Fire, invasive species and
livestock management
have changed western
landscapes
Fire
Of all the factors that
have shaped the
ecoregions in which
mule deer exist,
fire has been
the strongest one with the
greatest positive influence.
Fire is a critical force in maintaining
and creating habitat
for mule deer because fire
sets back succession.
Succession is the orderly
and progressive replacement
of one plant community by
another until a fairly stable
community occupies an area.
If left alone, an abandoned
crop field will not remain in
that state for very long.
Generally, grasses, forbs and
weeds will begin to grow,
followed by brushy plants,
then by saplings that invade
open areas, until the site is
finally occupied by a stand of
trees. Historically, fire has
been the most effective tool in
maintaining grasslands across
the United States. Today, it is
still considered to be the most
important tool a biologist has to
manage habitat.
A quick peak at national historical
wildfire data provides insight
into the frustration land managers
face with fire suppression efforts.
| Decade |
# of acres burned |
| 1920s |
26 million acres |
| 1930s |
39 million acres |
| 1940s |
23 million acres |
| 1950s |
9 million acres |
| 1960s |
4 million acres |
| 1970s |
3 million acres |
| 1980s |
4 million acres |
| 1990s |
3.6 million acres |
Since the decade of the 1940s,
fires have not burned in double
digit numbers in the United States.
Wyoming Game and Fish Biologist
Steve Kilpatrick attributes the heyday
populations of mule deer in
the middle of the 20th century to
the quantity and types of fires that
burned in the decades prior to the
1950s.
“In the 1920s through 1950,
we had some massive burns and
resprouting shrubs,” said
Kilpatrick. “We had high quality
browse, and a lot of quantity - lots
of acres of good (mule deer)
groceries. Browse was nutritious,
young, palatable and easy to
digest.” Now the plants are older,
and when it rains or they are
browsed, they don’t respond as
vigorously.
In addition to fewer fires burning
on fewer acres, fire suppression
has changed the intensity and
rate at which fires burn, resulting
in different and unpredictable
communities of plants. Fuel loads
build up such that when infrequent
fires occur, they cover large
amounts of land and burn very
hot. A recent example of that is the
Rodeo fire near Pinedale, Arizona,
that burned at 2,000 degrees
Fahrenheit. In general, areas that
burn fast and hot become monocultures,
in which there are fewer
types of plants that are similar
in age.
Daryl Lutz, Wildlife
Management Coordinator for
Wyoming Game and Fish in
Casper, said that lack of fire is
creating overaged less useful aspen
and sagebrush stands.
“On mule deer summer range,
aspen communities are being lost
at an alarming rate due to natural
vegetative succession,” said Lutz.
The reason these habitats are being
lost is lack of fire.
“In an aspen stand, you can see
a vegetative response within one
or two years of a fire,” said Lutz.
But some plant communities do
not respond as quickly.
Lutz said, “In a sagebrush stand, it could be
up to twenty years.”
Lutz emphasized the importance
of creating patterns of
habitat.
“Whenever we do things in
sagebrush communities, we always
emphasize and tailor our prescriptions
to a mosaic of burned and
unburned,” said Lutz. “We’re
starting to evaluate how we should
be doing prescribed burning so we
don’t eliminate brood rearing or
nesting habitat for sage grouse,
and help other species.”
Ken Mayer of the California
Department of Fish and Game
emphasized the changes that
happen to a landscape over time
if small, cool, frequent fires are
replaced by large, hot, infrequent
fires.
"Hot fires burn minerals from
the soil, and you don't get the
regeneration you should," said
Mayer. This lessens the potential
of the site to be productive, and
ultimately results in long-term
changes to the habitat.
"In alpine communities, there is
about a three month growing season,"
said Mayer.
"In some of that
country, the snow doesn't come off
until July. The plants have a short
window to grow, and have adapted
to fires over a long period of time.
If you eliminate fire, then introduce
fire in a big way (a large, hot,
intense fire), it takes 10 years for
those plants to become useful for
mule deer again."
Kilpatrick echoed the consequences
of large, hot fires. “Mother
Nature says you can pay me now or
you can pay me later with interest,”
said Kilpatrick. “Suppressed fires will
be a lot larger, and the intensity and
severity will be greater when they do
burn. Wildlife love resprouting
shrubs. But fires that burn hot can
kill resprouting species of shrubs.
It’s quite a while before the
moonscape appearance disappears.
We’re exacerbating the situation
by our actions.”
Mule deer thrive in early
successional habitats, where
forbs, grassy plants and
shrubs dominate. These
environments are not as
stable as forest habitats, and
they rely on fire or some
other type of disturbance to
return them to an early
successional stage. If they
are not disturbed, they
eventually become more
stable plant communities
dominated by trees and large
shrubs. Tree-dominated
habitats offer mule deer a
place to retreat from severe
weather, but these areas
offer very little in the way of
food. That is why it is important
to provide mule deer
with a mosaic or pattern of
habitats that can provide
food, cover and water.
Arizona Game and Fish
Department’s Chief of Research
Jim deVos said large, hot fires
contribute to soil erosion.
“Another problem associated
with the catastrophic fires that are
occurring due to long-term fire
suppression is that virtually all of
the vegetation is lost, which
increases soil erosion,” said deVos.
“It is important to remember that
it took eons to build the top soil
layer, and its loss will alter the
lands’ ability to rebuild. Where
this occurs, the land may never
recover its capacity to support
wildlife populations as it did
before these incredibly
intense fires.”
To complicate matters, habitats
with plant species such as mountain
big sagebrush are experiencing
fires every 100 or more years
compared to pre-European settlement
fire frequencies of 12-25
years. Wyoming big sagebrush, a
habitat with large amounts of the
invasive plant, cheatgrass, is now
subjected to fires every 10 years
instead of every 50 to 100 years.
Drastic changes in fire frequency
may result in changes in the types
of plants found in a given area.
Kilpatrick said that drought
years compound the problem,
making it more difficult for
biologists to use prescribed fire.
“We’re using prescribed fire as
much as we can, but it’s more difficult
to use during these drought
years because of the risk factor,”
said Kilpatrick. “It takes someone
that can find the dotted line to say
they’ll be responsible for doing
prescribed burns in a risky situation.
But fires normally burn twice
as many acres in drought years.”
Kilpatrick said land managers
are behind the curve burning on a
landscape scale, especially compared
to the amount of land that
used to burn on an annual basis.
Kilpatrick said federal agencies
responded to the Yellowstone Fire
in the late 1980s with a strong
educational effort, but that habitat
change often occurs over the longterm,
oftentimes longer than the
life span of a human being.
“Fire was THE main player
forming the very landscape that
we cherish and want to protect
now,” said Kilpatrick. “People
realize it’s a dynamic system, be it
ever so slow. For example, aspen
needs a fire every 80-100 years.
People don’t see those changes
taking place in their lifetime. But
the public is accepting fire – they
just don’t want to see their homes
burned down.”
To avoid seeing homes burned,
people are willing to pay a steep
price. Suppression costs for wildfires
are easily three to five times
greater than the cost of prescribed
fire per acre. In the last seven
years, the cost of fire suppression
for federal agencies has ranged
from a low of $256 million in
1997 to a high of $1.36 billion
in 2000.
According to Kilpatrick, the
effects of fire suppression are
worsened because of habitat
fragmentation.
“You couple what has happened
with fire, and compound winter
range being used by urban sprawl,
and then our exploration and
development for oil and gas on
winter ranges – it’s fragmenting
habitat,” said Kilpatrick.
As a result of these interactions, Kilpatrick said emphasis should be placed on maintaining critical areas such as important winter ranges.
“We need to put as much
management effort on important
winter ranges, keep them unfragmented
in terms of oil development
and maintain high quality
forages,” said Kilpatrick.
Kilpatrick attributes increases
in predation with habitat fragmentation.
“When you fragment the
habitat, prey doesn’t have the
landscape to escape predators.
Predators have a much easier
time catching prey in reducedand fragmented habitat.” He said
the increased presence of predators
such as mountain lions in
suburbs is likely a direct result of
the wildlife habitat that has been
created at the urban interface.
"We’re so far behind the curve in terms of a landscape scale that we’ll never catch up with prescribed fire,” said Kilpatrick. “Nature will catch us up, as she has during a drought.”
Kilpatrick cautioned, “Don’t
blame the predators. They’re the
symptom, we’re the problem.”
Invasive Species –
A growing threat
What harms 15 percent of our
country's ecosystems, costs the
United States at least $137 billion
a year in lost profit and eradication
efforts, and includes a group of
about 7,000 species? The answer –
invasive species. While many are
found throughout the West, one of
the most harmful is the winter
annual grass called cheatgrass,
alias downy brome.
Cheatgrass found its way to the
United States from Europe and Asia
in the late 1800s on the backs of
livestock, and in some grain and hay
feed. By 1920, it firmly established
itself as a formidable invasive plant.
It is a plant species with few
endearing qualities. Cheatgrass is
not very nutritious or palatable to
livestock and wildlife, although
livestock will graze on it in some
desert habitats in the winter and
spring, and mule deer will browse
on it in early spring.
When cheatgrass is present,
livestock overgraze native plants,
causing direct competition with
mule deer for food. But that's not the
worst of it. Overgrazing by livestock
actually helps cheatgrass gain a
foothold, both on the overgrazed
land, and on nearby land where
invasive plants
may not have
existed.
What gives
cheatgrass the
ability to outcompete
native
plants? John
Grahame and
Thomas Sisk,
editors of "Canyons,
cultures and
environmental
change: An
introduction to
the land-use
history of the
Colorado
Plateau," a
publication
from the
Center for
Environmental
Sciences and
Education at
Northern
Arizona
University,
describe the
unique ability of cheatgrass to
outcompete native plants.
"Most native bunchgrasses of the
Colorado Plateau are perennial,
whereas annual plants like cheatgrass
grow from a seed, then flower,
set seed, and die every year.
Cheatgrass usually germinates in fall
and grows during winter, opposite
the cycle followed by common
native perennial grasses. By the time
the rain stops in spring, cheatgrass
already is maturing its seeds. Unlike
native bunchgrasses, cheatgrass then
dies by the end of July, avoiding the
hottest and driest part of summer.
"Dead cheatgrass burns easily,
causing early and abundant wildfires
which tend to damage or kill
native grasses. During a fire, earlymaturing
cheatgrass seeds can take
advantage of many nutrients the
fire releases to grow large and
produce abundant seed, over a
thousand per plant in some cases.
"Because cheatgrass quickly
develops a large root system in the
spring, by the time native grass
seedlings start to grow in April or
May, cheatgrass has stolen most
water out of the top foot of soil.
Although mature native grasses
can get water from lower soil
regions, seedlings cannot get their
roots deep enough into soil to
access water before drought sets
in, and thus, die of thirst. Without
this ability to reproduce, native
grasses inevitably decline, and so
over time, cheatgrass becomes
more and more common until
eventually it dominates. Cheatgrass
often opens the way for secondary
invaders such as knapweed
and thistle."
A strong invader like cheatgrass
poses two threats to mule deer.
Cheatgrass outcompetes native
perennial forage, and increases the
frequency and intensity of
wildfires, altering the quality of
sagebrush habitat.
When cheatgrass takes hold, it
can ultimately outcompete every
native plant, creating a monoculture,
or a stand of plants that
contain one or a few species.
Except for the brief period in
spring when new green shoots of
cheatgrass emerge from the soil,
stands of solid cheatgrass have
about as much benefit to mule
deer as a paved parking lot.
Cal McCluskey, Bureau of Land
Management (BLM) Senior Wildlife
Specialist, said cheatgrass is altering
large tracts of land in the West.
Vast stands of cheatgrass cause
frequent, large fires, much to the
detriment of mule deer habitat.
Intense frequent fires destroy
native shrubs such as antelope
bitterbrush, an important food for
mule deer.
What is being done about the
continued threat of invading
plants?
The BLM is taking aggressive
steps to learn more about the
spread of invasive plants and
large-scale landscape changes that
have occurred since European
settlement. And they're developing
new and different approaches to
combat nonnatives.
"Cheatgrass has created a
fire cycle that has altered
substantially the historical
fire cycle,” said
McCluskey. “It has
increased the frequency of
fires, and in many areas,
once the landscape gets
burned two or three times,
it often comes back in a
monoculture of cheatgrass,
just prime for burning
again and again."
McCluskey said the Columbia
River Basin and Great Basin are of
particular concern to the BLM.
"Those are the two ecoregions
that have had the greatest invasion
problems with cheatgrass and
other annuals like Medusahead,"
said McCluskey.
McCluskey said an effort is
underway in the BLM to get a
better handle on the extent of
change on the landscape within
the sagebrush ecosystem.
"We have a major effort underway
to look at sagebrush habitat
throughout its range, but particularly
as it relates to sage grouse,"
said McCluskey. “We're working
with the United States Geological
Survey to put together a map of
sagebrush for the entire West to
show current versus historical
distribution."
Other large-scale efforts are
underway, as well. The BLM is
leading the Great Basin
Restoration Initiative, an interagency
effort to restore areas
burned by fire. Reseeding and
changing grazing practices are two
possible restoration strategies.
"The catalyst for that initiative
was the bad fire year of 1991 in
the Intermountain West," said
McCluskey. "Several million acres
burned, some of which was significant
mule deer winter range."
Through the Great Basin
Restoration Initiative, the BLM in
Nevada is cooperating with state
and local agencies and nonprofit
organizations to restore and maintain
native plant communities, and
slow or stop the spread of invasive
plants on about 10 million acres of
public land.
McCluskey also talked about
the BLM being the biggest
landowner of sagebrush habitat in
the West, and the importance of
using fire to manage sagebrush.
"We have a major fire rehabilitation
program to go back into
areas that burn and reseed," said
McCluskey. "State wildlife agencies
provide the native seed and bare
root stock. We target the areas
with the highest probability
of success."
Reducing the size and frequency
of fires by creating fire barriers
such as green strips is another
effective strategy on the rise
in the BLM.
"We've had some success with
planting firebreaks using green
stripping. We're planting them
with perennial grasses that green
up later and stay green long after
the cheatgrass is cured," said
McCluskey.
The BLM has another tool
to fight invasive plants. Use of
chemicals such as pre-emergents
may prevent cheatgrass from
germinating, lessening its ability to
outcompete natives.
McCluskey emphasized there
is no one solution to control the
spread of cheatgrass, or to improve
habitats that have been invaded
by cheatgrass.
"It's a combination of treatments,"
said McCluskey. "There
is no panacea."
What does the future hold for
wildlife habitats? McCluskey said
it's important to look at what's
happening on a very large scale.
"We're caught between a rock
and a hard spot from our program
perspective,” said McCluskey.
“We're grappling internally with
this in our agency. There's this
Jeckyll and Hyde personality with
a minerals mission on one side
and a wildlife conservation
mandate on the other side." That
conflict makes land use allocation
and management very challenging.
Understanding how sagebrush
communities have changed over
time and the management actions
needed to restore these important
habitats are keys to lessening the
threat of invasive plants and
restoring lands critical to mule
deer survival.
Livestock management
Livestock management on western
lands could be characterized as
good, bad and ugly. Fortunately for
mule deer, there’s a whole lot of
good going on.
Utah Division of Wildlife
Resources Big Game Coordinator
Steve Cranney has seen elements
of all three on lands in and around
Utah and the West. But overall,
Cranney is very positive about using
cattle to manage wildlife habitat –
if it’s done correctly.
“From our standpoint, livestock
grazing has a lot of positives and
negatives,” said Cranney. “When you
do it right, it does have its use.”
Well-managed livestock grazing
can improve the types and quantities
of desirable plants, and maintain and
create much-needed openings in
dense habitat.
Cranney said his agency uses
intense spring grazing on a number
of wildlife management areas in big
game winter ranges to graze grasses,
and maintain and encourage growth
of mule deer browse species.
“In the spring, cattle concentrate
on the grass species, where the
succulence is in the vegetation,” said
Cranney. “Spring grazing encourages
the growth of browse species such as
sage and bitterbrush. The cattle are
on the ground only for a month to a
month and a half in the spring –
strictly in the spring.”
Cranney said he varies how he
uses cattle each year, depending on
the status of the habitat, and the
vegetation response he would like to
see. He said his agency would use
grazing even if it had the ability to
use fire at any time because several
plant species on deer winter range
don’t respond favorably to fire,
particularly sagebrush.
Cranney said, “We can’t just torch
all winter range areas. Some browse
species such as mountain mahogany
and oakbrush respond favorably to
fire, but sagebrush does not. How
bitterbrush responds depends on the
intensity of the fire. Spring grazing
can be a valuable tool on many
winter ranges.”
Cranney commented that spring
grazing has other benefits, as well. It
helps the local ranching community
while helping mule deer.
“We enter into agreements with
ranchers that help us,” said Cranney.
“Spring grazing is very valuable to
livestock people, too, because their
cattle have been on hay all winter,
and the ranchers are anxious to get
their cattle off their ground so they
can plant.”
Livestock grazing sounds like a
win-win-win situation for state
wildlife agencies, ranchers and
mule deer. The bad and the ugly
side come into play when livestock
are not managed properly.
Poor livestock grazing practices
can help spread invasive plants,
interfere with plant succession,
reduce nitrogen in the soil, and
change the plant community. And
improper livestock grazing in and
around riparian areas may harm
the stream and the rich diversity of
wildlife that thrive in these environments.
Overgrazing reduces
water quality, changes stream flow,
compacts and erodes soil, and
affects native plants and animals
that live alongside and in streams.
Tom Fleischner, in his 1994
Conservation Biology article, "Ecological costs of livestock grazing
in western North America,"
said that livestock grazing has had
"the most severe impact on one of
the biologically richest habitats in
the region," and states that, "much
of the ecological integrity of a
variety of North American habitats
are at risk” because of poor
grazing practices.
What kind of risk?
Cottonwood/willow forests along
arid western streams have declined
about 90 percent since pre-settlement
times. A 1988 report on "Restoring Degraded Riparian
Areas on Western Rangelands"
noted that "those narrow bands
of green adjoining rivers, streams,
and lakes, are crucial to the
ecological health of arid western
rangelands."
Cranney commented that cattle
do the most harm in riparian areas.
“If they’re not fenced out, then
they camp on it,” said Cranney.
“The woody species and stream
bank cover in riparian areas get
taken out.” Cranney said this can
be a serious problem, especially in
states like Utah that are dry, and
have limited riparian areas.
The good news is that the bad
and ugly can be avoided. How can
land managers manage livestock
grazing for the benefit of people
and wildlife? By establishing a
sound range management program
based on good range science and
tailored to the local area. A good
range management program
should have the following
elements:
1. Conduct prescribed burns to
improve plant quality.
2. Do not graze stressed rangeland.
3. Control the number of livestock
on rangeland to prevent overgrazing.
Some ranchers recommend
stocking at a rate less than
70 percent of average rainfall
carrying capacity.
4. Use rotation grazing to prevent
intensive spot grazing.
5. Fence riparian areas and provide
off stream watering sources.
Cranney said state of the art
wildlife management includes
managing riparian areas as
pastures with fence control.
“When the animals are in riparian
areas, they are there strictly to
benefit those areas,” commented
Cranney. “The areas are grazed
outside the fences.” This results in
better grazing in upland areas, and
minimal damage to streams and
riparian habitat.
Cranney said that sometimes the
best wildlife management practice
on winter ranges is not the most
aesthetic, and visa versa.
“You go to Salt Lake City where
cattle have been excluded for
decades and it looks good from a
watershed standpoint, very little
open bare ground, and yet it’s poor
for big game because there are few
browse species,” said Cranney.
“That’s why we concentrate on
winter range areas. In most of
Utah, the condition of winter
range and the amount of it
is critical.”
Cranney said one strategy his
agency uses to protect mule deer
winter range is wildlife easements.
Said Cranney, “Wildlife easements
leave the property in the
hands of the owners and allow
them to conduct operations compatible
with good wildlife management.”
He also noted the most
important aspect of wildlife
easements is that they prevent
subdivision of property into
small ranchettes.
“Subdividing is the biggest
enemy,” said Cranney.
Glenn Erickson, Chief of
Montana Department of Fish,
Wildlife and Parks Wildlife
Management Bureau, echoed
Cranney’s emphasis on keeping
large tracts of land in private ownership.
“We want to keep large,
connected adjacent blocks of land
in private ownership if we can.”
He said his agency places a
strong emphasis on working with
private landowners to improve
livestock grazing practices.
“We’re providing consultation to
landowners whenever they request
it,” said Erickson. “We have a couple
of people assigned full time to
deal with grazing systems, and we
have a couple of consultants that
we work with through Montana
State University. So there’s a big
resource of information we
provide.”
Erickson said his agency uses
livestock grazing to improve the
vegetation and soil on the state’s
wildlife management areas.
“We modify how livestock graze,
and where they graze,” said
Erickson. “We typically try to protect
riparian zones and manage vegetation
zones in the pastures. It’s a rest
rotation system, and the purpose
is to benefit the vegetation for
all species.”
Erickson commented that working
with private landowners can multiply
benefits to wildlife. “In some
cases, we have our management
area tied to adjacent private land,
and we’re able to expand the advantage
using a cooperative agreement,”
said Erickson. “The landowner
benefits and we benefit.”
Western wildlife agencies and
provinces will continue to place an
emphasis on positive working relationships
with landowners and livestock
managers to create mutually
beneficial programs that ultimately
enhance wildlife habitat for mule
deer and other species. In doing so,
land managers can assure that
proper livestock management will
continue to be a strong, positive
change agent for mule deer habitat.
