When humanity emerged from the Cradle of Africa and began expanding across the world, we brought with us our large brains, our technologies, and our insatiable curiosity. Quickly, our ancestors inserted themselves into nearly every ecosystem on the planet. While some environments saw humans relatively late—the Polynesian islands, Iceland, and even Antarctica have only recently been inhabited—there are no ecosystems on Earth today that are not shaped by human presence.
Yet when we imagine “pristine” ecosystems, we often picture them without humans at all. This perspective, deeply embedded in conservation discourse, is historically recent—and misleading. In the United States, this idea of humanless wilderness took root during settler colonial expansion. As European-American pioneers moved west, they often encountered seemingly uninhabited landscapes. What they didn’t see were the effects of disease, displacement, and forced relocation that had reduced or removed Indigenous populations from those lands. The prairies they crossed were not untouched; they were actively managed landscapes, shaped by millennia of Indigenous stewardship. In the Great Plains, when settlers noticed forests creeping into former prairie lands, they were witnessing the ecological consequences of a disrupted human-environment relationship. Indigenous peoples had long used controlled burning to maintain grasslands, promoting biodiversity and reducing wildfire risk. Without these traditional practices, the ecosystem began to shift, losing its fire-dependent species and becoming less resilient to environmental stress.
This idea—that humans are inherently disruptive to ecosystems—misses a more complex and hopeful reality. In truth, there is no such thing as an ecosystem wholly untouched by people. Human beings have profoundly shaped the natural world, sometimes as agents of ecological decline, but often as careful stewards and ecosystem engineers. From the use of fire to promote savanna habitats to the management of aquatic systems to increase biodiversity, archaeological and ethnographic evidence reveals the many ways humans have enhanced the resilience, richness, and productivity of their environments.
Our ability to mold the niches around us predates our own species. Homo erectus, nearly two million years ago, was already using fire—a key moment in both human evolution and environmental transformation. Controlled fire allowed these early human ancestors to cook food, ward off predators, and survive in new climates, but it also began to alter landscapes at scale. By setting fires to clear underbrush or drive game, Homo erectus and later hominins may have helped create open savanna environments that attracted grazers and promoted new plant growth. These ecological effects had cascading impacts that shaped the evolution of both ecosystems and the humans within them. In essence, fire didn’t just warm our ancestors—it helped them engineer environments that supported more life.
Importantly, humans are not the only creatures to modify their environments. Beavers, for example, are expert niche constructors. By building dams, they create still ponds that benefit their own survival—providing food, safety, and space for their lodges. But these dams also generate broader ecological benefits: improved water quality, increased groundwater recharge, flood control, and higher biodiversity in both aquatic and terrestrial zones. In rivers across the American West and Europe, beaver activity fosters complex, productive ecosystems. Their impact is so profound that conservationists now are reintroducing beavers as a form of ecological restoration.
Like beavers, humans shape their environments in ways that can benefit many species. The Anthropocene—a term denoting the current epoch of human influence on Earth systems—is often framed through the lens of degradation: deforestation, habitat loss, climate change, and mass extinction. And these challenges are real. But the archaeological record also tells a deeper story—one in which humans have fostered biodiversity, enhanced ecosystem stability, and facilitated essential processes like seed dispersal, soil regeneration, habitat diversification, and the co-dependent species relationships we have developed and fostered with domesticated animals. These positive stories are too often overshadowed by the negative.
We must remember that ecological engineering is not a one-way path to destruction—it can also be a foundation for abundance.
One of the archaeological examples of humans having a positive impact on their ecosystems comes from the Western Desert of Australia where Aboriginal people had been living for at least 40,000 years. In the 1960s Martu Aboriginal People were forcibly removed to missions and cattle stations on the periphery of their homelands, and in the late 1980s they were allowed to return to their homelands. During this approximately 20-year period when people were no longer allowed to live their traditional nomadic existence, the ecosystem services that people provided the land also disappeared.
Researchers reconstructed ecological networks from pre-1964 and post-1980 and found that Martu Aboriginal people were a critical link in the networks of the Western Desert. Their hunting practices regulated predator populations, especially during the extremely hot and dry summer months. And their gathering of fruits helped disperse seeds, supporting plant regeneration. During their two-decade absence, several small-bodied animal species went extinct, revealing that people were not ecological disruptors but rather critical threads in the fabric of the desert’s biodiversity. When people returned and were allowed to practice their traditional way of life, the landscape’s resilience began to bounce back.
A similar story unfolds in the Sanak Archipelago of Alaska. There, the collapse of cod populations was often blamed on overfishing, including that by Indigenous communities. But archaeological and historical investigations revealed a different pattern. Cod populations have always fluctuated in boom-bust cycles, but what sustained them over the long term was the role Indigenous people played in managing broader ecosystem dynamics. By harvesting sea lions—whose skins were used for kayaks, two skins per kayak per year—humans kept predator populations in check. When these traditional practices ceased, sea lion numbers grew unchecked, putting new pressure on cod populations. The collapse was not a story of overfishing, but of a disrupted ecological balance once maintained by humans through systems of traditional ecological knowledge.
In the Amazon Basin, another story of long-term human ecosystem engineering comes to light. Early farmers in the region created Terra Preta—literally “dark earth”—by intentionally enriching soils with charcoal, pottery sherds, food waste, and other organic material. These anthropogenic soils, some as old as 5000 years but most around 300 to 1000 years old, remain more fertile than surrounding soils even today, demonstrating that ancient agricultural practices enhanced, rather than depleted, ecosystem productivity. Unlike modern intensive agriculture, which often degrades soils over time, these Indigenous practices improved them. Modern soil scientists and agronomists are now studying Terra Preta to learn how similar techniques might improve soil health and carbon storage in degraded agricultural landscapes around the world. What was once viewed as an anomaly is now a model for regenerative land management.
On the Northwest Coast of North America, Indigenous communities built clam gardens—broad stone terraces constructed to manage water flow and create ideal habitats for shellfish, increasing both the size and number of clams harvested. But the benefits went beyond human use. These gardens became biodiversity hotspots, fostering marine life across multiple trophic levels. The practice, far from extracting resources unsustainably, expanded and diversified ecological niches. Clam gardens, like Terra Preta, exemplify how ecological enrichment and human benefit are not mutually exclusive.
In the warmer regions of Hawai‘i, traditional fishponds (loko i‘a) took advantage of freshwater and agricultural runoff to create areas of high biodiversity and productivity. These ponds were built close enough to the ocean to allow them to be populated by fingerlings, but the inflow of nutrients from nearby cultivation encouraged the growth of algae, which in turn fed the fish. Ingenious gate systems allowed juvenile fish to enter from the ocean but prevented larger fish from leaving, effectively creating a managed nursery. These systems didn’t just provide food security; they turned coastal zones into vibrant, human-managed ecosystems. Restorations of loko i‘a today are reviving both biodiversity and cultural knowledge, showing how ancestral engineering can meet modern challenges, such as food security in a world of changing climates.
As in the oceans, so on land: people have long understood that their actions echo through ecological time. In Norse-era Iceland (9th to 13th century), the overharvesting of eider ducks—the source of the valuable down used in insulation and clothing—led to noticeable declines in populations. Recognizing this, Norse settlers instituted laws to protect eiders and their nesting grounds. These laws included prohibitions on disturbing nests and even bans on dogs running loose during nesting season. Remarkably, they understood that there was a three-year lag between chick hatching and adult breeding, and they planned accordingly. Today, thanks to this early management, Iceland still hosts large, sustainable populations of eider ducks, and eider down remains a renewable and ethically sourced product.
These examples—spanning deserts, coasts, forests, and rivers—challenge the prevailing narrative that humans are always ecological liabilities. Through activities related to hunting, gathering, burning, farming, and fishing, humans have often increased biodiversity, stabilized ecosystems, and sustained key species.
We are not external to nature—we are part of it, and our histories are entangled with those of the ecosystems we inhabit.
By disentangling the dynamics of sustainable land and marine use in the past, we can reframe our understanding of what is possible in the present. Recognizing humanity as an integral ecological force—not merely a negative influence—offers a framework for fostering resilience and biodiversity in an era of rapid environmental change. This understanding is not just academic; it has profound implications for conservation policy, climate adaptation, and ecological restoration. When we listen to what the past has to teach, we see not only our mistakes but our successes—many of which still endure on the landscape.
In the mid-20th century, as the United States reckoned with the environmental costs of industrial expansion, a different way of thinking about humans and nature began to emerge. Aldo Leopold, writing in A Sand County Almanac, argued for a “land ethic”—a reciprocal relationship between people and the ecosystems they inhabit. Leopold’s ethic was not abstract; it grew from his personal efforts to rejuvenate worn-out farmland in Wisconsin. He saw that people could be catalysts for ecological health, not just agents of extraction.
But the principles Leopold championed were not new. As we’ve seen, the idea that humans can live well within ecosystems is ancient. The practices of Indigenous communities in Australia, Alaska, the Amazon, and Hawai‘i show that humans have not only been good for ecosystems—they have been essential. Their knowledge, built over generations of lived experience, allowed them to tune their actions to the rhythms of the land and sea. These practices, too often dismissed or ignored, offer roadmaps for a more regenerative future.
As we’ve seen, humans have long shaped ecosystems in ways that promoted biodiversity and stability. The archaeological record provides abundant evidence of our capacity for care, restraint, and regeneration. These stories are not nostalgic—they are instructive.
To build a future in which humans and ecosystems thrive together, we must start by recognizing that we already have. The challenge is not to reinvent sustainability from scratch, but to remember and revive the long-standing relationships that once wove humans tightly into the web of life.
Dr. Stefani A. Crabtree is an early career scholar blending the fields or archaeology and ecology. Her research applies complex systems science modeling methodologies to problems in social science and ecology. Dr. Crabtree received her two Ph.D.s from Washington State University and the Université de Franche-Comté. She is an Associate Professor in Social-Environmental Modeling at Utah State University and an External Professor at the Santa Fe Institute.
