Post by L Roebuck on Jan 20, 2007 9:39:23 GMT -5
Going Under Down Under: Early people at fault in Australian extinctions
Sid Perkins Science News
A lengthy, newly compiled fossil record of Australian mammals bolsters the notion that humanity's arrival on the island continent led to the extinction of many large creatures there.
Archaeological evidence suggests that people arrived in northern and western Australia about 50,000 years ago (SN: 3/15/03, p. 173: Available to subscribers at www.sciencenews.org/articles/20030315/note10.asp). By 5,000 years later, about 90 percent of the continent's mammals larger than a house cat had gone extinct, says Gavin J. Prideaux, a paleontologist at the Western Australian Museum in Perth. Casualties of that era include several species of kangaroos and wombats as well as marsupials that filled the ecological niches elsewhere populated by lions, hyenas, hippos, and tapirs.
By unearthing and cataloging specimens from a group of fossil-rich caves about 300 kilometers southeast of Adelaide, Prideaux and his colleagues assembled a nearly complete record of the past 500,000 years. Most of the 62 species of nonflying mammals on the list fell into the caverns via sinkholes, but some remains were brought in by owls that roosted there.
Scientists had compiled a long-term climate record for southeastern Australia by analyzing the caves' stalactites. Those structures formed and grew when rainfall was plentiful but not during dry spells.
Full Article
Sid Perkins Science News
A lengthy, newly compiled fossil record of Australian mammals bolsters the notion that humanity's arrival on the island continent led to the extinction of many large creatures there.
Archaeological evidence suggests that people arrived in northern and western Australia about 50,000 years ago (SN: 3/15/03, p. 173: Available to subscribers at www.sciencenews.org/articles/20030315/note10.asp). By 5,000 years later, about 90 percent of the continent's mammals larger than a house cat had gone extinct, says Gavin J. Prideaux, a paleontologist at the Western Australian Museum in Perth. Casualties of that era include several species of kangaroos and wombats as well as marsupials that filled the ecological niches elsewhere populated by lions, hyenas, hippos, and tapirs.
By unearthing and cataloging specimens from a group of fossil-rich caves about 300 kilometers southeast of Adelaide, Prideaux and his colleagues assembled a nearly complete record of the past 500,000 years. Most of the 62 species of nonflying mammals on the list fell into the caverns via sinkholes, but some remains were brought in by owls that roosted there.
Scientists had compiled a long-term climate record for southeastern Australia by analyzing the caves' stalactites. Those structures formed and grew when rainfall was plentiful but not during dry spells.
Full Article