A Stanford study of South America's colonization finds that for much of human history on the continent, human populations grew like an invasive species, which are regulated by their environment as they spread into new places. Populations grew exponentially when people first colonized South America. But then they crashed, recovered slightly and plateaued for thousands of years after over-consuming local natural resources and reaching continental carrying capacity, according to the analysis. http://phys.org/news/2016-04-populations-early-human-settlers-grew.html
The entire story of the colonization of the Western Hemisphere by Homo sapiens is remarkable. For starters, recent DNA analysis indicates that the people who migrated into Alaska did not all come from the same place and did not all arrive at the same time. Yet they joined together to form communities, overcoming their differences in language and culture in order to survive. But once the ice began to melt and it became possible to walk down into the more temperate zones, they just kept walking. It took their descendants only one millennium to establish durable communities throughout the North and South American continents, all the way to Tierra del Fuego.
water on a fire Your linked ("finds that for much of human history on the continent, human populations grew like an invasive species,") and all commentary I could find is a ridiculous misuse of the science. At first blush, strong statements on scant evidence give one pause, then add in buzz phrases like "invasive species" and you gotta be looking for an agenda which may have little to do with the archaeology. and, here we have it: "The question is: Have we overshot Earth's carrying capacity today?" caveat: I have not seen the original paper which is pay-walled. However, the commentary and snippets I've seen are error laden. eg:"..."The first Americans were descendants of Siberians that crossed the ancient land bridge that connected Asia with Alaska some 15,000 to 30,000 years ago. They reached southern South America pretty rapidly, by at least 14,500 years ago. Unlike most other continents, South America was peopled during a single wave of invasion over a narrow time frame..." If the varied lithic assemblages weren't enough, we now have dna evidence which blows this old simple claim to rest. The point being, we have scant evidence for ancient people, and that evidence is ever changing, so bold statements are idiocy. To all field workers: Keep digging, and thanx.
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature17176.html Post-invasion demography of prehistoric humans in South America Abstract: As the last habitable continent colonized by humans, the site of multiple domestication hotspots, and the location of the largest Pleistocene megafaunal extinction, South America is central to human prehistory1, 2, 3, 4, 5, 6, 7. Yet remarkably little is known about human population dynamics during colonization, subsequent expansions, and domestication2, 3, 4, 5. Here we reconstruct the spatiotemporal patterns of human population growth in South America using a newly aggregated database of 1,147 archaeological sites and 5,464 calibrated radiocarbon dates spanning fourteen thousand to two thousand years ago (ka). We demonstrate that, rather than a steady exponential expansion, the demographic history of South Americans is characterized by two distinct phases. First, humans spread rapidly throughout the continent, but remained at low population sizes for 8,000 years, including a 4,000-year period of ‘boom-and-bust’ oscillations with no net growth. Supplementation of hunting with domesticated crops and animals4, 8 had a minimal impact on population carrying capacity. Only with widespread sedentism, beginning ~5 ka4, 8, did a second demographic phase begin, with evidence for exponential population growth in cultural hotspots, characteristic of the Neolithic transition worldwide9. The unique extent of humanity’s ability to modify its environment to markedly increase carrying capacity in South America is therefore an unexpectedly recent phenomenon. """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
