Quaternary International 438 (2017) 189e197

Contents lists available at ScienceDirect

Quaternary International

journal homepage: www.elsevier.com/locate/quaint

Environmental changes and human activities at a fortified site of the in eastern : Evidence from pollen and charcoal records

* Xiaocui Wang a, b, Duowen Mo c, Chunhai Li a, Shi-Yong Yu d, Bin Xue a, , Bin Liu e, Hui Wang f, Chenxi Shi g a State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China b University of Chinese Academy of Sciences, Beijing 100049, China c Laboratory for Earth Surface Processes, College of Erban and Environmental Sciences, Peking University, Beijing 100871, China d School of Geography, Geomatics, and Planning, Normal University, Xuzhou 221116, China e Provincial Institute of Relics and Archaeology, Hangzhou 310026, China f Institute of Archaeology, Chinese Academy of Social Sciences, Beijing 100710, China g National Educational Examinatios Authority, Beijing 100087, China article info abstract

Article history: Liangzhu culture represents the culmination of the culture in the Delta. Two archae- Received 12 December 2016 ological trenches (LZ-N and LZ-W) from a fortified archaeological site in close proximity to Hangzhou, Accepted 3 May 2017 eastern China, were excavated and studied. The sediments were analyzed to provide vegetation and fire Available online 9 May 2017 records for the reconstruction of environmental change and human impact during the past 5000 years. Pollen data reveal that mixed evergreen-deciduous subtropical broadleaved forests may have developed Keywords: around lakes or swamps in this area. Abundant charcoal detritus and Gramineae pollen with a size Liangzhu culture >38 mm indicate that rice agriculture flourished during 5000e4500 cal yr BP. Low concentrations of Mojiaoshan site > m Pollen charcoal detritus and Gramineae pollen with a size 38 m suggest that the site was abandoned after Charcoal 4500 cal yr BP. Pollen and charcoal data from the LZ-N section suggest that this area has experienced a Vegetation weakened human activity during the late period of the Liangzhu culture (between 4500 and 4300 cal yr Human activity BP), implying that the demise of the Liangzhu culture was a prolonged process rather than a short-lived event. © 2017 Elsevier Ltd and INQUA. All rights reserved.

1. Introduction the culmination of the Neolithic culture in the lower Yangtze River area. This culture is well known for its flourished rice-based agri- As one of the cradles of the Chinese culture, the Neolithic culture culture, making of diverse and sophisticated articles, advanced in the lower Yangtze River area has experienced a long and complex pottery technology with diversified types and decoration, the evolutional process during the Holocene. Beginning with the highly complex social structure reflected by large-scale architec- Shangshan culture (11.4e8.4 kyr BP), the Neolithic culture in this tural engineering (Zhejiang Provincial Institute of Cultural Relics area has experienced several periods such as the and Archaeology, 2008; Zheng et al., 2009; Fuller et al., 2009; Qin (7.0e5.9 kyr BP), Songze culture (5.9e5.3 kyr BP), and Liangzhu et al., 2011). However, the Liangzhu culture terminated mysteri- culture (5.3e4.3 kyr BP). Of these cultural periods, the Liangzhu ously and the regional culture was replaced by a less developed culture is the last stage of the prehistoric culture, which represents culture known as the Guangfulin/Maqiao culture (Chen et al., 1997; Zhu et al., 2003; Chen, 2005; Zong et al., 2011a). Therefore, scru- tinizing the reasons behind the termination of the Liangzhu culture is of great importance for better understanding the rise and fall of * Corresponding author. State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, regional Neolithic culture and the emergence of early Chinese Nanjing 210008, China. civilization. E-mail address: [email protected] (B. Xue). http://dx.doi.org/10.1016/j.quaint.2017.05.001 1040-6182/© 2017 Elsevier Ltd and INQUA. All rights reserved. 190 X. Wang et al. / Quaternary International 438 (2017) 189e197

The termination of the Liangzhu culture has received great Archaeological excavations reveal that this site appears to be the attention and it is still a matter of debate. Previous studies have central township of the Liangzhu culture in Yangtze Delta, repre- shown that the disappearance of the Liangzhu culture may have senting the highest stage of the Liangzhu culture in the Yangtze been ascribed to a catastrophic environmental event such as rapid River area (Zhejiang Provincial Institute of Cultural Relics and climate cooling (Yu et al., 2000; Innes et al., 2014), marine trans- Archaeology, 2008; Liu and Wang, 2014). As such, this site is of gression (Stanley and Chen, 1996; Chen et al., 2008), or flash great importance for unraveling the reason and process of the flooding (Zhang et al., 2004, 2005; Zong et al., 2012; Long et al., termination of the Liangzhu culture. 2014; Liu et al., 2015). However, evidence for such a rapid termi- Previous studies have focused on the structure and provenance nation of the Liangzhu culture is scarce. (Zhejiang Provincial Institute of Cultural Relics and Archaeology, The Mojiaoshan archaeological site is located in close proximity 2008; Hu et al., 2013), the internal and external layout of the wall to Hangzhou (Fig. 1), East China. It is the first Neolithic fortified surrounding the Mojiaoshan site (Zhejiang Provincial Institute of township has ever discovered in the lower Yangtze River area. Cultural Relics and Archaeology, 2015), the age when the earthen

Fig. 1. (A) Map showing the study area; (B) location of profiles LZ-N and LZ-W(redrawn from Fei and Chen, 2011; Shi et al., 2011; Zong et al., 2011a). X. Wang et al. / Quaternary International 438 (2017) 189e197 191 dike was constructed (Zhang et al., 2014; Liu et al., 2015), as well as earlier than when the site was settled. The LZ-W profile has been the hydroclimatic condition and palaeoecological background (Li described by Shi et al. (2011). Their work was based on AMS 14C et al., 2010; Shi et al., 2011; Liu et al., 2014b) of the Liangzhu cul- dating on bulk organic matter. In this study, we conducted detailed ture. There have been a few studies on the age constraint on the AMS 14C dating of these two profiles on charcoal and plant remains timing of the construction and abandonment of the wall at this site. that are believed to be free of old carbon. For example, base on archaeological evidence, archaeologists infer Five samples on charcoal and one sample on plant macrofossil that the wall was built no later than the late Liangzhu period were collected from the lower part of the two profiles (below (Zhejiang Provincial Institute of Cultural Relics and Archaeology, 120 cm) and submitted for AMS 14C dating. In order to obtain 2008), while AMS 14C and OSL dating suggests that the wall was reliable ages for the upper section, additional six samples on pollen built during 4.8e4.5 cal kyr BP (Liu et al., 2015). However, there is concentrates at the depth of 86e144 cm from the LZ-N profile was still a key question about the environmental context in which the dated using the AMS 14C method. Previous work revealed that the site was abandoned (Li et al., 2010; Shi et al., 2011; Long et al., 2014; age of pollen concentrates is slightly older than the actual age due Liu et al., 2014b, 2015). Here we aim to reconstruct vegetation to the introduction of pre-aged organic carbon in the fluvial setting history, environmental changes, and human activities at the (Stanley and Chen, 2000; Stanley and Hait, 2000; Li et al., 2014). Mojiaoshan site based on detailed AMS 14C dating, pollen and Paired samples of charcoal and pollen concentrates were taken charcoal analyses, which in turn may provide an ecological context from the depth of 120e122 cm and 142e144 cm of the LZ-N profile and a chronological framework for the abandonment of this to determine the age offset between these two kinds of materials. Neolithic Liangzhu township. Standard hydrofluoric (HF) acid method (Faegri and Iversen, 1989) was used for the extraction of pollen concentrates. The AMS 14C 2. Regional setting dating was conducted at Beta Analytic Inc. All results were cali- brated using the IntCal13 tree-ring dataset (Talma and Vogel, 1993; The Mojiaoshan site is located at the township of Pingyao, Reimer et al., 2013). The result was expressed as the 2s (95%) Hangzhou, Zhejiang Province (Fig. 1). It is surrounded by the Dax- confidence intervals. iongshan Mountain on the south, the Yaoshan and Nanshan A total of 58 pollen samples were taken at 2 cm intervals from Mountains on the west, and the Dazheshan Mountain on the north. the depth of 158e40 cm of the LZ-N profile, while 42 samples were This area is drained by several creeks such as North Tiaoxi, Middle collected at 2 cm intervals from the depth of 196e125 cm of the LZ- Tiaoxi, and South Tiaoxi, which originate in the west of the Tian- W profile. Note that the depth of 125e30 cm of the LZ-W profile mushan Mountain and merge into East Tiaoxi River, running down represents the post-Liangzhu cultural deposits. Therefore, samples the Tianmushan Mountain from southwest to northeast and dis- were taken at 10 cm intervals from this section due to the less charging into the Taihu Lake. importance of this section to our study. Standard HF method was Regulated by the subtropical monsoon, the regional climate used for the pretreatment of the samples (Faegri and Iversen, 1989; exhibits a significant seasonal variability. The mean annual tem- Moore et al., 1991), and the exotic Lycopodium spores were added as perature is about 16e18 C and annual precipitation is exotic markers to allow the calculation of pollen concentrations 1400e1700 mm, most of which occurs in the summer. The regional (22,340 spores per tablet). A minimum of 300 pollen grains were vegetation is characterized by mixed evergreen and deciduous counted for each sample. The micro-charcoals are counted along broad-leaved forests. Major tree and shrubs species are Castanopsis with pollen counting. Charcoal particles smaller than 10 mmwere sclerophylla, Castanopsis carlesii, Cyclobalanopsis glauca, Quercus not accounted. Charcoal concentrations (grains/ml) were used to myrsinaefolia, Cinnamomum camphora, Schima superba, Elaeocarpus infer the local fire history. decipiens, Pinus massoniana, Quercus acutissima, Quercus fabri, Rice pollen grains in sediments and topsoil demonstrate that Liquidambar formosana, Platycarya strobilacea, Ilex chinensis, Phoebe Gramineae with a size >35 mm might represent the existence of rice sheareri, Pistacia chinensis, Phyllostachys pubescens, Pistacia chi- agriculture. Palynological work on modern topsoil shows that the nensis, and Phyllostachys pubescens (Cai and He, 1980; Wu, 1980, pp. percentage of Gramineae>35mm pollen usually exceeds 40% in 849). The primeval forests almost have been cleared and turned to modern paddy fields (Li et al., 2012; Yang et al., 2012). Previous cropland for rice agriculture from the Iron Age (2700-2200 yr BP) studies in the Yangtze Delta also show the dominance of Grami- onward (Atahan et al., 2008; Innes et al., 2009). neae>35 pollen in ancient paddy fields. A larger diameter was generally used to differentiate the domesticated rice from the wild 3. Materials and methods Gramineae (Zong et al., 2007; Itzstein-Davey et al., 2007; Innes et al., 2009; Shu et al., 2010; Qin et al., 2011; Li et al., 2012; Zong Two profiles, hereafter referred to as LZ-N and LZ-W, were et al., 2012; Long et al., 2014; Liu et al., 2016). The size of large studied. Samples were taken from trenches artificially dug at the Gramineae are all larger than 38 mm in the profiles of LZ-N and LZ- outside of the northern and western parts of the Mojiaoshan site. W; therefore, we treat Gramineae>38 mm as an indication for the The LZ-N profile (3024.1310 N, 11959.2640 E) was dug in modern presence of domesticated rice in this study area. paddy field outside of the northern wall of the Mojiaoshan site (Fig. 2). According to field observation, the LZ-N profile can be 4. Results subdivided into four units. Unit 1 (180-92 cm) is dark-gray clayed silt; Unit 2 (92-56 cm) is yellowish brown silt; Unit 3 (56-40 cm) is 4.1. Radiocarbon chronology yellow-brown silt; and Unit 4 (40-0 cm) is modern paddy soil with abundant plant roots and modern porcelain shards. The LZ-W A total of 12 AMS 14C ages were obtained from the LZ-N and LZ- profile (3023.8240 N, 11958.6540 E) was dug in the artificial Wprofiles (Table 1). The age offset between charcoal and pollen channel outside of the western wall of the Mojiaoshan site. The LZ- concentrates was determined using paired samples at 120e144 cm Wprofile can be subdivided into three units. Unit 1 (200-125 cm) is deep of the LZ-N profile. Pollen concentrates are 70e685 years gray clayed silt; Unit 2 (125-30 cm) is yellow-gray silt; Unit 3 (30- older than charcoal. The age of pollen concentrates at the depth of 0 cm) is the topsoil with modern brick and porcelain shards. 86e88 cm of the LZ-N profile is 2230 years older than the age at According to archaeological survey, the channel was dug to 88e90 cm deep and older than that of all samples from the two protect the Mojiaoshan township and LZ-W began to deposit not profiles. Therefore, the age at 86e88 cm deep was rejected. Based 192 X. Wang et al. / Quaternary International 438 (2017) 189e197

Fig. 2. Lithology and chronology of profiles LZ-N and LZ-W (Shi et al., 2011).

Table 1 AMS 14C dating results from the LZ-W and LZ-N profiles.

Sample no. Depth (cm) Material dated d13C(‰, VPDB) Conventional age (yr BP) Calibrated age (2s range)

LZ-W -1 126e128 charcoal 27.6 4060 ± 30 4500e4615 LZ-W -2 184e186 plant 27.1 4400 ± 30 4865e5045 LZ-N-1 86e88 pollen concentrates 22.6 5630 ± 30 6390e6470 LZ-N-2 88e90 pollen concentrates 25.5 3350 ± 30 3555e3640 LZ-N-3 90e92 pollen concentrates 25.0 3710 ± 30 3975e4100 LZ-N-4 92e94 pollen concentrates 24.4 3640 ± 30 3880e3995 LZ-N-5 120e122 pollen concentrates 25.3 4530 ± 30 5050e5195 LZ-N-6 142e144 pollen concentrates 25.5 4090 ± 30 4520e4650 LZ-N-7 120e122 charcoal 26.0 4080 ± 30 4515e4645 LZ-N-8 142e144 charcoal 28.1 3960 ± 30 4405e4445 LZ-N-9 160e162 charcoal 27.6 4140 ± 30 4565e4825 LZ-N-10 176e178 charcoal 28.1 4060 ± 30 4500e4615

on the ages of charcoal and plant remains, the age below 120 cm of 2004). The stratigraphically constraint cluster analysis was con- the LZ-N profile is between 4825 and 4405 cal yr BP, corresponding ducted using the CONISS module (Grimm, 1987). Based on the li- to the middle to late Liangzhu cultural period. thology and cluster analysis, four and five zones for the LZ-W and The age at the depth of 126e128 cm of the LZ-W profile is LZ-N profile, respectively, can be divided (Figs. 4 and 5). 4500e4615 cal yr BP. The age at the depth of 184e186 cm is 4865e5045 cal yr BP. Therefore, the age of sediments below 126 cm is 4500e5045 cal yr BP, corresponding to the middle to late 4.2.1. Profile LZ-W Liangzhu cultural period. The age of pollen concentrates is probably Zone LZ-W-1 (196-125 cm). Quercus-E (0e35%, mean 10%), several hundred years older than the actual age, therefore, the age Cyclobalanopsis (0e26%, mean 9%), and Castanopsis/Lithocarpus at 88 cm deep of the LZ-N profile appears to post-date 3500 cal yr (0e19%, mean 4%) are the dominant tree genuses, which is followed BP and the section between 120 and 88 cm of the LZ-N profile by deciduous trees such as Liquidambar (0e16%, mean 3%) and belongs to the late Liangzhu to Maqiao cultural (about 3800 cal yr deciduous Quercus (0e22%, mean 6%). The percentage of coniferous BP) period (Fig. 3). tree Pinus (2e23%, mean 11%) is also high. Herb pollen is dominated by Gramineae with a size >38 mm(0e58%, mean 31%), Polygonum (0e37%, mean 9%), Gramineae with a size of 38e28 mm(0e12%, 4.2. Pollen assemblages mean 4%). Swamp plants are mainly composed of Typha (0e23%, mean 3%) and Cyperaceae (0e8%, mean 3%). Ferns (0e48%, mean A total of 118 pollen and spores taxa were identified from the LZ- 7%) are dominated by Polypodiaceae and Marsileaceae. Charcoal N and LZ-W profiles. However, the sample from the depth of concentrations are between 223,000 and 2,907,000 grains/ml, and 56e58 cm of the LZ-N profile was excluded from the pollen spectra, the highest value occurs at 196-140 cm deep. as there are only 13 pollen grains found in this sample. The Tilia Subtropical evergreen trees dominate the pollen spectra and the 1.7.16 computer program was used to calculate the percentage of percentage of deciduous trees is relatively high, which suggests each genus/family and construct the pollen diagrams (Grimm, that subtropical mixed evergreen broadleaved and deciduous X. Wang et al. / Quaternary International 438 (2017) 189e197 193

Fig. 3. Age-depth model for profiles LZ-N and LZ-W based on radiocarbon ages of macro-charcoal, pollen concentrates, and plant remains. Horizontal line denotes ages of macro- charcoal used in this paper, horizontal line with long vertical line represents the rejected ages of pollen concentrates, and horizontal line with short vertical line denotes ages of pollen concentrates used in this paper. forests were established in this area. Modern surface pollen study (10e36%), increase sharply. Charcoal concentrations are from indicates that high percentages of Gramineae with a size >38 mm 200,000e564,000 grains/ml. only occur in or near paddy fields (Li et al., 2012; Yang et al., 2012). The gradually increasing value of deciduous trees pollen in- The ancient paddy fields are also characterized by high percentages dicates that temperature was decreasing during this period. Rela- (>30%) of Gramineae with a size >38 mm(Li et al., 2007, 2012). tively high values of Cyperaceae and Typha pollen suggest that Because the sediments of LZ-W-1 are of fluvial origin, the relatively swamp expanded at or near the study site (Carrio et al., 2000; high values of Gramineae>38 mm could be explained by two rea- Atahan et al., 2007; Liu et al., 2014a). sons: one is that the sampling site is near the ancient paddy field, and the other is that the pollen grains were transported by water. In 4.2.2. Profile LZ-N either case, it is suggested that paddy fields occupied large areas of Zone LZ-N-1 (160-116 cm) is characterized by arboreal trees the study site during this period. (40e92%, mean 62%), among which Pinus is the highest. The ever- Zone LZ-W-2 (125-95 cm). Evergreen broad-leaved arboreal green taxa are dominated by Quercus-E (0e32%, mean 15%) and pollen such as Quercus-E (mean 19%), Cyclobalanopsis (22e43%), Cyclobalanopsis (0e33%, mean 18%), Altingia (1e10%, mean 5%), and Castanopsis/Lithocarpus (8e19%) increase substantially, whereas Castanopsis/Lithocarpus (0e8%, mean 3%). The deciduous taxa, Pinus decreases dramatically and deciduous arboreal pollen Quer- mainly Liquidambar, Betula, Ulmus, Quercus, Castanea, and Rosaceae, cus and Liquidambar almost disappear. Herb pollen such as are in low values. The percentage of herb pollen, such as Gramineae>38 mm(2e7%) and Polygonum (0e6%) as well as swamp Gramineae>38 mm(0e37%, mean 23%), Gramineae 38-28 mm plants (mean 2%) decrease sharply, and algae spores vanish. Fern (0e19%, mean 6%), and Gramineae <28 mm(0e12%, mean 3%) is spores especially Marsileaceae (16e75%) increase significantly. relatively high. Cyperaceae and Typha dominate the swamp pollen Charcoal concentrations reduce slightly (438,000e667,000 grains/ assemblage. Ferns and algae, mainly Marsileaceae (0e4%, mean 1%) ml) compared with the lower zone. and Zygnemataceae (0e9%, mean 1%), are present with relatively The percentages of Quercus-E, Cyclobalanopsis, and Castanopsis/ high value. The average concentration of charcoal is 731,000 grains/ Lithocarpus pollen increase, which indicate that evergreen broad- ml. leaved trees developed in response to the rise of temperature. The pollen spectra of LZ-N-1 is dominated by relatively high Low values of Gramineae>38 mm and charcoal concentrations values of evergreen trees and deciduous Quercus, indicating that suggest that there were lack of intensive human activities and rice the regional vegetation was subtropical mixed evergreen and de- agriculture at the study site. ciduous broadleaved forests during 4700e4500 cal yr BP, which is Zone LZ-W-3 (95-70 cm). The values of tree pollen and fern similar to the pollen spectra of the LZ-W-1 zone. spores decrease markedly. Herb pollen (49e72%), particularly Zone LZ-N-2 (116-102 cm) is characterized by the increasing Gramineae>38 mm, increases substantially. percentage of tree pollen (49e99%, mean 72%), especially Quercus-E High values of Gramineae>38 mm indicate the presence of (6e43%, mean 28%). Upland herb pollen decreases sharply, the paddy field at the study site during this period. According to his- relative abundance of Gramineae>38 mm reduces apparently torical documents, there have not been human activities until the (0e42%, mean 11%). Swamp pollen decreases slightly (0e10%, mean Han Dynasty (202BC-AD 220) after the Neolithic period in the study 6%), and algae spores disappear. Ferns increase significantly to 4% area (Zhejiang Provincial Institute of Cultural Relics and on average. The average concentration of charcoal (335,000 grains/ Archaeology, 2015). High values of Quercus pollen indicate that ml) is relatively low compared with the LZ-N-1 zone. deciduous trees expanded, reflecting that temperature dropped The stratigraphy was deposited after 4500 cal yr BP, corre- compared with the LZ-W-2 zone. sponding to the late Liangzhu cultural period. Subtropical trees Zone LZ-W-4 (70-30 cm). Trees, mainly Quercus-E (4e37%), still dominated the forests but show a decreasing trend, which Cyclobalanopsis (6e23%), Castanopsis/Lithocarpus (0e16%), and suggests that temperature dropped during this period (Yi et al., Quercus (4e37%) increase and reach 72%e83%. The percentage of 2003, 2006; Zong et al., 2011b). As to the depth of 116e112 cm, herb pollen (17e28%), especially Gramineae>38 mm(1e14%), de- Gramineae>38 mm almost disappeared, which probably suggests creases. Swamp plants, mostly Cyperaceae (1e18%) and Typha that the intensity of human activity decreased. 194 X. Wang et al. / Quaternary International 438 (2017) 189e197

Zone LZ-N-3 (102-88 cm, the Maqiao cultural period) is char- acterized by decreasing values of tree pollen and increasing values of upland herb pollen, similar to zone LZ-N-1 in light of the abundance of main taxa. Pinus slightly decreases compared to the lower zone. Gramineae>38 mm, Gramineae 38-28 mm, Gramineae<28 mm are consistent with the LZ-N-1 zone. Mean charcoal concentration increases to 680,000 grains/ml, almost close to the level of the LZ-N-1 zone. The pollen assemblage of this phase is similar to that of the LZ-N-1 zone, indicating a warm and humid climate and the prev- alence of lacustrine-swamp environment. High percentages of Gramineae>38 mm and charcoal concentrations suggest that this area had been settled again. Zone LZ-N-4 (88-56 cm) is marked by increasing values of tree pollen, especially deciduous Quercus. Gramineae>38 mm reduces greatly. Mean charcoal concentration, especially at the depth of 88e68 cm, decreases and it reaches nearly half of zone LZ-N-3. There are no radiocarbon ages due to lack of suitable dating materials during this stage. However, according to the age at the depth of 88 cm (3555e3640 cal yr BP), the sediments of this zone were deposited during the historical period. The dramatic decrease in rice pollen and charcoal concentration demonstrate that human activities disappeared after the Maqiao cultural period, which is consistent with archaeological excavation (Zhejiang Provincial Institute of Cultural Relics and Archaeology, 2015). A sudden in- crease in the abundance of deciduous Quercus pollen indicates a cooling climate. Also, the high percentage of swamp pollen such as Cyperaceae and Typha reveals the prevalence of lacustrine-swamp environment. Zone LZ-N-5 (56-40 cm) is characterized by a sharp increase in Pinus pollen (19e47%, mean 31%), while the percentage of Quercus- E(0e15%, mean 9%) and Cyclobalanopsis pollen (0e18%, mean 5%) drops. Gramineae>38 mm (25e50%, mean 35%) pollen increases sharply. Mean charcoal concentration increases and reaches the maximum of the profile (908,000 grains/ml). This stage represents the late historical period. High percentages of rice pollen and charcoal concentration imply intensified human activities. The percentage of Quercus-E and Cyclobalanopsis pollen decreases sharply and reaches the lowest value of the LZ-N profile. Pinus and Gramineae>38 mm pollen reaches the highest value of this profile. As a result of the intensified agricultural activities, the evergreen broadleaved trees were cleared and secondary Pinus forest expanded.

5. Discussion

5.1. Local vegetation history

Pollen data from profiles LZ-W and LZ-N indicate that subtrop- ical mixed evergreen and deciduous broadleaf forests with sub- tropical evergreen components such as QuercuseE and Castanopsis as the dominant genus developed at the study site since 5000 cal yr BP. Deciduous trees such as deciduous Quercus occurred in the following period. The pollen spectra of the LZ-W profile show that the percentage of deciduous Quercus increased at 4900 cal yr BP, reflecting that temperature dropped at this time as previously found in the Yangtze Delta and the neighboring regions of East China (Yi et al., 2003, 2006; Innes et al., 2014). The rise of deciduous Quercus also occurred at the depth of 88e56 cm in zone LZ-N-4 and at the depth of 70e30 cm in zone LZ-W-4. According to the pollen spectra, it can be inferred that the section of LZ-N-4 and LZ-W-4 recorded the same cold event. Lakes or swamps are important components of landscape in eastern China including the Yangtze Delta and the Ningshao Plain. These wetlands were exploited not only for fishing and gathering Fig. 4. Percentage pollen diagram for profile LZ-W. X. Wang et al. / Quaternary International 438 (2017) 189e197 195

Fig. 5. Percentage pollen diagram for profile LZ-N. 196 X. Wang et al. / Quaternary International 438 (2017) 189e197 economy of the Neolithic man, but also for rice-based agriculture vegetational and environmental changes and human activities at during the Neolithic period (Innes et al., 2009; Fuller and Qin, 2010; the Neolithic Mojiaoshan site. The early-middle Liangzhu cultural Qin et al., 2011; Liu et al., 2016). According to the pollen data, period (5000-4500 cal yr BP) was characterized by a warm and swamp communities such as Cyperaceae, Gramineae (<38 mm), and humid climate, and a lacustrine-swamp environment prevailed Typha indicate that the study site had been a wetland environment during this period. Rice farming in the study area was prosperous since 5000 cal yr BP. Our results also suggest that swamps or lakes during the early-middle Liangzhu cultural period and the rice- probably had ever been converted to paddy fields, because Cyper- based agriculture began to decline from 4500 cal yr BP when the aceae, Gramineae (<38 mm), Typha, and other swamp communities site was abandoned. There have been reduced human activities were present along with Gramineae >38 mm. during the late Liangzhu cultural period (4500-4300 cal yr BP), Charcoal data indicate that high charcoal concentrations indicating that the demise of the Liangzhu culture was a prolonged occurred along with extensive rice farming during the Liangzhu process rather than a short-lived event. culture, Maqiao culture, and historical period, which is also consistent with previous studies and suggests that charcoal can be Acknowledgments used as an indicator of ancient human settlement (Haberle and Ledru, 2001; Wick et al., 2003; Connor et al., 2007; Itzstein-Davey This work was supported by the National Natural Science et al., 2007; Innes et al., 2009; Zheng et al., 2009; Shu et al., 2010; Foundation of China (grant numbers 41372185 and 41372183), the fi Li et al., 2010). Note that pro le LZ-N is taken from the ancient National Science and Technology Supporting Projects of China fi arti cial channel surrounding the wall of the Mojiaoshan site, (grant number 2013BAK08B02), and the National Social Science therefore, the pollen spectrum represents a relatively large area, Foundation of China (grant number 11&ZD183). We thank three fi while pro le LZ-W was taken from outside of the wall, which anonymous reviewers for their helpful comments on the represents local pollen assemblage. manuscript.

5.2. Timing of the abandonment of the Mojiaoshan site References The LZ-W profile is located on the palaeochannel surrounding Atahan, P., Grice, K., Dodson, J., 2007. Agriculture and environmental change at the wall of the Neolithic Mojiaoshan site. Therefore, its age should Qingpu, Yangtze delta region, China: a biomarker, stable isotope and palyno- be equal to or younger than that of the wall (Zhejiang Provincial logical approach. Holocene 17 (4), 507e515. Institute of Cultural Relics and Archaeology, 2008; Zhang et al., Atahan, P., Itzstein-Davey, F., Taylor, D., Dodson, J., Qin, J., Zheng, H., Brooks, A., 2008. fi > m Holocene-aged sedimentary records of environmental changes and early agri- 2015). This is con rmed by high values of Gramineae 38 m and culture in the lower Yangtze, China. Quat. Sci. Rev. 27 (5), 556e570. charcoal concentrations in zone LZ-N-1. According to the AMS 14C Cai, R.H., He, S.J., 1980. Vegetation types and their distribution in west lake dating results of profile LZ-N, intensive human activities occurred mountain of Hangzhou city, China. J. Zhejiang Univ. Sci. Ed. 4, 100e112 (in Chinese). between 5000 and 4500 cal yr BP. This suggests that the wall was Carrio, J.S., Navarro, C., Navarro, J., Munuera, M., 2000. The distribution of cluster probably built at about 5000 cal yr BP (Jingwei Network, 2016). pine (Pinuspinaster) in Spain as derived from palaeoecological data: relation- Both the pollen and charcoal records from profiles LZ-N and LZ-W ships with phytosociological classification. Holocene 10 (2), 243e252. > m Chen, J., 2005. Ecological history view on the rise and decline of Liangzhu culture. reveal that the values of Gramineae 38 m and charcoal concen- Southeast Cult. 5, 33e40 (in Chinese, with English Abstract). trations were very low immediately after 4500 cal yr BP, indicating Chen, Z.Y., Hong, X.Q., Li, S., Wang, L., Shi, X.M., 1997. Study of archaeology-related that human activities disappeared as the site was abandoned. Ac- environment evolution of Taihu Lake in southern changjiang delta plain. Acta Geogr. Sin. 2, 131e137 (in Chinese, with English Abstract). cording to Zhang et al. (2015), the Bianjiashan site, located to the Chen, Z., Zong, Y., Wang, Z., Wang, H., Chen, J., 2008. Migration patterns of Neolithic north of the Mojiaoshan site, was also abandoned at 4500 cal yr BP. settlements on the abandoned Yellow and Yangtze River deltas of China. Quat. This suggests that human occupation may have been interrupted at Res. 70, 301e314. 4500 cal yr BP. However, archaeological evidence and our palyno- Connor, S.E., Thomas, I., Kvavadze, E.V., 2007. A 5600-yr history of changing vege- tation, sea levels and human impacts from the Black Sea coast of Georgia. logical results suggest that the study area has been occupied Holocene 17 (1), 25e36. episodically during the late Liangzhu cultural period (between Faegri, K., Iversen, J., 1989. In: Faegri, K., Kaland, P.E., Krzywinski, K. (Eds.), Textbook 4500 and 4300 cal yr BP). Archaeological investigations reveal that of Pollen Analysis, fourth ed. John Wiley and Sons, Chichester. Fei, G.P., Chen, H.S., 2011. The excavation report of Yuhang-Penggong Dam in Zhe- cultural relics preserved on the wall of the Majiaoshan site between jiang Province, China. Cult. Relics East 3, 60e66 (in Chinese). 4500 and 4300 cal yr BP (Zhejiang Provincial Bureau of Cultural Fuller, D.Q., Qin, L., Zheng, Y.F., Zhao, Z.J., Chen, X.G., Hosoya, L.A., Sun, G.P., 2009. Relics, 2011; Zhejiang Provincial Institute of Cultural Relics and The domestication process and domestication rate in rice: spikelet bases from the Lower Yangtze. Science 323 (5921), 1607e1610. Archaeology, 2008, 2015; Liu and Wang, 2014), which probably Fuller, D.Q., Qin, L., 2010. Declining oaks, increasing artistry, and cultivating rice: the reveals that the site had been abandoned at 4500 cal yr BP, prior to environmental and social context of the emergence of farming in the Lower the ultimate termination of the Liangzhu culture at about Yangtze Region. Environ. Archaeol. 15 (2), 139e159. > m Grimm, E.C., 1987. CONISS: a FORTRAN 77 program for stratigraphically constrained 4300 cal yr BP. High values of Gramineae 38 m at 112 cm deep of cluster analysis by the method of incremental sum of squares. Comput. Geosci. the LZ-N profile indicate that the study area has been occupied 13 (1), 13e35. again in a short period after 4500 cal yr BP. Based on our results, the Grimm, E.C., 2004. Tgview. Version 1.7.16. Illinois State Museum Collection Center, Springfield. decline of the Liangzhu culture appears to be a prolonged process Haberle, S.G., Ledru, M.P., 2001. Correlations among charcoal records of fires from rather than a short-lived event such as flood, rapid marine trans- the past 16,000 years in Indonesia, Papua New Guinea, and Central and South gression or cold event that lasts one or a few years as previously America. Quat. Res. 55 (1), 97e104. thought (Zhu et al., 1996; Yu et al., 2000; Zhang et al., 2004, 2005; Hu, X.P., Shi, Y.X., Dai, X.R., Wang, J.T., Liu, B., Wang, N.Y., 2013. Characteristics and source of city wall's earth in the Neolithic Liangzhu City based on XRD analyses Shi et al., 2008; Zhang, 2008). Our results suggest that the decline of of clay minerals. Acta Petrol. Mineral. 32 (3), 373e382 (in Chinese, with English the Liangzhu culture was a very complex process lasting a few Abstract). hundred years. Innes, J.B., Zong, Y.Q., Chen, Z.Y., Chen, C., Wang, Z.H., Wang, H., 2009. Environ- mental history, palaeoecology and human activity at the early Neolithic forager/ cultivator site at Kuahuqiao, Hangzhou, eastern China. Quat. Sci. Rev. 28 (23), 6. Conclusions 2277e2294. Innes, J.B., Zong, Y.Q., Wang, Z.H., Chen, Z.Y., 2014. Climatic and palaeoecological changes during the mid-to Late Holocene transition in eastern China: high- Based on detailed pollen and charcoal analyses as well as resolution pollen and non-pollen palynomorph analysis at Pingwang, Yangtze radiocarbon dating, we are able to reconstruct the process of coastal lowlands. Quat. Sci. Rev. 99, 164e175. X. Wang et al. / Quaternary International 438 (2017) 189e197 197

Itzstein-Davey, F., Atahan, P., Dodson, J., Taylor, D., Zheng, H.B., 2007. A sediment- Res. 16 (4), 1126e1132. based record of Lateglacial and Holocene environmental changes from Stanley, D.J., Hait, A.K., 2000. Deltas, radiocarbon dating, and measurements of Guangfulin, Yangtze delta, eastern China. Holocene 17 (8), 1221e1231. sediment storage and subsidence. Geology 28 (4), 295e298. Jingwei Network, 2016. The Neolithic Liangzhu City was Thousand Years Earlier Talma, A.S., Vogel, J.C., 1993. A simplified approach to calibrating C14 dates. than the Project of King Yu Tamed the Flood! It Revealed the Dawn of Zhejiang Radiocarbon 35 (2), 317e322. Civilization. http://www.huaxia.com/zhwh/whrd/whrdwz/2016/05/4845572. Wick, L., Lemcke, G., Sturm, M., 2003. Evidence of Lateglacial and Holocene climatic html (in Chinese). change and human impact in eastern Anatolia: high-resolution pollen, charcoal, Li, C.H., Zhang, G.Y., Yang, L.Z., Lin, X.G., Hu, Z.Y., Dong, Y.H., Cao, Z.H., Zheng, Y.F., isotopic and geochemical records from the laminated sediments of Lake Van, Ding, J.L., 2007. Pollen and phytolith analyses of ancient paddy fields at Chuo- Turkey. Holocene 13 (5), 665e675. dun site, the Yangtze River Delta. Pedosphere 17 (2), 209e218. Wu, Z.Y., 1980. Vegetation of China. Science Press, Beijing (in Chinese). Li, C.H., Zheng, Y.F., Yu, S.Y., Li, Y.X., Shen, H.D., 2012. Understanding the ecological Yang, S.X., Zheng, Z., Huang, K.Y., Zong, Y.Q., Wang, J.H., Xu, Q.H., Rolett, B.V., Li, J., background of rice agriculture on the Ningshao Plain during the Neolithic Age: 2012. Modern pollen assemblages from cultivated rice fields and rice pollen pollen evidence from a buried paddy field at the Tianluoshan cultural site. Quat. morphology: application to a study of ancient land use and agriculture in the Sci. Rev. 35, 131e138. Pearl River Delta, China. Holocene 22 (12), 1393e1404. Li, C.H., Li, Y.X., Burr, G.S., 2014. Testing the accuracy of 14C age data from pollen Yi, S., Saito, Y., Yang, D.Y., 2006. Palynological evidence for holocene environmental concentrates in the Yangtze Delta, China. Radiocarbon 56 (1), 181e187. change in the changjiang (Yangtze River) delta, China. Palaeogeogr. Palae- Li, Y.Y., Wu, J., Hou, S.F., Shi, C.X., Mo, D.W., Liu, B., Zhou, L.P., 2010. Palaeoecological oclimatol. Palaeoecol. 241 (1), 103e117. records of environmental change and cultural development from the Liangzhu Yi, S., Saito, Y., Zhao, Q.H., Wang, P.X., 2003. Vegetation and climate changes in the and Qujialing archaeological sites in the middle and lower reaches of the Changjiang (Yangtze River) Delta, China, during the past 13,000 years inferred Yangtze River. Quat. Int. 227 (1), 29e37. from pollen records. Quat. Sci. Rev. 22, 1501e1519. Liu, B., Wang, N.Y., 2014. Findings of archaeological survey of prehistoric city at Yu, S.Y., Zhu, C., Song, J., Qu, W.Z., 2000. Role of climate in the rise and fall of Liangzhu during 2006-2013. Southeast Cult. 2, 31e38 (in Chinese). Neolithic cultures on the Yangtze Delta. Boreas 29 (2), 157e165. Liu, R., Qin, J.G., Mei, X., 2014a. Sedimentary environment changes of the Ningshao Zhang, L., Chen, Z.Y., Liu, Y., Wu, J.P., 2014. The emergence of the ancient city Plain since the later stage of the Late Pleistocene: evidence from palynology and Liangzhu with large-scale hydrological development in the Yangtze Delta and stable organic carbon isotopes. Quat. Int. 333, 188e197. its bearings on environmental geography. Sci. Sin. Terrae 44, 957e966 (in Liu, Y., Li, M.T., Sun, Q.L., Chen, Z.Y., 2014b. Palaeoclimatic and environmental Chinese, with English Abstract). changes since the Mid-Holocene in the Hangzhou Bay and their possible im- Zhang, Q., Jiang, T., Shi, Y.F., Lorenz, K., Liu, C.L., Martin, M., 2004. Paleo-environ- pacts on the evolution of Liangzhu Culture. J. Lake Sci. 26 (2), 322e330 (in mental changes in the Yangtze Delta during past 8000 years. J. Geogr. Sci. 14 (1), Chinese, with English Abstract). 105e112. Liu, Y., Sun, Q.L., Fan, D.D., Lai, X.H., Xu, L.C., Finlayson, B., Chen, Z.Y., 2016. Pollen Zhang, Q., Zhu, C., Liu, C.L., Jiang, T., 2005. Environmental change and its impacts on evidence to interpret the history of rice farming at the Hemudu site on the human settlement in the Yangtze Delta, PR China. Catena 60 (3), 267e277. Ningshao coast, eastern China. Quat. Int. 426, 195e203. Zhang, X.Y., Huang, D.S., Deng, H., Snape, C., Meredith, W., Zhao, Y., Du, Y., Chen, X., Liu, Y., Sun, Q.L., Thomas, I., Zhang, L., Finlayson, B., Zhang, W.G., Chen, J., Chen, Z.Y., Sun, Y.G., 2015. Radiocarbon dating of charcoal from the Bianjiashan site in 2015. Middle Holocene coastal environment and the rise of the Liangzhu City Hangzhou: new evidence for the lower age limit of the Liangzhu Culture. Quat. complex on the Yangtze delta, China. Quat. Res. 84 (3), 326e334. Geochronol. 30, 9e17. Long, T.W., Qin, J.G., Atahan, P., Mooney, S., Taylor, D., 2014. Rising waters: new Zhang, Y.L., 2008. Cause investigation of Liangzhu Culture's vanishment based on geoarchaeological evidence of inundation and early agriculture from former analysis of sporo-pollen and alga. J. Tongji Univ. Nat. Sci. 36 (3), 402e405 (in settlement sites on the southern Yangtze Delta, China. Holocene 24 (5), Chinese, with English Abstract). 546e558. Zhejiang Provincial Bureau of Cultural Relics, 2011. New Process on the Neolithic Moore, P.D., Webb, J.A., Collinson, M.E., 1991. Pollen Analysis. Blackwell Scientific Liangzhu City of Archaeological Discovery. http://www.zjww.gov.cn/news/ Publications, Oxford, UK. 2011-03-18/293671602_2.shtml (in Chinese). Qin, J.G., Taylor, D., Atahan, P., Zhang, X.R., Wu, G.X., Dodson, J., Zheng, H.B., Itzstein- Zhejiang Provincial Institute of Cultural Relics and Archaeology, 2008. Report of Davey, F., 2011. Neolithic agriculture, freshwater resources and rapid environ- archaeological excavation on Liangzhu city-site in Hangzhou City for the period mental changes on the lower Yangtze, China. Quat. Res. 75 (1), 55e65. 2006~2007. Archaeology 7, 586e579 (in Chinese). Reimer, P.J., Bard, E., Bayliss, A., Beck, J.W., Blackwell, P.G., Bronk, R.C., Buck, C.E., Zheng, Y.F., Sun, G.P., Qin, L., Li, C.H., Wu, X.H., Chen, X.G., 2009. Rice fields and Cheng, H., Edwards, R.L., Friedrich, M., Grootes, P.M., Guilderson, T.P., modes of rice cultivation between 5000 and 2500 BC in east China. J. Archaeol. Haflidason, H., Dajdas, I., Hatte, C., Heaton, T.J., Hoffmann, D.L., Hogg, A.G., Sci. 36 (12), 2609e2616. Hughen, K.A., Kaiser, K.F., Kromer, B., Manning, S.W., Niu, M., Reimer, R.W., Zhejiang Provincial Institute of Cultural Relics and Archaeology, 2015. Report of the Richards, D.A., Scott, E.M., Southon, J.R., Staff, R.A., Turney, C.S.M., van der detection of outer city of Liangzhu ancient city and the excavation of Meirendi Plicht, J., 2013. IntCal13 and Marine13 radiocarbon age calibration curves 0- and Biandanshan sites. Archaeology 1, 14e29 (in Chinese). 50,000 years cal BP. Radiocarbon 55 (4), 1869e1887. Zhu, C., Song, J., You, K.Y., Han, H.Y., 1996. Study on the formation of cultural fault of Shi, C.X., Mo, D.W., Li, C.H., Liu, B., Mao, L.J., Li, M.L., 2011. The relationship between Maqiao site. . Chin. Sci. Bull. 41 (2), 148e152 (in Chinese). environmental evolution and human activities in Liangzhu sites group, Zhejiang Zhu, C., Zheng, C.G., Ma, C.M., Yang, X.X., Gao, X.Z., Wang, H.M., Shao, J.H., 2003. On Province, China. Earth Sci. Front. 18 (3), 347e356 (in Chinese, with English the holocene sea-level highstand along the Yangtze delta and Ningshao plain, Abstract). east China. Chin. Sci. Bull. 48 (24), 2672e2683. Shi, W., Ma, C.M., Zhu, C., Wang, F.B., Li, S.J., 2008. Analysis of stratigraphy on multi- Zong, Y., Chen, Z., Innes, J.B., Chen, C., Wang, Z., Wang, H., 2007. Fire and flood profiles in the Taihu Lake region and paleoenvironmental events in the management of coastal swamp enabled first rice paddy cultivation in east Liangzhu culture epoch. Geogr. Res. 27 (5), 1129e1138 (in Chinese, with English China. Nature 449 (7161), 459e462. Abstract). Zong, Y., Wang, Z., Innes, J.B., Chen, Z., 2011a. Holocene environmental change and Shu, J.W., Wang, W.M., Jiang, L.P., Takahara, H., 2010. Early Neolithic vegetation Neolithic rice agriculture in the lower Yangtze region of China: a review. Ho- history, fire regime and human activity at Kuahuqiao, Lower Yangtze River, East locene 22 (6), 623e635. China: new and improved insight. Quat. Int. 227, 10e21. Zong, Y.Q., Innes, J.B., Wang, Z.H., Chen, Z.Y., 2011b. Mid-Holocene coastal hydrology Stanley, D.J., Chen, Z., 1996. Neolithic settlement distributions as a function of sea and salinity changes in the east Taihu area of the lower Yangtze wetlands, level-controlled topography in the Yangtze delta, China. Geology 24, China. Quat. Res. 76, 69e82. 1083e1086. Zong, Y., Innes, J.B., Wang, Z., Chen, Z., 2012. Environmental change and Neolithic Stanley, D.J., Chen, Z.Y., 2000. Radiocarbon dates in China's Holocene Yangtze delta: settlement movement in the lower Yangtze wetlands of China. Holocene 22 (6), record of sediment storage and reworking, not timing of deposition. J. Coast. 659e673.