罗亚岛国家公园仅剩三只野狼

Only three wolves seem to remain in Isle¹ Royale National Park. Researchers from Michigan Technological² University observed the wolves during their annual Winter Study, and the lone³ group, at an unprecedented⁴ low, is a sharp decline from nine wolves observed last winter. The study's report, released today, marks the project's 57th year of observing wolves and moose in Isle Royale. It is the longest running predator⁵-prey⁶ study in the world. This year, along with the three resident wolves, scientists estimated 1,250 moose on the island and observed two visiting wolves, which came and then left across an ice bridge to the mainland. This growing gap between the predator and prey populations is a trend that Michigan Tech researchers have tracked over the past four years.   "It's not the presence of wolves that matters so much, it's whether wolves are performing their ecological⁷ function," says John Vucetich, an associate professor of wildlife ecology who leads the study along with Rolf Peterson, a research professor at Michigan Tech.   Last April, the Isle Royale National Park released a statement concerning wolf intervention⁸ options. Part of the statement reads: "There is still a chance of nature replenishing the gene⁹ pool as wolves are able to move to and from the island when ice bridges form."   But with only three wolves remaining, Vucetich says, "There is now a good chance that it is too late to conduct genetic¹⁰ rescue." He also points out that one of the Isle Royale wolves left on an ice bridge last winter, and this winter, two wolves visited the island and promptly¹¹ traveled back over the ice bridge.