New study shows that humans, not climate, caused decline of megafauna 50,000 years ago
New research from Aarhus University confirms that it was humans, not climate, that caused the dramatic decline in large mammal populations over the past 50,000 years. Scientists have long debated whether humans or climate were to blame, but new DNA analysis of 139 extant large mammal species shows that climate cannot explain the decline.
About 100,000 years ago, the first modern humans migrated from Africa, settling in every type of terrain and hunting large animals using clever techniques and weapons. Unfortunately, this led to the extinction of many large mammals during the era of human colonization, and new research reveals that the surviving large mammals also experienced a dramatic decline.
According to Jens Christian Svenning, professor and director of the Danish National Research Foundation’s Center for New Biosphere Ecodynamics at Aarhus University, the populations of nearly all 139 species of large mammals declined about 50,000 years ago. DNA analysis shows that the decline is related to human dispersal rather than climate change.
This study used DNA analysis to map the long-term history of 139 large mammal species that have survived without extinction for the past 50,000 years, and scientists were able to estimate the population size of each species over time. The results are conclusive that human dispersal is the most likely cause of the decline in large mammal populations.
The study also showed that woolly mammoths are a poor example for climate-based models of extinction, as the vast majority of megafauna species that went extinct lived in temperate and tropical regions, not mammoth grasslands. Despite ongoing debate, the evidence strongly points to human activity rather than climate change as the main cause of the dramatic decline in large mammal populations.
Source: scitechdaily.com
