A new study found that the main cause for the extinction of giant beasts such as the woolly mammoth, the the woolly rhino, sabertooth tiger and the giant armadillo is not climate change, but early humans.
The two most prominent and vital factors associated with the late Quaternary megafaunal extinctions are human settlement and climate changes. Some extinctions have also been clearly linked to either of these elements. Majority of the available studies are limited by geographical and taxonomical restrictions. Some investigations involving quantitative data are bounded by rude temporal resolution or extremely simplified weather reconstructions. In the new study, the researchers from the University of Exeter, University of Cambridge, University of Reading and University of Bristol investigated the rationales of the extinctions in a global perspective, utilizing high-resolution climate reconstructions and precisely examining the responsibility of the findings to the ambivalence in the paleological data.
The researchers, led by Lewis Bartlett from the University of Exeter, carried out about a thousand models that present the time period when each species is believed to have become extinct, as well as when humans are known to have appeared in the various regions of the Earth. The data collected in this analysis were studied alongside the climate reconstructions that occurred in the past 90,000 years.
The findings of the study, published in the journal Ecography, show that there were various events in which both human arrival and species extinction coincide, representing that humans were the the primary causes of the widespread disappearance of the species. Climate change also played a role. However, the experts found that weather factors only exacerbated the events that humans primarily created. The researchers also discovered that the patterns of extinction in some parts of the world, particularly in Asia, were not brought about by either of the two main causative factors in the study. This then signifies that new series of studies with an entirely different focus should be performed to consider the neglected areas. Understanding why megafauna in mainland Asia is so resilient is the next big question," says Dr. Andrea Manica, lead supervisor of the study from the Cambridge University.
"As far as we are concerned, this research is the nail in the coffin of this 50-year old debate - humans were the dominant cause of the extinction of megafauna," says Bartlett. The exact features or actions of the ancient settlers that caused the demise of the species remain unknown. The researchers were not able to differentiate whether the men used them for food, for making fire or if the humans simply drove the animals away. Nonetheless, the study has shown that more than climate change, human colonization caused the extinction, refuting the myth that humans have always lived peacefully with nature.
Photo: Rob Pongsajapan | Flickr
