Courtesy of USFS and ADF&G
An Alexander Archipelago wolf emerges from her den, as seen from a game cam.
Posted: February 4, 2015
Courtesy of USFS and ADF&G
Wolf pups emerge from a den on Prince of Wales Island, as seen from a game camera.
The wolves of the Alexander Archipelago are mysterious; scientists
don’t even agree about whether or not they’re a subspecies of the gray
wolf. But there are things they do know: Prince of Wales Island’s wolf
population has declined in recent years. Southeast’s wolves have adapted
to make full use of salmon streams. Wolves may use the same dens for
hundreds of years. And timber harvests makes wolves vulnerable in more
than one way: roads expand hunting and trapping opportunities; wolves
frequently travel logging roads, bringing them into closer contact with
humans; and timber harvest can negatively affect Sitka black-tail deer,
wolves’ primary food source.
At a recent Mendenhall Glacier Visitors Center Fireside Lecture, US Forest Service biologist and Tongass Wildlife Program Manager Brian Logan spoke about what the Forest Service and the Alaska Department of Fish and Game know about the wolves, and what they’re working to learn.
One of the first things is something everyone who’s encountered wolves knows. “Wolves are really, really cool animals,” Logan said. “Everybody has some kind of emotional attachment, some emotional reaction to wolves.”
ARRIVAL IN SOUTHEAST ALASKA, GENETICS
Genetic evidence suggests that Southeast Alaska’s wolves, “canis lupus ligoni,” are descended from canis lupus nubilus, otherwise known as the Great Plains wolf, which was extirpated from the Lower 48 in the 1900s, Logan said.
In 1937, taxonomist Edward Goldman described the Alexander Archipelago wolf as smaller, with shorter, coarser, darker hair than wolves in the Northern and Interior areas of Alaska. He said they had an average length of 3 ½ feet, height of 2 feet, and weight of 30 to 50 pounds.
To modern researchers, this seems smaller than the wolves actually are, Logan said.
Modern-day researcher Matthew Cronin, the lead author of a study published this fall, said recent genetic evidence says the wolves are not a subspecies. “There is considerable differentiation of wolves in Southeast Alaska from wolves in other areas,” Cronin said in a December Juneau Empire article. “However, wolves in Southeast Alaska are not a genetically homogenous group, and there are comparable levels of genetic differentiation among areas within Southeast Alaska and between Southeast Alaska and other geographic areas.”
The same pool of evidence suggests to Logan and some other scientists, however, that “there’s some (genetic) clustering going on in Southeast Alaska,” which could lead to the Alexander Archipelago wolf gaining subspecies status.
Fossil samples from caves on Prince of Wales show brown bear, caribou, arctic fox, black bear, ringed seal, hoary marmot and other bones, some up to 40,000 or 50,000 years old. Domestic dog records date back 4,500 years — but not a single wolf bone has been found in those caves, Logan said. “It’s a head scratcher,” he said.
When they arrived, they likely traveled north following Sitka black-tail deer’s range expansion as the glaciers melted. They now roam from Hyder to the forelands of Yakutat.
The wolves in Interior Alaska, by contrast, are probably descended from wolves that inhabited the land bridge of Beringia during the Ice Age, he said. “Wherever there’s something to eat, wolves will probably be there,” Logan said — unless, that is, you’re talking about Admiralty, Baranof, or Chichagof Islands, all of which are rich both in Sitka black-tail deer — and in brown bears.
“That’s the 10,000 dollar question,” Logan said of why the wolves aren’t on those islands (though some in the audience mentioned they’d seen them there, they don’t appear to maintain a presence.) “Nobody has a really good explanation.”
Few brown bears live in islands south of Frederick Sound, where some of the largest populations of wolves roam. Because of Southeast Alaska’s terrain — the icefield between Southeast and Canada, and the nature of the archipelago— the wolves been largely isolated from other species; some may occasionally enter the area from the north, but not many, Logan said. What extent they’re isolated from each other isn’t yet clear. Wolves can swim, so may be crossing from island to island at times; that’s something scientists hope to research in the future.
Alexander Archipelago wolves have also evolved to use the Southeast Alaskan landscape to their advantage. Like many other wolves, they prey on moose, beaver, mustelids and deer. They also camp out on salmon streams, especially toward the end of the summer, when pups are most need nutrition and the salmon runs are at their densest.
PRINCE OF WALES
The Forest Service and the Alaska Department of Fish and Game began focusing their studies on Prince of Wales in 1992. Their first challenge: figuring out how many wolves populate the region.
In the interior, it’s much easier: researchers get in a plane, find wolves, and count them. Southeast’s heavily forested terrain offers other challenges, however.
Prince of Wales is the most heavily managed landscape in Southeast Alaska, with the highest timber harvest, and, associated with that, a lot of road building. Along with road building comes increased hunting and trapping, and, therefore, an increased need to manage the population.
Recently retired ADF&G Research Biologist Dave Person began investigating the population with noninvasive techniques like counting tracks and doing scat surveys, Logan said. But scat surveys — analyzing the wolves’ feces — also posed challenges; Southeast’s heavy rainfall led to droppings degrading quickly. “We had some issues with sample integrity, if you will,” Logan said.
They also used radio collars.
Now, they’re using hair snares to collect DNA (though when more than one wolf is attracted to the scent and leaves hair samples, that method also gets complicated) and GPS/radio collars to estimate population size and learn more. “Our technology keeps advancing tremendously,” Logan said. “We’re learning a lot — even more than we planned on learning.”
GPS data tells them about the wolf’s movements and pack range. It also helps them get aerial counts, which are also used in estimating wolf populations. The average pack size in POW is around 9.5, ranging between three and 16; the average home range size is 363 square miles. That’s a figure only relevant to POW, as the “most managed landscape on the Tongass.”
“These wolves move around a lot — a lot more than we ever expected them to. And a lot of the time, they’re using the road. It makes sense; it’s easier. But it also makes them more vulnerable,” Logan said.
MORTALITY
Wolves have a relatively short life expectancy. “Seven years is probably a really long time for a wolf to live,” Logan said. “Nine is pushing it.”
They’re also extremely tough, however, “bouncing back” from broken bones and ribs. “The pack works to take care of the individual, in a sense,” he said.
Though estimation methods used in different years were “apples to oranges,” wolves’ population also appears to have declined on POW, from an estimated 356 in 1994, to 345 in 2003, to 221 in 2013. The estimated number of wolves per 100 square miles decreased from 10.2, to 9.8, to 6.3.
Logan said the decline is “not necessarily… alarming,” though he added that it led to the Board of Game reducing the quota 20 percent.
High trapping pressure can lead to small populations and “genetic bottlenecks,” Logan said. High levels of mortality are also leading to a high pack turnover, which may be affecting the pack’s overall health.
POW also has high levels of trapping mortality; some places, “virtually the whole pack gets trapped over a given year,” Logan said, emphasizing that trapping is “a legitimate use of the resource.”
It’s not just human predation they’re vulnerable to: canine parvovirus, for example, could have a disastrous effect if the populations weren’t genetically diverse enough, he said.
Some questions after the talk touched on timber harvests, about which Logan was circumspect, saying that growth after clear-cutting is good for deer initially, but that a later phase provides much less available forage and is therefore bad for them, and bad for wolves.
One of the fiercest critics of the Forest Service’s Big Thorne timber sale is former ADF&G biologist Dave Person, who called it, in a 21-page declaration, “the final straw that will break the back of a sustainable wolf-deer predator-prey ecological community on Prince of Wales Island.” He also wrote that “the Big Thorne project puts the viability of the wolf population on the Prince of Wales and the surrounding islands (the Prince of Wales Archipelago) in doubt.”
Old growth is important winter habitat for deer, as less snow sifts down through the canopy and more winter forage is available, Person said; in winter months, deer are up to 90 percent of wolves’ diet, so old growth is important for wolf populations, as well.
Naturally, he said, wolf mortality is around 5 percent; more than 30 to 33 percent may make their sustainability less likely.
Eighty-seven percent of wolf mortality on POW is from hunting and trapping, Person wrote; during the highest harvest year, in 1996-1997, almost 50 percent of POW’s population was trapped.
POW and its surrounding islands may make up 30 percent of Southeast’s wolf population, Person wrote. “Once we have good, robust, solid techniques to monitor wolf populations, then we’ll be in a better position to manage populations,” Logan said. “That’s why we’re putting all this effort into that.”
FUTURE RESEARCH:
The wolves offer ample opportunity for future Forest Service and ADF&G research.
One area has to do with dens: wolves in Southeast Alaska typically den under large, old trees with a big root structure. They also prefer trees on elevated ground, so the rains don’t fill up the den and soak them, and like to be near fresh water — and, therefore, near prey.
Logan has a theory he’d like to test. “The more time I spent at these, the more I realized these aren’t brand new dens,” he said. “These are dens that get reused. They might alternate between years; it might be three years before they go back — but I’m starting to think (with help from Person’s research) these structures are not all that common on the landscape.”
Other questions Logan would like to research in the future, depending on funding, are:
Are Alexander Archipelago wolves a distinct subspecies?
What kind of populations exist on the various islands in the archipelago?
How dependent are the wolves on trees?
How old are dens?
Do the wolves swim between islands to mate, and if so, how far? What kind of gene flow exists between the islands?
What are the implications of high trapping pressure and the high pack turnover that exists on POW?
• Mary Catharine Martin is a staff writer for the Capital City Weekly, and Outdoors reporter for the Juneau Empire.
source
At a recent Mendenhall Glacier Visitors Center Fireside Lecture, US Forest Service biologist and Tongass Wildlife Program Manager Brian Logan spoke about what the Forest Service and the Alaska Department of Fish and Game know about the wolves, and what they’re working to learn.
One of the first things is something everyone who’s encountered wolves knows. “Wolves are really, really cool animals,” Logan said. “Everybody has some kind of emotional attachment, some emotional reaction to wolves.”
ARRIVAL IN SOUTHEAST ALASKA, GENETICS
Genetic evidence suggests that Southeast Alaska’s wolves, “canis lupus ligoni,” are descended from canis lupus nubilus, otherwise known as the Great Plains wolf, which was extirpated from the Lower 48 in the 1900s, Logan said.
In 1937, taxonomist Edward Goldman described the Alexander Archipelago wolf as smaller, with shorter, coarser, darker hair than wolves in the Northern and Interior areas of Alaska. He said they had an average length of 3 ½ feet, height of 2 feet, and weight of 30 to 50 pounds.
To modern researchers, this seems smaller than the wolves actually are, Logan said.
Modern-day researcher Matthew Cronin, the lead author of a study published this fall, said recent genetic evidence says the wolves are not a subspecies. “There is considerable differentiation of wolves in Southeast Alaska from wolves in other areas,” Cronin said in a December Juneau Empire article. “However, wolves in Southeast Alaska are not a genetically homogenous group, and there are comparable levels of genetic differentiation among areas within Southeast Alaska and between Southeast Alaska and other geographic areas.”
The same pool of evidence suggests to Logan and some other scientists, however, that “there’s some (genetic) clustering going on in Southeast Alaska,” which could lead to the Alexander Archipelago wolf gaining subspecies status.
Fossil samples from caves on Prince of Wales show brown bear, caribou, arctic fox, black bear, ringed seal, hoary marmot and other bones, some up to 40,000 or 50,000 years old. Domestic dog records date back 4,500 years — but not a single wolf bone has been found in those caves, Logan said. “It’s a head scratcher,” he said.
When they arrived, they likely traveled north following Sitka black-tail deer’s range expansion as the glaciers melted. They now roam from Hyder to the forelands of Yakutat.
The wolves in Interior Alaska, by contrast, are probably descended from wolves that inhabited the land bridge of Beringia during the Ice Age, he said. “Wherever there’s something to eat, wolves will probably be there,” Logan said — unless, that is, you’re talking about Admiralty, Baranof, or Chichagof Islands, all of which are rich both in Sitka black-tail deer — and in brown bears.
“That’s the 10,000 dollar question,” Logan said of why the wolves aren’t on those islands (though some in the audience mentioned they’d seen them there, they don’t appear to maintain a presence.) “Nobody has a really good explanation.”
Few brown bears live in islands south of Frederick Sound, where some of the largest populations of wolves roam. Because of Southeast Alaska’s terrain — the icefield between Southeast and Canada, and the nature of the archipelago— the wolves been largely isolated from other species; some may occasionally enter the area from the north, but not many, Logan said. What extent they’re isolated from each other isn’t yet clear. Wolves can swim, so may be crossing from island to island at times; that’s something scientists hope to research in the future.
Alexander Archipelago wolves have also evolved to use the Southeast Alaskan landscape to their advantage. Like many other wolves, they prey on moose, beaver, mustelids and deer. They also camp out on salmon streams, especially toward the end of the summer, when pups are most need nutrition and the salmon runs are at their densest.
PRINCE OF WALES
The Forest Service and the Alaska Department of Fish and Game began focusing their studies on Prince of Wales in 1992. Their first challenge: figuring out how many wolves populate the region.
In the interior, it’s much easier: researchers get in a plane, find wolves, and count them. Southeast’s heavily forested terrain offers other challenges, however.
Prince of Wales is the most heavily managed landscape in Southeast Alaska, with the highest timber harvest, and, associated with that, a lot of road building. Along with road building comes increased hunting and trapping, and, therefore, an increased need to manage the population.
Recently retired ADF&G Research Biologist Dave Person began investigating the population with noninvasive techniques like counting tracks and doing scat surveys, Logan said. But scat surveys — analyzing the wolves’ feces — also posed challenges; Southeast’s heavy rainfall led to droppings degrading quickly. “We had some issues with sample integrity, if you will,” Logan said.
They also used radio collars.
Now, they’re using hair snares to collect DNA (though when more than one wolf is attracted to the scent and leaves hair samples, that method also gets complicated) and GPS/radio collars to estimate population size and learn more. “Our technology keeps advancing tremendously,” Logan said. “We’re learning a lot — even more than we planned on learning.”
GPS data tells them about the wolf’s movements and pack range. It also helps them get aerial counts, which are also used in estimating wolf populations. The average pack size in POW is around 9.5, ranging between three and 16; the average home range size is 363 square miles. That’s a figure only relevant to POW, as the “most managed landscape on the Tongass.”
“These wolves move around a lot — a lot more than we ever expected them to. And a lot of the time, they’re using the road. It makes sense; it’s easier. But it also makes them more vulnerable,” Logan said.
MORTALITY
Wolves have a relatively short life expectancy. “Seven years is probably a really long time for a wolf to live,” Logan said. “Nine is pushing it.”
They’re also extremely tough, however, “bouncing back” from broken bones and ribs. “The pack works to take care of the individual, in a sense,” he said.
Though estimation methods used in different years were “apples to oranges,” wolves’ population also appears to have declined on POW, from an estimated 356 in 1994, to 345 in 2003, to 221 in 2013. The estimated number of wolves per 100 square miles decreased from 10.2, to 9.8, to 6.3.
Logan said the decline is “not necessarily… alarming,” though he added that it led to the Board of Game reducing the quota 20 percent.
High trapping pressure can lead to small populations and “genetic bottlenecks,” Logan said. High levels of mortality are also leading to a high pack turnover, which may be affecting the pack’s overall health.
POW also has high levels of trapping mortality; some places, “virtually the whole pack gets trapped over a given year,” Logan said, emphasizing that trapping is “a legitimate use of the resource.”
It’s not just human predation they’re vulnerable to: canine parvovirus, for example, could have a disastrous effect if the populations weren’t genetically diverse enough, he said.
Some questions after the talk touched on timber harvests, about which Logan was circumspect, saying that growth after clear-cutting is good for deer initially, but that a later phase provides much less available forage and is therefore bad for them, and bad for wolves.
One of the fiercest critics of the Forest Service’s Big Thorne timber sale is former ADF&G biologist Dave Person, who called it, in a 21-page declaration, “the final straw that will break the back of a sustainable wolf-deer predator-prey ecological community on Prince of Wales Island.” He also wrote that “the Big Thorne project puts the viability of the wolf population on the Prince of Wales and the surrounding islands (the Prince of Wales Archipelago) in doubt.”
Old growth is important winter habitat for deer, as less snow sifts down through the canopy and more winter forage is available, Person said; in winter months, deer are up to 90 percent of wolves’ diet, so old growth is important for wolf populations, as well.
Naturally, he said, wolf mortality is around 5 percent; more than 30 to 33 percent may make their sustainability less likely.
Eighty-seven percent of wolf mortality on POW is from hunting and trapping, Person wrote; during the highest harvest year, in 1996-1997, almost 50 percent of POW’s population was trapped.
POW and its surrounding islands may make up 30 percent of Southeast’s wolf population, Person wrote. “Once we have good, robust, solid techniques to monitor wolf populations, then we’ll be in a better position to manage populations,” Logan said. “That’s why we’re putting all this effort into that.”
FUTURE RESEARCH:
The wolves offer ample opportunity for future Forest Service and ADF&G research.
One area has to do with dens: wolves in Southeast Alaska typically den under large, old trees with a big root structure. They also prefer trees on elevated ground, so the rains don’t fill up the den and soak them, and like to be near fresh water — and, therefore, near prey.
Logan has a theory he’d like to test. “The more time I spent at these, the more I realized these aren’t brand new dens,” he said. “These are dens that get reused. They might alternate between years; it might be three years before they go back — but I’m starting to think (with help from Person’s research) these structures are not all that common on the landscape.”
Other questions Logan would like to research in the future, depending on funding, are:
Are Alexander Archipelago wolves a distinct subspecies?
What kind of populations exist on the various islands in the archipelago?
How dependent are the wolves on trees?
How old are dens?
Do the wolves swim between islands to mate, and if so, how far? What kind of gene flow exists between the islands?
What are the implications of high trapping pressure and the high pack turnover that exists on POW?
• Mary Catharine Martin is a staff writer for the Capital City Weekly, and Outdoors reporter for the Juneau Empire.
source
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