HABITAT LOSS AND HUMANS: CAUSE OF MASS EXTINCTIONS
IN THE FAUNA OF NORTH AMERICA
Geography 361 - Natural Hazards
By Jake McDonald
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HABITAT LOSS AND HUMANS: CAUSE OF MASS EXTINCTIONS IN THE FAUNA OF NORTH AMERICA
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By the end of the Pleistocene period, when the last ice age retreated, there had been a mass extinction of 35 to 40 large mammal (megafauna) species in North America. Examples include mammoths, saber-toothed cats and giant ground sloths. All previous ice ages before the Pleistocene period saw extinctions, but they were distributed across all sizes of animals, not just megafauna. The rate of extinction which was found at the end of the most recent ice age also far exceeded that of previous extinction events. These extinctions were due to changes in habitat along with the migration of a new predator: humans. Using carbon dating, scientists found that 80% of the North American mammal population disappeared within 1000 years of the arrival of humans. Currently, North American fauna are experiencing similar habitat loss. It is estimated that at current rates of human destruction of the biosphere, one-half of all species of life will be extinct in 100 years. Humans are converting habitats from forest and savannah to agriculture and suburbia to fit the needs of an exponentially growing population. Habitats are also being increasingly fragmented by road construction, which increases the rate of extinctions dramatically. By understanding the areas of wilderness that are most susceptible to conversion and fragmentation, conservation efforts and public education can be more effective in preventing mass extinctions. By studying the past, hopefully, we can try and see what happened to cause these great mammals to go extinct and not repeat these mistakes again in the present. |