本研究对牛坡洞遗址从旧石器时代晚期至新石器时代晚期的四期文化遗存中的92例动物骨骼进行碳氮稳定同位素分析，探讨人类狩猎策略及所处环境的变化。水鹿、梅花鹿等五种哺乳动物的碳氮稳定同位素数据反映出栖息在林地的生态习性，且在不同时期未见明显变化，表明这些动物都是人类狩猎所获，没有人工驯养痕迹。无论是样品量最大且最具代表性的水鹿，还是所有哺乳动物，其δ¹³C值的分布范围在前三期有所增大，却在第四期有所减小。这可能与先民的狩猎半径呈正相关，表明在前三期，牛坡洞先民的狩猎范围逐渐扩大，而在第四期却有所缩小。这种变化可能与第二期和第三期石器技术的进步以及前三期文化中较高的狩猎强度相关。尽管该区域在约万年的历史中经历了气候环境的巨大变化，但牛坡洞先民依然能长期有效地利用周边环境中的动物资源，在黔中地区长期生存。

The recovery of animal prey remains from archaeological sites provides a direct link to human hunting activity and serves as a valuable indicator of paleoenvironmental changes. In this study, we conducted carbon and nitrogen isotope analyses on mammalian bones from the Niupodong site in Guizhou Province to explore the mammalian paleoecological shifts across the first to the fourth cultural phases, with the aim of elucidating the chronological changes in human activities and paleoenvironments spanning from the Upper Paleolithic to Upper Neolithic.
Out of 92 mammalian bone specimens, collagen was successfully extracted from 80, with 72 yielding qualified isotopic data. The mean δ¹³C and δ¹⁵N values of various species including Cervus unicolor (sambar), Cervus nippon (sika deer), Muntiacus sp. (muntjac), Sus scrofa (wild boar), and Bubalus sp. (water buffalo) were −20.3‰±1.5‰ (n=72) and 4.9‰±0.9‰, indicating that these mammals mainly inhabited forest environments dominated by C₃ vegetation during the time of ancient human occupation at the Niupodong site. This indicates that these animals were primarily obtained through human hunting, with no apparent signs of domestication.
The range of mammalian δ¹³C values gradually expanded from Phase 1, potentially indicating an expansion of hunting areas due to increased demand for food resource after Phase 2. Cultural connotation changes were observed during the second and third phases, possibly suggesting advancements in hunting techniques. Coinciding with these cultural shifts, animal bones were highly fragmented at the Niupodong site during the first three phases but became less fragmented during Phase 4. The δ¹³C range of all the mammals, indicated by the standard deviations of the δ¹³C values, was narrower during Phase 4 compared to Phase 3, possibly due to the shrinkage of their hunting areas. The standard deviations of δ¹³C values for sambar specimens were relatively large in the first three periods, peaking in Phase 2 and decreasing to the smallest in Phase 4. This similar trend in data variations among sambar specimens may also reflect changes in hunting intensity.
Based on paleoenvironmental studies, Phase 1 of the Niupodong site, estimated to be approximately 15,000 BP, corresponds to the late glacial period. The second and third phases align roughly with the Holocene climatic optimum, characterized by a strong monsoon signal and a warm, humid climate, while Phase 4 corresponds to a weakening monsoon signal and a trend towards arid, cold conditions. In this study, the δ¹³C values of water buffalo specimens during the second and third phases were higher than those of Phase 4, exhibiting a C₄ signal during Phase 3. Since water buffalo are better indicators of paleoenvironmental conditions compared to cervids, which prefer inhibiting forests, the observed changes are likely associated with large-scale climate variations and shifts in vegetation. Moreover, isotopic data from other animals show minimal temporal changes. This suggests that despite significant paleoenvironmental and paleoclimatic fluctuations across the four cultural phases at the Niupodong site, early humans effectively utilize the animal resources in the surrounding forests, sustaining long-term survival in this region. However, given the gaps between different cultural phases at the Niupodong site, further researches are needed to explore the environmental characteristics of the surrounding areas in the absence of human activity and to determine whether human use of the cave is linked to environmental changes.