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

了解旱地生态系统社会复杂性演变的生态制约因素仍然是考古研究的主要挑战。大多数关于旱地从觅食到农耕转变的全球案例研究缺乏必要的时间精度和细粒度的环境信息，这些信息是在这些生存变化、人口增长和社会发展的重要时刻重建环境与社会之间微妙相互作用所必需的。北美西部的早期社会为农业的短暂采用和社会复杂性的发展提供了一个罕见的例子。有关园艺村及其直接水文气候背景的不精确年表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：最大和社会最复杂的村庄拥有最长的占领时间；被占领时间最长的村庄位于对水文气候变化机制最不敏感的流域。该项目为犹他州立大学印第安人暑期导师计划的参与者提供研究地点，这是一项针对土著学生的重点研究经验，鼓励转学和成功完成学位。pi与东部史前博物馆和人类学博物馆的教师和学生合作，开发了一个项目发现的巡回展览，将在全州的四个公共博物馆举办，每个博物馆为期三个月。一个由三部分组成的系列讲座伴随着展览，每个项目调查员介绍他们个人的研究结果。研究小组将基于树木年轮重建过去两千年的当地河流流量，建立并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、高精度的年代学模型评估村庄的寿命、规模和复杂性。在不太频繁地越过脆弱性阈值的条件下发展的社区应该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，这些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。该项目系统地结合了树木年代学、地质考古学和高精度考古放射性碳定年法，以确定多年/多代尺度的时间，以捕捉限制早期农业社会稳定性、规模和社会复杂性发展的动态社会生态过程。该项目的研究结果是对过去和现代旱地农业社会的可持续性进行全球比较分析的关键案例研究。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.