Blame the bison.
If it wasn’t for the woolly, boulder-sized beasts that once roamed North America in great herds, ancient people might have looked past the little barley that grew beneath those thundering hooves. But people soon relied on barley and other native plants with small seeds as their staple food.
New research from Washington University in St. Louis is helping shape the origin story of the so-called “lost crops.” These plants may have fed indigenous people as much as corn, but were lost in history until the 1930s.
As early as 6,000 years ago, people in the Northeast and Midwest of the US used fire to maintain the prairies where bison thrived. As Europeans slaughtered the bison to near extinction, the plants that relied on these animals to disperse their seeds also began to decline.
Prairies have been ignored as potential sites for plant domestication, largely because the disturbed, biodiverse tallgrass prairies created by bison have only been recreated in the past three decades after a century of extinction, said Natalie Mueller, assistant professor Archeology in Art Sciences.
Follow the bison
In a new publication in The Anthropocene ReviewMueller reports on four field visits in 2019 to the Joseph H. Williams Tallgrass Prairie Preserve in eastern Oklahoma, the largest protected remnant of the tallgrass prairie on Earth. The reserve of about 40,000 hectares nowadays lives about 2,500 bison.
Mueller waded into the bison sinks after years of trying to grow the lost crops from wild-collected seed in her own testing grounds.
“One of the great unsolved mysteries about the origins of agriculture is why people chose to spend so much time and energy growing plants with tiny, unpalatable seeds in a world full of juicy fruits, savory nuts and plump roots,” said Mueller.
They may have gotten their ideas from bison tracking.
Anthropologists struggle to understand why ancient collectors chose to harvest plants that seemingly offer such a low labor efficiency.
“Before a mutualistic relationship could develop, people had to come across a heap of seed-bearing annuals that were dense and homogeneous enough to give rise to the idea of harvesting seed for food,” Mueller said.
Recent reintroductions of bison in tallgrass prairies provide some clues.
Scientists such as Mueller are for the first time able to study the effects of grazing on prairie ecosystems. Turns out chewing bison cause the kind of disturbance that opens up ideal habitats for annual forbs and grasses – including the crop precursors Mueller is studying.
Harvesting at the edge of the swamp
At the Tallgrass Prairie Preserve, Mueller and her team members got some tips from local expert Mike Palmer.
“Mike gave us roughly where on the prairie to look for the bison,” Mueller said. “His occurrence data was at about a square mile resolution, but that helps when you’re on 60 square miles of grassland.
“I thought it would be difficult to find trails before heading out, but it isn’t,” she said. “They’re super easy to find and easy to follow, so much so that I can’t imagine people moving through a prairie any other way!”
Telltale signs of grazing and trampling marked the “tracks” that bison make through shoulder-high grass. Following recently trodden trails through the prairie, the scientists were able to harvest seeds from contiguous groups of barley and mayegrass during their June visit, and sumpweed in October.
“Although distribution was much more limited, we also observed a species of Polygonum closely related to the crop precursor and wild sunflowers in bison pools and we did not encounter any of these in the non-grazed areas,” said Mueller.
It was easier to cross the bison trails through the prairie than to get off it.
“The ungrazed prairie felt treacherous because of the risk of stepping into burrows or on snakes,” she said.
With few landscape features for miles in any direction, the parts of the prairie not touched by bison can seem disorienting.
“These observations support a scenario where ancient people would have moved across the prairie along tracks where they existed,” Mueller said. “If they had, they would certainly have encountered bushy stands of the same plant species they eventually domesticated.”
Mueller encourages others to consider the role of bison as ‘co-creators’ – along with indigenous peoples – of disruptive landscapes that gave rise to greater diversity and greater agricultural opportunities.
“Indigenous peoples in the middle continent created resilient and biodiverse landscapes rich in food for humans,” she said. They managed floodplain ecosystems instead of using dikes and dams to convert them into monocultures. They used interactions with fire and multiple species to create mosaic landscapes of prairie, savannah and forest that provided a variety of resources on a local scale. . “
Mueller now grows seeds she has harvested from plants in the Tallgrass Prairie Preserve as well as seeds she has separated from bison droppings from the reserve. In the coming years, Mueller plans to return to the reserve and also to visit other prairies to quantify the distribution and abundance of crop precursors under different management regimes.
“These enormous prairies would not have existed if the Native Americans had not maintained them,” Mueller said with fire and other means. But for what purpose? Archaeologists have found no caches of bones or other evidence indicating that the indigenous people ate many prairie animals. Perhaps the ecosystems created by bison and anthropogenic fire benefited from the lost crops.
“We don’t think of the plants they ate as prairie plants,” she said. However, this research suggests that they are actually prairie plants, but they only occur on prairies when there are bison.
“I think we’re just starting to understand what the botanical record told us,” said Mueller. “People got a lot more food from the prairie than we thought.”
Five Facts About Bison, the New American National Mammal
Natalie G. Mueller et al. Bison, Anthropogenic Fire and the Origins of Agriculture in Eastern North America, The Anthropocene Review (2020). DOI: 10.1177 / 2053019620961119
Provided by Washington University in St. Louis
Quote: Secrets of the ‘Lost Crops’ Revealed Where Bison Roam (2020, November 23) Retrieved November 23, 2020 from https://phys.org/news/2020-11-secrets-lost-crops-revealed-bisonroam.html
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