For hundreds of years, Indigenous communities in what is now British Columbia cleared small patches amid dense conifer forest. They planted and tended food and medicine-bearing trees and plants—sometimes including species from hundreds of miles away—to yield a bounty of nuts, fruits, and berries. A wave of European disease devastated Indigenous communities in the late 1700s, and in the 1800s, colonizers displaced the Indigenous people and seized the land. The lush, diverse forest gardens were abandoned and forgotten.
A few years ago, Chelsey Geralda Armstrong, an ethnobotanist at Simon Fraser University, was invited by First Nation elders to investigate why hazelnut trees were growing at abandoned village sites near the coast. The plants were far from their native habitat in the dry interior and seemingly lost among towering cedars and hemlocks. Armstrong began to suspect she was studying human-created ecosystems—and they were thriving, even with no one caring for them. She brought her suspicions to community elders, who confirmed them by sharing memories of ancestors cultivating edible and medicinal plants.
Armstrong gathered colleagues to study these ancient gardens’ ecology. In a new paper published this week in the journal Ecology and Society, the team reports a striking finding: After more than a century on their own, Indigenous-created forest gardens of the Pacific Northwest support more pollinators, more seed-eating animals and more plant species than the supposedly “natural” conifer forests surrounding them.
“When we look at forest gardens, they’re actually enhancing what nature does, making it much more resilient, much more biodiverse—and, oh yeah, they feed people too,” says Armstrong.
The paper may be the first to quantify how Indigenous land stewardship can enhance what ecologists call functional diversity—a measure of how many goods an ecosystem provides. It joins a growing scientific literature revealing that Indigenous people—both historically and today—often outperform government agencies and conservation organizations at supporting biodiversity, sequestering carbon, and generating other ecological benefits on their land. Leaving nature alone is not always the right course, scientists are finding—and the original land stewards often do it best.
This is, of course, a claim that Indigenous groups have long made. Western scientists, by contrast, have often written Native people out of forests and other ecosystems they helped create. An increasing number of scientists are now questioning this practice—and in the process, forcing ecology and conservation to undergo what some would say is a long-overdue reckoning.
“Western science for too long has embraced the idea of primordial wilderness,” says Jesse Miller, an ecologist at Stanford and Armstrong’s coauthor. “We’re seeing this paradigm shift to recognizing how much of what was thought of as primordial wilderness were actually landscapes shaped by humans.”
Getting people to listen
The forest gardens Armstrong studied once supplied Indigenous villages with food and medicine, including plants that had been imported from elsewhere. “Historically it was really important to have all the resources here,” says Willie Charlie, a former chief and current employee of the Sts’ailes Nation of the Coast Salish people. “If you had all that in your family, you were pretty self-sustaining.”
Armstrong and her team studied 12 forest gardens in southern and central British Columbia, between 100 square meters (roughly 1,100 square feet)—about half a tennis court—to a square kilometer, the size of a very small town. The gardens are open, sunny patches within dense, shady conifer forests, thick with deciduous trees and shrubs.
The researchers laid out rectangular plots in the gardens and adjacent forests. They counted the number of plant species, and recorded how they are pollinated and what kinds of seeds they produce, among other factors.
(In this episode of our podcast Overheard, National Geographic Explorer Nirupa Rao shares her passion to illustrate the wonder of native plant life in India's Western Ghats. Listen now on Apple Podcasts.)
Compared to forest plots, gardens had roughly 1.3 times as many total plant species and 1.5 times as many plants with seeds spread by animals. Species in the gardens produced seeds that were on average twice as large as those in forest plots, making the gardens far better at feeding animals—a measure of functional diversity. Hazelnuts, fruit-bearing shrubs such as cranberry and elderberry, and edible understory plants like wild ginger and northern rice root were all more common in gardens than in surrounding forests, which were dominated by conifers that produce fewer foods for humans or animals.
“Functional diversity is kind of a hot topic in ecology,” says Miller. Many ecologists see it as a better measure of an ecosystem’s health and resilience than the simple species counts that go into conventional biodiversity metrics. That resilience may be why the forest gardens have survived so long without maintenance, Miller and Armstrong suspect.
The wonky-sounding metric also seemed to measure something of importance to the Indigenous people whose land the gardens sit on. Elders told Armstrong that it made sense gardens were found to support more animals than surrounding forests because the elders already knew the gardens were “the best places to hunt” due to the abundance of game.
The study shows that “it’s really critical to have people as part of the ecology,” says Tony Marks-Block, an anthropologist at California State University, East Bay, who was not part of the study. “Excluding people from the land is not actually restoring the land.”
Armstrong says publication of the study is only a first step toward helping First Nations revitalize their plant-based cultures. “The goal is to apply what we learn to bringing these gardens back” by helping Indigenous communities use them again, she says.
To that end, Charlie is working to create trails to the gardens and to get village members—especially young ones—to use and maintain them again. He says that studies like Armstrong’s can help with that.
“Old people don’t believe something until somebody tells them,” he says. “Young people don’t believe something until it’s in writing.”
A bias toward pristine nature
The disconnect between Indigenous knowledge and Western science has deep roots. By the time ecology became organized as a scientific discipline, in the early 1900s, European colonizers had displaced Indigenous groups throughout much of the world. So the landscapes that scientists interpreted as “natural” or “pristine” often, in fact, once had human residents who carefully managed them.
Erasing Indigenous land stewardship also fed into a “fortress conservation” model under which removing people from an area was seen as essential to conserving it. A prominent example is Yosemite National Park, whose development included the eviction of Native people.
“In the conservation movement, we’re so used to thinking about ‘anthropogenic’ as a synonym for bad,” Miller says. “We often ignore Native American land management.”
In the 1960s and 1970s, as Indigenous groups in the United States and elsewhere gradually gained self-determination, many of them asserted that they had rights to manage the land they had once owned according to traditional practices.
That often collided with both government policies and the scientific establishment. For example, supposedly science-backed fire suppression policies made it nearly impossible for Indigenous communities to burn land for ecological and cultural benefits. When ecologist and Potawatomi Nation member Robin Wall Kimmerer arrived at the State University of New York College of Environmental Science and Forestry in the 1970s to study botany, as she recounts in her 2013 book Braiding Sweetgrass, she encountered an academic establishment ill prepared to consider traditional ecological knowledge or beneficial interactions between humans and other species.
“Ecologists wanted to study ‘natural’ systems, which they defined as absent of people, so they would try to seek out places where people weren’t,” says Don Waller, a retired ecology professor at the University of Madison-Wisconsin, who was also starting his career at that time.
But discoveries revealing that the supposedly pristine Amazon rainforest had actually been profoundly shaped by people for thousands of years began to change researchers’ minds. More recently, the United Nations’ Food and Agriculture Organization surveyed more than 300 previous studies and found that areas in Latin America occupied by Indigenous people had lower deforestation rates and higher carbon stores than other places, including government-protected areas. A 2019 study found that Indigenous lands in Australia, Brazil, and Canada had comparable vertebrate biodiversity to government-protected areas.
And just this week, researchers reported that Indigenous people inhabited and shaped three-quarters of Earth’s land for thousands of years, but that biodiversity loss accelerated only with global colonization.
In the 1980s, Waller became aware of an exceptional forest belonging to the Menominee Nation of northeastern Wisconsin—a mostly rectangular, 365-square-mile forest so dense and green that it pops out from the surrounding landscape in satellite images. Since the 1800s, the tribe has harvested wood only as fast as their forest can regrow; in 1992, it became the first in the U.S. certified as sustainable.
With permission, Waller began collecting ecological data from the reservation and other forests around the state. In a 2018 study, he and a coauthor reported that Wisconsin forests owned and stewarded by the Menominee and Ojibwe perform as well or better than any others in Wisconsin, including Forest Service- and Park Service-owned forests, on five different metrics of forest volume and health. Those include number of tree seedlings, understory plant diversity, and deer populations closer to historical baselines.
The value of putting things in writing
A new generation of ecologists and anthropologists is increasingly asking similar questions not just about how humans might harm ecosystems, but also about how people can enhance them. A few years ago, Marks-Block collaborated with Indigenous forest scientist Frank Lake of the U.S. Forest Service to study the impact of fire by the Yurok and Karuk tribes of northern California on hazelnut, an important species for both food and basketry.
In February, the team reported that compared to not burning, traditional fire practices produced 13 times more hazelnut stems that basket makers could use and decreased the distance they needed to travel to gather stems by nearly a factor of four.
Beyond hazelnut, Native people of the area used fire to manage a sophisticated rotation of oak trees, burning at the right time to kill insects that might otherwise cause acorns to spoil and become inedible, says Bill Tripp, director of natural resources for the Karuk tribe. Since fire was suppressed in the late 1800s, most oak savannas have been taken over by conifers like Douglas fir, making the overall landscape both less diverse and less edible.
Outcomes of scientific studies such as Marks-Block’s often affirm what Native people already know from tradition and experience, but that doesn’t mean the studies aren’t useful, Tripp says.
“We knew what the outcome was going to be,” he says. “But nobody listens if it isn’t written down like that.”
Being able to cite scientific literature may be especially important as Indigenous groups push for more rights, especially on territories they still claim but no longer own. For example, Karuks want more burning rights on Forest Service land, while neighboring Yuroks are pushing to co-manage and conduct controlled burns in Redwood National Park. With Deb Haaland recently confirmed as the first Native Interior Secretary, many tribal leaders are cautiously optimistic that the time for such change has arrived.
In other cases, however, government policy continues to diverge from both Indigenous knowledge and science. This spring, for example, the state of Wisconsin authorized a wolf hunt that both scientists and tribes had protested.
“People outside the tribal community tend to … think a lot of our positions are culturally based. But I would argue they tend to align much more with science than the non-tribal worldview,” says Peter David, a wildlife biologist for the Great Lakes Indian Fish and Wildlife Commission, which represents 11 Midwestern Ojibwe tribes.
“The tribal worldview says wolves ought to be able to establish their own population levels, and they do that at very low levels…it aligns much better with the science.”
Despite an increasing convergence between science and Indigenous knowledge, the academy still has work to do, too, says Waller. “I would like to see forestry schools routinely sending forestry students, for example, to Menominee Tribal Enterprises,” he says. “I would like to see ecologists have an option to take an ethnobotany or traditional ecological knowledge course.”
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