Hospitable habitats Less than 21 percent of the earth’s land area still contains all of the large mammal species that lived there 500 years ago, according to a study by David Wilcove *85, professor of ecology and evolutionary biology and public affairs, and colleagues from Texas A&M and the World Wildlife Fund. While many of the intact assemblages are in remote areas like northern Canada, Siberia, or western Australia, a few regions with more substantial human activity, such as the Congo and Amazon basins, have managed to retain native mammal populations, according to the study, which was published in the December 2007 Journal of Mammalogy. Large mammals, whether carnivores or herbivores, play an important role in ecosystems, shaping the populations of their prey or the distribution of vegetation. But they are vulnerable to human development, changes in habitat, or “direct exploitation” through activities such as hunting, the authors write.
Cosmic fireworks Dwarf stars are dim, commonplace, and typically unremarkable, but a team of astronomers has found one extraordinary dwarf that creates “spectacular fireworks displays” of flares when its powerful magnetic fields merge and collide. The astronomers, led by Princeton postdoctoral researcher Edo Berger, observed the unusual star in the constellation Boötes, about 35 light-years from Earth, according to a release from the Gemini Observatory in Hilo, Hawaii. An enormous hot spot covers half of the dwarf star’s surface and may indicate atypical activity below the surface that generates the flashy magnetic behavior, Berger said. A still-unseen companion star also could affect the dwarf’s magnetism. The team’s findings were published in the Astrophysical Journal Feb. 10.