June 29, 2014
Ray Slayton / U.S. Forest ServiceBiologists are
using new techniques to study wolf populations, including those on
Prince of Wales Island in Southeast Alaska.
U.S. FOREST SERVICE
Researchers such as Logan and his Alaska Department of Fish and Game colleagues are tasked with counting the animals in Southeast Alaska. For years that chore meant trapping the elusive wolves and fitting them with tracking collars, then flying circles above the canopy of spruce and hemlocks in hopes of sighting a pack. The problem? Clear days for flying are rare in the Alaska rainforest, and finding a few dozen wolves on the third-largest island in the United States is no easy job.
For the past year, however, they have been testing a powerful, CSI-style tool that promises to deliver new data on one of Alaska's most closely-watched wolf populations. The project began in fall 2012 and works like this: Researchers sleuth out areas on Prince of Wales frequented by wolf packs and their prey. There, the biologists hide planks of wood stapled with lengths of barbed wire and scented with a cocktail of odors, such as coyote urine, that are irresistible to wolves. Then they wait. Motion-sensing trail cameras capture what happens next. "Wolves are dogs and anybody knows, that has a dog, they like to roll in stinky things," Logan said.
Photo courtesy of U.S. Forest
Service
When the animals sniff out the wooden planks and rub against the wire, they leave strands of fur behind that Alaska researchers collect and ship 1,000 miles away for study at a Montana university for genetics testing. The DNA results can show how many different wolves came into contact with the lures -- a less invasive, less dangerous method than trying to collar or count the animals from the air.
The approach now being tested across 540 square miles on Prince of Wales might also be used to determine the ancestry and sibling relationships among the animals. The more scientists know about the wolves, the theory goes, the better they can regulate hunting and trapping.
Fish and Game and the U.S. Forest Service have partnered to study the effectiveness of the counting technique, with the effort expected to continue through early 2016, Logan said. A legal fight over the fate of Southeast Alaska wolves has been simmering for years. The new research comes at a key moment.
Photo courtesy of U.S. Forest
Service
Conservationists, including Greenpeace, have filed an administrative appeal to prevent old-growth logging in the area and have petitioned to list a sub-species of the wolves as endangered or threatened. In 2013 the U.S. Forest Service announced it would delay a decision to open the Big Thorne timber project that would allow logging on 9 square miles of the island, pending a review of the project's potential impact on wolves.
The Center for Biological Diversity and others sued the U.S. Fish and Wildlife Service on June 10, accusing the agency of "delaying Endangered Species Act" protection for the Alexander Archipelago wolf. Native to Southeast Alaska, the animals are often black or dark gray, eat salmon in the fall and are smaller than mainland wolves. "As the old-growth is logged, there's less habitat for the deer which means there is less food for the wolves and the hunters," said Rebecca Noblin, Alaska director for the center.
The status of the wolf is under review, according to Fish and Wildlife. The work published by wolf biologists for Fish and Game and the federal government avoids wading into the wildlife politics debate and instead focuses on how their new counting effort is working.
It's unclear exactly how many gray wolves live on Prince of Wales and small, surrounding islands. Tough to trap and rarely seen, the animals are notoriously hard to count. The number peaked at 250 to 350 wolves in the mid-1990s, according to 2012 estimates by now-retired Fish and Game biologist David Person.
The sub-species conservationists are hoping to list as threatened or endangered is named for the cluster of 1,000 islands that includes Prince of Wales. The area under study for hair-snaring techniques is a fraction of the total island, which is larger than Delaware.
Researchers estimated there were about 24 wolves in the study area in early 2013, although many had died by spring. A dozen were legally harvested by humans. One was hit by a car and two more were killed illegally. Others vanished.
In addition to estimating the number of animals overall -- which could be used to set harvest limits and monitor land-management tactics -- the researchers intend to start looking at deeper questions of how the wolves are related genetically to other wolves in the area. "Do they share DNA markers in common with some of those other islands? Are they a distinct population segment? These are all questions that remain to be answered," Logan said.
Between Jan. 1 and May 31 of last year, biologists set the hair-snaring boards at more than 30 locations in areas where wolf and deer tracks have been spotted. When the animal rubs against the board, hair can become trapped in the barbed wire. The researchers collected 67 hair samples. "Wolves aren't the only things that like to roll in stinky things. We've gotten many, many samples of black bear, and we've also got some dogs, of course," Logan said.
Logan said the Southeast Alaska effort is the first attempt to use hair-snaring lures to count a wolf population in Alaska, although the methods have been used here and elsewhere to learn about bears, lynx, marten and other animals. "Non-invasive genetic sampling using hair snares is becoming more common everywhere," he said.
Montana researchers wrote in a 2011 report in the Wildlife Society Bulletin on efforts to study hair-trapping of wolves and coyotes in that state. The scientists used plywood lined with barbed wire or the bristles from metal brushes used to clean shotguns to snag hairs from the animals.
Among their conclusions: Setting smelly lures that carnivores are likely to rub their fur against has advantages over a more commonly used DNA-collection method of sampling animal scat. Species like wolves have relatively small populations and cover a lot of ground, meaning it can be hard to find their droppings.
That's particularly true on Prince of Wales Island, Logan said. Wolf scat doesn't last long in the rain.
For the Alaska project, researchers have trapped and placed collars on wolves and continue to fly above the area about once of month to see how well the new counting method compares to the old.
The hair-snaring tactic could one day reduce the need for flying, which Logan said is expensive, prone to weather delays and sometimes dangerous. Wolf biologist Gordon Haber died in 2009 when the Cessna 185 he was flying in to monitor Denali packs crashed in spruce trees. "(It is) relatively risky, being a small plane and trying to find animals on the ground," Logan said.
source
No comments:
Post a Comment