‘Pristine’ landscapes have not existed for thousands of years.
The Industrial Revolution had profound impacts on nature and marked a major turning point in the Earth’s ecology. But human activities have in fact been altering landscapes for millennia, ever since our ancestors started expanding across the globe.
A new study published in Proceedings of the National Academy of Sciences reveals how a long history of human activity has left its mark on every landscape on Earth. In fact, the researchers report that pristine landscapes have not existed anywhere in the world for at least several thousand years.
The study presents archaeological evidence of human activities that have not only led to extinctions, but have also caused permanent changes to species abundance, composition, and genetic diversity all over the world.
According to the research, four key phases of human transformation have impacted natural ecosystems: global human expansion during the Late Pleistocene; the Neolithic spread of agriculture; the era of humans colonising islands; and the emergence of early urbanised societies and trade networks.
The study shows that by 12,000 years ago, humans had dispersed to the far corners of Eurasia, Australia, and the Americas, and megafauna extinctions followed soon after. The disappearance of so many species had lasting effects on the structures of entire ecosystems.
The spread of agriculture over large swaths of the Old and New Worlds during the Neolithic forever changed the species distributions. For example, the data reveal that domesticated sheep, goats, and cattle were first in the Near East 10,500 years ago, and arrived in Europe, Africa, and South Asia within a few millennia.
When humans began to reach remote ocean islands, they usually brought domesticated animals and crops along with them. Extinction of indigenous animals was a common consequence of prehistoric colonization of islands, which often lacked the resilience of ecosystems on the continents.
By the Bronze Age, agriculture and the production of food surpluses had paved the way for the emergence of intensive networks of trade in many parts of the world. Increased deforestation was linked to agricultural intensification and urbanization during this time.
However, the researchers note that certain agricultural practices of early civilizations may have actually helped maintain the ecosystems. According to the research, parts of the Amazon supported densely settled societies before European arrival, which created areas of fertile soil that enabled cultivation of lands now considered marginal.
“Cumulative archaeological data clearly demonstrates that humans are more than capable of reshaping and dramatically transforming ecosystems,” study lead author Nicole Boivin, from the School of Archaeology at the University of Oxford, said in a press release.
“Now the question is what kind of ecosystems we will create for the future. Will they support the wellbeing of our own and other species or will they provide a context for further large-scale extinctions and irreversible climate change?”
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