Hydroclimate Variability and the Evolution of Socioecological Complexity in Dryland Farming Communities

了解旱地生态系统中社会复杂性演化的生态制约因素仍然是考古学研究中的一大挑战。大多数关于旱地牧草-耕作转变的全球案例研究缺乏必要的年代精确度和细粒度的环境信息，以重建在这些生存变化、人口增长和社会发展的重要时刻环境与社会之间的微妙相互作用。北美西部的早期社会提供了一个罕见的例子，说明农业的短暂采用和社会复杂性的发展。相关园艺村庄的年表不准确及其直接的水文气候背景导致对社会复杂性的发展缺乏共识。该项目检验了关于此类村庄形成的两个假设：最大和最复杂的村庄的占用时间最长；被占用时间最长的村庄位于对水文气候变化制度最不敏感的河流流域。该项目为犹他州州立大学美国原住民暑期导师计划的参与者提供了研究网站，这是一项针对原住民学生的重点研究体验，鼓励转学和成功完成学位。PI们与东部史前博物馆和人类学博物馆的教职员工和学生合作，开发了一个项目发现的巡回展览，将在全州四个公共博物馆举办，每个展览为期三个月。展览由三个部分组成，每个项目调查员都展示了他们各自的研究成果。研究小组将开发基于树木年轮的过去两千年当地溪流流量的重建，建立和测试连接当地水文气候和地貌变量的流域敏感性模型，并使用高密度、高精度的年表模型评估村庄的寿命、规模和复杂性。在脆弱性阈值较少且频率较低的条件下发展起来的社区应该具有更长的职业持续时间、更大的规模和更多的复杂性证据。该项目提供了一个比较框架，解释了农业社区形成和稳定的基本过程，使旱地生态系统中的人口增长和社会复杂性得以实现。该项目系统地结合树状年代学、地质考古学和高精度考古放射性碳测年，在数十年/多代尺度上解析时间，以捕捉制约早期农业社会社会复杂性的稳定性、规模和发展的动态社会生态过程。该项目的发现是对过去和现代旱地农业社会可持续性的全球比较分析中的一个关键案例研究。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Understanding the ecological constraints on the evolution of social complexity in dryland ecosystems remains a major challenge in archaeological research. Most global case studies of foraging-farming transitions in drylands lack the requisite chronological precision and fine-grained environmental information necessary to reconstruct the subtle interactions between environment and society during these important moments of subsistence change, population growth, and social development. Early societies in western North America provide a rare example of the ephemeral adoption of agriculture and development of social complexity. Imprecise chronologies for relevant horticultural villages and their immediate hydroclimatic contexts have led to a lack of consensus on the development of social complexity. This project tests two hypotheses about the formation of such villages: the largest and most socially complex villages had the longest occupation spans; and the longest occupied villages occurred in river basins that are least sensitive to hydroclimate variability regimes. The project provides research sites for participants in the Utah State University Native American Summer Mentorship Program, a focused research experience for native students that encourages transfer and successful degree completion. The PIs collaborate with faculty and students at the Eastern Prehistoric Museum and Anthropology Museum to develop a traveling exhibit of the project findings that will be hosted at four public museums throughout the state for three months each. A three-part lecture series accompanies the exhibit where each project investigator presents the results of their individual studies. The research team will develop tree-ring-based reconstructions of local stream discharge for the last two millenia, build and test a basin sensitivity model connecting local hydroclimate and geomorphic variables, and evaluate village longevity, size and complexity using high-density, high-precision chronological models. Communities that developed under conditions where vulnerability thresholds were crossed with less frequency should have longer occupational durations, larger sizes, and more evidence of complexity. This project provides a comparative framework explaining the fundamental processes of agricultural community formation and stability that enabled the growth of populations and social complexity in dryland ecosystems. The project systematically combines dendrochronology, geoarchaeology, and high-precision archaeological radiocarbon dating to resolve time at the multidecadal/multigenerational scales necessary to capture the dynamic social-ecological processes constraining the stability, size, and development of social complexity in early agricultural societies. The project findings are a key case study in the global comparative analyses of the sustainability of past and modern dryland agricultural societies.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.