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Alpine ecosystems are particularly vulnerable to climate change, and studies suggest that mountain dwellers from delicate flowers in the Swiss Alps to pygmy possums in Australia are in trouble. Although it can be difficult to tease out other factors, including fire suppression and livestock grazing, a growing number of researchers fear that if the heat keeps rising, many alpine plants and animals will face quick declines or extinction. In neighboring New Zealand, a paper presented in 2003 in Arctic, Antarctic, and Alpine Research predicts that a 3ºc temperature rise over the next century, moderate as estimates go, will wipe out 80 percent of alpine islands and extinguish a third to a half of 613 known alpine plants.

The article comments on the paper by S.-S. Liu and colleagues, which offers unique insights into how one type of the sweet potato whitefly was able to spread throughout China and Australia and replaced indigenous subtypes. It is pointed out that these displacements should be considered as a complete victory of the invading whiteflies and that it remains to be seen whether populations of the indigenous biotypes still exist and respond to the invaders.

This article focuses on a study related to paleoanthropology. This week, the original Australian-Indonesian discovery team unveiled new specimens of Homo floresiensis. Their paper in the journal Nature describes bones of seven additional adults at least as small as the original, as well as a child's arm and leg bones so tiny that they snuggle neatly on a bank note . The discovery team, led by Michael Morwood of the University of New England in Armidale, Australia, found the latest bones in Liang Bua cave during the 2004 field season. Paleoanthropologist and team member Peter Brown, who described the bones, says the distinctive similarities among the specimens show that they are a new species rather than diseased moderns. Brown draws special attention to the right arm bone because it completes the skeleton of the little lady of Flores. He notes that her limb proportions differ from those of all other known members of Homo but match those of "Lucy," the 3-million-year-old Australopithecus afarensis from Africa, who also stood about 1 meter tall. However, many researchers are skeptical about that idea, because there's no evidence that such primitive hominids ever left Africa.

This article reports that an analysis of ancient Brazilian skulls has lent new weight to the controversial theory that not one but two distinct populations from Asia colonized the Americas. Scientists have long believed that starting about 12,000 years ago, the ancestors of present-day American Indians migrated from northeast Asia across the Bering land bridge. But in recent years, Walter Neves of the University of Sao Paolo in Brazil has argued that these immigrants were preceded by people from Southeast Asia who came from the same stock that settled Australia and Melanesia. Last week, Neves and his colleague Mark Hubbe claimed new support for this idea from an analysis of 81 skulls, ranging in age from 7500 to 11,500 years, found in the Lagoa Santa region of southeast Brazil. Detailed comparisons revealed that the skulls did not resemble people from northeast Asia, who tend to have short, wide skulls with relatively flat faces, but rather took after present-day people from Australia and Melanesia, whose skulls tend to be long and narrow with projecting faces. Because other, similar ancient skulls have been found in North and South America, Neves and Hubbe concluded in a paper published online in the journal "Proceedings of the National Academy of Sciences," that two distinct populations probably colonized the New World.