New research support"Anthropocene"(anthropocene epoch), which is a geological period marked by the significant impact of humans on the planet. This study used pollen fossil data to analyze vegetation changes in North America since the end of the Pleistocene. Their findings suggest that recent vegetation changes are comparable to those observed during the transition of the previous epoch, suggesting a significant shift in ecosystem functioning that justifies its division into a new epoch.
Researchers have determined that human activity has had as much of an impact on the environment as glaciers retreated at the end of the Ice Age.
Scientists are right"Anthropocene"(anthropocene epoch) has a long history of controversy. "Anthropocene"is a proposed geological time unit that corresponds to the most recent historical period. It is characterized by the fact that humans have had a huge impact on the planet.
We live in"Anthropocene"Is it?If so, when did it start?
Trisha Spanbauer, Ph.D., of the University of Toledo, and Allison Stegner, M., Stanford UniversityIn a research article published this month in the Proceedings of the National Academy of Sciences, Dr. Allison Stegner provides an argument for the existence of the Anthropocene. They analyzed publicly available data on vegetation changes in North America since the end of the Pleistocene and concluded that human influence on the landscape was no less than the retreat of glaciers at the end of the ice age.
Spanbauer, an assistant professor in the Department of Environmental Science, said"As a paleoenvironmentalist, I am very interested in what the past can tell us about the future. Biological change has been used in the past to divide epochs, so this analysis provides us with valuable background information on whether the changes we see today are largely similar to those between the Pleistocene and Holocene epochs. "
Spanbauer and Stegner made use of the NETOMA paleoecology database, a repository of multiple paleoecological data edited by the community. In particular, they studied fossilized pollen data from 386 sediment core records from lakes in North America.
The sediment core is a sample taken from the bottom of the lake that preserves the sedimentary sequence. Spanbauer and Stegner considered the study of the late Pleistocene (c. 140,000 years ago).
They analysed the data based on seven indicators: taxonomic richness, which is the diversity of pollen species;First occurrence baseline, last occurrence baseline, and short-term increase or decrease in taxa, which measure the frequency with which species appear and disappear from the fossil record;Community mutations, which refer to species found in a sample. They organized the data points over a 250-year time period, on continental and regional scales, and incorporated the uncertainty of the age model, accounting for differences in sample size, to arrive at conservative estimates.
The results show that the vegetation changes over the past few hundred years are comparable to those in the transition period of the previous epoch, including the first and last vegetation increases and abrupt changes in the community.
Spanbauer said"The power of such a database is that we are able to ask questions about macroecological change. Scientists have documented the impact of human activities on individual species and biodiversity as a whole, but our research puts these observations in a broader context. It shows a change in the way the ecosystem operates, supporting the division of the new era"。
Reference: "The North American pollen record provides evidence for macroecological changes in the Anthropocene", by MAllison Stegner and Trisha LSpanbauer, October 16, 2023, Proceedings of the National Academy of Sciences.
doi: 10.1073/pnas.2306815120
Compilation**: scitechdaily