Date of Award
Doctor of Philosophy (PhD)
Humans are the ultimate ecosystem engineers, and in transforming ecosystems we also change the selective environment for the plants and animals that live among us. The bodies and behaviors of domesticated plants and animals are thus rich artifacts of traditional ecological knowledge and practice. I study the morphology and behavior of domesticated plants as a proxy for ancient agricultural communities of practice. The transition from food procurement to food production is one of the most significant shifts in human history. I consider this process as the evolution and spread of a knowledge system. Domestication studies are usually focused on differentiating wild from domestic types, but I wanted to investigate variation under cultivation. Normally discussed in the context of contemporary or historical small-scale farming, landraces are plant varieties that have been developed to grow particularly well under local conditions or to suit local preferences. Because landraces need to be maintained across generations of both plants and people, they are reflections of communities of practice, social learning, and Traditional Ecological Knowledge systems. By undertaking a detailed case study of variation within a single crop, I hoped to be able to use seeds in the same way that pottery, lithic tools, or iconography are used: to reveal shared traditions and connections between communities. This dissertation is focused on the "lost crops" of Eastern North America: a suite of annual seed crops that were cultivated for thousands of years before the introduction of maize and other tropical crops through trade. These crops are referred to as the Eastern Agricultural Complex (EAC). I chose to investigate one of these, erect knotweed (Polygonum erectum L.), which was cultivated for its edible seeds by Indigenous people in Eastern North American for ~2,000 years. My goals were 1) to establish whether or not erect knotweed had been domesticated by ancient farmers; and 2) to document variation under cultivation that might reveal different communities of practice in Eastern North America. This dissertation consists of five chapters: 1) A formal description of the domesticated sub-species of erect knotweed (Polygonum erectum ssp. watsoniae N.G. Muell.) including taxonomic background and a comparative analysis of other species of Polygonum native to the study area/ 2) An overview of domestication syndrome in a desiccated assemblage of erect knotweed from the Whitney Bluff site, Arkansas, and a discussion of its implications for ancient agricultural practice in Eastern North America. 3) The results of field studies and experimental cultivation of erect knotweed over two growing seasons, with a discussion of the hypothesized roles of plasticity and heredity in the domestication of this species. 4) An experimental study of the processes that affect preservation of erect knotweed seeds and fruits, namely: carbonization (burning in anoxic conditions) and taphonomy (physical weathering after deposition). These processes systematically bias the archaeobotanical record and need to be accounted for in domestication studies. 5) A review of the archaeological background, and a comparison of ancient erect knotweed assemblages from 14 archaeological sites spanning 2,000 years. My concluding thoughts place this research in the context of global studies of domestication and food production. I suggest that optimal foraging models used in human behavioral ecology may consistently under-rank the seeds of small seeded annuals, and that plasticity under cultivation may have been one factor that made disturbance adapted plants attractive to ancient foragers. I argue that niche construction, food production, and delayed return strategies are all roughly synonymous terms, and that domestication is a likely, but not predetermined, outcome of such systems and behaviors. The spread of food producing economies was dependent on the spread of complex systems of knowledge through interacting communities of practice and without these systems of traditional ecological knowledge domesticated varieties could not be maintained.
Chair and Committee
Gayle J. Fritz
Tristram R. Kidder, Fiona Marhsall, Xinyi Liu, Kenneth Olsen,
Mueller, Natalie Graham, "Seeds as Artifacts of Communities of Practice: The Domestication of Erect Knotweed in Eastern North America" (2017). Arts & Sciences Electronic Theses and Dissertations. 1133.