About 100 times annually a team of Biologists sedates Grizzlies in the Greater Yellowstone to determine the health of the overall population there.......Surveys showed a decline in the grizzly population until the early 1980s................. Then, between 1983 and the early 2000s, the overall population increased by somewhere between 4 percent and 7 percent a year. (Grizzlies are slow reproducers; they have two cubs once every three years, and only become fertile at age four or five.)..........................Since 2000, that growth curve has been flattening with only a 1 to 2% expansion each year.........The Griz likely need more habitat to mitigate what is known as the "Density Dependent Effect", which impacts many animals when there is just not enough territory and food for the population to increase(we humans offset this condition through technology advances, only to kill ourselves through the poisons and stresses that those new technologies yield as byproducts)............................In combination with key foodstuffs, Whitebark Pine seeds and Cutthroat Trout declning rapidly, is this really the time to Federally delist the Griz and turn over their management to trigger happy State Game Commissions?

Daring to Trap

 Grizzlies, 

Researchers 

Tackle Population

 Puzzle

livescience.com

The kerchief over the bear's eyes protects it from dust and debris and reduces visual stimulation. The small tubing in  its nose, known as a nasal cannula, delivers oxygen to the  animal while it is tranquilized.

It takes a trained team, a healthy dose of caution and
 about an
 hour of work to restrain a grizzly bear and get the
samples
 needed for research on the iconic western species.
 This
 research that could help scientists solve a puzzling
 trend
 in the bear's population numbers.

Here's how it works: Researchers scout out an area
 where
 grizzlies are known to wander. There, scientists leave
 roadki
ll bait in a metal box-trap, masked so the bears can't
 detect it
. Once the trap catches a grizzly, scientists use a
 sedative
 to immobilize the animal. Then, they have only an
 hour to
take blood and hair samples, do some measurements
 and
 fit a radio collar on the animal before it wakes up.

A team led by the U.S. Geological Survey (USGS) goes
 through this complicated procedure in the Yellowstone 
National Park area about 70 to 100 times a year. Despite
 the inherent danger, the research is a critical means of
gleaning information about the local grizzly population's
 health."The safety of the animal is important, as well as
the safety of our research teams," said Frank van Manen,
a researcher with the USGS who leads the interagency
team.

"You are working with a wild animal — a very powerful
 wild
animal. Obviously, there's always a risk of something
happening that we haven't seen before, so vigilance is
 incredibly important here."

Population growth flattens

Researchers have conducted grizzly bear monitoring in
 various forms since 1973. At that time, Yellowstone was
completing the closures of garbage dumps that had
 attracted bears. Because of these dumps, the grizzlies
started roaming for food in areas too close to the park's
 tourists, leading to policies of euthanization and removal.

Surveys showed a decline in the grizzly population until
 the early 1980s. Then, between 1983 and the early 2000s,
 the overall population increased by somewhere between
 4 percent and 7 percent a year. (Grizzlies are slow
reproducers; they have two cubs once every three years,
 and only become fertile at age four or five.)

That growth has leveled off, however, in the past decade
. Current growth is estimated to be only as high as 2
percent
 a year. Figuring out why is one of the reasons grizzly
 scientists are trapping and studying the bears.

"We estimate 600 to 700 bears in this population. Is it\
 possible that we now have reached a density where the
population is being affected by what we call density
 dependent effect?" van Manen said, naming one question
 the scientists are asking. This occurs when the growth of
the population itself regulates its own size. In the specific
 case of the grizzlies, he added, this would mean that the
 older males are killing the young cubs.

Scientists have proposed competing theories on what's
 causing the population to level off, however. One of the
explanations focuses on whitebark pine, an important
food as grizzlies bulk up for hibernation in the fall.
Grizzlies eat caches of whitebark pine seeds
embedded in the tree.

Climate change effect?

Van Manen's team completed surveys of the whitebark
 pine population, finding a marked decrease (74 percent)
 in the number of trees in the past few years. As these
pines are high-altitude trees, growing best above 8,000
 feet (about 2,400 meters), some have proposed that
 the warming climate might facilitate outbreaks of native
 mountain pine beetles, which kill off the trees. Climate
change could mean the trees' high altitude can't protect
 them from infestations any longer.

"The winter temperatures aren't cold enough to break
 the cycle for the beetles. One hypothesis is that we're
going to see more frequent outbreaks and more severe
 outbreaks," van Manen said.

It's unclear how greatly this is affecting the grizzly bears,
 though. In response to lost pine trees, the animals could
 switch to eating more meat or find other plants as a
substitution, van Manen said.

The researcher's team has submitted a paper examining
 the body composition and fat content of grizzlies over time,
taken from the samples obtained when the scientists trap
the grizzlies. While van Manen declined to give specifics
 about the results until they are published, he said there are
"no major indications" that body fat as a percentage of bear
 weight is declining This could, with further study, suggest
that the food source isn't the explanation.

Other participants in the ongoing bear research study include
the U.S. Forest Service, the U.S. Fish and Wildlife Service,
the Wind River tribe, and the wildlife agencies for Idaho,
Montana, Wyoming.