Climatic Fluctuations Research Articles

The interplay between prehistoric vegetation, climatic fluctuations and anthropogenic activities in Central China

The interaction between climate, hydrological environment, and human activities in prehistoric times has consistently attracted significant interest. However, the process and mechanism of this interaction remain unclear due to a lack of detailed materials that provide information on both human activity and environmental evolution. Here we present a comprehensive dataset of optically stimulated luminescence (OSL) dating and pollen analysis derived from lacustrine facies deposits in the vicinity of the Dongzhao Site in Central China, which is a key region for the origin and development of Chinese civilization. These data have revealed the existence of multiple cycles of environment-human interaction during prehistoric periods. The gradual improvement in the climate and minor fluctuations facilitated the settlement of prehistoric populations in the region, fostering uninterrupted cultural development for millennia since the early Holocene. The increase in population and intensification of human activities significantly affected regional vegetation, resulting in a decrease in the number of trees around 4.0 ka BP. Environmental changes influenced the prehistoric architectural style, resulting in a decrease in houses with “wood bone and mud walls” that were prevalent during the Yangshao periods (7.0–5.0 ka BP) due to a lack of trees. Our research once again highlights the perpetual cycle of interdependence and interaction between natural environments and human activities.

Sedimentary evolution of the Holocene subaqueous Changjiang Delta, with an emphasis on contributions of the two major Rivers, the Changjiang and Yellow Rivers

Subaqueous deltas of large rivers are important repositories of historical environmental changes, and understanding the evolution of deltas is essential for extracting paleoenvironmental data. This study focuses on investigating the evolution of the Holocene subaqueous Changjiang Delta using a long core CJK11 (72.2 m long). The uppermost Holocene mud layer (36.7 m thick) is divided into three units with varying accumulation rates. Through the analysis of source-discriminating proxies, such as clay mineral composition, geochemical trace elements, and strontium isotope ratios (87Sr/86Sr), it is determined that a significant proportion of sediments were derived from the Yellow River (peaking at 36.6 % and averaging 18.4 %), in addition to the predominant sediments from the Changjiang River. By integrating these results with core isochronous correlations and geological contexts, this study establishes the evolution pattern of the modern subaqueous Changjiang Delta, characterized by three distinct stages. During the initial stage (10–5 ka), the study area shifted to neritic environments far from the Changjiang Estuary and experienced slow accumulation due to limited input from the Changjiang and Yellow River-derived sediments. In the middle period (5–3 ka), the study area was situated in neritic environments near the Changjiang Estuary and experienced a sedimentary hiatus due to the absence of contributions from both rivers under cold and arid climatic conditions. High accumulation rates observed locally during the earlier periods may have been influenced by marine hydrodynamic reworking and redeposition processes. In the recent period (3–0 ka), the study area transitioned to prodelta environments, with spatially and temporally varying contributions from the two rivers due to coastal changes resulting from rapid delta progradation. The sedimentary evolution of the subaqueous Changjiang Delta was primarily controlled by climate fluctuations, which may encompass specific factors such as delta progradation, Yellow River channel shifts, and coastal current processes.

Cliff-foot sandy cones: A proxy to study the time frames, patterns and rates of sandstone caprock decay?

Constraining time frames, patterns and rates of sandstone caprock disintegration in tablelands under temperate climate remains challenging. This is due to the scarcity of material in the appropriate geomorphological context that could be dated. Sandy cones are widespread below the sandstone plateaus and may serve as a direct sedimentological evidence of caprock disintegration via subsurface erosion. However, they have not been utilised to their full potential. The paper presents the results of investigation of two sandy cones in the Stołowe Mountains tableland, SW Poland, and soil profiles developed within them. The study also included collecting material for charcoal 14C and single grain Optically Stimulated Luminescence (OSL) dating. Both soil profiles (Dystric Arenosols (Humic)) are dominated by sand fraction. The lens–like laminae of light-coloured sand and darker material enriched in organic matter result from changing sedimentation dynamics. Charcoals were found to be widespread and occur down to the bottom of the studied soil profiles. While they record some of the oldest fire events ever documented in the tableland (mostly from Preboreal and Boreal, in one case from the Younger Dryas), we show that they are inappropriate to determine the timing of sediment deposition because of long residence time in the fissure network. Contrarily, single grain OSL dating is far better suited to trace the sedimentological history of the cones that initiated 10.5 ± 1.5 ka ago. The overall sedimentation trends are similar, likely reflecting climate fluctuations throughout the Holocene and the impact of deforestation. Although sandy cones may serve as a universal geochronological proxy in sandstone tablelands under temperate climate, the patterns and rates at which they develop are site-specific and controlled primarily by local geomorphological and topographical circumstances, governing the efficiency of the sediment supply. This finding was supported by a novel approach to the analysis of FMM components.

Late Quaternary fluvial terrace characteristics and ages of the Pamir‒Tian Shan convergence zone: indications of regional climate change and tectonic uplift

The Pamir‒Tian Shan collision zone, located at the northwestern edge of the Himalaya‒Qingzang orogenic belt, provides a natural laboratory for investigating the development of fluvial terraces controlled by regional climate change and tectonic uplift. In this study, we conducted geomorphological mapping and terrestrial cosmogenic nuclide 10Be dating of fluvial terraces in the Wuheshalu syncline, within the Pamir‒Tian Shan collision zone. Four major fluvial terraces were identified in the Wuheshalu syncline, with ages of approximately 187, 141, 90, and 19 ka, respectively. These terraces were abandoned during three glacial‒interglacial transition periods (Marine Isotope Stage 6/5 (MIS6/5), cold-to-warm transition period of MIS5, and end of MIS2 or MIS2/1) and one interglacial‒glacial period (MIS7/6), and exhibit a strong correlation with regional climate change. Tectonic uplift contributed only one-third of the observed fluvial incision. These results suggest that river incision and terrace formation in the Pamir‒Tian Shan collision zone are primarily driven by periodic fluctuations in climate, with a lesser contribution from tectonic uplift.

Climate Resilience in Farm Animals: Transcriptomics-Based Alterations in Differentially Expressed Genes and Stress Pathways

The livestock sector, essential for maintaining food supply and security, encounters numerous obstacles as a result of climate change. Rising global populations exacerbate competition for natural resources, affecting feed quality and availability, heightening livestock disease risks, increasing heat stress, and contributing to biodiversity loss. Although various management and dietary interventions exist to alleviate these impacts, they often offer only short-lived solutions. We must take a more comprehensive approach to understanding how animals adapt to and endure their environments. One such approach is quantifying transcriptomes under different environments, which can uncover underlying pathways essential for livestock adaptation. This review explores the progress and techniques in studies that apply gene expression analysis to livestock production systems, focusing on their adaptation to climate change. We also attempt to identify various biomarkers and transcriptomic differences between species and pure/crossbred animals. Looking ahead, integrating emerging technologies such as spatialomics could further accelerate genetic improvements, enabling more thermoresilient and productive livestock in response to future climate fluctuations. Ultimately, insights from these studies will help optimize livestock production systems by identifying thermoresilient/desired animals for use in precise breeding programs to counter climate change.

Rainwater harvesting technologies in arid plains of Argentina: small local strategies vs. large centralized projects

Access to water has been and remains one of humanity’s greatest challenges. Especially in arid plains exposed to significant climatic fluctuations and future global change trends. In the past and present, local communities of the arid plains of central-western Argentina (i.e., Guanacache Lagoons, Cuyo region) have developed multiple strategies to manage water supply problems. The aims of this study are: i) to characterize the different water harvesting technologies (pre-Hispanic and modern) used, and ii) to compare the small local strategies of water harvesting (bottom-up solutions) with the large centralized projects (top-down solutions). On the one hand, we show the transformations of these technologies over time, and the challenges faced by inhabitants in the context of climate change trends. On the other hand, we analyze the role of the state through hydraulic policies and projects implemented by the provincial states over the last two centuries and how this impacted the study area. This review is based on a historical and archaeological bibliography, and recent publications about the region, including articles based on our ethnographic fieldwork. Our results demonstrate the valuable experience accumulated by local populations in water harvesting methods, particularly in areas where groundwater is deep and saline, and shows the adaptability of these technologies in contexts of increasing scarcity. We considered that local indigenous knowledge can largely contribute to the sustainable management of water resources. This study might be useful for decision-makers and water managers in drylands around the world to find and equitable approach that combines technical advances with local knowledge.

High-resolution cyclic framework for the Songliao Basin in northeastern China, and its implications for sedimentation and organic matter enrichment

The study of fine-grained sedimentation has consistently concentrated on investigating the mechanisms and principles governing the enrichment of organic matter. However, the lack of unified stratigraphic framework has always existed as fine-grained sedimentation covers two distinct grain-size grades, namely, mud and silt, which has impeded the progress of subsequent production research. This study exemplified this issue by analyzing the first member of the Qingshankou Formation in the southern Songliao Basin. We established reconstructed gamma and density curves that mitigated filter noise interference, integrated high-resolution sequence results with astronomical cycle divisions, and created a high-frequency isochronous stratigraphic framework for clastic fine-grained sedimentation by leveraging the weak sensitivity of sandstone density curves and the robust stability in eccentricity cycle extraction. This approach addresses the inconsistencies in stratigraphic division methodologies and mismatched outcomes stemming from the use varying techniques to delineate mud and silt components within clastic fine-grained sedimentary sequences. Furthermore, it elucidates how tectonic-scale variations in sediment supply coupled with potential accommodation changes dictate macroscopic stacking patterns within strata, whereas climate fluctuations on orbital time scales govern sand-mud progradation degrees within these layers, culminating in periodic rhythmic characteristics characterized by vertical sand-mud interbedding. A model for stratigraphic development pertaining to lake delta systems constrained by a “synchronous heterotopy” paradigm is proposed for the southern Songliao Basin. The organic matter enrichment pattern aligns with its filling dynamics, indicating an “overfilling” type developmental pattern at lower strata levels where organic material predominantly originates from terrestrial plant debris external to the basin; this material accumulates primarily within silty zones along layers—with areas exhibiting heightened enrichment values slightly lagging behind short-eccentric maxima positions. In contrast, under an upper “balanced filling” type developmental framework, sources of organic matter are derived both internally and externally relative to the basin—exhibiting substantial heterogeneity—and regions marked by elevated organic matter concentrations are directly associated with locations identified as short-eccentric maxima.

Indication of Deep-Water Gravity Flow Types by Shelf-Edge Trajectory Migration Patterns: A Case Study of the Quaternary Qiongdongnan Basin, South China Sea

The shelf-edge trajectory is comprehensively controlled by tectonics, sediment supply, sea level, and climate fluctuations; its migration and evolution have a strong influence on what happens in the deep-water depositional system during the Quaternary. The shelf-edge trajectory pattern, sediment-budget partitioning into deep-water areas, and reservoir evaluations are focused topics in international geosciences. In this paper, the Qiongdongnan Basin (QDNB) in the northern South China Sea is taken as an example to study how shelf-edge trajectory migration patterns can influence the types of deep-water gravity flow which are triggered there. Through quantitatively delineating the Quaternary shelf-edge trajectory in the QDNB, four types of shelf-edge trajectory are identified, including low angle slow rising type, medium angle rising type, high angle sharp rising type, and retrogradation-slump type. A new sequence stratigraphic framework based on the migration pattern of shelf-edge trajectory is established. There are four (third-order) sequences in the Quaternary, and several systems tracts named lowstand systems tract (LST), transgressive systems tract (TST), and highstand system tract (HST) are identified. This study indicates that the type of deep-water gravity flow can be dominated by the shelf-edge trajectory migration patterns. When the shelf-edge trajectory angle (α) ranged between 0° and 4°, the continental canyons were mostly small-scaled and shallowly incised, with multiple large-scale sandy submarine fan deposits with few MTDs found in the deep-water area. When the angle (α) ranged from 4° < α < 35°, the size and incision depth of the continental slope canyons increased, relating to frequently interbedded sandy submarine fan deposits and MTDs. When angle (α) ranged from 35° < α < 90°, only a few deeply-incised canyons were present in the continental slope; in this condition, large-scaled and long-distance MTDs frequently developed, with fewer submarine fans deposits. When angle (α) ranged from 90° < α < 150°, the valley in the slope area was virtually undeveloped, sediments in the deep-sea plain area consisted mainly of large mass transport deposits, and submarine fan development was minimal. Since the Quaternary, the temperature has been decreasing, the sea level has shown a downward trend, and the East Asian winter monsoon has significantly enhanced, resulting in an overall increase in sediment supply in the study area. However, due to the numerous rivers and rich provenance systems in the west of Hainan Island, a growing continental shelf-edge slope has developed. In the eastern part of Hainan Island, due to fewer rivers, weak provenance sources, strong tectonic activity, and the subsidence center, a type of destructive shelf-edge slope has developed. The above results have certain theoretical significance for the study of shelf-edge systems and the prediction of deep-water gravity flow deposition type.

Morphology and ecological significance of Holocene palynomorphs from the Indian Ocean Coastal Belt Biome of South Africa

Palynomorphs are indicators of past vegetation change. Since it is accepted that vegetation reflects the local climate, based on modern analogues, palynological analyses are a good proxy for climates of the past. In view of a demand for information on palynomorph types to support palaeoclimatic studies, we present an atlas of palynomorph taxa from the Indian Ocean Coastal Belt of eastern South Africa and Mozambique. Photomicrographs of the fossils are provided as well as brief descriptions and ecological information obtained from the literature. The palynomorphs in this atlas represent a vast variety of pollen, spores (algae, pteridophytes and fungi) and other palynomorphs such as types that were derived from the marine environment and incorporated into the lagoonal deposits. The holistic analysis of all microfossils found here is intended to assist palaeoecological interpretations of wetland dynamics, fire regimes, climate fluctuations and anthropogenic disturbances in the Indian Ocean Coastal Belt.

The Impact of Seasonal Climate on Dryland Vegetation NPP: The Mediating Role of Phenology

Dryland ecosystems are highly sensitive to climate change, making vegetation monitoring crucial for understanding ecological dynamics in these regions. In recent years, climate change, combined with large-scale ecological restoration efforts, has led significant greening in China’s arid areas. However, the mechanisms through which seasonal climate variations regulate vegetation growth are not yet fully understood. This study hypothesizes that seasonal climate change affects net primary productivity (NPP) of vegetation by influencing phenology. We focused on China’s Windbreak and Sand-Fixation Ecological Function Conservation Areas (WSEFCAs) as representative regions of dryland vegetation. The Carnegie–Ames–Stanford Approach (CASA) model was used to estimate vegetation NPP from 2000 to 2020. To extract phenological information, NDVI data were processed using Savitzky–Golay (S–G) filtering and threshold methods to determine the start of season (SOS) and end of season (EOS). The structural equation model (SEM) was constructed to quantitatively assess the contributions of climate change (temperature and precipitation) and phenology to variations in vegetation NPP, identifying the pathways of influence. The results indicate that the average annual NPP in WSEFCAs increased from 55.55 gC/(m2·a) to 75.01 gC/(m2·a), exhibiting uneven spatial distribution. The pathways through which seasonal climate affects vegetation NPP are more complex and uneven. Summer precipitation directly promoted NPP growth (direct effect = 0.243, p < 0.001) while also indirectly enhancing NPP by significantly advancing SOS (0.433, p < 0.001) and delaying EOS (−0.271, p < 0.001), with an indirect effect of 0.133. This finding highlights the critical role of phenology in vegetation growth, particularly in regions with substantial seasonal climate fluctuations. Although the overall ecological environment of WSEFCAs has improved, significant regional disparities remain, especially in northwestern China. This study introduces causal mediation analysis to systematically explore the mechanisms through which seasonal climate change impacts vegetation NPP in WSEFCAs, providing new insights into the broader implications of climate change and offering scientific support for ecological restoration and management strategies in arid regions.

Investigating the impacts of climate variations and armed conflict on drought and vegetation cover in Northeast Syria (2000–2023)

Over the last decades, The Northeast part of Syria (NES) has been significantly affected by multiple drought events, which are exacerbated by armed conflict and climate variations. In this study, the spatiotemporal effects of climate fluctuations on drought episodes and agricultural areas in NES from 2000 to 2023 were examined by utilizing diverse meteorological parameters combined with the normalized difference vegetation index. The relationships between the change in climatic variables and vegetation cover alterations were determined by performing different statistical methods, such as the Pearson correlation coefficient and Mann-Kendall trend analysis. The results indicated a significant decrease in the agricultural area, especially in recent years, accompanied by a notable increase in the precipitation levels. Moreover, there has been a substantial increase in temperatures, particularly in the minimum temperatures. The results also indicate that drought severity and frequency have increased since the armed conflict despite the area receiving higher precipitation amounts, highlighting the role and impacts of violence. Therefore, we recommend further research on how different vegetation species have been affected by climate change and armed conflict, defining specific growing seasons for each vegetation species, and creating land use land cover maps to understand the spatial alteration of these types better.

Analyzing Monterrey blue/green infrastructure for the mitigation of heat islands using Earth Observation and WUDAPT method

Abstract. The Metropolitan Area of Monterrey has grown excessively along with its population in recent decades, resulting in an urban area with problems of distribution of spaces and services. In addition to this, factors such as pollution resulting from industrial activities and the reduction of green areas are related to the increase in temperatures in the area and the creation of urban heat islands, which are mitigated by the cooling action provided by the green/blue infrastructure of urban rivers. Because the rivers in the study area do not have a continuous channel throughout the year and the water supply problems that have recently worsened due to the drought in the north of the country, the riparian vegetation of its 3 rivers (Pesqueria, Santa Catarina and La Silla) plays a crucial role in reducing temperatures by acting as a natural heat sink, so its conservation and restoration is essential. In this research, the influence of rapid urbanization on the deterioration of rivers during 2003, 2013 and 2021 was evaluated using Google Earth Engine and the WUDAPT scheme for local climatic zones, finding that there is a correspondence between local climatic zones and fluctuations in temperature. The results obtained over a period of approximately two decades indicate that natural climate zones register lower temperatures compared to impervious surfaces, and that there is also considerable variation between areas with dense green/blue infrastructure and natural covers with little or no vegetation, since the latter have temperatures similar to those of the built classes.

The impact of temperature on non-typhoidal Salmonella and Campylobacter infections: an updated systematic review and meta-analysis of epidemiological evidence

As temperatures rise, the transmission and incidence of enteric infections such as those caused by Salmonella and Campylobacter increase. This study aimed to review and synthesise the available evidence on the effects of exposure to ambient temperatures on non-typhoidal Salmonella and Campylobacter infections. A systematic search was conducted for peer-reviewed epidemiological studies published between January 1990 and March 2024, in PubMed, Scopus, Embase, and Web of Science databases. Original observational studies using ecological time-series, case-crossover or case-series study designs reporting the association between ambient temperature and non-typhoidal Salmonella and Campylobacter infections in the general population were included. A random-effects meta-analysis was performed to pool the relative risks (RRs) per 1°C temperature increase, and further meta regression, and subgroup analyses by climate zone, temperature metrics, temporal resolution, lag period, and continent were conducted. The Navigation Guide systematic review methodology framework was used to assess the quality and strength of evidence. The study protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO). Out of 3472 results, 44 studies were included in this systematic review encompassing over one million cases each of Salmonella and Campylobacter infections. Geographically, the 44 studies covered 27 countries across five continents and most of the studies were from high income countries. The meta-analysis incorporated 23 Salmonella studies (65 effect estimates) and 15 Campylobacter studies (24 effect estimates). For each 1°C rise in temperature, the risk of non-typhoidal Salmonella and Campylobacter infections increased by 5% (RR: 1.05, 95% CI: 1.04-1.06), and 5% (RR: 1.05, 95% CI: 1.04-1.07%), respectively, with varying risks across different climate zones. The overall evidence was evaluated as being of "high" quality, and the strength of the evidence was determined to be "sufficient" for both infections. These findings emphasise the relationship between temperature and the incidence of Salmonella and Campylobacter infections. It is crucial to exercise caution when generalising these findings, given the limited number of studies conducted in low and middle-income countries. Nevertheless, the results demonstrate the importance of implementing focused interventions and adaptive measures, such as the establishment of localised early warning systems and preventive strategies that account for climatic fluctuations. Furthermore, our research emphasises the ongoing need for surveillance and research efforts to monitor and understand the changing dynamics of temperature-related enteric infections in the context of climate change. Australian Research Council Discovery Projects grant (ARC DP200102571) Program.

Lineage Differentiation and Genomic Vulnerability in a Relict Tree From Subtropical Forests.

The subtropical forests of East Asia are renowned for their high plant diversity, particularly the abundance of ancient relict species. However, both the evolutionary history of these relict species and their capacity for resilience in the face of impending climatic changes remain unclear. Using whole-genome resequencing data, we investigated the lineage differentiation and demographic history of the relict and endangered tree, Bretschneidera sinensis (Akaniaceae). We employed a combination of population genomic and landscape genomic approaches to evaluate variation in mutation load and genomic offset, aiming to predict how different populations may respond to climate change. Our analysis revealed a profound genomic divergence between the East and West lineages, likely as the result of recurrent bottlenecks due to climatic fluctuations during the glacial period. Furthermore, we identified several genes potentially linked to growth characteristics and hypoxia response that had been subjected to positive selection during the lineage differentiation. Our assessment of genomic vulnerability uncovered a significantly higher mutation load and genomic offset in the edge populations of B. sinensis compared to their core counterparts. This implies that the edge populations are likely to experience the most significant impact from the predicted climate conditions. Overall, our research sheds light on the historical lineage differentiation and contemporary genomic vulnerability of B. sinensis. Broadening our understanding of the speciation history and future resilience of relict and endangered species such as B. sinensis, is crucial in developing effective conservation strategies in anticipation of future climatic changes.

Stable isotope of Mesolithic remains of Pila wernei of the Nile area, Sudan: A tool for palaeoenvironment reconstruction

The article deals with stable isotopes of oxygen and carbon on current and archaeological semi-aquatic gastropod shell of the Pila wernei from Sudan and reports some new 14C analyses on archaeological Pila specimens. This, with the aim of obtaining new information on climatic and environmental changes in the al-Khiday area during the first phase of Holocene. The Pila shells come from a well-preserved shell midden present at al-Khiday and dated 8700-7000 cal yr BP. The area of al-Khiday was inhabited since at least 10 ka. Pila wernei species has never been studied in detail; this study demonstrates that the O and C isotope composition of aragonite shell is able to record the environmental and diet changes during the gastropod life. The comparison between the isotope data obtained on present-day and archaeological shells show a prevalence of C4 plants and higher rainfall during the Mesolithic. Two climatic fluctuations have been recognised: the first one indicating wetter conditions from 8650-8400 to 8500-8050 cal yr BP (decrease of the δ18O values), the second one pointing less wetter conditions from 8500-8050 to 7850-7600 cal yr BP (increase of δ18O values). Despite the difficulties in studying semi-aquatic gastropods due to their lifestyle habit, the identification of climatic fluctuations in the Early Holocene confirms the reliability of this proxy for climatic reconstructions. Despite the high number of isotopic analyses (1556) used in this work, they were not sufficient to mirror the fast climate changes characterising the studied period and finally obtain a detailed reconstruction for nearly the two millennia considered. Nonetheless, future projects may benefit greatly from unveiling the shell-environment relationship of the species.

Diversified subsistence patterns and their influencing factors revealed by ancestral paleodiet during the first millenium BC in Northwest Yunnan, China

The in-depth research into how prehistoric human subsistence patterns responded to environmental shifts during the transcontinental spread of crops, livestock, and cultural interactions between the second and first millenium BC is a pivotal scientific endeavor that has aroused widespread attention. Northwest Yunnan, as a vital corridor for human migration, facilitated ancient human dispersals and fostered cultural exchanges. Analyzing prehistoric subsistence patterns in Yunnan, particularly in Northwest Yunnan, is crucial for understanding the dynamics and repercussions of agricultural expansion in Eurasia during prehistory. This study examined stable isotopes extracted from human bone and plant microfossils extracted from dental calculus samples collected from two sites in Northwest Yunnan. The comprehensive analysis revealed that the inhabitants of Northwest Yunnan during the first millenium BC primarily consumed C3 plants (including rice, wheat, barley, buckwheat, legumes, roots and tubers, etcetera), with C4 plants as supplements (such as millets), alongside a high intake of animal protein. With the integration of existing archaeobotanical and zooarchaeological data from neighboring sites, what emerges is a composite subsistence strategy developed by the ancestors in Northwest Yunnan during the first millenium BC, characterized by coexisting practices of planting-gathering and animal husbandry-fishing/hunting. These diversified subsistence patterns were shaped by the cultural influences from Northwest China and the local natural environment, indicating an adaptation to geographical constraints and a strategic response to climatic fluctuations during periods of low productivity.

Holocene environmental evolution and its relationship with human culture in the Luoyang area, Central China

As a key region for the origin and development of Chinese civilization, the relationship between the Holocene environment and human culture in the Luoyang area has garnered significant attention. However, the lack of long-term and multi-factor studies impedes our understanding of the overall characteristics of environmental systems and their interactions with human cultures. Based on extensive field investigations, we conducted a comprehensive study of the BZ profile, which exhibits continuous sedimentation and abundant paleoenvironmental information. The Holocene evolution of climate, deposition, hydrology, and landforms was analyzed, and the human-environment interaction was also examined. The findings demonstrate that the regional Holocene climate also exhibits fluctuations, albeit within a relatively narrow range. The regional sediment was predominantly composed of aeolian loess-paleosols during the early to middle Holocene, while the process of alluviation gradually intensified in the late Holocene. The moderate climatic fluctuations have facilitated the sustainable development of ancient cultures. The intensification of anthropogenic activities may contribute to the increased alluviation during the late Holocene. Ancient humans effectively adapted to this adverse condition by constructing city walls with flood control functions. Our study is significant for enhancing the comprehension of the operational characteristics inherent in human ecological systems.

Spatiotemporal variations of global precipitation concentration and potential links to flood-drought events in past 70 years

The evaluation of precipitation events is crucial for predicting severe droughts and floods, particularly in the context of global warming. This study presents a comprehensive spatiotemporal analysis of the global precipitation concentration index (CI) from 1950 to 2020, comparing CI with nine extreme precipitation indices to assess its applicability. The world map was divided into three distinct regions related to flood-drought events using the standardized precipitation index (SPI). Key findings include: 1) CI exhibited significant spatial heterogeneity, with elevated values in seasonally warm coastlines and arid regions. Seasonal changes in CI were not synchronized, particularly lower in Northern Hemisphere winters, while the Southern Hemisphere displayed minor seasonal variation, alongside a long-term growth trend in approximately 36.5 % of the global area. 2) CI's spatiotemporal variations helped delineating regional precipitation patterns, revealing a strong correlation (R2 = 0.87) with the extreme precipitation index R95c, but a negligible relationship with total precipitation (P) (R2 = −0.05). This facilitated the global partitioning into three regions: Humidity Amplification Region (I), Dryness Intensification Region (II), and Climate Fluctuation Region (III). 3) Flood-drought events were potentially linked to variations in CI and P, where In Region I experienced increased flood risk due to rising CI and P, Region II faced heightened drought risk from rising CI and declining P, and Region III showed opposing effects on floods due to reduced CI and increased P, with P variability significantly influencing flood frequency. 4) The main atmospheric circulation factors varied by region, typically including the Antarctic Oscillation (AAO), Atlantic Multi-decadal Oscillation (AMO) and Arctic Oscillation (AO), with AAO being most significant. This research underscores the intricate relationships between climatic indices and hydrological extremes, emphasizing the challenges posed by global warming, atmospheric circulation changes, and data uncertainties in assessing drought and flood disasters.

Hydrogeochemical Processes in Basement Areas Using Principal Component in Burkina Faso (West African Sahel)

The basement aquifers in Burkina Faso are increasingly exposed to groundwater pollution, largely due to socio-economic activities and climatic fluctuations, particularly the reduction in rainfall. This pollution makes the management and understanding of these aquifers particularly complex. To elucidate the processes controlling this contamination, a methodological approach combining principal component analysis (PCA) and multivariate statistical techniques was adopted. The study analyzed sixteen physicochemical parameters from 58 water samples. The primary objective of this research is to assess groundwater quality and deepen the understanding of the key factors influencing the spatial variation of their chemical composition. The results obtained will contribute to better planning of preservation and sustainable management measures for water resources in Burkina Faso. The results show that three principal components explain 72% of the variance, identifying anthropogenic inputs, with two components affected by mineralization and one by pollution. The study reveals that the groundwater is aggressive and highly corrosive, with calcite saturation. Water-rock interactions appear to be the main mechanisms controlling the hydrochemistry of groundwater, with increasing concentrations of cations and anions as the water travels through percolation pathways. PCA also revealed that the residence time of the water and leaching due to human activities significantly influence water quality, primarily through mineralization processes. These results suggest that rock weathering, coupled with reduced rainfall, constitutes a major vulnerability for aquifer recharge.

Sympatric diversity pattern driven by the secondary contact of two deeply divergent lineages of the soybean pod borer Leguminivora glycinivorella.

The soybean pod borer, Leguminivora glycinivorella (Matsumura), is an important tortricid pest species widely distributed in most parts of China and its adjacent regions. Here, we analyzed the genetic diversity and population differentiation of L. glycinivorella using diverse genetic information including the standard cox1 barcode sequences, mitochondrial genomes (mitogenomes), and single-nucleotide polymorphisms (SNPs) from genotyping-by-sequencing. Based on a comprehensive sampling (including adults or larvae of L. glycinivorella newly collected at 22 of the total 30 localities examined) that covers most of the known distribution range of this pest, analyses of 543 cox1 barcode sequences and 60 mitogenomes revealed that the traditionally recognized and widely distributed L. glycinivorella contains two sympatric and widely distributed genetic lineages (A and B) that were estimated to have diverged ∼1.14 million years ago during the middle Pleistocene. Moreover, low but statistically significant correlations were recognized between genetic differentiation and geographic or environmental distances, indicating the existence of local adaptation to some extent. Based on SNPs, phylogenetic inference, principal component analysis, fixation index, and admixture analysis all confirm the two divergent sympatric lineages. Compared with the stable demographic history of Lineage B, the expansion of Lineage A had possibly made the secondary contact of the two lineages probable, and this process may be driven by the climate fluctuation during the late Pleistocene as revealed by ecological niche modeling.