Ancient Farming in Eastern North America

COMMENTARY

Ancient farming in eastern North America

T. Douglas Price1 Laboratory for Archaeological Chemistry, University of Wisconsin, 1180 Observatory Drive, Madison WI 53706; and Department of Archaeology, University of Aberdeen, Aberdeen AB24 3FX, Scotland

nswers to one of the great archaeological questions are changing. The origins of agriculture have been a center- Apiece of research for many years. Specific what, where, and when questions are being resolved. Recent years Pepo Squash 5,000 B.P. Broomcorn Millet, Sunflower 4,800 B.P. have seen an extraordinary burst of new Pepo Squash 10,000 B.P. Foxtail Millet - Marshelder 4,400 B.P. 8,000 B.P. Maize 9,000 - 7,000 B.P. Chenopod 4,000 B.P. information about this fascinating sub- Common Bean 4,000 B.P. Rice 8,000 B.P. ject (1–3). Today, there are at least 10 Foxnut 8,000 B.P. Arrowroot 8,000 B.P. recognized regions in the world where Yam (D. trifida) 6,000 B.P Emmer wheat 10,000 B.P Cotton 5,000 B.P. Einkorn wheat 10,000 B.P. different species of plants and animals Sweet potato 4,500 B.P. Barley 10,000 B.P. African rice 2,000 B.P. were first domesticated (Fig. 1). Various Pearl millet 3,000 B.P. Sorghum 4,000 B.P. theories have arisen over the last cen- Potato 7,000 B.P.? Quinoa 5,000 B.P. tury and a half to explain how and why Peanut? Manioc 8,000 B.P.? Yam (D. alata) 7,000 B.P.? Chile Peppers 6,000 B.P. Banana 7,000 B.P. this happened, but no consensus has Taro 7,000 B.P.? emerged. A variety of causal factors have been explored as potential drivers for domestication: climate change, car- Fig. 1. The major centers of primary domestication and dates for the earliest domestication of various bon dioxide increases, population plant and animal species. Illustration by Marcia Bakry. growth, developments in human cogni- tion, ideology, and increasing social pepo) is the first recognized domesti- long experiments with different combi- complexity and differentiation (4–8). cated plant from 5025 years B.P. (only nations of domesticates and wild foods New information from the eastern calibrated dates are used here). Sub- to find a coherent whole in terms of United States in the article by Smith sequent modified species include reliable food supply. In various parts of and Yarnell in this issue of PNAS (9) Helianthus annuus mac- provides much food for thought. sunflower ( var. the world, as the last cold cycle of the rocarpus) at 4840 B.P. (Fig. 2) and Pleistocene was ending human societies Advances in our knowledge about the Ϸ first farmers are caused in large part by marsh elder (Iva annua)at 4400 B.P. began to add more plant species to their new technology and development. Ac- Three other seed plants have been iden- diet (15–17). The transition from hunt- celerator mass spectrometry (AMS) tified as potential crops, the subject of ing and gathering to full agriculture was radiocarbon dating permits the measure- deliberate planting and harvesting of a long process, spanning thousands of ment of very small samples and now has stored seed stock, based on their abun- years. The initial domestication of plants been used to directly date many early dance in seed assemblages before 2000 and animals began within a larger con- crops. The antiquity of domestication B.P.: erect knotweed (Polygonum erec- text of increasing manipulation and has been pushed deeper into the past in tum), little barley (Hordeum pusillum), management of a wide range of wild many areas. Today, an eerie synchronic- and maygrass (Phalaris caroliniana). species. The individual domesticates of a ity in the timing of the first domesticates Maize (Zea mays), the most important particular region were not created all at around the end of the Pleistocene is crop plant in this region in later years, once in one place, but apparently over emerging. Genetic studies of modern does not arrive until 2150 B.P. time, in a number of different locales, and ancient DNA in domesticated plants Smith and Yarnell (9) identify the by small, interacting societies. Eventually and animals are providing remarkable emergence of a ‘‘crop complex’’ in east- these different crops and/or herd ani- information on species distribution and ern North America, as more domesti- mals coalesced into a set of species, or evolution (10, 11). Genetic markers for cates are added to the diet and can be complex, that provided the majority of domestication are starting to be identi- identified as part of an important set of the human diet. fied (12). In addition, the number of foods. The essential evidence comes This scenario appears to fit the areas archaeological excavations around the from the Riverton site in southeastern for which we have data. We have sub- world has increased by an order of mag- Illinois, dating to 3800 B.P. Unusual stantial information from the early agri- nitude in recent years because of devel- conditions of preservation, large-scale cultural cradle of Southwest Asia. The opment and construction as legislated archaeological excavation, and a deliber- picture in eastern North America is be- assessment and salvage of threatened ate search for plant remains provided coming clearer. Much new data are historical and archaeological materials documentation of the utilization of a coming from China and South America. has been enforced. Lots of new data are rich diet and the cultivation of at least 5 We know very little about Mexico, Af- available in some areas. (and perhaps as many as 7) different rica, Southeast, and Insular Asia. As the In the last 20 years, these advances crop plants. In addition to the species Smith and Yarnell study (9) indicates, and some excellent archaeological detec- listed above, 2 varieties of chenopod tive work have added the eastern (Chenopodium berlandieri) were abun- United States to the list of agricultural dant in the archaeobotanical remains Author contributions: T.D.P. wrote the paper. cradles (13, 14). A series of original do- from the site. The author declares no conﬂict of interest. mesticates has been identified and A crop complex (or plant and animal See companion article on page 6561. radiocarbon-dated. Squash (Cucurbita complex) represents the end result of 1E-mail: [email protected].

www.pnas.org͞cgi͞doi͞10.1073͞pnas.0902617106 PNAS ͉ April 21, 2009 ͉ vol. 106 ͉ no. 16 ͉ 6427–6428 Downloaded by guest on September 27, 2021 investigations and often have conditions The nuts of hickory, walnut, and oak of less than ideal preservation. To en- invariably dominate the plant remains, hance our understanding of the origins reflecting the minor importance of the of agriculture, archaeologists will have seeds of wild, annual plants. One of the to spend more time in the field opening more intriguing questions about the ori- big holes looking for the seeds, bones, gins of agriculture is raised by the low and other evidence of domesticated spe- incidence of the domesticated species cies. The need for more and better in- and the abundance of wild foods in gen- formation is huge. eral. Why did these societies with suc- The growing body of information cessful, long-term adaptations to re- from eastern North America does pro- source-rich river valleys begin to vide insight on this process of domesti- manipulate plants in the first place? cation and the origins of farming in The initial domestication of crop plants takes place at the beginning of other parts of the world. At the same Ϸ time, like all new research, it raises the Holocene, 8,000–10,000 years ago, many questions. The evidence for this in Southwest Asia, China, Mexico (19, 20), and South America. In a few areas, region documents a situation some 4,000 the first species to be changed appear years ago where hunter–gatherer much later, however, Ͻ5,000 years ago. groups, living in abundant environments Another question requiring an answer and spending substantial periods in sed- then is why are these later regions de- entary residences, were changing nature, Fig. 2. A sunﬂower seed (Helianthus annuus var. layed in the process of agricultural ori- domesticating a variety of plant species gins. What differences or distinctions macrocarpus) excavated at Newt Kash Shelter, that increased their food supply. Why? Kentucky. The missing half of the shell from the are involved in this gap? seed was used to obtain an AMS radiocarbon date And why here? There are numerous As the evidence surrounding the ori- of ca. 3500 B.P. locations in North America, and else- gins of agriculture continues to expand, where, where there are many species of answers to basic questions are gradually wild plants growing in rich environ- being discovered. The future of archaeo- visibility and serendipity play a huge ments inhabited by hunter–gatherer so- logical research is exciting in part because role in our knowledge about agricultural cieties where domestication does not it will involve the continuing resolution transitions. The breakthrough at the Ri- appear to have resulted. of this issue. At the same time, we still verton site came because of a congru- The archaeological remains from sites do not understand why these changes ence of preservation, large excavation, like Riverton yield evidence of utiliza- were initiated, nor why agriculture ex- and an intentional search for plant re- tion of a wide range of aquatic re- panded to become the preeminent mode mains. Many other sites, in many parts sources, including fish, bivalves, and of human subsistence across the globe. of the world, may well contain informa- snails, while the white-tailed deer, tur- Answers to these mysteries may require tion on early domesticated species, but key, raccoon, rabbits, and squirrels (18) completely new questions about human they are known only from small-scale provided the terrestrial animal protein. society and adaptation.

1. Barker G (2006) The Agricultural Revolution in Prehis- 8. Sage RF (1995) Was low atmospheric CO2 during the 15. Weiss E, Wetterstrom W, Nadel D, Bar-Yosef O (2004) tory. Why Did Foragers Become Farmers? (Oxford Univ Pleistocene a limiting factor for the origin of agricul- The broad spectrum revisited: Evidence from plant re- Press, Oxford). ture? Global Change Biol 1:93–106. mains. Proc Natl Acad Sci USA 101:9551–9555. 2. Bellwood P (2005) First Farmers: The Origins of Agri- 9. Smith BD, Yarnell RA (2009) Initial formation of an 16. Fritz G (1990) Multiple pathways to farming in pre- cultural Societies (Blackwell, Oxford). indigenous crop complex in eastern North America at contact Eastern North America. J World Prehist 3. Zeder MA, Bradley D, Emshwiller E, Smith, BD, eds (2006) 3800 B.P. Proc Natl Acad Sci USA 106:6561–6566. 4:387–435. Documenting Domestication: New Genetic and Archae- 10. Armelagos GJ, Harper KJ (2005) Genomics at the origins 17. Smith BD (2006) Eastern North America as an indepen- ological Paradigms (Univ California Press, Berkeley). of agriculture. Evol Anthropol 14:68–77. dent center of plant domestication. Proc Natl Acad Sci 11. Fang M, Larson G, Soares Ribeiro H, Li N, Andersson L 4. Denham TP, Iriarte J, Vrydaghs L, eds (2007) Rethinking USA 103:12223–12228. (2009) Contrasting mode of evolution at a coat color Agriculture: Archaeological and Ethnoarchaeological 18. Winters H (1969) The Riverton Culture (Illinois State locus in wild and domestic pigs. PLoS Genet, Perspectives (Left Coast Press, Walnut Creek, CA). Museum, Springﬁeld). doi:10.1371/journal.pgen.1000341. 5. Bocquet-Appel J-P, Bar-Yosef O, eds (2008) Neolithic 19. Ranere AJ, Piperno DR, Holst I, Dickau R, Iriarte J (2009) 12. Smith BD (2001) Documenting plant domestication: Demographic Transitions (Springer, New York). The cultural and chronological context of early Holo- The consilience of biological and archaeological ap- 6. Cauvin J (2000) The Birth of the Gods and the Origins proaches. Proc Natl Acad Sci USA 98:1324–1326. cene maize and squash domestication in the Central of Agriculture (Cambridge Univ Press, Cambridge, 13. Flannery KV (1969) in The Domestication and Exploi- Balsas River Valley, Mexico. Proc Natl Acad Sci USA UK). tation of Plants and Animals, eds Ucko PJ, Dimbleby 106:5014–5018. 7. Hayden B (1995) in Last Hunters–First Farmers: New GW (Aldine, Chicago), pp 73–100. 20. Piperno DR, Ranere AJ, Holst I, Iriarte J, Dickau R (2009) Perspectives on the Prehistoric Transition to Agricul- 14. Stiner MC (2001) Thirty years on the ‘‘Broad Spectrum Starch grain and phytolith evidence for early ninth ture, eds Price, TD, Gebauer, AB (School of American Revolution’’ and paleolithic demography. Proc Natl millennium B.P. maize from the Central Balsas River Research Press, Santa Fe, NM), pp 273–299. Acad Sci USA 98:6993–6996. Valley, Mexico. Proc Natl Acad Sci USA 106:5019–5024.

6428 ͉ www.pnas.org͞cgi͞doi͞10.1073͞pnas.0902617106 Price Downloaded by guest on September 27, 2021