Many scientists believe we’ve now crossed a new geological epoch known as the Anthropocene, in recognition of the fact that, despite their short time on Earth, humans have fundamentally altered the physical, chemical, and biological makeup of the planet. Agriculture, urbanization, deforestation, and pollution have all caused extraordinary changes on Earth. But, perhaps, ironically it may have all started with a different, extinct species of humans.

The earliest evidence of ecosystem change at the hands of hunter-gathers has been pinpointed at a lignite quarry near Halle in Germany, where researchers found Neanderthal activities from 125,000 years ago transformed closed forests into open grasslands. The deforestation seems to have been mostly done through fire.

“Archeologists have long been asking questions about the character and temporal depth of human intervention in our planet’s ecosystems. We are increasingly seeing very early, generally weak signs of this,” says Wil Roebroeks, an archeology professor at Leiden University in the Netherlands.

Roebroeks and colleagues have analyzed evidence collected over the decades at the Neumark-Nord quarry, including hundreds of slaughtered animals, numerous stone tools, and charcoal remains. Some 130,000 years ago, the region experienced a prosperous warm spell that promoted the growth of thick deciduous forests stretching from the Netherlands to Poland, which were inhabited by deer and cattle, but also elephants, lions, and hyenas.

These forest lands attracted communities of Neanderthal hunter-gatherers, who rapidly moved in, especially into areas with lakes. They effectively competed with other carnivores and occupied their own ecological niche until the region was occupied by advancing ice 115,000 years ago.

Compared to forested regions where Neanderthals didn’t live, the scientists found that the Neanderthal-inhabited regions experienced a significant decrease in tree cover. Instead of dense forests, the Neanderthal habitat was much lighter and open. There are also signs that these ancient people settled at least semi-permanently in the region, which is unusual in itself since Neanderthals are thought of as highly mobile groups. Perhaps the open landscape, which attracted plenty of game and offered reasonable shelter, was attractive enough to keep some Neanderthal groups more or less settled in one place.

However, there’s a chicken or egg problem. While it’s tempting to look at the charcoal data and imagine Neanderthal activity burned the local vegetation, they could have also moved into more advantageous open areas after wildfires did all the hard work for them.

Whether or not the Neanderthals initiated the deforestation, one thing is at least clearer: they kept these areas open, and they did so for at least 2,000 years. At similar neighboring lakes where there was no Neanderthal activity, such as hunting, collecting wood, making tools, and building shelters, the dense forest vegetation remained largely intact.

There’s ancient evidence that modern humans altered the landscape much in the same way, but these kinds of practices were seen only in the past 50,000 years. In contrast, the new findings point to much earlier artificial ecosystem changes at the hand of Neanderthals.

The ability of humans to alter nature is obvious today when our cities stretch over hundreds of square miles and carbon emissions from our activities have grown to such copious amounts that we’ve come to change the climate. The origin of this long process of changing the planet to suit our needs is typically considered the advent of agriculture, which appeared about 10,000 years ago. But recent research, such as the present study, increasingly suggests environmental alteration by hominins started much earlier, albeit at a smaller scale. Neumark-Nord is, perhaps, the earliest example of such interventions.

“It also adds something to the behavioral spectrum of early hunter-gatherers. They weren’t simply ‘primal hippies’ who roamed the landscape picking fruit here and hunting animals there. They helped shape their landscape,” says Roebroeks.

The findings appeared in the journal Science Advances.