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In this paper, we investigate Holocene precipitation changes in northern China to improve the understanding of the East Asian summer monsoon (EASM) and provide an environmental context for the development of Chinese civilisation. Our study is based on an analysis of 260 pollen samples from Holocene lacustrine sediments at Ningjinpo in northern China, and employs the biomisation method to reconstruct regional vegetation types and vegetation changes, and to decipher their driving factors, by incorporating regional climatic data and information on human activities. Results indicate that, in the early Holocene (10,000–8100 cal yr B.P.), regional climate was dry, with annual precipitation of 470 mm. In the middle Holocene (8100–3000 cal yr B.P.), a rapid increase was observed in precipitation, reaching 580 mm. During the late Holocene (2600–600 cal yr B.P.), climate became drier again, with annual precipitation decreasing to 480 mm. Between 10,000–600 cal yr B.P., vegetation exhibited distinct successional patterns dominantly influenced by climate, transitioning from meadow-steppe to forest, and then back to meadow-steppe. After 600 cal yr B.P., vegetation succession decoupled from climate change, with human activities emerging as the primary driving force, as indicated by the substantial increase in anthropogenic pollen and charcoal concentrations. In the future, under the combined influence of global warming and intensified human activity, the implementation of scientific environmental planning measures will become increasingly important for the restoration and sustainable development of regional vegetation ecosystems. • Unambiguous high-resolution precipitation record from the North China Plain. • Human activities variedly impact vegetation evolution since 2600 cal yr B.P. • A shift from natural to anthropogenic vegetation change happened at 600 cal yr B.P. [ABSTRACT FROM AUTHOR]

Quantifying the relative influences of anthropogenic activities and climate change on soil erosion and deposition during the Holocene, when both forces have been interacting is a complex problem. Analysis of long-term patterns in soil erosion and lake deposition in a basin can provide the basis for untangling the complexities of climate and anthropogenic forcings. In this paper, sedimentary sequences from Xingyun Lake are compared with simulated soil erosion rates in the basin to explore the relationship between river basin soil erosion and lake deposition during the Holocene in Yunnan, China. Modern soil erosion rates are calculated using RUSLE, while Holocene soil erosion rates are estimated using modern rates with reconstructed precipitation and vegetation cover sequences. Through this investigation, we found the following results. First, Holocene vegetation in the lake basin was mainly affected by climate change, and the vegetation experienced the same pattern of changes as the climate. Soil erosion and lake deposition rates, along with changes to vegetation cover, were synchronous with precipitation trends during the Holocene. Second, soil erosion and lake deposition have been exacerbated by human activities, such as deforestation and land reclamation in the Xingyun Lake basin. Finally, this study provides new insights into the effects by anthropogenic impacts and climate forcing on the processes of soil erosion and lake deposition on the millennium scale. [ABSTRACT FROM AUTHOR]

The Salawusu River Valley cuts through the Mu Us Desert in north central China, and lies at the interface of the East Asian Summer and Winter Monsoonal regions. Exposed at numerous locations in the valley side are extensive late Quaternary deposits, consisting of interbedded aeolian sands, fluvio-lacustrine units and palaeosols. Due to the importance of the location in potentially elucidating both summer and winter monsoonal regimes, and the quality of the sedimentary record, the region has a rich history of study, and yet even within the Holocene sequence, many conflicting interpretations have arisen based on studies on different sections. This paper aims to synthesize and explore these differences by exploring the lateral continuity of the Holocene sequences along a ~ 45 km reach of the valley, and presenting new, detailed physical and geochemical analyses of three sections, focusing on the lacustrine Holocene Dagouwan Formation. The absence of the lacustrine unit at several locations confirms that rather than representing a single lake, the Dagouwan Formation instead represents a series of palaeolakes, probably at least partially hydrologically isolated from each other by aeolian sands. All begin with sand-dominated deposits during the early−/mid-Holocene, which is interpreted as the result of abundant sand-supply to the north and west, under the influence of an enhanced East Asian Winter Monsoon, and all switch to silt-dominated, more carbonate-rich deposits during the mid−/late-Holocene, which is attributed to an enhanced East Asian Summer Monsoon bringing loessic silts from the Chinese Loess Plateau to the east and south. The timing of this change, perhaps as late as 5.5 ka, supports the idea of a relatively enhancement late mid-Holocene of the summer monsoonal circulation in the region. However, despite the proximity of the sections and consistent analytical approaches, marked differences between the sections occur in all proxies studied. The timing and rate of the switch from sand- to silt-dominated lacustrine deposition varies between the sites by as much as 2000 years within just a few kilometres of each other, and at some sites the switch was gradual, whereas at others it was very rapid. Similar dramatic variations are also seen with organic carbon content, carbonate content, C:N ratio, and especially the δ13C isotopic ratio. These point to the lake basins behaving very differently, and emphasize that consideration must be given to the local geomorphology and palaeolimnological evolution of individual sections. • Differences in lacustrine Holocene monsoon records in northern China are explored. • The occurrence of the lakes is geomorphologically, not climatologically, controlled. • Different sections of similar units represent different lakes with varied histories. • Consistent changes in sediment suggest mid-Holocene decline of winter monsoon. • Study of individual sections or proxies cannot be used to infer regional climate. [ABSTRACT FROM AUTHOR]

Ecosystems in arid regions with sandy substrates are vulnerable to various environmental challenges. Understanding the vegetation evolution of such regions over a long timescale and the possible drivers of change is important for optimizing ecological restoration. In this paper, we present multi-proxy data to understand Holocene vegetation dynamics and their drivers in the Horqin Sandy Land in northern China. Phytoliths are used to reconstruct vegetation; grain size and magnetic susceptibility are used to reconstruct the climate; and sedimentary charcoal contents and the numbers of regional archaeological sites are used to reconstruct the fire activity and human activity intensity, respectively. Results indicate that the Horqin Sandy Land was covered mainly by grassland vegetation during the Holocene, and that the trajectory of vegetation evolution was as follows: sparse and species-poor Leymus chinensis grassland from 9300 to 6150 cal yr BP, relatively sparse and species-rich mesophytic herb grassland from 6150 to 2300 cal yr BP, and dense and species-rich L. chinensis grassland from 2300 to 250 cal yr BP. Climate change was the main driver of vegetation evolution, but fire and human activities also influenced the vegetation to varying degrees. Fire made the greatest contribution to the vegetation change during the 6150–2300 cal yr BP interval, and human activities contributed throughout the 8200–2300 cal yr BP interval. The evolution of plant species richness and the number of C 3 plants show a significant ∼1000-yr periodicity during 9300–4500 cal yr BP, which we speculate was caused by the effect of solar activity on East Asian monsoon intensity, which likely controlled the vegetation change on a millennial timescale. • The Holocene vegetation in Horqin Sandy Land is qualitatively reconstructed. • Climate dominated the vegetation evolution, while fire and human activity were additional influences. • The vegetation change shows a ∼ 1000-yr periodicity during 9300–4500 cal yr BP. • The vegetation change on a millennium cycle was likely driven by the solar activity. [ABSTRACT FROM AUTHOR]

A comprehensive and integrative view of East Asian monsoon evolution during the Holocene is still under debate, and additional high-resolution proxy records from climatically sensitive locations are requisite to solve this complex issue. In this paper, we present three well-dated mud/peat cores from a paleo-pingo depression in the Sanjiang Plain, a climatically sensitive region to monsoon variation, to reveal the paleoenvironmental history of the wetland and discuss the regional impacts from monsoon evolution. A paleolake developed in the study area before 5.5 ka BP, and a peatland initiated thereafter consequent upon the gradual shrinking of the paleolake. This transition lasted until 4.5 ka BP, when the paleolake changed entirely to a wetland. Considering the prevalent monsoon climate in the Sanjiang Plain, we suggest that the lake-to-wetland transition from 5.5 to 4.5 ka BP indicates a rapid decline of the East Asian summer monsoon in addition to autogenic basin infilling processes. Such a remarkable monsoon weakening event has been documented across northern China, and we associate this with ocean–atmosphere interactions throughout low-latitude regions. [ABSTRACT FROM AUTHOR]

China is the country with the most population in the world, and its climate is extremely diverse due to tremendous differences in latitude, longitude, and altitude, ranging from tropical in the far south to subarctic in the far north and alpine in the higher elevations of the Qinghai-Tibetan Plateau. Accurate assessment of its modern climate change is conductive to addressing global warming threat. Along with the development of Past Global Changes (PAGES) research, the focus has changed from paleo-climate reconstructions to using paleo-data for assessing the present and predicting the future. Previous studies have been devoted to climate change assessment using modern climate observations and simulations. This paper presents a new assessment approach based on the mid-Holocene, which provides a naturally oriented warming that can be compared to modern human-made global warming. A variety of climatic data, including modern observations, paleo-climate records, CMIP5 (Coupled Model Intercomparison Project Phase 5) and PMIP3 (Paleoclimate Modelling Intercomparison Project 3) simulations, as well as lake level models, were applied in this synthesis. Numerical climate classification was introduced to evaluate climate change impacts to Chinese climate zones on various time scales. The results show that winter and summer seasons have different response to the naturally oriented mid-Holocene warming but human-made global warming makes the warming trend appear in all seasons. Temperate and continental dry winter climates expand dramatically during the mid-Holocene warm period; however, the future global warming could have few impacts to Chinese climate zones. Furthermore, the East Asian summer monsoon was strengthened obviously by the mid-Holocene warm climate and strong low-latitude insolation. There is no consistent trend both for the winter and summer monsoon on the background of human-made global warming. In this study, a new benchmark was established based on paleo-climate to evaluate the impacts of human-made global warming. [ABSTRACT FROM AUTHOR]

In this paper, we examine the Early to Middle Holocene evolution of a prominent group of ground-water fed lakes in the southeastern hinterland of the Badain Jaran Desert (BJD) of northwest China. Specifically, we describe a sediment profile record from the Taoerlegetu (TR) palaeolake basin using multiple proxies of total organic carbon (TOC), total nitrogen (TN), C/N ratio, δ13C org , grain size and mineral composition based on a well-dated trench profile. As C/N values suggest that sedimentary organic matter mainly originated from aquatic plants, δ13Corg values can be used as a qualitative proxy for water level because aquatic plants in different biotopes (water depth) have different δ13C values. Our results show that from 10.9 to 9.1 cal kyr B.P., water level rose slowly, and aquatic macrophytes occupied the lake basin. From 9.1 to 5.5 cal kyr B.P., water level reached an even higher level and phytoplankton replaced macrophytes as the major contributor to organic matter. The humid episode of the lakes in the hinterland of the BJD in the early Holocene might be related to the increased groundwater supply from the northeast region of the Tibet Plateau. These findings are consistent with earlier studies of lacustrine and peat sediments found in periphery of the modern lake group, which indicate that their geographic extent may have been larger in the past. A relative drought period recorded in the studied succession from 8.5 to 8.0 cal kyr B.P. marks an interval of reduced ground-water transport from the Tibet Plateau. This interval probably corresponds to the "8.2 ka cold event" and provides evidence that this widespread climate episode influenced groundwater processes across inland Asia. • The δ13C org value could be used as a qualitative indicator for the change of water level. • Lakes in the hinterland of the Badain Jaran Desert shows different evolution progress with these in the edge. • The main water source of lakes in the hinterland of the BJD in the Early Holocene comes from the Tibet Plateau. [ABSTRACT FROM AUTHOR]

The source to sink process of terrigenous sediment from East Asia continent to the marginal seas is crucial for the understanding of land–ocean interaction and marine sedimentary process in the West Pacific continental margin. This paper presents element geochemical and Sr–Nd isotopic records of core CM97 in the Changjiang (Yangtze River) Estuary and core MD06–3040 on the inner shelf of East China Sea, aiming to reconstruct the Changjiang sediment source–to–sink transport process and its major controlling mechanism during the Holocene. Driven by the asynchronous evolution of the Indian and East Asian summer monsoon, the provenance of sediments accumulated in the Changjiang Estuary gradually changed from the upper catchment during the late glacial period to the mid–lower valley in the early–mid Holocene. With the intensive agricultural cultivation and urbanization development in the catchment during the late Holocene, the major source of Changjiang sediment into the sea shifted back to the upper catchment, again. The high–frequency ENSO activity may superimpose the effect of human disturbances on sediment source–to–sink process in the late Holocene. Therefore, the Holocene provenance evolution of Changjiang sediments in the East China Sea witnessed the changes of governing sediment erosion process within a large catchment from monsoon climate–dominated to anthropogenic driving. Our study also suggests the strong effect of hydrodynamics in coastal and shelf environments on sedimentary geochemical compositions, which deserves more attention in further sediment provenance study. [ABSTRACT FROM AUTHOR]

This paper addresses the surface and Holocene aeolian deposits in the southeastern Mu Us Desert, N. China, systematically analysing the evolution of the geochemical characteristics of aeolian sand-palaeosol sequences and their environmental significance. Our results indicate that the geochemical components of the Holocene aeolian deposits and surface deposits had the similar material sources, sediment transport and deposition processes in the study region, which were dominated by SiO2, Al2O3, and Na2O. In the weathering process of the Jinjie (JJ) profile, the Na, K, and Si presented the slight leaching and migration in general, while the other elements were relatively accumulated. The Holocene aeolian deposits and surface deposits incurred weaker geochemical weathering under cold and dry conditions and were only weakly leached, which implies a relatively arid environment in the Holocene epoch and the modern era. The weathering degree was controlled by the regional temperature and precipitation, and was probably more sensitive to the precipitation changes. In the sedimentary profile, the geochemical parameters and migration of elements demonstrated that there have been several alternating warm-wet and cold-dry intervals in the Mu Us Desert in the Holocene epoch; there were relatively warm and wet conditions prior to 4.6 ka, and it has been cold and dry since then. Six millennial-scale dry events were recorded during the Holocene, which were not only accordant with the history of palaeoclimatic changes in the different latitudes and archives of the Northern Hemisphere, but also correspond to the millennial-scale variation of cosmic radiation and solar activity during that period. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In recent years, more and more record-breaking extreme weather/climate events have been reported from the Asian monsoon region, which have caused tremendous loss of property and lives. In this paper, we analyzed the Asian summer monsoon (ASM) variability during the Holocene and evaluated future climate extremes in monsoonal China from a paleoclimatic view. We found a significant regime transition to more chaotic fluctuations, with enhanced decadal variability of the ASM since 6.6 ka BP. We suggested the gradual intensification of ENSO was responsible for enhancing the ASM variability since the late mid-Holocene. If the observed relationship of monsoon mean intensity, ENSO and decadal variability of the ASM in the past 11.2 ka continue to exist, enhanced decadal variability of ASM in the future warming world will be expected. As a result, the intensification of daily precipitation extremes, superimposed on enhanced decadal variability of ASM, might make the record-breaking extremes more frequent in the future, increasing the risk of climate-related disasters in China. [ABSTRACT FROM AUTHOR]

Abstract: In the regions surrounding the Qinghai Tibet Plateau, changes in erosion rates have been linked to the tectonics, climate and topography over different time scales. To understand the mechanisms governing the changes of erosion rates, it is important to study erosion rates by different methods and for different time scales. In inland drainage basins, deposition rates of terminal lake sediments can indicate basin-wide erosion rates at the millennial-scale. This paper presents three lake records of the Last Deglaciation and Holocene (Huahai Lake, Zhuye Lake and Yanchi Lake) from the Hexi Corridor, north of the Qilian Mountains, in arid China. Organic matter, terrestrial pollen concentrates, seeds, grasses and plant debris are used for conventional and AMS 14C dating. On the basis of 66 radiocarbon dates, lithology and grain-size, we infer relatively high basin-wide erosion rates during the Last Deglaciation and early Holocene in the three drainage basins, when the three lake sediments were seriously affected by reworking. The deposition rates were an order of magnitude or greater in these lakes during the Last Deglaciation and early Holocene than during the mid-to-late Holocene. During the transition period of the last glacial–interglacial cycle, significant climatic changes occurred in East and Central Asia, corresponding to the strengthening of the Asian summer monsoon and to increasing effective moisture in arid Central Asia, which can have strong impacts on basin-wide erosion rates north of the Qinghai Tibet Plateau. Moreover, melting glaciers in the Qilian Mountains probably also contributed to the high basin-wide erosion rates. At the same time, tectonic activity was not recognizable in the study area during that period. In the arid and semiarid regions surrounding the Qinghai Tibet Plateau, dramatic changes in erosion rates appear during the transition periods of the glacial–interglacial cycles, which illustrate the climatic controls on erosion rates at this time scale. [Copyright &y& Elsevier]

In this paper, we summarize the Holocene environmental history of the lower Yangtze region, east China, based on the sedimentary records and microfossil diatom, pollen, fungal and charcoal data that were published in the past two decades. We then examine the linkage between changes in the coastal environment and the development of rice agriculture in the region, with reference to the available archaeological evidence and historical archives. Based on the sedimentary and archaeological evidence, we conclude that during the early Holocene sea-level movements and sedimentary processes significantly changed the region’s landscape from an open, brackish water environment to a largely enclosed, wetland system. This newly established freshwater marsh environment provided a habitat favourable to rice agriculture. The early Neolithic farmers took the opportunity presented to them and started rice cultivation in locations where freshwater wetland systems were established. During the middle Holocene, environmental conditions were largely stable, and the coastal wetlands evolved slowly. Environmental change was only a supportive player in the Neolithic cultural processes, because the Neolithic people were able to adapt to these changes and took advantages of the newly emerging marsh land for food collection and production. Around 4200 years ago, the prosperous Liangzhu society fell, but there is no evidence to suggest the fall was related to a significant environmental change. The coastal environment continued to evolve slowly during the late Holocene. But this period saw rapid technological development in irrigation and flood protection, and the environmental factor was reduced to background noise. Throughout the Holocene, the main strategy taken by the Neolithic people to cope with environmental change was migration to find better food sources. Along with this strategy was the development of technology in landscape management to ensure a more reliable food production in addition to food collection through hunting, gathering and fishing. [ABSTRACT FROM AUTHOR]

Coastal morphodynamics and environmental changes have been obviously altered by global warming, sea-level fluctuations, and human activities. Palynological analysis is one of the most important tools for providing information on vegetation, climate, and environmental change, which can be relatively sensitive indicators of human activity during the Holocene. However, Holocene coastal morphodynamics and palynological evidence from the Pearl River Delta and coastal areas has not been sufficiently studied. In this paper, we carry out analyses using detailed grain-size and palynological records of pollen, spores, freshwater algae, and marine dinoflagellate cysts from Borehole QZK13 in the Pearl River Estuary (PRE), southern China. The results show information relating coastal morphodynamics, vegetation evolution, climate changes, and anthropogenic activities during the Holocene based on radiocarbon chronology. In general, the PRE experienced marine transgressive processes; sea-level and the coastline tended to migrate landward between 10,700 and 4250 cal yr BP. Meanwhile, abundant arboreal pollen (mainly Castanopsis , Quercus -evergreen, Oleaceae, and Castanea) and small amounts of non-arboreal pollen (mainly Poaceae, Cyperaceae, and Artemisia) were observed in Borehole QZK13, which suggests that subtropical evergreen broadleaved forests were distributed throughout the PRE and adjacent areas, and relatively warm and moist climatic conditions were present during the early-middle Holocene. After that, there were relatively cool and wet climatic conditions, and marine regressive processes occurred in the PRE during the Late Holocene (ca. 4250–960 cal yr BP) indicated by an abrupt increase in aquatic herbs and Dicranopteris. Moreover, we hypothesize that the Neolithic "cultural fault" in the PRE is likely related to frequent storm surges induced by extreme typhoon events that occurred ca. 3000–2700 yr BP. • Grain size, pollen, spores, freshwater algae and dinoflagellate cysts from the Pearl River Estuary were investigated. • Three major phases shown by palynological results were corresponding to the changes in vegetation and climate. • We hypothesized that the Neolithic "cultural fault" is probably related to the storm surges induced by extreme typhoon events. • Natural vegetation cover has suffered large-scale destruction by ancient humans during the Late Holocene. [ABSTRACT FROM AUTHOR]

Peatlands are one of the most significant carbon reservoirs in the terrestrial ecosystem. Understanding past peatland carbon accumulation processes and their responses to varying external and internal forcing factors would help reveal the general development patterns of peatland ecosystems and provide useful insights into projecting the fate of carbon reservoirs into the future. In this paper, the basal ages of 17 peat cores were used to explore the lateral expansion processes of the Laolike peatland, northeast China. Two cores were selected to calculate carbon accumulation rates (CAR) and reconstruct moisture/precipitation records based on δ13C and grain size analyses. The basal ages show that the peatland was initiated at 12.1 cal kyr BP, then laterally expanded with its fastest rate occurring during the early Holocene, and reached its largest area around 6 cal kyr BP. The time-weighted mean CAR in the Laolike peatland ranged from 31.1 to 52.9 g C/m2/yr (with an average of 42 g C/m2/yr) during the Holocene. The peatland experienced a high CAR of 52.5 g C/m2/yr from 11.7 to 5 cal kyr BP, followed by a low CAR of 35.1 g C/m2/yr after 5 cal kyr BP. Both lateral expansion and vertical accretion are consistent with the summer insolation, climate seasonality, and the strength of the East Asia summer monsoon (EASM) over multi-millennium timescales, where the CAR correlated well with δ13C and grain size, implying moisture/precipitation might be the primary factors controlling carbon accumulation over millennium timescales. Local conditions, such as topography and hydrology, also played an important role in the process of peatland initiation and lateral expansion, as well as the discrepant CAR within the peatland. This study reveals the roles of climate and local conditions in peatland initiation, expansion, and CAR during the Holocene. In addition, we provide a window for a better understanding of the driving factors of peatland development in the temperate zones of the Northern Hemisphere. • Climate conditions are the primary control on the lateral expansion and vertical accretion of Laolike peatland over multi-millennium timescales. • Moisture/precipitation affects carbon accumulation of Laolike peatland over millennium timescales. • Local conditions play an important role in the lateral expansion and the internal differences of carbon accumulation rate. [ABSTRACT FROM AUTHOR]

• We review the state of research on human-environment interaction in Holocene China. • We demonstrate the benefits of a multidisciplinary, regionally focused approach. • We conclude datasets must be local and specific, and integrate data on multiple scales. • China is large, well-documented, and critical for understanding social-natural systems. This paper reviews recent archaeological research on human-environment interaction in the Holocene, taking continental China as its geographic focus. As China is large, geographically diverse, and exceptionally archaeologically and historically well-documented, research here provides critical insight into the functioning of social-natural systems. Based on a broad review of the field as well as recent advances and discoveries, the authors reflect on research themes including climate change and adaptive systems theory, spatial and temporal scale, anthropogenic environmental change, risk management and resilience, and integration of subdisciplines. These converge on three overarching conclusions. First, datasets relevant to climate change and ancient human-environment interaction must be as local and specific as possible, as the timing of environmental change differs locally, and the human response is highly dependent on local social and technological conditions. Second, the field still needs more robust theoretical frameworks for analyzing complex social-natural systems, and especially for integrating data on multiple scales. Third, for this work to contribute meaningfully to contemporary climate change research, effective communication of research findings to the public and to scientists in other disciplines should be incorporated into publication plans. [ABSTRACT FROM AUTHOR]

• Identify ancient flood events, which may be the reason for decline of the culture. • Pollen and heavy metals can be used to reflect the strength of human activities. • Pollen and heavy metals revealed the process of culture from prosperity to decline. • This paper defined the chronology from prosperity to decline of Shijiahe culture. • Climate change has been revealed by pollen and heavy metals since 4800 cal. yr BP. The Shijiahe Culture (ca. 4800–4100 yr BP), which originated in the middle Yangtze Basin, was a milestone of prehistoric Chinese civilization. To reveal the interactions between climatic changes and human activities during this time interval, the geochronology and multiple proxies (pollen and heavy metals) of samples from a 220-cm-deep outer wall at the Sanfangwan Site (a typical site of the Shijiahe Culture) were analyzed. Radiocarbon dating indicates that the age range of the Sanfangwan Site is ca. 4800 to 4100 cal. yr BP. From ca. 4800 to 4600 cal. yr BP (the early Shijiahe Culture), pollen assemblages were dominated by Gramineae and an anthropogenic plant community (e.g. Ranunculaceae, Chenopodiaceae, Labiatae, and Cruciferae), indicating an expansion in rice agriculture during this interval. High metal concentrations in the same interval indicate a large flux of metals from smelting and farming activities. Between ca. 4600 and 4100 cal. yr BP (the middle and late Shijiahe Culture), decreases in Gramineae and anthropogenic pollen mirrored the recession of farming. Concurrent decreases in heavy metals may be attributable to a decline in the smelting industry. Three episodes of high pollen concentrations and visible increases in hygrophyte pollen, Pinus pollen, and fern spores at 4600–4550, 4450–4350, and 4200–4100 cal. yr BP probably indicate the occurrence of several flooding events during the middle and late Shijiahe Culture, resulting in the migration of local inhabitants. This study highlights the driving effect of flood events on the collapse of the Shijiahe Culture. [ABSTRACT FROM AUTHOR]

Schematic figure showing climate driving mechanisms on wetland hydrological and vegetational evolution. The relatively strong East Asian summer monsoon (EASM) with high precipitation tends to generate a higher water-level condition with more hygrophilous herbaceous plants while blocking the deposition of coarse grain-size fractions (a), and vise versa for weak EASM stages (b). [Display omitted] • The late-Holocene hydrological and vegetational regimes were reconstructed. • An ecological lake-to-wetland transition occurred at ~4.5 ka BP. • The wetlands evolution was largely controlled by monsoonal precipitation. The responding mechanism of wetland ecosystem to climate change is currently unclear due to a lack of long-term records incorporating multiple ecological factors. This paper presents a well-dated and multi-proxy cored record from a natural freshwater wetland developed in a paleo-pingo-related depression on the Sanjiang Plain. The study aims to reconstruct the wetland water-level and vegetational regimes during the past ~6.0 ka BP and discuss the wetland evolution response to the East Asian summer monsoon (EASM) circulation. The results show that a shallow-water lake with hygrophilous herbs developed in the depression with a strong EASM during ~6.0–4.5 ka BP. The paleolake was succeeded by a wetland with a lowered mean water level and an increase in tree cover controlled by the weakened EASM during the past 4.5 ka BP. Such an ecological lake-to-wetland transition corresponds well to the sharp decline of the EASM around 4.5 ka BP which has been well documented in various geological records across the EASM domain. During the wetland developing stage over the past 4.5 ka BP, the water-level and vegetational changes in the studied depression were also closely related to the EASM variations. The strengthened EASM usually generated higher water levels with more hygrophilous herbs around 4.0 ka BP, 3.5 ka BP, 3.0 ka BP, 2.0 ka BP, and 1.3 ka BP. Considering the prevalent EASM climate serving as the predominant water supply for the wetlands on the modern Sanjiang Plain, we suggest the EASM circulation has played a critical role in driving the wetland ecological evolution during the mid-to-late Holocene Epoch. The past 0.4 ka BP is an exception as the local Trees/Herbs ratio visibly increased with the declined water level, while the monsoonal precipitation shows no equivalent shift. The wetland evolution at this stage was attributed to human interference. [ABSTRACT FROM AUTHOR]