly restricted to sandy soils. To investigate the current geographic distribution of suitable habitat for B. yatay while assessing the significance of soil variables, we employed two distinct algorithms in species distribution modeling (SDM). We also determined whether the distribution of B. yatay has changed since the Pleistocene and whether these changes align with previously proposed Pleistocene refugia. In the present SDMs, we considered two separate sets of predictors, one set with bioclimatic variables only and the other set with bioclimatic topographic and soil variables. Additionally, we reconstructed the historical geographic distribution of suitable habitats using bioclimatic data. Our results suggested that the primary determinants of B. yatay's current distribution include precipitation and temperature of the driest month and soil cation exchange capacity. Incorporating soil variables affected the estimated size and range of suitable areas. Projections into the past indicated similar suitable habitat distributions during interglacial periods compared with the present. During the Last Glacial Maximum, climatically suitable habitat may have shifted northward, partially overlapping with previously suggested Pleistocene refugia located between the Paraná and Uruguay Rivers. These findings indicate the main factors driving the distribution and ecology of B. yatay and enhance understanding of subtropical flora shifts during the Quaternary. The approach also may prove valuable for other studies within the Chaco. [ABSTRACT FROM AUTHOR]

Reconstructing the extent and timing of palaeoglaciers and their associated climate is of great importance for understanding the responses of glaciers to climate change. Glacial landforms are well-preserved in Zheduo Shan, one of the high mountain ranges on the eastern Tibetan Plateau (TP). However, few studies have constrained glacial chronologies and estimated palaeoclimate in this area. We investigated the glacial advance during the Last Glacial Maximum (LGM) in Zheduo Shan using 10Be surface exposure dating. We then reconstructed the extent and thickness of LGM glaciers based on geomorphological mapping and a flowline-based glacial model-PalaeoIce. Eleven 10Be exposure ages confirmed a major LGM glacial advance between 20.0 ± 3.2 ka and 19.3 ± 2.8 ka. The reconstructed LGM glaciers in this mountain range covered an area of 499.16 km2 with an average ice thickness of 54.4 m and a total ice volume of 52.82 km3. The regional average equilibrium-line altitude (ELA) was estimated as 4524 ± 140 m, 535 ± 140 m lower than the present value. Based on the empirical relationship between precipitation and temperature (P-T model) at the ELAs on the TP, the temperature and precipitation were estimated as 3.10–5.27 °C and 10–16% lower during the LGM than the present values, respectively. These results suggest that the LGM glacial advance was more sensitive to temperature than precipitation in Zheduo Shan. [ABSTRACT FROM AUTHOR]

Soil and sediment mixing and associated permafrost processes are not widely studied or understood in the McMurdo Dry Valleys of Antarctica. In this study, we investigate the stability and depositional history of near-surface permafrost sediments to ∼ 3 m depth in the Pearse and lower Wright valleys using measured cosmogenic 10 Be and 26 Al depth profiles. In Pearse Valley, we estimate a minimum depositional age of ∼ 74 ka for the active layer and paleoactive-layer sediments (< 0.65 m). Combined depth profile modelling of 10 Be and 26 Al gives a depositional age for near-surface (< 1.65 m) permafrost in Pearse Valley of 180 +20/-40 ka, implying that the deposition of permafrost sediments predates MIS 5 advances of Taylor Glacier. Deeper permafrost sediments (> 2.09 m) in Pearse Valley are thus inferred to have a depositional age of > 180 ka. At a coastal, lower-elevation site in neighbouring lower Wright Valley, 10 Be and 26 Al depth profiles from a second permafrost core exhibit near-constant concentrations with depth and indicate the sediments are either vertically mixed after deposition or sufficiently young so that post-depositional nuclide production is negligible relative to inheritance. 26Al/10Be concentration ratios for both depth profiles range between 4.0 and 5.2 and are all lower than the nominal surface production rate ratio of 6.75, indicating that prior to deposition, these sediments experienced complex, yet similar, exposure–burial histories. Assuming a single-cycle exposure–burial scenario, the observed 26Al/10Be ratios are equivalent to a total minimum exposure–burial history of ∼ 1.2 Myr. In proximity to the depth profile core site, we measured cosmogenic 10 Be and 26 Al in three granite cobbles from thin, patchy drift (Taylor 2 Drift) in Pearse Valley to constrain the timing of retreat of Taylor Glacier. Assuming simple continuous exposure, our minimum, zero-erosion exposure ages suggest Taylor Glacier partially retreated from Pearse Valley no later than 65–74 ka. The timing of retreat after 65 ka and until the Last Glacial Maximum (LGM) when Taylor Glacier was at a minimum position remains unresolved. The surface cobble ages and permafrost processes reveal Taylor Glacier advances during MIS 5 were non-erosive or mildly erosive, preserving the underlying permafrost sediments and peppering boulders and cobbles upon an older, relict surface. Our results are consistent with U/Th ages from central Taylor Valley and suggest changes in moisture delivery over Taylor Dome during MIS 5e, 5c, and 5a appear to be associated with the extent of the Ross Ice Shelf and sea ice in the Ross Sea. These data provide further evidence of antiphase behaviour through retreat of a peripheral lobe of Taylor Glacier in Pearse Valley, a region that was glaciated during MIS 5. We suggest a causal relationship of cold-based glacier advance and retreat that is controlled by an increase in moisture availability during retreat of sea ice and perhaps the Ross Ice Shelf, as well as, conversely, a decrease during times of sea ice and Ross Ice Shelf expansion in the Ross Sea. [ABSTRACT FROM AUTHOR]

Warm‐edge populations, that is, those usually small and isolated populations at the boundary of species maximum temperature range limit, are of particular scientific and conservation interest. This is especially the case for those that have long been geographically isolated, possibly through multiple glaciations, as they can contribute significantly to species' overall genetic diversity. However, distinguishing between glacial relict and more recently established warm‐edge populations is difficult especially in the absence of a continuous fossil record. In this study, we investigate the origin of anomalously low‐elevation warm‐edge populations of the dominant cool temperate Japanese tree Fagus crenata in the northeast Kanto (NEK) region. We sought to determine whether these populations are glacial relicts or, rather, were established via dispersal in the Holocene using chloroplast and nuclear genetic data, species distribution modeling and comparison with populations in a well‐established glacial refugia (south‐central Kyushu [SCK]) and of mid‐late Holocene age (southern Hokkaido [SH]). Whole chloroplast genome "mining" revealed a similar amount of haplotype diversity in NEK and SCK while there was no chloroplast variation in SH. Populations in NEK, particularly the lowest elevation sites, harbored unique haplotypes providing evidence for their persistence since the Last Glacial Maximum as supported by species distribution models under two of three general circulation models. NEK populations also lacked the genetic signatures of recent expansion that characterize the most northern‐edge populations in SH. We conclude that warm‐edge populations in NEK are most likely relicts of glacial refugia and should be given high priority for conservation. [ABSTRACT FROM AUTHOR]

Aim: Research on population genetic patterns and potential distribution dynamics can provide insights into the development of pest management strategies. Herein, we integrated population genetic analyses with the climatic niche approach to investigate spatial population genetic variations and potential geographical distribution (PGD) of the herbivorous pest Phytomyza horticola. We also analysed its population response patterns to both late Pleistocene climatic events and future climate change. Location: China. Methods: We analysed the patterns of genetic diversity distribution in 29 populations from 19 regions across China using three mitochondrial (COI, COII and Cytb) genes as markers. We estimated demographic histories using neutrality tests, mismatch distributions and Bayesian skyline plots. Changes in PGD were assessed using an ecological niche model. Results: High genetic diversity was found in most populations, and the northern population exhibited higher haplotype diversity. The population genetic structure included the Tibet lineage and a large lineage comprising the remaining populations. Demographic analyses indicated that rapid population expansion occurred during the cold Last Glacial Maximum. In addition, our projections suggested that P. horticola currently has a vast PGD in China, for which the human influence index was the strongest variable. Large areas of cold northern regions were highly suitable for its survival. Under future global warming, highly suitable habitats will shift towards the higher latitudes. Main conclusions: P. horticola is widely distributed across varied environments, which may be attributed to its high degree of genetic variation. Human activities likely facilitated the current PGD and the frequent gene flow that homogenized differentiation among most populations. In addition, P. horticola exhibits strong adaptability to cold climates and environments from the past to the future. Considering future climatic changes, prevention and control should focus on high‐latitude regions, and vigilance regarding human‐mediated pest dispersals and outbreaks should be maintained. [ABSTRACT FROM AUTHOR]

Understanding climate variability from millennial to glacial–interglacial time scales remains challenging due to the complex and nonlinear feedbacks between ice, ocean, sediments, biosphere, and atmosphere. Complex climate models generally struggle to dynamically and comprehensively simulate such long time periods as a result of the large computational costs. Here, we therefore coupled a dynamical ice sheet model to the Bern3D Earth system model of intermediate complexity, which allows for simulating multiple glacial–interglacial cycles. The performance of the model is first validated against modern observations and its response to abrupt perturbations, such as atmospheric CO2 changes and North Atlantic freshwater hosing, is investigated. To further test the fully coupled model, the climate evolution over the entire last glacial cycle is explored in a transient simulation forced by variations in the orbital configuration and greenhouse gases and aerosols. The model simulates global mean surface temperature in fair agreement with reconstructions, exhibiting a gradual cooling trend since the last interglacial that is interrupted by two more rapid cooling events during the early Marine Isotope Stage (MIS) 4 and Last Glacial Maximum (LGM). Simulated Northern Hemispheric ice sheets show pronounced variability on orbital time scales, and ice volume more than doubles from MIS3 to the LGM in good agreement with recent sea level reconstructions. At the LGM, the Atlantic overturning has a strength of about 14 Sv (1 Sv ≡ 106 m3 s−1), which is a reduction by about one-quarter compared to the preindustrial. We thus demonstrate that the new coupled model is able to simulate large-scale aspects of glacial–interglacial cycles. [ABSTRACT FROM AUTHOR]

Disjunct distribution is a key issue in biogeography and ecology, but it is often difficult to determine the relative roles of dispersal vs. vicariance in disjunctions. We studied the phylogeographic pattern of the monotypic Conandron ramondioides (Gesneriaceae), which shows Sino‐Japanese disjunctions, with ddRAD sequencing based on a comprehensive sampling of 11 populations from mainland China, Taiwan Island, and Japan. We found a very high degree of genetic differentiation among these three regions, with very limited gene flow and a clear Isolation by Distance pattern. Mainland China and Japan clades diverged first from a widespread ancestral population in the middle Miocene, followed by a later divergence between mainland China and Taiwan Island clades in the early Pliocene. Three current groups have survived in various glacial refugia during the Last Glacial Maximum, and experienced contraction and/or bottlenecks since their divergence during Quaternary glacial cycles, with strong niche divergence between mainland China + Japan and Taiwan Island ranges. Thus, we verified a predominant role of vicariance in the current disjunction of the monotypic genus Conandron. The sharp phylogenetic separation, ecological niche divergence among these three groups, and the great number of private alleles in all populations sampled indicated a considerable time of independent evolution, and suggests the need for a taxonomic survey to detect potentially overlooked taxa. [ABSTRACT FROM AUTHOR]

Sedimentary records from the Kumtag (also known as Kumtagh) Desert (KMD) in northwestern China are investigated to better understand Late Quaternary paleoenvironmental changes in this hyper-arid region. Presented here are the results of probably the first systematic survey of sedimentary sequences from the KMD, with the chronology determined by the optically stimulated luminescence dating. The variation of sedimentary facies, supported by granular and geochemical paleoenvironmental proxies, is used to decipher the history of Late Quaternary environment changes. The results demonstrate that a constantly dry condition characterized the eastern KMD since the last glacial maximum, but with occurrences of wetter periods. From ca. 17 to 15 ka, fluvial activity was probably triggered by melting of glaciers in mountains located south of the KMD. A distinctly drier stage (ca. 13-7 ka) was recognized due to the prominent occurrence of aeolian sands. A wetter environment likely persisted between ca. 4.4 and 2.2 ka, consistent with evidence of human activities. While the causes of paleoenvironmental changes in the eastern KMD are still a matter of debate, the melting of glaciers in the Altyn-Tagh Mountains in the south must be considered as an important factor. [ABSTRACT FROM AUTHOR]

The distribution patterns of the paleo-Changjiang River deltas formed during the MIS 3 period before the last glacial maximum (LGM) contain important information about the deltaic deposits in response to climate and sea-level changes. However, so far, they are still poorly understood. Here, we reconstruct the stratigraphic and chronological framework of the deltaic system based on the analysis of 1835 km of high-resolution seismic profiles obtained from the northern East China Sea, together with a comparison with the research results from four existing boreholes and three groups of published seismic profiles from the study area. Within the strata from MIS 5 to MIS 1 that are preserved on the northern shelf of the East China Sea, we discovered a large-scale paleodeltaic complex formed during the MIS 3 period. During MIS 3, sea level dropped slowly; the paleodelta formed was large in scale and was distributed between water depths of 40 and 150 m. It is now directly exposed at the seabed at a depth of more than 100 m. The paleodelta had extended from the northwest to the southeast, with maximum thickness of the deposits around 55 m. The extensions in the east–west and south–north directions both exceeded 300 km, with a total area around 1.35 × 105 km2. Since the late Pleistocene, the tectonic structure beneath the East China Sea has been relatively stable. As such, sea-level fluctuations, sediment supply, and original topography were the main controlling factors for the development of the delta. [ABSTRACT FROM AUTHOR]

The Antarctic ice sheet (AIS) is the Earth's largest store of frozen water; understanding how it changed in the past allows us to improve projections of how it, and sea levels, may change. Here, we use previous AIS reconstructions, water isotope ratios from ice cores, and simulator predictions of the relationship between the ice-sheet shape and isotope ratios to create a model of the AIS at the Last Glacial Maximum. We develop a prior distribution that captures expert opinion about the AIS, generate a designed ensemble of potential shapes, run these through the climate model HadCM3, and train a Gaussian process emulator of the link between ice-sheet shape and isotope ratios. To make the analysis computationally tractable, we develop a preferential principal component method that allows us to reduce the dimension of the problem in a way that accounts for the differing importance we place in reconstructions, allowing us to create a basis that reflects prior uncertainty. We use Markov chain Monte Carlo to sample from the posterior distribution, finding shapes for which HadCM3 predicts isotope ratios closely matching observations from ice cores. The posterior distribution allows us to quantify the uncertainty in the reconstructed shape, a feature missing in other analyses. [ABSTRACT FROM AUTHOR]

The seasonal changes in East Asian monsoon precipitation during the Last Glacial Maximum (LGM, 23,000–19,000 years B.P.) and its isotopic expression remain ambiguous. This study investigates changes in the seasonal precipitation δ18O (δ18Op) over East Asia during the LGM relative to the preindustrial (PI) and the underlying mechanisms using an isotope‐enabled atmospheric general circulation model. We show more depleted δ18Op in summer and a meridional tripolar δ18Op pattern in winter during the LGM compared to the PI. The depletion of summer δ18Op resulted from stronger upstream convective rainout due to the intensification of the Intertropical Convergence Zone. In contrast, the mechanisms for winter δ18Op changes were more complicated. With a series of sensitivity tests, we demonstrate that sea surface temperature controlled δ18Op changes across the whole of East Asia in summer and in the southern part of East Asia in winter. The depletion of winter δ18Op in central China arose largely from the suppression of droplet evaporation due to higher snow fraction. Our work provides important insights into the aspect of seasonal isotope changes during the LGM and may help facilitate an improved level of paleoclimatic interpretation of speleothem δ18O records from East Asia. Plain Language Summary: The climate over East Asia during the Last Glacial Maximum (LGM) was colder and drier than it is today according to paleoclimatic records. However, interpretations of paleo‐isotopic records have been inconsistent in previous research, and the seasonal isotope changes are still unclear. Here we use an isotope‐equipped climate model to explore summer and winter precipitation δ18O (δ18Op) behaviors in East Asia during the LGM. Compared to the preindustrial, the LGM was characterized by depleted summer δ18Op, largely due to the intensification of the Intertropical Convergence Zone which resulted in stronger rainout along the moisture transport pathways. The winter δ18Op, however, was more complex and exhibited a tripolar spatial pattern, with δ18Op depletion in central China but enrichment in both south and north. This pattern probably reflected the combined effect of sea surface temperature driven rainout en route and droplet evaporation. Key Points: Isotope‐enabled atmospheric general circulation model reasonably reproduces East Asian climate and precipitation δ18O changes between the Last Glacial Maximum (LGM) and preindustrialDepleted δ18O in LGM summer precipitation was driven by upstream rainout due to an intensification of the Intertropical Convergence ZoneWinter precipitation δ18O changes in southern and central China were controlled by rainout and droplet evaporation, respectively [ABSTRACT FROM AUTHOR]

The low latitude Indian Ocean is warming faster than other tropical basins, and its interannual climate variability is projected to become more extreme under future emissions scenarios with substantial impacts on developing Indian Ocean rim countries. Therefore, it has become increasingly important to understand the drivers of regional precipitation in a changing climate. Here we present a new speleothem record from Anjohibe, a cave in northwest (NW) Madagascar well situated to record past changes in the Intertropical Convergence Zone (ITCZ). U‐Th ages date speleothem growth from 27 to 14 ka. δ18O, δ13C, and trace metal proxies reconstruct drier conditions during Heinrich Stadials 1 and 2, and wetter conditions during the Last Glacial Maximum and Bølling–Allerød. This is surprising considering hypotheses arguing for southward (northward) ITCZ shifts during North Atlantic cooling (warming) events, which would be expected to result in wetter (drier) conditions at Anjohibe in the Southern Hemisphere tropics. The reconstructed Indian Ocean zonal (west‐east) sea surface temperature (SST) gradient is in close agreement with hydroclimate proxies in NW Madagascar, with periods of increased precipitation correlating with relatively warmer conditions in the western Indian Ocean and cooler conditions in the eastern Indian Ocean. Such gradients could drive long‐term shifts in the strength of the Walker circulation with widespread effects on hydroclimate across East Africa. These results suggest that during abrupt millennial‐scale climate changes, it is not meridional ITCZ shifts, but the tropical Indian Ocean SST gradient and Walker circulation driving East African hydroclimate variability. Plain Language Summary: Long term monsoon dynamics in the southern Indian Ocean and Global South are not well constrained due to a lack of observational data. Paleoclimate records generated from archives like speleothems can help us fill gaps in our understanding. Here we use a speleothem record from Madagascar to test whether north‐south shifts in the tropical rain belt or west‐east changes in Indian Ocean temperatures are more important for precipitation in tropical East Africa. We find that ocean temperature gradients are the most important control on precipitation at our study site during previous instances of abrupt climate change linked to variability in the strength of North Atlantic ocean circulation. This work has important implications for how we think about the future of the tropical Indian Ocean sector in a changing climate. Key Points: Speleothem stable isotope and trace metal data agree on a dry Heinrich Stadial 1 and a wet Bølling–Allerød in northwest MadagascarHeinrich Stadial 1 and the Bølling‐Allerød show conditions contrary to responses expected from north‐south Intertropical Convergence Zone shiftsMillennial‐scale tropical East African hydroclimate variability is likely driven by zonal Indian Ocean sea surface temperature gradients [ABSTRACT FROM AUTHOR]