Quaternary International 521 (2019) 66–74 Contents lists available at ScienceDirect Quaternary International journal homepage: www.elsevier.com/locate/quaint Early urban impact on vegetation dynamics: Palaeoecological reconstruction T from pollen records at the Dongzhao site, Henan Province, China Xiaolin Rena,b,*, Duowen Mob, Michael Storozumc,d, Ximena Lemoined, Yanyan Yua, Wanfa Gue, Xingshan Leif, Jiaqiang Zhange, Jianqing Lüb, Tristram R. Kidderd,** a Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China b Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China c Institute of Archaeological Science, Fudan University, Shanghai, 200433, China d Department of Anthropology, Washington University in St. Louis, MO, 63130, USA e Zhengzhou Municipal Institute of Cultural Relics and Archaeology, Zhengzhou, 450000, China f School of Archaeology and Museology, Peking University, Beijing, 100871, China ARTICLE INFO ABSTRACT Keywords: Archaeologists have focused on the social conditions surrounding the development of urbanism around the Dongzhao world; however, the environmental impact of these ancient cities remains unclear. In this paper, we present Pollen analysis palynological data from the early Bronze Age city of Dongzhao, Henan Province, China. Our data indicate that Vegetation dynamics vegetation change and the development of early urban settlements are closely linked, with the advent of urban Early urban impact development significantly accelerating deforestation and altering the composition of local vegetation commu- Human-environmental interaction nities. The pollen record from Dongzhao provides new evidence to support the claim that urban expansion, Urbanization coupled with a drying climate and the expansion of agriculture, dramatically reconfigured the landscapes of Bronze Age China. 1. Introduction 2013; Schlapfer et al., 2014). This perspective has similarly been ap- plied to archaeological contexts, where the longevity of many pre- Archaeological assessment of the environmental impact of early modern cities is also credited to environmental advantages conferred by cities can provide a baseline for thinking about the complex challenges the landscape-transforming activities of urban settlements (Isendahl of contemporary urban living. Current research on urbanism has re- and Smith, 2013). sulted in two divergent views on the environmental consequences of Despite these notable applications, archaeological research on cities city living. One perspective contends that the dense population of cities and urbanism has tended to focus on the political, economic, and social which requires a large amount of natural resources provokes an “urban origins and contexts of cities, as well as their roles in broader society penalty” resulting in environmental degradation beyond the city, as (Cowgill, 2004; Marcus and Sabloff, 2008; Smith, 2003, 2007, 2010). well as the concentration of harmful diseases and pollutants within the There are far fewer archaeological studies on the relationship between city (Brown, 2009; Ehrlich and Ehrlich, 2013; Elmqvist et al., 2013; cities and their environments, and the majority of work on this topic Grimm et al., 2008; Seto et al., 2012). The Bronze Age site of Akko placed the emphasis on urban systems sustained by agricultural systems (Acre) in Israel has provided evidence for this “urban penalty” in an- that were typical to Mesoamerica or Southeast Asia (Barthel and tiquity (Kaniewski et al., 2013). Isendahl, 2013; Elmqvist et al., 2013; Fletcher, 2009, 2012; Isendahl, Proponents of the second view argue that cities actually provide an 2010; Isendahl and Smith, 2013; Sinclair et al., 2010). In contrast to “urban advantage”, because they are environmentally efficient. That is, such low-density systems in Mesoamerica or Southeast Asia, early cities can produce positive feedback from social interactions that gen- Chinese cities are characterized by high-density settlements supported erates more economic value relative to resource consumption by intensive land use practices. As such, early Chinese cities provide an (Bettencourt, 2013; Bettencourt et al., 2007; Dodman, 2009; Meyer, important context that more closely resembles modern cities (von * Corresponding author. Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China. ** Corresponding author. Department of Anthropology, Washington University in St. Louis, St. Louis, MO 63130, USA. E-mail addresses: [email protected] (X. Ren), [email protected] (T.R. Kidder). https://doi.org/10.1016/j.quaint.2019.07.012 Received 1 March 2019; Received in revised form 5 July 2019; Accepted 6 July 2019 Available online 08 July 2019 1040-6182/ © 2019 Elsevier Ltd and INQUA. All rights reserved. X. Ren, et al. Quaternary International 521 (2019) 66–74 Faukenhausen, 2008; Yang, 2004). are common, with Salix sinopurpurea and Typha spp. common in wet- In this paper we investigate the sustainability of cities in the past by lands (Wang et al., 1989; Zhang et al., 2018). At present, the landscape examining urban impact on the environment in Bronze Age China, as is dominated by agricultural fields that have almost entirely replaced revealed from the archaeological site of Dongzhao in Henan Province. the natural vegetation. The annual mean temperature is 14.4 °C, and the This urban settlement features qualities associated with the “penalties” annual mean precipitation is about 650 mm with the majority occurring as well as with “advantages” of urban systems (Gu, 2015; Lei et al., from May to September (Zhengzhou Committee of Chorography, 1999). 2016; Hao and Zhang, 2016). Using geoarchaeological, chronometric, Previous studies have provided basic evidence of vegetation shifts in and palynological data from Dongzhao site in Henan Province, we test the Central Plains from middle to late Holocene (Yan et al., 1986; Wang the “urban advantage” and “urban penalty” models within a densely- et al., 2004; J. Xu et al., 2013). Pollen analysis from the Sihenan profile populated and intensive agricultural land-use system. in the Luoyang Basin, Henan Province, shows a forest steppe landscape The rapid expansion of modern cities and associated environmental dominated by Pinus spp. and Artemisia in the period of 4580–3545 yr changes witnessed in the present underscore the importance of this line BP, followed by a period (3545–3090 yr BP) of rapid increase in of research; however, the environmental consequences of urbanism are Amaranthaceae/Chenopodiaceae pollen percentage (Sun and Xia, poorly understood (Fletcher, 2012). By providing an archaeological 2005). Evidence from Anyang in northern Henan Province has shown example of urban activities and their effects on local vegetation dy- that mixed deciduous and evergreen broad-leaved forests were domi- namics of the past, we can contribute to the broader scholarly endeavor nant between 8200 and 3400 cal. BP and the component of evergreen of discerning what makes societies sustainable or vulnerable in the face broad-leaved forests decreased sharply after 3400 cal. BP (Xu et al., of environmental challenges. 2010; Cao et al., 2010). Since 2014, the Dongzhao site has been extensively excavated by the Zhengzhou Municipal Institute of Relics and Archaeology and the 2. Study site School of Archaeology and Museology of Peking University. The site area is about 1 km2 and contains three urban settlements that are dated The Dongzhao site (113°29′38″E, 34°46′56″N) is located to the west to the early period of the Xinzhai Culture (ca. 1870–1790 BC), the early of Zhengzhou City in Henan Province. It lies within the broad region period of the Erlitou Culture (ca. 1735–1565 BC), and the eastern Zhou known as the Central Plains (Zhongyuan) that has traditionally been Dynasty (770–256 BC), respectively (Gu, 2015; Lei et al., 2016; X. called the “Cradle of Chinese Civilization” (Yan, 1987; Zhao, 2000) and Zhang et al., 2007). Recent excavations at Dongzhao have unearthed is within close proximity to a number of other important Bronze Age house foundations, burials, sacrificial remains, ditches, wells, ash pits, urban settlement sites (Fig. 1). Geographically, Dongzhao is bounded by as well as a large number of artifacts including oracle bones, ceramics, the Yellow River to the north and the Songshan Mountains to the and various grains (Gu, 2015; Lei et al., 2016). The site features mul- southwest (Fig. 1). It is situated on the northeastern piedmont of Mount tiple periods of large-scale urban settlement, which are punctuated by Tan and has an altitude of approximately 125 m above sea level. The intervals of smaller-scale and less socio-economically complex occu- nearby Suo and Xushui rivers flow to the east into the upper reaches of pations. This provides the opportunity to see how vegetation around the Huai River. In terms of geomorphology, the dominant landform of Dongzhao responded to site-wide socio-economic dynamics. the study area is a loess platform composed of re-deposited Pleistocene and Holocene loess (Lu et al., 2014). The Songshan Mountains to the southwest of the site are primarily composed of limestone, dolomite, 3. Materials and methods and siltstone (Webb et al., 2007). Regional vegetation is characterized by coniferous-deciduous forests 3.1. Field work and particle size analysis and shrubs found