A new study that analyzed DNA samples recovered from Alaskan permafrost suggests that megafauna such as woolly mammoths and ancient horses did not die off around 13,000 years ago as is commonly thought. Instead, these animals were living in central Alaska about 10,000 years ago. The new evidence suggest that they also could have lived as recently as 7,600 years ago. The new study, rather than analyzing fossilized remains of an animal, analyzed DNA in the form of skin cells and feces in the permafrost samples. The researchers conducting the study turned to permafrost because of the difficulty of finding the fossilized remains of the last Ice Age megafauna.
Posted tagged ‘extinction’
A new study by University of Wisconsin – Madison researchers sheds new light on why large North American mammals, like the Mammoth, became extinct. Published in Science, this study focuses on fossil pollen, charcoal and fungus spores found in fossil dung. The study illustrates that the decline of these large mammals started about 14,800 years ago. This decline was essentially complete a thousand years later. This study seems to rule out a mass extinction caused by a meteor strike about 12,900 years ago since the decline was well underway by then. Other previously theories suggested that Clovis hunters created the extinction via over-hunting, but, again, the die off predates the arrival of Clovis hunters in North America. Finally, this study contradicts the theory that significant changes in climate caused the extinction because it suggests that the extinction of these major species actually helped create the change in climate. By losing these major plant-eaters, trees were able to become widespread.
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On Tuesday, the International Union for Conservation of Nature released this year’s Red List, a list of endangered species that are at risk of extinction. This year’s list included a total of 47,677 assessed species, of which 17,291, or 36%, are at risk of extinction. According to the survey, more than 20% of all known mammals, over 25% of reptiles and 70% of plants are threatened. This list includes such species as the black-footed ferret, a reintroduced species of which approximately 250 were born in the wild. This year’s list also included 2,800 new assessed species. Science currently recognizes approximately 1.8 million species out of an estimated 5-30 million species. For more information, see the Scientific American.
A recent study of coastal seagrasses published in the Proceedings of the National Academy of Sciences found that 58 percent of seagrass meadows are in decline. Seagrass meadows provide important habitat for ocean life and help decrease the impact of sediment and nutrient pollution. Since 1980, 29% of seagrass has disappeared, but even more troubling is the speed with which seagrass is disappearing. According to the study, the rate of loss has increased from 0.9% a year, before 1940, to 7% a year, since 1990. For more information on this study, see ABC Science.
The International Union for Conservation of Nature recently released a report that describes a losing battle to protect species and natural habitats from the impact of human development. The IUCN analyzed more than 44,000 of the 1.8 million known species. The two most significant harms to wildlife were habitat destruction and overuse, such as over-fishing or over-hunting. The report also found that while currently climate change is having only a minimal impact on biodiversity, this will likely change. Additionally, the IUCN reported that many species that are not currently threatened are susceptible to climate change. For more information on the report, see the Scientific American.
Recently, the Australian lemuroid ringtail possum (Hemibelideus lemuroides) was thought to be the first species to be declared extinct due to climate change. Last month scientists stated that a population has been identified and the possum was never thought to be extinct. But, the lemuroid ringtail possum is very much at risk and has suffered a severe decline in population. They have an inability to tolerate high temperatures and, as such, have a very limited range. For more information on this story, see here.
A rare quail found in the Philippines, previously thought to be extinct, was photographed right before it was whisked away and sold as food in the local market! The KAMS Blog thinks it was actually sort of cute (for a bird), but hopefully there are few more in the wilds of the Philippines. For more information see the National Geographic website here.