Humans can increase biodiversity, archaeological study shows

The article fits into the current thematic focus 'Multispecies Conviviality' of the University of Cologne's Research Hub MESH (Multidisciplinary Environmental Studies in the Humanities).

In their publication, the scientists examine the role of past humans in the evolution and control of biodiversity on our planet. The archaeologists offer a deep-time perspective grounded in material and ecological data to argue that the idea that humans had lived harmoniously with nature as hunter-gatherers mischaracterizes the fundamental problem of human interaction with ecosystems. The scientists also criticize that in the recent past, with regard to the aforementioned extinction events, the so-called biodiversity loss in the Anthropocene, attempts have often been made to highlight that people had actively intervened in their ecosystem more than 10,000 years ago, notably with negative consequences.

The researchers suggest that the relationship between humans and ecosystems has always been much more complicated and complex, and that, in addition to negative effects, there are also positive effects on biodiversity that follow certain rules. "Oftentimes, it can even be said that biodiversity loss occurs locally due to human activity, but biodiversity is strongly promoted elsewhere; these dynamics must therefore be placed in a wider context," said Hussain.

The research combines various case studies from the Late Pleistocene (approx. 120,000 to 11,800 years before present) and is also based on a recent study of the two authors on ravens from the ice age, which shows that these birds benefited from humans as neighbours about 30,000 years ago -- especially from food options that hunter-gatherers in the environment provided for these animals.

The archaeologists based their research on the results of zooarchaeological and stable isotope analyses, which were applied in the case of ravens, and used this and other already published, contextual archaeological information to show that such processes can lead to an increase in biodiversity on a local level. This is because certain animals benefit from human influence and others that are excluded locally by humans, such as larger predators, move to other areas. Overall, this increases the heterogeneity and complexity of such ecosystems, thereby often resulting in a positive effect on overall biodiversity.

"Ultimately, we try to argue that biodiversity regimes cannot be separated from human influence and that not all of these influences are merely negative," explained Shumon Hussain. "It also follows that increased diversity in human life forms probably has an overall positive effect on biodiversity as a whole, and that a decisive driver of the biodiversity crisis in the Anthropocene is in part also the homogenization of human life in nature and with it."