Environmental Influences on Human Subsistence Strategies in Southwest China During the Bronze Age: A Case Study at the Jiangxifen Site in Yunnan

Abstract

The study of human dietary structures is an effective means of elucidating the subsistence patterns of our prehistoric ancestors and can highlight the processes through which humans interacted with the environment. We conducted stable isotope and archeobotanical analyses of human, animal, and plant remains at the Jiangxifen site, dated to ~900–400 BC, to explore human paleodiets and determine the environmental adaptation strategies adopted by humans in the middle valley of the Jinshajiang River in Yunnan Province. Humans predominantly consumed C4 foods (e.g., millet) and C4 food-fed animal protein sources, with smaller contributions from C3 food plants (e.g., rice) and C3 food-fed animal protein sources. We argued that the local dry-hot environment was the reason for the accessibility of C4 plants in the studied area. A comparison of our results with previously published archeobotanical data and isotopic evidence from human bones in other Bronze Age sites in Yunnan Province revealed high spatial variability in diets of human and subsistence strategies during this period. These differences were caused by the highly varying living environment of each region, which was related to fragmentation resulting from the geomorphological features of Yunnan Province.

Diverse subsistence strategies related to the spatial heterogeneity of local environments in the Hengduan Mountain Region during the Bronze Age

“…The Jiangxifen site and the Shilianggang site lie at roughly the same elevation, though the average annual precipitation of Shilianggang is ~300 mm higher. Jiangxifen data suggests that the consumption of C 4 foods exceeded that of Shilinggang and Gaozhai (Figure 3C; Liu, 2016;Lu et al, 2021). Based on such data, we infer that human dietary strategies in the HRM during the Bronze Age were related to precipitation to a certain extent, though more information regarding the specific variation in subsistence strategies is needed.…”

“…The δ 13 C value (−18.4‰ ± 0.4‰) indicates that humans at Gaozhai primarily consumed C 3 foods (Figure 2; Table 2). Archaeobotanical studies from contemporaneous sites on the terraces of rivers and lakes in the HRM, such as Yubeidi, Shilinggang, and Jiangxifen, suggest that rice served as the dominant crop (Figure 3A; Yang, 2016;Li et al, 2016;Lu et al, 2021). At the same time, wheat/ barley and millets served as auxiliary crops in these areas during the early third Millennium BP.…”

“…The differences in animal protein intake and the natural environment are both possible reasons. Previous studies analyzed human bone collagen's carbon and nitrogen isotopic data from Jiangxifen and Shilinggang Bronze sites in the HMR (Liu, 2016;Lu et al, 2021). The human δ 13 C signals in the Shiligang site are almost similar to those in the Gaozhai tombs (Liu, 2016): in both sites, the human diet appears to have been dominated by C 3 foods (likely rice and rice byproducts), and auxiliary with mixed C 3 and C 4 foods (Figure 3C).…”

“…These same crops were utilized in the comparatively low-lying areas of southern HMR until ~4,600 BP (Dal Martello et al, 2018). Cropping patterns in the HMR during the late Neolithic and especially during the Bronze period (~3,400-2,200 BP) demonstrated diverse characteristics across different landforms (e.g., mountain areas, dry-hot valleys) (Lu et al, 2021;Ma et al, 2022a). However, the importance of different crops in plant subsistence and their relation to local environments throughout the HMR remains unclear, mainly due to the absence of human bone collagen stable isotopic data from different geomorphological positions.…”

“…Humans engaged in hunting-gathering in the HMR until the arrival of Neolithic farming groups from the Yellow River Valley during the sixth Millennium BP (Chen and Chen, 2006;Zhao and Chen, 2011;Huan et al, 2022). Following this introduction to agriculture, human strategies for food production transformed with notable spatial variability in the subsequent thousands of years (Lu et al, 2021;Ma et al, 2022a). According to the radiocarbon dates of the crop remains, millets, rice, and wheat/ barley first spread to the HMR around 5,300 BP, 5,000 BP, and 3,400 BP, respectively (d'Alpoim Guedes et al, 2015;Huan et al, 2022).…”