Internet Naturalist – June 9, 2014

  • Fall of the wild: The trapped wolves of Isle Royale | Al Jazeera America 060414
    Mary Catherine O’Connor : “Isle Royale’s once-robust wolf pack appears to be trotting toward extinction. From 2011 through 2012, the island’s wolf population declined 56 percent, and it has remained at its lowest total, just eight or nine individuals, since the Wolfe-Moose Study began, in 1956. | When an ice bridge, the only conduit between the island packs and the mainland wolves, formed during this past, frigid winter, Peterson and Vucetich felt buoyed with hope. During the first decade of the study, an ice bridge formed during three out of four winters. But during the past 17 years, because of rising temperatures, ice bridges have been documented only three times. One formed in 1997, followed by an 11-year gap. This winter marked the first bridge since 2008. | Rising water temperatures and declining ice cover in Lake Superior (the National Oceanic and Atmospheric Administration found that by 2011 the lake’s yearly ice coverage had declined 76 percent, compared with 1973 levels) have combined with strong winds to reduce the frequency of ice bridges connecting the 45-mile-by-9-mile island to the mainland of Ontario and Minnesota. Because of this, the last time a new wolf entered the island was in 1997, and that male bolstered the island’s “gene flow.” |
    Within a decade, however, all wolves on the island carried that new arrival’s genes. Today, the nine wolves that live on the island are all closely related. With most organisms, including wolves, this sort of genetic inbreeding reduces the rate of reproduction, and it is the major factor behind the Isle Royale population’s decline.x | [S]ome geneticist are keen to learn how the genetic depression exhibited in the inbred wolves on the island — many have spinal deformities and at least one appears to be half blind — plays out in the future. Others back a third option: waiting until the wolves are unviable but not extirpated, comprising only males or females, and then perform genetic rescue. | “The scientific implications of these present wolves recovering — and that, in my opinion, would be a population of 20 to 30 wolves — if that were to happen without new genes coming that would be remarkable. It would go against decades of genetic understanding,” says Peterson. “So, yes, it would certainly be important if it happened, but expecting it to happen would be a pretty big stretch.”
This entry was posted in Link Blog. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *