. | . |
Humans were altering ecosystems with fire some 92,000 years ago by Brooks Hays Washington DC (UPI) May 5, 2021 Humans living along the northern shores of East Africa's Lake Malawi were altering the local ecosystem with fire as early as 92,000 years ago, according to a new study. Analysis of stone artifacts and paleoenvironmental data -- detailed Wednesday in the journal Science Advances -- suggests fire use by early humans prevented regrowth of the region's forests, yielding the expansive bushland that persists today. "This is the earliest evidence I have seen of humans fundamentally transforming their ecosystem with fire," lead author Jessica Thompson said in a press release. "It suggests that by the Late Pleistocene, humans were learning to use fire in truly novel ways. In this case, their burning caused replacement of the region's forests with the open woodlands you see today," said Thompson, an assistant professor anthropology at Yale University. Scientists were able to discern the impacts of human behavior on local ecosystems by analyzing both stone artifacts and sediment cores collected from dig sites across the lake's alluvial fan, as well as from the bottom of Lake Malawi. Field observations revealed several unique patterns, including increases in sedimentation and charcoal accumulation some 92,000 years ago. Researchers found that shortly after the first spike in charcoal accumulation, pollen signatures revealed a flattening of the region's species diversity. "The pollen that we see in this most recent period of stable climate is very different than before," said co-author Sarah Ivory, assistant professor of geosciences at Penn State. "Specifically, trees that indicate dense, structurally complex forest canopies are no longer common and are replaced by pollen from plants that deal well with frequent fire and disturbance," Ivory said. What at first looked like distinct archaeological and climate patterns started to appear interconnected, the researchers said. Around the same time that the region's forests were disappearing and a large alluvial fan first formed along Lake Malawi's northern shores, scientists noted a proliferation of archeological sites. Fire use by early human populations in the region not only helped transform the region's ecosystem, but also ensured the preservation of thousands of artifacts from the Middle Stone Age. "Dirt rolls downhill unless there is something to stop it," said co-author David Wright, an archaeologist at the University of Oslo. "Take the trees away, and when it rains, there is a lot of dirt moving downhill in this environment." Researchers aren't sure why these early human groups were burning so much land. In addition to burning fuel for warmth and cooking, it's possible hunter-gatherers in the region were using controlled burns to create open landscapes more conducive to hunting. What is clear, however, is that these weren't forest fires. "One way or another, it's caused by human activity," Thompson said. "It shows early people, over a long period of time, took control over their environment rather than being controlled by it. They changed entire landscapes, and for better or for worse that relationship with our environments continues today."
Wildfire smoke trends worsen for western U.S., study says Washington DC (UPI) Apr 30, 2021 Smoky summers in the west can now be linked to a worsening trend of wildfire smoke impacting air quality clear into September, according to new research. University of Utah researchers on Friday published a study in Environmental Research Letters showing that trends in poor air quality events will affect an area from the Pacific Northwest to the Rocky Mountains in the years to come. "In a big picture sense, we can expect it to get worse," lead study author Kai Wilmot said in a press rele ... read more
|
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |