The critically endangered American red wolf might have been saved from extinction.
In a scathing court decision Monday, a federal judge in North Carolina ripped the Interior Department’s management of the last red wolf population
in the wild, saying that an agency sworn to uphold a congressional
mandate to preserve the animals violated it over and over, and even gave
private landowners the right to shoot them.
Chief
Judge Terrence W. Boyle reminded the U.S. Fish and Wildlife Service,
which gave the authorization, of its own statement in 1999. “Wildlife
are not the property of landowners but belong to the public and are
managed by state and federal governments for the public good,” he wrote.
Boyle
ruled that a temporary injunction issued against Fish and Wildlife’s
shoot-to-kill authorization in 2016 during the Obama administration is
permanent. The agency must prove that a wolf is a threat to humans or
livestock before it can make a decision to take its life.
A U.S. District Court judge has restored federal protections to about 700 grizzly bears living in and around Yellowstone National Park, canceling planned hunts in Wyoming and Idaho and overturning a Trump administration finding that the iconic population had recovered. The ruling was based on his determination that the U.S. Fish and Wildlife Service had illegally failed to consider how removing the Yellowstone bears from the endangered species list would affect other protected grizzly populations, and that its analysis of future threats to the bears was “arbitrary and capricious.”
Phil Manlick releases a collared marten on the west end of Isle Royale in March 2018.
Credit: Jonathan Pauli
After decades of trapping, the last
known American marten was spotted on Isle Royale in 1917. Fifty years
later, in 1966, the National Park Service planned to reintroduce martens
to the national park situated in Lake Superior, but nobody knows if the
agency ever followed through. Then, in 1993, martens were confirmed on
the island for the first time in 76 years.
Whether these small, forest-dwelling carnivores -- valued
historically for their fur -- had been hiding there the whole time,
found their way back, or were introduced in the 1960s without any
records has remained a mystery for the last quarter century.
But in new research published today (Aug. 23, 2018) in the journal Scientific Reports,
University of Wisconsin-Madison researchers in the Department of Forest
and Wildlife Ecology, collaborating with the National Park Service,
traced the recolonization to martens likely arriving in the 1990s,
shortly before they were spotted.
Genetic studies of martens from Isle Royale and nearby populations in
America and Canada showed that the contemporary population came from
nearby Ontario, Canada. The animals likely wandered over on an ice
bridge in the winter, the researchers speculate.
The results provide much-needed context about the natural history of
an island long considered an unspoiled wilderness, but one with a long
history of ecological disruptions and recoveries. The island park may be
best known for the ebb and flow of its wolf and moose populations,
which have been tracked for 60 years.
With additional wolves set to be relocated to Isle Royale in the
coming months, the new research provides ecologists and land managers
with a fuller picture of how dynamic even seemingly isolated island
ecosystems can be.
After all, say the researchers, if the house-cat-sized marten can
find its way over, islands like Isle Royale may be less isolated and
static than we think.
Jonathan Pauli, a professor of forest and wildlife ecology at
UW-Madison, has studied martens for years as part of efforts to
understand how communities of wild animals respond to human disturbance.
In 2015, his group provided evidence that martens had long escaped
detection on islands in southeastern Alaska prior to deliberate
reintroduction efforts in the 20th century. And in work published in
2016 with graduate student Phil Manlick, Pauli called into question the
effectiveness of periodic augmentations of reintroduced marten
populations in Wisconsin, where the once-extirpated carnivore remains an
endangered species.
Part of the problem in studying martens: They're hard as heck to spot in the wild.
"I've never seen a Wisconsin marten without trapping one," says Manlick.
Manlick, Pauli and co-author Mark Romanski of the National Park
Service collected marten scat samples on the island from 2006 to 2008
and again from 2012 to 2013. They gathered additional samples from
nearby marten populations in Canada, Minnesota, Wisconsin and Michigan's
Upper Peninsula. Samples from a different species, the Pacific marten,
located in Colorado, served as a comparison. In total, the researchers
collected samples from 230 individuals.
They analyzed DNA extracted from the samples to get a genetic
fingerprint of the different populations. The team then evaluated three
possible colonization scenarios: that an ancient population of martens
had escaped detection after presumed extirpation, that the planned 1966
reintroduction actually occurred and was successful, or that a more
recent reintroduction took place.
An initial analysis of the martens' DNA showed that the Isle Royale
population was related to martens from Ontario. But the island
population's DNA fingerprint was different, unique enough to suggest
that they might have been isolated from the mainland for sufficient time
to diverge into their own subpopulation. This distinct pattern
supported the idea that a hidden population of martens had escaped
detection during the 20th century.
"If something's been isolated out there for thousands of years,
there's going to be some (genetic) mutations that build up in that
population, where they're going to look distinct from everybody else
around them," says Manlick, explaining how, over generations, genomes
slowly accumulate mutations. "And that's what we anticipated seeing. But
we didn't."
A closer look at DNA from the mitochondria -- the energy-generating
part of the cell has its own, tiny genome -- revealed that the Isle
Royale martens were part of one larger, common population around Lake
Superior.
"They actually look just like all the other martens in the region who
have come from Ontario and Minnesota and Michigan, and all these groups
of martens all kind of look the same" genetically, says Manlick.
The low genetic diversity of the Isle Royale martens indicated that
their population had experienced a severe genetic bottleneck. Analysis
of the bottleneck estimated that the island's population began with just
two individuals -- or even one pregnant female -- and that they
migrated to the island less than a generation before samples were first
collected in the early 2000s.
In other words, Isle Royale's martens repopulated the island just
before they were spotted again, in 1993, after a 76-year absence. Though
it's impossible to prove, the researchers venture that the martens
walked 16 miles over an ice bridge from Ontario, a known pathway for
other animals. Such connections to land are becoming less common in a
warming climate.
"Much of what we understand about the island and its ecosystem
evolves as we develop new techniques for analysis. At the onset of the
project I was pulling for a remnant population, but to find out that
martens just arrived blew my mind," says Romanski. "I am used to being
wrong, but in this instance I certainly don't mind, as the story is
richer."
"If they naturally colonized the island, it has implications for the management of Isle Royale in general," says Pauli.
That's because ongoing management decisions, such as the relocation
of more wolves to the island slated for this fall, are based in part on
assumptions that the island ecosystem won't recover from disturbances
without human help. But the small marten found its way back. So might
other species. The take-home lesson, say the researchers, is that even
protected, isolated ecosystems can be resilient and are rarely static.
"This does suggest that these islands are maybe not as insulated as
we think," says Pauli, "and that they are indeed way more dynamic than
we give them credit for."
Utah State University scientists
have shown that a 'landscape of fear' does not keep Yellowstone elk
from using risky habitats where wolves kill them. In an Early View
online article of Ecological Monographs, the researchers discuss how elk
use nightly lulls in wolf activity to safely access dangerous areas.
Credit: Chad Wildermuth
After wolves were reintroduced to
Yellowstone National Park in the mid-1990s, some scientists thought the
large predator reestablished a 'landscape of fear' that caused elk, the
wolf's main prey, to avoid risky places where wolves killed them. This
fueled the emerging idea that predators affect prey populations and
ecosystems not only by eating prey animals, but by scaring them too. But
according to findings from Utah State University ecologists Michel Kohl
and Dan MacNulty, Yellowstone's 'landscape of fear' is not as scary as
first thought.
"Contrary to popular belief, the wolf is not a round-the-clock threat
to elk; it mostly hunts at dawn and dusk, and this allows elk to safely
access risky places during nightly lulls in wolf activity," says Kohl,
who completed a doctoral degree at USU in 2018 and is lead author of the
paper. "Despite their Hollywood portrayal as nighttime prowlers, wolves
tend to hunker down at night because their vision is not optimized for
nocturnal hunting."
With colleagues Daniel Stahler, Douglas Smith, and
P.J. White of the U.S. National Park Service, Matthew Metz of University
of Montana, James Forester of University of Minnesota, Matthew Kauffman
of University of Wyoming, and Nathan Varley of University of Alberta,
Kohl and MacNulty report their findings in an Early View online article
of Ecological Monographs. The article will appear in a future print
edition of the Ecological Society of America publication. The team's
research is supported, in part, by the National Science Foundation.
The researchers revisited data from 27 GPS radio-collared elk that
had been collected in the early years after the reintroduction,
2001-2004, but never fully analyzed. These collars recorded the location
of each elk every 4-6 hours. This was the first time GPS technology had
been used to track Yellowstone elk, and no one imagined that elk might
sync their habitat use to the wolf's 24-hour schedule. Little was known
about this schedule until researchers first equipped wolves with GPS
collars in 2004.
"In the days before GPS, when we tracked wolves by sight and with VHF
radio-telemetry, we knew they hunted mainly in the morning and evening,
but we didn't know much about what they did at night" says MacNulty, a
veteran Yellowstone wolf researcher and associate professor in USU's
Department of Wildland Resources and the USU Ecology Center. "GPS data
showed that wolves were about as inactive in the middle of the night as
they were in the middle of the day."
Kohl used the GPS data to quantify the 24-hour schedule of wolves,
and he compared how elk use of risky places -- sites where wolves killed
elk -- differed between periods of high and low wolf activity. "Elk
avoided the riskiest places when wolves were most active, but they had
no problem using these same places when wolves were least active," says
Kohl. "An elk's perception of a place as dangerous or safe, its
landscape of fear, was highly dynamic with 'peaks' and 'valleys' that
alternated across the 24-hr cycle in response to the ups and downs of
wolf activity."
The ability of elk to regularly use risky places during wolf
downtimes has implications for understanding the impact of wolves on elk
and the ecosystem at large. "Our results can explain why many other
studies found no clear-cut effect of wolf predation risk on elk stress
levels, body condition, pregnancy, or herbivory," says MacNulty. "If our
results reflect typical elk behavior, then actual killing rather than
fear probably drives most, if not all, of the effect of wolves on elk
and any cascading effect on the plants that elk eat such as aspen and
willow."
This conclusion runs counter to popular views about the ecological
importance of fear in Yellowstone and elsewhere. "Although our study is
the first to show how a prey animal uses predator downtime to flatten
its landscape of fear, I suspect other examples will emerge as more
researchers examine the intersection between prey habitat use and
predator activity rhythms," says Kohl.
IMAGE: 'After 60 years, the Isle Royale
wolf-moose project continues. Today, wolves prosper again in several
regions of North America. But our relationship with wolves in many parts
of the world...
view more
Credit: Sarah Bird/Michigan Tech
Researchers from Michigan Technological University have released the
annual Winter Study report detailing updates on the ecology of Isle
Royale National Park. For the third year in a row, the Isle Royale wolf
population remains a mere two, while the moose population continues to
stay above the historic average. Without the pressure of predation, the
expanding moose population will have a greater impact on the island's
forest ecology.
The study co-authors include Research Professor Rolf Peterson,
Professor John Vucetich and Assistant Research Professor Sarah Hoy. They
say the heart of the study's success has been the more than 1,000
citizen science volunteers who have bolstered the study's fieldwork
efforts in small teams totaling about 40 people each year for the last
30 years. Together, they helped gather enough skulls to document the
shrinking moose of Isle Royale, observe seasonal wolf activity and
earned more than their fair share of hiking boot blisters.
In terms of population trends, little changed on the island this
past year. As Peterson, Vucetich and Hoy write in the report about the
last male-female pair of wolves, "there was no evidence of any change in
their status, except they are older by a year."
The pair are closely related--both as siblings and as
father-daughter--and the inbreeding within the island's isolated wolf
population is what contributed to their demise. The wolves' numbers
started plummeting in 2009, declining by 88 percent from 24 to 2 wolves
for that period; historical levels of wolves typically varied between 18
and 27. The pair, aged eight and ten years old, may have produced a pup
several years ago but the female has continued to reject the male as a
mate.
One meager hope for new wolves formed briefly in early February. For
almost a week, an ice bridge connected the island to the Ontario
mainland. However, the ice conditions were rough, the bridge did not
last long, and the researchers found no evidence of wolves crossing
over. With fewer ice bridges and warmer winters, the chances of wolves
recovering naturally is slim to none.
As the wolf population declined and forage remained abundant, the
moose population has been able to expand. Counting conditions for the
past two winters have not been ideal, but the team estimates the moose
population to be around 1,475 members. The population usually numbers
between 700 and 1,200 moose. Hoy, who led the skull size study of the
island's moose that found their size decreased by 16 percent over 40
years, says we are observing a population in transition.
"Although the effects on body size are quite subtle, there was a
marked decline in lifespan over the study period," she says, explaining
that wolves are not the only factor affecting moose. The changes in both
populations impact the rest of the island, particularly balsam fir,
which is a staple winter food for moose. "Maybe the trees can withstand
one major source of stress, but with the lack of predation and a
changing climate, can it withstand two or more?"
Peterson, who has been a part of the Isle Royale research for the
past 50 years, says the island is a unique place to study moose and
wolves. Unlike big, complex spaces like Yellowstone, where the cascading
effects of wolf populations are still debated among scientists, Isle
Royale is a neatly contained ecosystem that can provide insight into
other Northwoods settings.
"This is the perfect environment to observe predator-prey
interactions--but doesn't make it easy," he says. "We anticipate big
things are about to happen, with wolf predation restored, that will once
again change the direction of the island's ecosystem. It might take a
long time to see the full impact of those changes."
The National Park Service has proposed introducing 20-30 wolves to
the island over the next three years. The final environmental impact
statement was completed and the identified preferred alternative is to
restore wolf predation, but the final decision on the plan is pending as
of the Winter Study report publication.
IMAGE: The researchers measured the length, width
and height of moose skulls to study the impact of climate change on the
iconic Northwoods species. The team measured 662 moose skulls and...
view more
Credit: Sarah Bird/Michigan Tech
Researchers from Michigan Technological University know the smartest
way to know a moose is by its brain. Specifically, skull measurements
reveal information about body size, physiology and the conditions of a
moose's early life. Put together, measurements through time reveal the
health of a population and even changes in their environment.
For the booming moose population of Isle Royale, a key species in
the world's longest running predator-prey study on the island, skulls
have shrunk by about 16 percent over a 40-year period. The results were
published recently in Global Change Biology.
Sarah Hoy, a research fellow in the School of Forest Resources and
Environmental Science (SFRES) at Michigan Tech, led the study.
"The conditions you're born into have a massive impact on not only
how big you are but also how long you're going to live," Hoy says. "This
idea isn't new--what we're trying to do is establish how climate
warming is affecting this iconic, cold-adapted species. We found
evidence suggesting that moose experiencing a warm first winter tended
to be smaller as adults and live shorter lives."
The results from the Isle Royale moose study are significant for
several reasons, especially taken in the context of nearby moose
populations.
In northern Minnesota, moose populations have been halved in the
past 12 years. Many ecologists consider three main factors at play:
predation, disease and climate change. In particular, the influence of
warmer temperatures on moose nutritional condition and moose parasites,
including a fatal brain worm parasite that is spread by white-tail deer,
which have moved farther north into moose territory as the climate has
gotten milder.
"The moose populations in northern Minnesota have tanked," Hoy says.
"Climate is considered a main driver, whether it's direct through
warmer winter temperatures causing heat stress and influencing the
nutritional condition of moose or indirectly by establishing more
favorable habitat for white-tail deer."
As Minnesota moose have declined, the Isle Royale moose have
flourished, the population growing annually by more than 20 percent for
the past six years. There are also no white-tail deer to spread
parasites on Isle Royale. Yet the two groups of moose do share a similar
climate, so Hoy and her team wondered if the skulls of Isle Royale
moose would reveal adverse impacts of climate change.
Moose--who are naturally creatures of the north--prefer the cold.
Warmer winters in the Northwoods raise concerns about how animal
populations will adapt to climate change.
By measuring the length, width and height of moose craniums--on 662
skulls gathered on Isle Royale by hundreds of citizen science volunteers
over four decades--clear patterns emerge. First, the skulls have
decreased in size and, second, the evidence suggests that moose calves
experiencing a warm first winter tended to be smaller as adults and live
shorter lives. Hoy's collaborator Rolf Peterson, an SFRES research
professor at Michigan Tech, helped haul in some of the skulls.
"The farthest we had to hike was 20 miles," Peterson says. "These
aren't changes you can see out in the field; we're looking for trends
over time in the whole population."
Hoy, Peterson and their collaborator John Vucetich, a professor of
ecology at Michigan Tech, suggest the trends reflect a population in
transition. Part of the Isle Royale moose's transition has to do with
another of the island's key species--wolves.
It seems like a paradox: a growing population with shrinking
individuals and shorter lifespans. Yet when the ecological balance of
food availability and predation are considered, the contradiction makes
more sense. As the wolves have died off on the island--only two remained
during last year's winter study--the moose population has tripled in
the past decade, reaching about 1,600 in the 2017 survey. Competition
for food can also contribute to malnutrition and therefore smaller
moose.
"Decreasing skull size may be an early indicator of population
change," Vucetich says. "We're likely looking at a population in
transition, and the healthiest transition would almost certainly involve
restoring wolf predation to Isle Royale."
Adapting to climate change is already tough on moose; adding the
present day's imbalance in the predator-prey dynamics puts additional
stress on the Isle Royale ecosystem. Drawing from six decades of data,
the Isle Royale Winter Study will come out later this winter to document
the impacts of population change in the island's ecosystem.
In the meantime, the National Park Service plans to release its
decision this winter on whether or not to reintroduce wolves to Isle
Royale.
Wolf behavior undeterred by tailings ponds and pit mines
Study shows wolves hunt moose as usual in the Athabasca Oil Sands
University of Alberta
IMAGE: Two wolves peer into a wildlife camera in Alberta's Athabasca Oil Sands region.
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Credit: Wildlife Habitat Effectiveness and Connectivity, 2014
Wolves do not avoid areas of
human disturbance when hunting moose in Alberta's oil sands region.
New UAlberta research shows that predation rates of moose have
increased near areas of high human disturbance, but low human activity,
such as tailings ponds and pit mines.
"Wolves are not avoiding these features," explained UAlberta PhD
candidate Eric Neilson, who compared the population density of moose to
the distribution of wolf-related moose deaths in the region. "In fact,
they are using space near mines as they usually would, demonstrating
that these spaces are not a deterrent."
If anything, Neilson says these spaces provide effective hunting ground for wolves.
Environmental changes
When habitat is cleared for mining or oil extraction, there are
large changes to the landscape that create barriers around which wolves
move. A similar effect, Neilson said, is shown around rivers.
"Wolves are coursing predators. This means that they like to move
across the landscape to encounter their prey. It could be that the edge
of the mine provides a feature similar to rivers that they can move
along and around in the same way," he said.
However, the intensification of wolf activity and moose kills near
the edges of these mines and tailings ponds is not shown near camps or
upgrader sites, likely due to the presence of humans.
Future investigation
"There is a lot more research to be done in this area," said
Neilson, adding the impact upon moose populations is not yet clear.
"With any change in habitat that causes changes in animal behaviour,
there are many factors to consider and much more we can learn about what
is really going on here."
