Europeans began
settling the West a
mere 150 years ago, a
drop in the geological
bucket of time. The
streaming of settlers westward created
big changes on the landscape,
as land was planted to row crops
and grazed by livestock. Although
no accurate way to estimate mule
deer populations was available at
the turn of the century, accounts of
their presence indicate numbers
were very low.
Hunting regulations, increased
law enforcement, creation of
wildlife refuges
such as the Grand
Canyon National
Game Preserve,
and improvements
in wildlife habitat
and predator management
resulted
in a collective
explosion of mule
deer herds, with
population estimates
totaling 2.3
million in 1950.
The 1950s and
1960s were
considered the "hey days" of
mule deer populations.
The population highs of the
1950s and 1960s were followed
by sharp declines in mule deer
numbers. Biologists don't believe
there is one silver bullet that
explains the declines in both
numbers and distribution of mule
deer. What biologists know is that
the many changes that have taken
place across large landscapes
result in fewer mule deer that can
call the West home.
Chris Madson, Wyoming Game
and Fish Publications Supervisor
and Editor of Wyoming Wildlife
Magazine, included some of
these issues in an essay titled, "The Quiet Crisis" in the
September 2001 issue of
Wyoming's magazine.
"The problems facing wildlife
and wild places in North America
are deeper and more complex
than they have ever been before,
but their root causes attract little
attention," said Madson. "All of us
who care about wildlife face a
challenge of unprecedented
dimensions, an emergency that
western conservationist and statesman
Stuart Udall once called the
quiet crisis.”
The quiet crisis began with the
settling of the West. After livestock
were introduced into the Great
Basin in the 1860s, native bunch
grasses were overgrazed and
replaced by sagebrush. A severe
winter in the late 1800s decimated
many livestock herds and wildlife
populations. This was followed by
an abundance of wildfires and
about seven wet years in the Great
Basin, which led to the widespread
establishment of bitterbrush, a high
quality preferred food of mule
deer.
The increase in quality and
quantity of plants preferred by
mule deer caused mule deer
populations to rebound by 1950.
During the 1950s, biologists noted
fawn:doe ratios of 75 to 100, or
even 100 to 100, something that is
unheard of in many places in the
West today.
Then some of the quiet crisis
factors kicked in, resulting in
greater competition for natural
resources and a lesser ability of the
land to support large numbers of
mule deer.
These include:
1. Habitat changes caused by fire
suppression, invasive plants and
livestock management have lessened
the ability of habitats to support
mule deer populations.
2. Gas, mineral and oil exploration
fragment habitat and continue to
threaten important traditional
mule deer range.
3. Predators play a shifting role as
habitat loss and urban sprawl concentrate
mule deer populations on
smaller tracts of land near human
populations.
4. Climatic changes such as
drought and severe winters play a
key role in quality and quantity of
habitat, and the ability of mule
deer young to survive one year to
breeding age.
5. Habitats are fragmented and lost
as a result of human population
growth and development in traditional
summer and winter mule
deer range.
6. Interactions with elk may
increase when habitat is poor
or limited.
Today, virtually every ecoregion
has a lesser ability to produce
and maintain mule deer when compared to the mid-1950s. The
term biologists give to the amount
of food, water and cover an area
can support is carrying capacity.
Carrying capacity can be
likened in simpler terms to the
amount of clothes a suitcase will
hold. You can fill a suitcase, but at
some point, there is no room left
for additional items. Habitat is
much the same way. Land cannot
support the numbers of mule deer
it once had if the
quality habitat
doesn't exist to
provide food,
cover, water and
shelter to those
animals yearround.
A combination of fire suppression, oil-gas-mineral exploration and mining, predation, habitat fragmentation, spread of invasive plants, drought, competition between species, livestock management and other human factors such as urban development have affected the habitats of mule deer.
On a landscape
scale,
mule deer populations
have not
recovered since
habitat began
declining in the
latter half of the
last century. And
realistically,
unless the
human population stops growing
and habitat loss and degradation
ceases, people are facing a West
that will continue to look much
different from the one that existed
during the mule deer “hey days.” And this land will more than likely
contain fewer mule deer.
"Removing fire has had a dramatic effect," said Mayer. "We've taken fire out of the ecosystem in the forest environment. When we finally get a big fire, 2-4-D (a herbicide) is sprayed to kill the shrubs, then it's planted to trees. That eliminates early successional stages."
Ken Mayer, Chief of the
Scientific Branch for Oil Spill
Prevention and Response with the
California Department of Fish and
Game, and co-author of “A
Sportsman’s Guide to Improving
Deer Habitat in California,” offered
several insights to habitat changes
after his lengthy tenure as a deer
biologist for California Fish and
Game. He said that while many
factors have caused mule deer
declines, fire suppression and conversion
of shrub-scrub habitats
have literally changed the face of
the landscape.
Early successional stages commonly
have young forbs and
shrubs that are high in protein,
very nutritious and within the
reach of mule deer. Later successional
stages can provide cover for
mule deer, but generally provide
poor habitat because of the lack of
food present.
A stand of cheatgrass that resulted from a 2001 wildfire, showing the
skeletons of dead sagebrush plants that will not resprout due to the lack
of moisture at this elevation. By Mike Cox.
On a very large scale, there are
fewer habitats in early successional
stages than there were 50 years
ago. Mayer referred to a research
study on mule deer food habits in
1954. "Ninety percent of the diet
of mule deer was shrub component,
with the remainder herbs
and grasses," said Mayer. "We did
the same study again in 1994 and
we got 80 percent herbaceous
material in the diet. That shows
what is happening to our ranges.
You can't support large numbers of
deer on grasses."
Mayer predicts it will be
impossible to return to the mule
deer population levels of the
1950s and 1960s.
"I don't think it’s feasible from a
resource habitat perspective or a
political perspective," said Mayer.
"There's a hell of a lot more people
living in places like Colorado
and California than the 50s and
60s, and we're converting habitat
at a high rate."
If it isn't possible to mule deer
numbers that existed in the mid
1950s, then what is possible?
- It is possible to manage mule deer
populations at optimum levels given
existing habitat conditions, and to
work hard to manage the
factors that limited mule deer populations
over the past half century.
- It is possible to maximize the benefits
to wildlife from development
of all kinds.
- It is possible to restore habitats on a
large scale to improve the ability of
existing habitats to support mule
deer and offset habitat loss.
Mayer said it is especially important
to manage public perspective.
"If we're really going to change
things, we need to change the perspective
of the public regarding what
a healthy forest ecosystem is," said
Mayer. "The public has a perception
that a forest is trees. But a forest is
really a variety of things, from grasses
and forbs to old growth."
The Sierra Nevada Story
The Sierra Nevada Story
George Gruell, a retired wildlife biologist from the U.S. Forest
Service, compared landscape photos from the late 1800s and early
1900s to recent times of the Sierra Nevada is his book, “Fire in
Sierra Nevada Forests.” His photographic essay is a mule deer’s
nightmare.
The Sierra Nevada is a 15.5 million acre chunk of land that
spans 360 miles north to south from California’s Central Valley to
50 plus miles east. Elevations range from sea level to 14,000 feet,
and annual precipitation ranges from 20 to 75 inches.
Gruell’s goal was to identify the factors that have caused
landscape changes. He noted that the health of the forests and
habitats are declining, and that excessive fuel loads, a direct result
of widescale fire suppression, make many areas susceptible to
catastrophic fires. Gruell said changes in climate, livestock
grazing, logging and fire have been the biggest agents of change
in the Sierra Nevada. The end result, he concludes, is a dense
forest with much less wildlife habitat.
The future of the Sierra Nevada may be bleak for wildlife and
people if public opinion about management of the landscape does
not change. Gruell believes it is possible to improve the landscape
of the Sierra Nevada for people and wildlife, but only if fire is
restored to the ecosystem.
Is the habitat situation in the Sierra Nevada unique? Hardly. While this
example is specific to California, each of the mule deer ecoregions has been subjected to many factors that have lessened the ability of western landscapes to provide homes for deer and other species of wildlife.
Biologists have taken an in-depth look at each of the factors contributing
to mule deer declines, and offer suggestions to improve habitats that
support not only mule deer, but many western wildlife populations.
