The Silk Road (Chinese: 丝绸之路), first popularized by the German geographer Ferdinand von Richthofen in 1877, refers to a network of trade routes that stretched from central China to the Pamir, through central Asia and Arabia to India and Rome. The oasis routes have been active for 4000 years though precursors of the Silk Road date back nearly 5000 years and extended to the northern steppes of Central Eurasia. Meanwhile, the Silk Road played a key role in facilitating exchanges in religions, arts, culture, science and technology between East and West. Early trans-Eurasia exchanges and the historical Silk Road reshaped the development of civilizations in Eurasia.
The Silk Road was an exceptional landmark of continental-scale exchanges throughout human history, spanning thousands of years across the vast landscapes of the Gobi Desert, oases, mountains, basins, forests, and steppes in Eurasia. The mechanisms of early human migrations in the paleolithic periods, agriculture origin and early farming diffusion, and civilization development along the Silk Road have attracted high interest from both natural and social scientists. In 2019, the Association for Trans-Eurasia Exchange and Silk Road Civilization Development (ATES) was established to fill the gaps of ongoing Silk Road Study.
The vision of ATES aims to deepen understanding of the interactions between environmental changes, long-term trans-Eurasia exchanges and Silk Road civilizations, by promoting interdisciplinary research of natural sciences, social sciences, and humanities across Eurasia. The main scientific issues of ATES include: 1) Routes and driving forces of ancient human migrations across Eurasia in the Paleolithic; 2) Agriculture origin and prehistoric trans-Eurasian diffusion of early farming and herding; 3) Mechanisms of establishment, shift and demise of routes and key towns along the ancient Silk Road; 4) Pattern and trajectory of knowledge production and dissemination of scientific and technical knowledge and their impact on the multiethnic societies along the Silk Road; 5) Effects of environmental changes on the development of the Silk Road civilization related to trans-Eurasia exchanges in terms of economy, technology and culture.
As of right now, ATES has involved over 200 scientists from more than 50 research institutes across more than 20 countries. There are six working groups established with distinct objectives in ATES. Through the ATES platform, we hope to develop cooperative research and education centers/laboratories with institutes and scientists from all over the world, as well as co-host activities such as young scientist training, collaborative research, conferences, workshops and exhibitions. Currently, ATES-branded activities include the ATES Silk Road Civilization Forum, the ATES Open Science Conference, the ATES Workshop, and the ATES Lecture, among others.
How to cite: Chen, F., Meadows, M., Luterbacher, J., Hou, J., and Ai, L.: Trans-Eurasia Exchange and Silk Road Civilization Development, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14436, https://doi.org/10.5194/egusphere-egu25-14436, 2025.
Lakes are widespread on the Tibetan Plateau, which play a crucial role in reconstructing past climate, environment, ecology, and human activities on the plateau. In the past decades, hundreds of paleolimnological records, employing various proxy indicators, have been reported, promoting our understanding the mechanism of climate changes. However, interpretations of the some paleolimnological records are conflicting, even for the records from the same lake. In this presentation, I will discuss several fundamental scientific issues in the study of paleolimnology and paleoclimatology on the Tibetan Plateau, including 1) the thermodynamic classification of plateau lakes, 2) the transition between open and closed states of lakes, 3) the implication of the proxy indicators, and 4) the issue of dating lake sediments. These issues not only affect the interpretation of proxy indicators in lake sediments but also impact the comparison of records from different proxy indicators within the same lake or the same proxy indicators from different lakes.
How to cite: Hou, J.: Fundamental questions in paleolimnology and paleoclimatology on the Tibetan Plateau, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3366, https://doi.org/10.5194/egusphere-egu25-3366, 2025.
The semi-arid region on the Northeast Tibetan Plateau is characterized by insufficient water resources, sparse vegetation coverage, and fragile ecology, making it highly vulnerable to hydroclimate change. However, the long-term hydroclimate changes in this region and the correlation with ecology change are unclear. Here, we present a highly resolved multi-proxy stalagmite record from an open cave (Yanwu Cave), Northeast Tibetan Plateau, for the past ~1300 years. The antiphased relationship between stalagmite isotope (δ18O and δ13C) records with trace elements (Sr/Ca, Mg/Ca, and Ba/Ca) from Yanwu Cave and regional stalagmite δ18O records indicate a significant influence of kinetic isotope effects on δ18O and δ13C. Utilizing the trace elements records, we reconstruct long-term hydroclimate change on the Northeast Tibetan Plateau. Our records suggest that the increased amplitude of decadal-scale hydroclimate variability during the Little Ice Age (LIA) increased the frequency of extreme climate events. Natural hydroclimatic conditions rather than human activity could have regulated regional vegetation composition change at the transition from Medieval Warm Period to LIA, although human activity has significantly enhanced over the past millennium.
How to cite: Zhang, J., Tang, H., and Tan, L.: The Hydroclimate Change on the Northeast Tibetan Plateau Recorded by Stalagmite from an Open Cave, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14089, https://doi.org/10.5194/egusphere-egu25-14089, 2025.
Investigating the spatiotemporal variations in hydroclimate is essential for addressing the challenges posed by future climate change. The Asian drylands, encompassing Arid Central Asia (ACA) and West Asia (WA), are regions where water vapor transport is predominantly governed by the westerlies. These regions have exhibited a dipole pattern in precipitation variations over recent decades and throughout the Holocene. However, whether this pattern persisted during the past millennium remains uncertain. Our study reveals that both proxy records and PMIP4 models consistently identify a dipole precipitation pattern between ACA and WA on centennial scales over the past millennium. This pattern is attributed to inconsistent seasonal precipitation changes. During the Medieval Warm Period, ACA experienced decreased winter-spring precipitation, while WA observed increased summer rainfall. This trend reversed during the Little Ice Age. The seasonal shifts in precipitation are likely driven by the migration of the westerlies, influenced by internal variability within the Earth's system, particularly the North Atlantic Oscillation (NAO). These findings provide valuable insights for policymakers aiming to address water management challenges in Asia's drylands, offering a foundation for strategies to mitigate and adapt to the impacts of future climate change.
How to cite: Ma, S., Ding, G., and Chen, S.: Characteristics and physical mechanisms of the dipole precipitation variations in the Asian drylands over the past millennium based on proxy-model comparisons, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6095, https://doi.org/10.5194/egusphere-egu25-6095, 2025.
The Central Asian region, characterized by its arid climate and fragile ecological environment, is highly sensitive to climate change, necessitating focused research on its future climate. This study utilizes two global climate model (MPI-ESM1.2-HR and BCC-CSM2-MR) simulations from the sixth Coupled Model Intercomparison Project (CMIP6) to drive the regional climate model WRF for high-resolution (25 km) simulations within the Coordinated Regional Downscaling Experiment (CORDEX) program. These simulations target future climate changes under both low and high emission scenarios, SSP1-2.6 and SSP5-8.5. The historical simulation (1995-2014) was evaluated, indicating that the WRF models can reproduce better spatial and temporal patterns of temperature and precipitation in Central Asia compared to global models, with reduced mean biases and more detailed topography insights especially in mountainous regions. Future climate projections (2021-2060) indicate a significant temperature increase across Central Asia, correlating with rising greenhouse gas concentrations. The most pronounced warming is expected in north-central Kazakhstan. Under SSP1-2.6, the average annual temperature rise for 2041-2060 is projected at 1.37°C, and under SSP5-8.5, it could reach 2.36°C. Winter warming is most rapid, especially in the western regions, while the eastern high-altitude areas experience less warming. In contrast, summer temperatures show an opposite trend. The study also predicts an overall increase in average annual precipitation, with the most significant rise in the southwestern region and a decrease in the northeast. Both SSP1-2.6 and SSP5-8.5 scenarios project a precipitation increase of about 0.50 mm/month (3-4%) during 2041-2060. Precipitation is expected to rise in winter and spring, but decrease in summer, with winter seeing an increase across Central Asia and summer showing a varied pattern of increase in the west and decrease in the east.
How to cite: Zhou, J., Huang, J., Yao, Y., Shi, W., Yuan, H., Qiao, C., and Luo, Y.: Near and Mid-Term Climate Change in Central Asia in the 21st Century from High-Resolution WRF Simulations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7870, https://doi.org/10.5194/egusphere-egu25-7870, 2025.
The southeastern Tibetan Plateau (SETP) is the preeminent summer heavy precipitation region within the Tibetan Plateau (TP). However, the large-scale circulation types and dynamics driving summer heavy pre- cipitation in the SETP remain inadequately elucidated. Using the hierarchical clustering method, two dis- tinctive atmospheric circulation patterns associated with heavy precipitation were identified: the Tibetan Plateau vortex type (TPVT, constituting 56.6 % of the events) and the mid-latitude trough type (MLTT, 43.4 %). A comprehensive examination of the two atmospheric circulation patterns reveals a clear nexus between the occurrences of summer heavy precipitation and positive vorticity anomalies, moisture con- vergence, as well as the southeastward displacement of the westerly jet core. Specifically, TPVT events are characterized by the eastward and dry-to-wet potential vorticity progression processes, while MLTT events are linked to the intrusion of a deep extratropical trough into the SETP. This study advances our understanding of the complex mechanisms governing the summer heavy precipitation in the SETP, shedding light on critical meteorological processes in the region.
How to cite: Cao, D., Chen, X., Chen, D., Du, Y., Luo, Y., Hu, Y., Zhang, Q., Ma, Y., and Chen, F.: Two types of heavy precipitation in the southeastern Tibetan Plateau , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14241, https://doi.org/10.5194/egusphere-egu25-14241, 2025.
Pacific Walker Circulation (PWC) is one of the most active components of tropical atmospheric circulation. Current studies have mainly focused on PWC changes over recent decades and the near future, while less effort has been devoted to long-term PWC variability. In this study, we examine PWC variability over the last millennium (LM) based on the Community Earth System Model Last Millennium Ensemble (CESM-LME). The simulated PWC variations show no significant trend but do reveal decadal fluctuations during the LM, which underestimate the strengthened LIA-MCA PWC differences indicated by proxy records. A quantitative estimation of the contributions made to PWC variability from internal variability and external forcing is conducted by using multiple linear regression (MLR) analysis. The Interdecadal Pacific Oscillation (IPO) accounts for approximately 40% of the PWC variability at the decadal time scale. Volcanic forcing is also an important contributor to PWC variability during the LM. The positive IPO-like SST anomalies are associated with a weakened Indo-Pacific SLP gradient. The low-level wind change is characterized by enhanced westerlies in the tropical western Pacific, which is consistent with a weakened PWC. A significant PWC weakening appears during the first post-eruption year and returns to normal conditions thereafter. This east‒west contrast in equatorial Pacific SSTs, occurring in conjunction with strengthened surface westerly winds, has been suggested to be responsible for the change in PWC strength following large volcanic eruptions.
How to cite: Man, W., Wang, S., and Zhou, T.: The relative contributions of internal variability and external forcing to Pacific Walker Circulation over the last millennium, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16956, https://doi.org/10.5194/egusphere-egu25-16956, 2025.
Yak (Bos grunniens) has a strong adaptability to the alpine ecological environment, and is also known as the "boat of the plateau" and "omnipotent livestock". The domestication of yaks has provided an important survival basis for human beings from seasonal migration to permanent nomadic habitation on the Qinghai-Tibetan Plateau (QTP). However, there are still many controversies and unresolved issues regarding the domestication history of yaks, especially the time, location, and pathway of yak domestication. This study conducted Carbon-14 dating and ancient DNA analysis on 37 cattle (Bos taurus) and yak bone remains excavated from 13 archaeological sites on the QTP. The ancient genomes dating from 40 to 0.14 thousand years ago (Kya) was obtained, and population genetic analysis was conducted based on species identification. The results show that cattle have been introduced to the QTP before 4 Kya, and the hybridization between cattle and wild yaks started before 3.4 Kya. The domestication of yaks occurred after cattle were introduced to the QTP. All ancient domesticated yaks discovered so far are no earlier than 2.6 Kya. In the nearly 1 thousand years from the beginning of hybridization between cattle and wild yaks until the emergence of domesticated yaks, genes related to docility have been introgressed into yak population from cattle population by interspecific hybridization, promoting prehistoric humans successfully domesticate wild yaks. Unlike the three known animal domestication pathways (commensal pathway, prey pathway and directed pathway), yak domestication is more in line with the hybridization pathway. No earlier than 3 Kya, wild yaks were successfully domesticated and cattle gradually adapted to the alpine and hypoxic environment, leading to the formation of yak-cattle husbandry on the QTP. This study is the first case of ancient DNA research focused on yaks, demonstrating that prehistoric Trans-Eurasia exchange not only promoted the spread of livestock, but also facilitated the domestication of related species, changed the livelihood patterns of humans on the QTP, and thus facilitated permanent human occupation of the QTP.
Keywords: yak; domestication; archaeology; genetics; ancient DNA
How to cite: Chen, S., Chen, N., Gao, Y., Yang, X., and Chen, F.: Hypothesis of yak domestication based on archaeological and ancient DNA evidence, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11465, https://doi.org/10.5194/egusphere-egu25-11465, 2025.
Loss of alpine biodiversity under global warming poses a serious threat to biodiversity conservation and ecosystem services, yet few studies have addressed the discrepancies in alpine biodiversity across multiple altitude gradients over the millennia timescale. Here, our study selected three sites (Buqun Lake, Gongka Lake, and Shusong Co) at varying altitudes in the southeastern Tibet Plateau to reconstruct the evolution of vegetation communities during ~3500-0 cal BP using environmental metagenomics in lake sediment. The results suggest: 1) the biodiversity index increased rapidly at low altitude (~1500 m a.s.l) but decreased slowly at median altitude (3500 m a.s.l) and high altitude (4400 m a.s.l) during ~3500-2000 cal BP; 2) the biodiversity index at all three sites remained stable between 0.7 and 0.9 with slight fluctuations during ~2000-0 cal BP; 3) the biodiversity index at low altitude became more similar to those at median and high altitudes over the past millennium, despite differing community compositions among the sites at the three altitude gradients. Considering climate change and internal community interactions, our study primarily interprets that continuous regional warming during ~3500-2000 cal BP contributed to an increase in woody taxa with wide ecological niches (e.g., Salix, Populus, and Quercus) across multiple altitude gradients, further leading to a loss of diversity in alpine shrub-grassland. Meanwhile, these woody taxa with wide ecological niches were able to help resist further impacts from climate change after 2000 cal BP. Our study provides a new perspective on how internal community interactions can influence alpine biodiversity from a millennia-scale environmental metagenomics viewpoint.
How to cite: Dong, H., Wang, Y., Zhang, J., Feng, X., Shao, S., Wu, D., and Hou, J.: Evolution of alpine biodiversity across various altitude gradients in the southeastern Tibetan Plateau over the past 3000 years, as revealed by sedaDNA in lakes, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17697, https://doi.org/10.5194/egusphere-egu25-17697, 2025.
Traditional GIS-based statistical models are intended to extrapolate patterns of settlements and their interactions with the environment. They contribute significantly to our knowledge of past human–land relationships. Yet, these models are often criticized for their empiricism, lopsided specific factors, and for overlooking the synergy between variables. Though largely untested, machine learning and artificial intelligence methods have the potential to overcome these short-comings comprehensively and objectively. The northeastern Tibetan Plateau (NETP) is character-ized by diverse environments and significant changes to the social system from the Neolithic to Bronze Age. In this study, this area serves as a representative case for assessing the complex re-lationships between settlement locations and geographic environments, taking full advantages of these new models. We have explored a novel modeling case by employing GIS and random forests to consider multiple factors, including terrain, vegetation, soil, climate, hydrology, and land suitability, to construct classification models identifying environmental variation across different cultural periods. The model exhibited strong performance and a high archaeological prediction value. Potential living maps were generated for each cultural stage, revealing distinct environ-mental selection strategies from the Neolithic to Bronze Age. The key environmental parameters of elevation, climate, soil erosion, and cultivated land suitability were calculated with high weights, influencing human environmental decisions synergistically. Furthermore, we conducted a quan-titative analysis of temporal dynamics in climate and subsistence to understand driving mecha-nisms behind environmental strategies. These findings suggest that past human environmental strategies were based on the comprehensive consideration of various factors, coupled with their social economic scenario. Such subsistence-oriented activities supported human beings in over-coming elevation limitation, and thus allowed them to inhabit wider pastoral areas. This study showcases the potential of machine learning in predicting archaeological probabilities and in in-terpreting the environmental influence on settlement patterns.
How to cite: Li, G.: GIS and Machine Learning Models Target Dynamic Settlement Patterns and Their Driving Mechanisms from the Neolithic to Bronze Age in the Northeastern Tibetan Plateau, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15070, https://doi.org/10.5194/egusphere-egu25-15070, 2025.
Bacterial lipid branched glycerol dialkyl glycerol tetraethers (brGDGTs) are a valuable tool for reconstructing past temperatures. However, a gap remains regarding the influence of bacterial communities on brGDGT profiles. Here, we identified two distinct patterns of brGDGTs from the surface sediments of 38 Tibetan Plateau lakes using an unsupervised clustering technique. Further investigation revealed that salinity and pH significantly change bacterial community composition, affecting brGDGT profiles and causing brGDGT-based temperatures to be overestimated by up to 2.7 ± 0.7 °C in haloalkaline environments. We subsequently used the trained clustering model to examine the patterns of bacterial assemblages in the global lacustrine brGDGT dataset, confirming the global applicability of our approach. We finally applied our approach to Holocene brGDGT records from the Tibetan Plateau, showing that shifts in bacterial clusters amplified temperature variations over timescales. Our findings demonstrate that microbial ecology can robustly diagnose and constrain site-specific discrepancies in temperature reconstruction.
How to cite: Xie, H., Liang, J., Hou, J., and Herzschuh, U.: Discrepancies in lacustrine bacterial lipid temperature reconstructions explained by microbial ecology, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2354, https://doi.org/10.5194/egusphere-egu25-2354, 2025.
Vegetation is sensitive to climate change, and the Normalized Difference Vegetation Index (NDVI) is an important indicator in studies of changes in surface vegetation coverage. However, observed NDVI data only became available in the 1980s, and thus reconstructing long-term changes in NDVI on the Earth's surface has become an important topic in paleoclimate reconstruction. In this study we established a tree-ring width index chronology for Juniperus excelsa in the western Elburz Mountains in west Asia; we then analyzed the correlation between the tree-ring width index and NDVI, and reconstructed the vegetation dynamics in response to climate change in this region since 1943. Our findings show that the tree-ring width index effectively represented the changes in NDVI from April to August. The NDVI changes reconstructed from the tree-ring width index show that fluctuations in the vegetation cover since the 1990s were more pronounced compared to the 1940s–1980s. Notably, periods of low vegetation cover occurred in the early 21st century, while high vegetation cover occurred in the early 2020s. Overall, our study integrates dendrochronology and remote sensing techniques to develop a methodology for the long-term reconstruction of the vegetation dynamics in the study region, and the results contribute to an improved understanding of the vegetation dynamics in west Asia and their response to climate change.
How to cite: Wang, Y., Chen, S., Xie, H., Su, Y., Ma, S., and Xie, T.: Tree-Ring Reconstruction of Changes in Surface Vegetation Cover in west Asia since AD 1943, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14508, https://doi.org/10.5194/egusphere-egu25-14508, 2025.
Atmospheric dust has important influences on atmospheric circulation, global biogeochemical cycles, and hydrological processes. However, understanding the history of dust storms on the Tibetan Plateau (TP) remains challenging due to the lack of suitable geological archives. Lakes in dust-influenced regions act as dust repositories, offering the opportunity to trace the history of dust emissions and eolian activity. Here we present a synthesis of eolian activity on the eastern TP covering the past 15,000 years. It is based on records of grain size and n-alkanes from a sediment core from Gahai lake, which we combined with published pollen and other records from the same core, to reconstruct variations in surface runoff and eolian activity in this region. Our results indicate a correlation between vegetation conditions and eolian activity during different periods. Increased eolian activity occurred during the transition from the last deglaciation to the early Holocene, due to suboptimal vegetation conditions. Between 7.5 and 3.5 cal ka BP (ka), higher moisture levels resulted in the dominance of arboreal vegetation, which suppressed eolian activity. However, after 3.5 ka a sustained intensification of eolian activity occurred in the Gahai area, which was linked to decreasing vegetation cover, reduced regional humidity, and growing human impacts, especially in the eastern plateau, in southern Gansu. In recent decades, human interventions have suppressed eolian activity. Additionally, a ~1435-year cyclicity in our record, and other regional records, suggests a link between increased eolian activity on the eastern TP and ice-rafting events in the North Atlantic. Generally, Holocene eolian dynamics were primarily influenced by the regional vegetation and climatic conditions which were controlled by the atmospheric circulation. However, in the late Holocene, climatic shifts and human influences had a synergistic effect which intensified the eolian activity, highlighting the important role of humans on recent dust dynamics in this region.
How to cite: Hou, X.: Lake sediment record of eolian activity on the eastern Tibetan Plateau since 15 cal ka BP, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14084, https://doi.org/10.5194/egusphere-egu25-14084, 2025.
Flooding and warfare were important challenges to the development of human societies in the Late Holocene, especially in flood-prone areas, including the Bailongjiang Basin in the northeastern Tibetan Plateau. It is not clear how ancient societies in this region fought against flooding and war, and its study is an important way to explore the patterns of human-environment interactions. In response to these questions, a detailed survey of ancient cities in the upper Bailongjiang River during the historical period was carried out, and 42 dating samples were collected from six ancient cities and one site. The results showed that these ancient cities were mainly built during the Tang and Qing dynasties. Among them, a unique three-dimensional defence system was discovered for the first time in the investigation and research in the area of the ancient city of Diezhou, including city walls and water retaining walls from the Sui and Tang dynasties, as well as enclosure walls and beacon flints from the Qing dynasty. A combination of geomorphological surveys, historical documents, and paleoclimatic data suggests that ancient humans constructed the three-dimensional defence system in this area mainly in response to high-frequency flooding triggered by climate change, as well as wars between the Tang and Tubo, and between the Qing and the Heshuit Khanates. This study provides a typical example of human-water-war interactions during the historical period in the high mountain valley area of the northeastern Tibetan Plateau, which is of great academic value for the in-depth understanding of the process and mechanism of the evolution of human-earth relations in the high mountain valley area.
How to cite: Zhang, S.: Human struggled against floods and wars in mountain-gorge of NE Tibetan Plateau: unique city-wall system evidence, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9695, https://doi.org/10.5194/egusphere-egu25-9695, 2025.
Climate change and water availability in arid West Asia are critical to understanding human adaptation to long-term environmental changes. While droughts are well-documented, water availability remains insufficiently quantified. Using high-resolution satellite imagery and deep learning, we examined water bodies across West Asia, revealing long-term changes and their drivers from 1990 to 2020. By 2020, 12,725 water bodies covering 32,860 km2 were identified, with 94% being previously unreported artificial bodies. Despite a 42% increase in artificial water area and the addition of 3,400 new reservoirs since 1990, water resources in West Asia have declined by 140 km2 annually, primarily due to the shrinking of natural lakes like Lake Urmia, driven by the effects of reservoirs. Our findings indicate that ineffective water management, especially overreliance on infrastructure, has aggravated water imbalances, leading to severe shortages. With predicted droughts and rising demand, Lake Urmia may dry up by 2090, and the regional water crisis is projected to worsen, underscoring the urgent need for effective water resource management.
How to cite: Su, Y., Chen, S., Feng, M., and Chen, F.: Ineffective actions on water scarcity exacerbate the water crisis in West Asia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12026, https://doi.org/10.5194/egusphere-egu25-12026, 2025.
Tibetan antelope (Chiru, Pantholops hodgsonii), an endemic species of the Tibet Plateau, inhabits the open alpine and desert steppe areas ranging 3250 to 5500 m altitude. In the past decades, the antelope population has been significantly affected by human activities, including massive illegal hunting, followed by strict protection policies and establishments of natural reserves. Various techniques have been devoted to monitor antelope population changes and study their habitat, but these are limited to the past several decades and can only provide limited information on past changes in antelope population. We reconstructed antelope population changes during the Holocene using sediment cores at Lake Zonag, one of the most important calving grounds for Tibetan antelope. We measured the content of 24-ethyl-coprostanol and 24-ethyl-epicoprostanol, signature fecal sterols of herbivores, as a proxy for the antelope population. The fecal sterols captured the sudden decrease in antelope population due to illegal hunting in 1980s, as well as the recent recovery because of protection, giving us confidence in using fecal sterol as the proxy for population changes of the Tibetan antelope. The results show the antelope population in Lake Zonag region fluctuated significantly during the past 9000 years, with clearly low population at 5.1-4.5 and 4.1-3.7 ka. Fluctuation of antelope in the Lake Zonag catchment show strong response to environment changes during the Holocene. When the environment was relatively humid with dense vegetation cover, the antelope population increased, and vice versa. Over the past 400 years, the changes in the population size of Tibetan antelope have been affected by human activities.
Our study was the first to identify the signature fecal sterols to represent the population changes of the Tibetan antelope. Understanding how the population size of Tibetan antelopes responded to environment changes in the past would provide scientific basis for long-term conservation policies for Tibetan antelopes.
How to cite: Wang, Z., Qu, Q., and Hou, J.: Responses of Tibetan antelope population to environment changes during the Holocene, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3914, https://doi.org/10.5194/egusphere-egu25-3914, 2025.
The Tibetan Plateau (TP) is an important link between the South Asian monsoon region, the East Asian monsoon region, and the drylands of Central Asia. Climate changes within these regions are dominated by both the monsoon and the westerlies with precipitation primarily concentrated in the summer. Although previous research has examined the characteristics of interdecadal precipitation variations in these regions, the interconnectivity among these variations remain underexplored. Here, we summarize the current understanding on precipitation variations, with the aim of elucidating the interconnections among regional interdecadal precipitation variations from the perspective of the Asian summer precipitation region. Recent research has identified a "North-South dipole pattern” of precipitation variations across the TP over the past few decades, characterized by increased precipitation in the northern TP and decreased precipitation in the southern TP. This regional pattern is a manifestation of a broader "Mega-sandwich pattern" of interdecadal precipitation variations in Asian summer precipitation. The "Mega-sandwich pattern" includes the North-South dipole pattern in High Mountain Asia, the "Westerlies-dominated climatic regime" in mid-latitude Asia, and the "South Flood (Drought) and North Drought (Flood)" pattern in the East Asian monsoon region. This pattern not only exists at the present day under rapid global warming, but also that it may have occurred throughout the Holocene. Future research on the "Mega-sandwich pattern" of precipitation changes in the Asian summer monsoon region should focus on larger spatial and longer temporal scales, leveraging extensive paleoclimate records, modern observational data, and high-resolution climate models to deepen our understanding of its characteristics and underlying mechanisms.
How to cite: Chen, F., Huang, L., Cao, D., Chen, J., Chen, S., Ma, S., and Zhou, T.: ‘‘Mega-sandwich pattern” of interdecadal precipitation variations and itsregional manifestation in the Asian summer precipitation region, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15021, https://doi.org/10.5194/egusphere-egu25-15021, 2025.
The Middle Paleolithic is a hotly debated issue in China, in particular with the intriguing findings in recent years in both northern and southern China. Here we present a new Middle Paleolithic site named the Longtan site located in the Heqing couty, Yunnan Province. The age of Longtan has been dated to ca. 60-50 ka. Lithic assemblage excavated from the site shows distinct technological and morphological features, with the Quina retouch being the most representative feature. Results show that Quina scrapers at the site were mainly made on thick and big-sized flake blanks and the functional edges exhibit scaled and invasive retouching scars. Resharpening flakes have also been identified, suggesting the existence of rejuvenation behavior and the lengthy use-life of Quina scrapers at Longtan. The finding of Quina-type lithic assemblage at the Longtan site provides key evidence for our understanding of the diversity and complexity of the Middle Paleolithic techno-complexes in China and relevant human environmental adaptations in the region.
How to cite: Li, H., Ruan, Q., Xiao, P., Dalpiano, D., Peresani, M., and Chen, F.: The Quina techno-complex in southwestern China and implications for human environmental adaptation , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14480, https://doi.org/10.5194/egusphere-egu25-14480, 2025.
Ancient DNA (aDNA) analysis offers valuable insights into the domestication and spread of foxtail millet (Setaria italica) across northern China and the Tibetan Plateau. This study leverages advanced genomic techniques to reconstruct the evolutionary history and adaptation of this crucial crop.
To overcome the limitations of ancient environmental DNA (aeDNA) in paleoecology and evolutionary studies, we developed eProbe, a flexible toolkit for designing, assessing, and validating hybridization capture probes. Benchmarking a foxtail millet probe set generated by eProbe demonstrated a 455-fold increase in target DNA recovery and high genome coverage, enabling detailed population and evolutionary genetic analyses.
Using these custom-designed probes, we enriched foxtail millet aDNA from archaeological and lake sediment samples across the Tibetan Plateau and northern China. This approach provides unprecedented insights into the spread and adaptation of foxtail millet as it ascended the plateau and underwent domestication. Combined with data from ancient seed enrichment, this dual analysis offers a comprehensive understanding of foxtail millet's evolutionary history and its role in high-altitude agricultural adaptation.
By integrating data from both ancient seed enrichment and environmental samples, this study offers critical insights into the complex processes of foxtail millet domestication and its impact on ancient agricultural systems in East Asia. Furthermore, these findings provide valuable context for understanding how ancient trade networks, such as the Silk Road, may have facilitated the exchange and adaptation of staple crops, influencing agricultural development and cultural interactions across Eurasia.
How to cite: Huang, Z., Sun, X., and Wang, Y.: Ancient DNA of millets shed new lights for its spread in northern China and Tibetian plautue, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17473, https://doi.org/10.5194/egusphere-egu25-17473, 2025.
Sedimentary ancient DNA (sedaDNA) extracted from sediment samples at the high-altitude Marbuco site (4400 meters above sea level) provides critical insights into human-environment interactions. With increasing climate impacts on high-altitude human activities, the Marbuco site offers valuable information on early subsistence strategies, species utilization, pastoralism, trade practices, and responses to climate change. The sedaDNA analysis revealed genetic signatures from various species, including those closely linked to pastoralism, such as goat (Capra), sheep (Ovis), and cattle (Bos), with strong signals indicating the importance of these animals in the site’s pastoral activities. Additionally, DNA from aquatic species, including cormorant (Phalacrocorax), golden-line carp (Sinocyclocheilus), and Tibetan loach (Triplophysa), was also prevalent, corresponding to numerous bone tools and fish remains, suggesting the site's residents actively utilized aquatic resources. Beyond domesticates and aquatic species, the sediment also contained abundant DNA from wild animals, highlighting the diverse resource use at the site. Common wild species included the Mongolian gerbil (Meriones), Tibetan gazelle (Procapra), wild rabbit (Lepus), and eagle (Aquila). The genetic signals from these species suggest that ancient residents likely relied on hunting and foraging for these wild animals, which may have been used for food or other necessities. The presence of the Mongolian gerbil and Tibetan gazelle further suggests hunting activities in the high-altitude environment, as well as the role these wild species played in the subsistence strategies of the settled population. Crop DNA, particularly from wheat (Triticum) and barley (Hordeum), was also detected, providing direct evidence of trade activities at Marbuco. The presence of crop DNA supports the hypothesis of early trade practices, possibly involving exchanges with Southeast Asia.
This study underscores the potential of constructing a comprehensive sedaDNA database to provide higher-resolution insights into the species utilized by the ancient residents of Marbuco. By analyzing the DNA signatures of different species, the study highlights the role of sedaDNA in understanding how climate change influenced subsistence strategies, particularly in extreme high-altitude environments. These findings contribute valuable evidence for understanding the diverse livelihoods, pastoral activities, wild species utilization, and adaptation strategies of high-altitude settled populations.
How to cite: Cai, Y., Yang, X., Chen, F., Gao, Y., and Wang, Y.: Sedimentary Ancient DNA Reveals Further Evidence of Early Settlement Strategies, Pastoralism, and Trade Practices of High-Altitude Populations at the Mabu Co Site on the Tibetan Plateau, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20018, https://doi.org/10.5194/egusphere-egu25-20018, 2025.
Posters virtual: Thu, 1 May, 14:00–15:45 | vPoster spot 5
EGU25-10025 | Posters virtual | VPS6
Discussion of the “warming and wetting” trend and its future variation in the drylands of Northwest China under global warmingThu, 01 May, 14:00–15:45 (CEST) vPoster spot 5 | vP5.14
Since Shi et al. proposed that the climate in the drylands of Northwest China experienced a significant transition from a “warming and drying” trend to a “warming and wetting” trend in the 1980s, researchers have conducted numerous studies on the variations in precipitation and humidity in the region and even in arid Central Asia. In particular, the process of the “warming and wetting” trend by using obtained measurement data received much attention. However, there remain uncertainties about whether the “warming and wetting” trend has paused and what its future variations may be. In this study, we examined the spatiotemporal variations in temperature, precipitation, the aridity index (AI), vegetation, and runoff during 1950–2019. The results showed that the climate in the drylands of Northwest China and the northern Tibetan Plateau is persistently warming and wetting since the 1980s, with an acceleration since the 1990s. The precipitation/humidity variations in North China, which are mainly influenced by summer monsoon, are generally opposite to those in the drylands of Northwest China. This reverse change is mainly controlled by an anomalous anticyclone over Mongolia, which leads to an anomalous easterly wind, reduced water vapor output, and increased precipitation in the drylands of Northwest China. While it also causes an anomalous descending motion, increased water vapor divergence, and decreased precipitation in North China. Precipitation is the primary controlling factor of humidity, which ultimately forms the spatiotemporal pattern of the “westerlies-dominated climatic regime” of antiphase precipitation/humidity variations between the drylands of Northwest China and monsoonal region of North China. The primary reasons behind the debate of the “warming and wetting” trend in Northwest China were due to the use of different time series lengths, regional ranges, and humidity indices in previous analyses. Since the EC-Earth3 has a good performance for simulating precipitation and humidity in Northwest and North China. By using its simulated results, we found a wetting trend in the drylands of Northwest China under low emission scenarios, but the climate will gradually transition to a “warming and drying” trend as emissions increase. This study suggests that moderate warming can be beneficial for improving the ecological environment in the drylands of Northwest China, while precipitation and humidity in monsoon-dominated North China will persistently increase under scenarios of increased emissions.
How to cite: Xie, T.: Discussion of the “warming and wetting” trend and its future variation in the drylands of Northwest China under global warming, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10025, https://doi.org/10.5194/egusphere-egu25-10025, 2025.
Posters virtual: Fri, 2 May, 14:00–15:45 | vPoster spot 5
EGU25-10215 | Posters virtual | VPS7
Human activity has decoupled oasis evolution from climate change since ~2 ka in the Tarim BasinFri, 02 May, 14:00–15:45 (CEST) vPoster spot 5 | vP5.6
EGU25-12114 | Posters virtual | VPS7
Reconstruction of dust activity using geochemical proxy from cave stalagmite in the northern Taklimakan DesertFri, 02 May, 14:00–15:45 (CEST) vPoster spot 5 | vP5.4
Located in the arid inland of Asia, the eastern part of the Silk Road is marked by certain routes being close to or even crossing large deserts, such as the Taklimakan Desert, one of the largest deserts worldwide. As a result, sand and dust activities have a considerable impact on the transport routes, the desert-oasis ecosystem, and human society along the Silk Road. However, the evolution of dust activity over the past two millennia and its relation to the changes of the Silk Road civilization remains ambiguous. Here, we present a high-resolution (~3 yr) stalagmite record from Xinjiang (northwest China) spanning the past 2,500 years, dated with 19 U/Th ages. Although the stable isotopes and trace elemental ratios of the stalagmite reveal remarkable decadal- to centennial-scale variability of the regional hydroclimate, the Mg/Ca ratio shows a quite different variation pattern compared with other geochemical proxies. Considering various factors that might influence the Mg/Ca ratio of stalagmites, our analysis reached the conclusion that the geographical location close to the desert made the imported dust likely to predominate the increase of Mg/Ca in stalagmites during many characteristic periods. For instance, we found significant increases in the Mg/Ca ratios lasting for more than two centuries during approximately 650-850 CE and 1650-1950 CE (i.e., the Little Ice Age). This generally demonstrates a pattern of reduced dust activities during the Medieval Warm Period and enhanced dust activities throughout the Little Ice Age, which is supported by evidence from the eolian sedimentary section in the southern margin of the Taklimakan Desert that directly reflects dust activity. We further found that the enhanced dust activity during the 650-850 CE might have caused the route shift of the Silk Road from south to north in the Tarim Basin. In addition, the rapid drying of Lop Nur in recent decades could also be attributed to abnormally increased dust activity, as this period was characterized by the most intense dust activity in our records over the last 2,000 years. Our findings further substantiate the argument regarding the association between societal and climatic change along the Silk Road, where the dust production from large deserts poses challenges to sustainable development in the present and the future.
How to cite: Liu, X., Chen, S., Chen, J., Wang, H., Shen, C.-C., Wang, X., and Chen, F.: Reconstruction of dust activity using geochemical proxy from cave stalagmite in the northern Taklimakan Desert, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12114, https://doi.org/10.5194/egusphere-egu25-12114, 2025.
EGU25-16630 | Posters virtual | VPS7
Loess-paleosol sedimentological characteristics in northern Iran since the last interglacial and their paleoenvironmental significanceFri, 02 May, 14:00–15:45 (CEST) vPoster spot 5 | vP5.5
The climatic signals recorded by loess sequences vary between different regions, which makes it important to study loess sequences worldwide. The loess deposits in northern Iran are situated in the transitional zone between the European loess and Central Asian loess. However, the depositional dynamics and paleoenvironmental significance of the loess deposits in this region are not well understood, making it difficult to establish detailed correlations with loess deposits elsewhere, partly due to the lack of systematic and high-resolution chronological control. We used K-feldspar pIR50IR290 and MET-pIRIR250 luminescence dating protocols to date fifty-two K-feldspar samples from the Toshan-19 section in the northern foothills of the Alborz Mountains, northern Iran. These chronological data, along with the climate proxies of magnetic susceptibility and redness, combined with a comparison with published loess records from various regions, indicate the following: (1) K-feldspar luminescence ages obtained using pIRIR and MET-pIRIR protocols are consistent, and their luminescence ages up to ~200 ka are deemed dependable. The loess at Toshan was primarily deposited during 78–24 ka, corresponding to MIS 4–2, and the paleosols developed during 139–78, and 24–1.7 ka, corresponding respectively to MIS 5, and late MIS 2–MIS 1. (2) Drier conditions prevailed during the last glacial and wetter conditions dominated during the last interglacial. Moisture variations during the substages of MIS 5 in this region indicate cold-dry and warm-wet climatic characteristics. The reasons for increased moisture from late MIS 2 onwards in this region still require further investigation. (3) The loess-paleosol records indicate a consistent pattern of climate change over Eurasia on the scale of the last interglacial-glacial cycle. During the substages of MIS 5, warm-wet and cold-dry conditions in northern Iran were in-phase with those on the Chinese Loess Plateau, Europe, and southern Tajikistan; however, they were anti-phased or out-of-phase with those in Xinjiang.
How to cite: Li, D., zhao, H., and Xie, H.: Loess-paleosol sedimentological characteristics in northern Iran since the last interglacial and their paleoenvironmental significance, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16630, https://doi.org/10.5194/egusphere-egu25-16630, 2025.
EGU25-14138 | ECS | Posters virtual | VPS7
Late Quaternary lake level variations of Mabu Co-Gala Co, southern Tibetan Plateau, and the impacts on early inhabitantsFri, 02 May, 14:00–15:45 (CEST) vPoster spot 5 | vP5.14
Lakes on the Tibetan Plateau (TP) play a major role in the regional hydrological cycle and underpin vital ecosystem services. However, the long-term lake evolution and underlying mechanisms, especially on the exorheic southern TP, remain unclear. Here, we reconstructed the lake level variations of Mabu Co and Gala Co on the southern TP through detailed paleo-shoreline dating using post-infrared infrared stimulated luminescence (pIRIR) signals of K-feldspar single grains, and explored the driving forcings based on a comparison of paleoclimate records and geomorphological analysis. The results show that a unified paleolake at Mabu Co and Gala Co at a level ~20 m above the modern level (a.m.l.) of Mabu Co developed during the late MIS 3 (35.9±1.9-29.1±1.4 ka) in response to increased glacial meltwater and Indian summer monsoon (ISM) rainfall. Under intensive glacier melting, the paleolake reached its maximum level (~29 m a.m.l.) and area (190 km2, ~22 times larger than the modern areas of Mabu Co and Gala Co) during the last deglacial (16.8±1.0-13.6±0.7 ka) and began to outflow, which triggered incision and lowering of the spill-point. The lake level showed an overall decreasing trend since the last deglacial largely influenced by the lowering of the spill-point. During the last deglacial-early Holocene (12.7±0.6-9.8±0.6 ka), a high-stand lower than that in the previous stage (~24 m a.m.l.) was maintained by the strengthened ISM and glacial meltwater. In the mid-Holocene (8.7±0.9-4.1±0.3 ka), the paleolake experienced two rapid lake level drops in response to the weakening events of the ISM. The exposed shoreline terrace between the two lakes following the lake level drop after ~6 ka provided an ideal living surface for the inhabitants at the Mabu Co site during 4.5-4.0 ka. We found that glacial meltwater and lake spillover processes, apart from the ISM, have exerted great impacts on the hydrological history of Mabu Co and Gala Co. The paleolakes have provided critical resources for humans at the Mabu Co site living in the alpine anoxic environment. Additionally, we suggest that lakes with low spill-points adjacent to exorheic basins on the southern TP should be given more attention regarding flooding hazard risks against increasing precipitation and glacial meltwater in the future.
How to cite: Zhang, S.: Late Quaternary lake level variations of Mabu Co-Gala Co, southern Tibetan Plateau, and the impacts on early inhabitants, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14138, https://doi.org/10.5194/egusphere-egu25-14138, 2025.
