Wildlife Management: Issues Concerning the Management of Bison and Elk Herds in Yellowstone National Park

Published by the Government Accountability Office on 1997-07-10.

Below is a raw (and likely hideous) rendition of the original report. (PDF)

                    United States General Accounting Office

GAO                 Testimony
                    Before the Subcommittee on National Parks, Historic
                    Preservation and Recreation, Committee on Energy and
                    Natural Resources, U.S. Senate

For Release
on Delivery
Expected at
                    WILDLIFE MANAGEMENT
2 p.m. EDT
July 10, 1997
                    Issues Concerning the
                    Management of Bison and
                    Elk Herds in Yellowstone
                    National Park
                    Statement of Victor S. Rezendes, Director,
                    Energy, Resources, and Science Issues,
                    Resources, Community, and Economic
                    Development Division

Mr. Chairman and Members of the Subcommittee:

We are pleased to be here today to provide you with the results of the
work that we performed at your request on wildlife management issues at
Yellowstone National Park. As you know, Mr. Chairman, Yellowstone is
the world’s first national park. It is considered the “crown jewel” of our
National Park System, with about 2.2 million acres of land, over 3 million
visitors in 1996, and the largest concentration of free-roaming wildlife in
the lower 48 states. The controversy over the impact of these free-roaming
animals, especially the bison and elk herds, as well as their health, is the
subject of our remarks today. Specifically, our testimony will focus on
(1) the National Park Service’s current policy for managing free-roaming
bison and elk in Yellowstone, (2) the controversy surrounding the impact
of these herds on the park’s rangeland and riparian areas, and (3) the
controversy surrounding the risks to domestic livestock posed by
exposure to diseased bison and elk. As you know, Mr. Chairman,
interested parties hold widely divergent views on these issues.

In summary, we found that current laws and regulations provide park
managers with broad discretion on how to manage their park’s resources.
As a result, parks with similar wildlife resources, such as Yellowstone and
the neighboring Grand Teton National Park, can apply different
approaches to managing these resources. While Yellowstone uses “natural
regulation”—a policy that allows natural forces, such as climate, food
supply, and predation—to regulate the size of its bison and elk herds,
Grand Teton has established specific goals and objectives to control the
size of its bison herd.

Critics of Yellowstone’s natural regulation management policy—including
some scientists, state officials, and representatives of livestock
interests—believe that the policy’s implementation has produced bison
and elk herds that are too large and damage the park. In their view, the
park’s rangelands are being overgrazed; the riparian areas are being
damaged; and because these lands are being depleted, bison and elk are
migrating from the park in search of forage on private lands and public
grazing areas. According to the Park Service’s recently published studies,
however, researchers have found that Yellowstone’s grasslands are not
overgrazed, and several factors, such as climate, fire, and a lack of
predators, have contributed to the decline of the range and of the riparian
areas’ woody vegetation. In addition, park officials believe that bison are
leaving the park for a combination of reasons. Specifically, these animals
are nomadic by nature; they do not have access to sufficient forage during

Page 1                                                     GAO/T-RCED-97-200
             harsh winters, such as that of 1996-97; and, except in the northern range
             area, they can follow snowmobile trails out of the park. In addition, by
             allowing bison to avoid deep snow and thus conserve energy, snowmobile
             trails may also contribute to the growth in their numbers.

             The health of Yellowstone’s bison and elk herds is a major concern for
             livestock owners and public officials in the states bordering the park.
             Because many Yellowstone bison and elk are infected with brucellosis—a
             disease that can cause cattle to abort during pregnancy—these parties fear
             that the wild animals may transmit the disease to domestic cattle. A state
             with infected livestock may lose its federal brucellosis-free classification,
             jeopardizing its right to freely transport cattle across state lines. As a
             result, these parties believe that the risk of transmitting brucellosis from
             bison to domestic cattle must be eliminated by containing bison within the
             park, by using vaccines, or by shooting or capturing bison that leave the
             park. Because elk have a lower rate of infection than bison, the states
             currently differ in the methods they use to manage the disease in elk.
             However, according to the Park Service, the risk that brucellosis will be
             transmitted from either elk or bison to cattle is likely to be very low, and
             no such transmission in a wild, uncontrolled setting has been verified in
             the scientific literature. Furthermore, park officials maintain that existing
             vaccines have not been proven effective for bison and elk. Both the park
             and its critics have scientific evidence to support their positions. This past
             winter, the Yellowstone bison herd was reduced to about a half of its size
             the previous year. In the short term, this reduction may provide an
             opportunity for the Park Service and its critics to complete and assess the
             results of studies, potentially going a long way toward resolving this

             Yellowstone was created by an act of Congress in 1872 as a public park for
Background   the benefit and enjoyment of the people and for the preservation and
             retention of its resources in their natural condition. Yellowstone’s
             mandate, creating a dual mission to preserve natural resources while
             providing for the public’s enjoyment of them, has served as a model for the
             rest of the park system and for parks around the world.

             Yellowstone is at the center of approximately 20 million acres of land,
             commonly called the Greater Yellowstone Area or ecosystem. These lands
             are managed by four different federal agencies—the National Park Service,
             the Forest Service, the Fish and Wildlife Service, and the Bureau of Land

             Page 2                                                      GAO/T-RCED-97-200
Management (BLM); three different states—Idaho, Montana, and Wyoming;
and numerous private land holders.

The Park Service manages bison and elk only within Yellowstone. Outside
the park, the neighboring states of Idaho, Montana, and Wyoming manage
wildlife not only on their own lands but also on BLM and Forest Service
lands. Although the Forest Service manages wildlife habitat on its lands,
the states manage the wildlife. For example, in Gallatin National Forest,
the Forest Service manages wildlife habitat, while the Montana
Department of Fish, Wildlife, and Parks manages wildlife within the
forest’s borders. The Fish and Wildlife Service manages wildlife refuges,
such as the National Elk Refuge south of Yellowstone, and the Bureau of
Land Management manages land used by both wildlife and cattle in the
Greater Yellowstone Area.

This past winter, park officials estimated the size of the northern elk herd
at about 17,000 in Yellowstone and the total number of elk in the Greater
Yellowstone Area1 at about 120,000. The population of Yellowstone’s
northern range elk herd has ranged between 16,000 and 20,000 since 1991.
At the beginning of this past winter, about 3,500 bison lived within the
park, 900 of which occupied the northern range. Subsequently, about 1,100
bison left the park and were shot or shipped to slaughter because of
concerns about brucellosis. About 700 other bison were killed by the
severe winter, leaving approximately 1,700 bison in the park this spring,
including about 300 in the northern range.

For thousands of years, various animal species have routinely migrated in
and out of what is now Yellowstone National Park. Bison and elk herds
seasonally migrate out of the park to seek forage, especially in severe
winters like that of 1996-97. While elk have traditionally migrated widely in
the Greater Yellowstone Area, bison have more recently left the park,
primarily through its northern and western borders, to seek available
winter range. Appendix I illustrates the Greater Yellowstone Area elk
herds’ winter ranges and migration routes. Appendix II illustrates the
Greater Yellowstone Area bison herds’ winter ranges and migration routes

Because bison that migrate outside Yellowstone may be infected with
brucellosis and may interact or share rangeland with domestic cattle, the
U.S. Department of Agriculture’s Animal and Plant Health Inspection

The area includes Yellowstone and Grand Teton national parks and six national forests:
Beaverhead-Deerlodge, Bridger-Teton, Custer, Gallatin, Shoshone, and Targhee.

Page 3                                                                        GAO/T-RCED-97-200
Service (APHIS) and its state counterparts also have a strong interest in the
management of Yellowstone’s wildlife. APHIS is responsible for eradicating
brucellosis from cattle in the United States. According to APHIS, it also has
statutory authority to eradicate brucellosis in all animals—including bison.
Since a national brucellosis control program was first instituted in 1934,
more than $3.5 billion in federal, state, and industry funds have been spent
trying to eradicate the disease. According to APHIS, nationwide, only 22
herds of domestic cattle and bison are now known to be infected. The
states also play a major role in the effort to eradicate brucellosis. Because
federal statutes on controlling disease in livestock pre-empt the states’
authority only when cattle and bison are moving in interstate commerce,
most states have enacted their own statutes to supplement federal
regulatory efforts.

The Brucella abortus organism, a bacterium, is transmitted among animals
primarily through exposure to infected reproductive material, such as
aborted fetuses. APHIS tests cattle and bison for antibodies to the Brucella
abortus organism. Antibodies in blood samples may indicate either past
exposure to the disease or current infection. Positive tissue cultures for
Brucella abortus confirm the presence of live bacteria and the potential for
animals to be infectious. However, according to APHIS, negative tissue
cultures do not prove the absence of bacteria because the organism
cannot always be isolated even when it is present. After surveillance tests
and procedures are conducted to ensure that cattle and bison herds are
free of the disease, APHIS may certify states as brucellosis-free. This
certification allows the states to ship their cattle and bison in interstate
commerce without having to perform expensive testing to assure
importing states that the cattle or bison do not pose a threat of the disease
to their livestock industry. As of June 1997, Idaho, Montana, Wyoming, and
34 other states were certified as brucellosis-free.

The economic consequences of infection with brucellosis could be
significant. Under the requirements of APHIS’ eradication program, if a
single herd of cattle or bison in a state that is designated brucellosis-free
becomes infected, the infected animals must be slaughtered, the herd
quarantined, and the herds in the surrounding area tested to ensure that
the disease has not spread. If the herd is slaughtered and no additional
infection is found, the state can remain classified as brucellosis-free. If the
herd is not slaughtered or additional infection is found, the state’s
classification will be lowered and additional interstate testing
requirements implemented. Montana estimates that it saves between
$1 million and $2 million annually because it does not have to test cattle

Page 4                                                       GAO/T-RCED-97-200
                         for brucellosis. A state with infected cattle or bison may also be subject to
                         restrictions imposed by other states. For example, because of the
                         increased movement of brucellosis-infected and -exposed bison out of the
                         Greater Yellowstone Area, the state of Oregon decided in March 1997 to
                         protect the interests of its cattle industry by immediately requiring the
                         testing of any cattle entering Oregon from Montana or Wyoming. Other
                         states have imposed, or threatened to impose, similar restrictions.

                         The management of Yellowstone’s wildlife, especially of bison and elk, has
Yellowstone’s Wildlife   gone through many phases as wildlife managers have gained experience
Management Policy        and scientific knowledge has grown. When the park was founded in 1872,
                         there were numerous elk, estimated at 25,000 in 1891, and, according to
                         park officials, bison were also very common. However, no estimates of the
                         bison population exist for that period. After almost two decades of
                         slaughter by market hunters, the bison population in Yellowstone
                         dwindled to about 44 in 1901-02. Yellowstone officials saved the bison
                         from extinction by aggressively protecting the remnant population and
                         supplementing it with bison imported from Montana and Texas. For
                         several decades, Yellowstone also aggressively reduced the populations of
                         wolves and other predators. As a result, the park’s bison population
                         gradually increased, growing to more than 1,000 in 1930. However, from
                         about 1935 to 1968, park rangers controlled the elk and bison populations
                         by shooting or by trapping and removing animals. This “culling program”
                         reflected the then-prevailing view that wildlife populations had to be
                         controlled to meet an area’s carrying capacity—a determination of how
                         many animals can live in an area without degrading the range. In the early
                         1960s, however, elk kills initiated by park officials to reduce the size of a
                         herd that was considered too large, led to a public outcry, studies, and U.
                         S. Senate hearings on Yellowstone’s wildlife management policy. As a
                         result, in the late 1960s, Yellowstone’s wildlife management policy
                         changed significantly. According to park staff, although little information
                         was available on how functioning elk and bison populations might respond
                         in a natural environment, park managers thought that Yellowstone might
                         be a place to develop this knowledge and resolve the controversy over the
                         size of the herds by letting natural forces regulate the populations.
                         Therefore, in Yellowstone, natural regulation replaced the capture and
                         culling of elk and bison herds.

                         The park’s master plan, written in 1974, reflects the shift to natural
                         regulation, stating that “Yellowstone should be a place where all the
                         resources in a wild land environment are subject to minimal management”.

                         Page 5                                                      GAO/T-RCED-97-200
For wildlife, the plan proposes to reduce or eliminate disruptive human
influences, relying, whenever possible, upon natural controls to regulate
animal numbers. For the past 30 years, the Park Service has been
implementing natural regulation in Yellowstone, in essence, following the
park’s master plan. However, the Park Service recognizes that because of
the pervasiveness of human influences in today’s world, true natural
process management is seldom feasible. In the lower 48 states, the Park
Service believes that Yellowstone is the only park large enough to test the
effects of natural regulation.

At Yellowstone today, the Park Service relies on natural forces within the
park—mainly animal behavior, climate, food supply, and predation—to
regulate bison and elk populations. In addition, elk have always been
hunted in the surrounding states. More recently, bison have been killed
when they have migrated out of the park, and some public hunting of
bison has occurred in both Wyoming and Montana. However, in 1991,
Montana discontinued public hunting. According to park officials, once
humans stopped controlling the size of the herds and Yellowstone adopted
the natural regulation policy, the bison and elk populations increased
considerably. For example, from 1967 to 1988, the bison population rose
from 397 to more than 2,500 and then peaked at about 4,200 in the summer
of 1994. Yellowstone’s elk population grew about sixfold, from 3,200 in
1968 to about 19,000 in 1994. Park officials point out that without human
intervention, the low bison and elk populations of the 1960s would not
have occurred. They stated that these low numbers were achieved only by
large-scale reductions involving the slaughter of thousands of animals
each year. In addition, park officials noted that a key predator, the wolf,
was missing during this period. Wolves were reintroduced to Yellowstone
in 1995, and park officials believe time is needed to determine their impact
on the elk population.

Current laws and regulations give park managers broad discretion on how
to manage wildlife in the park. While an overall mandate of the Park
Service is to conserve wildlife, wildlife management policies can vary from
park to park, depending on the history of the park, the enabling legislation,
the neighboring land, and the local geography. For example, Grand Teton
National Park (330,000 acres), just south of Yellowstone (2.2 million
acres), has a different mandate, history, neighbors, and geography and has
adopted a different policy for managing bison and elk. Grand Teton
National Park’s legislation provides for hunting elk within portions of the
park and for grazing cattle—two uses that are not allowed in Yellowstone.
Hunting gives the park some direct control of elk populations, and the

Page 6                                                     GAO/T-RCED-97-200
                       presence of cattle adds management challenges and increases working
                       relationships with ranchers. The National Elk Refuge, which is adjacent to
                       Grand Teton, provides winter range and feed for both bison and elk, as do
                       22 feedgrounds operated by the state of Wyoming. However, feeding these
                       animals further complicates issues by concentrating their populations and
                       increasing the risk of disease transmission.

                       In Grand Teton National Park the bison herd grew from 16 in 1969 to
                       about 320 this past winter. Park officials said that at the conclusion of this
                       year’s calving season, the bison herd will number nearly 380. The growth
                       of the herd has raised a number of management concerns, including
                       questions about the need to set specific objectives for the herd’s size.
                       Grand Teton’s draft management plan states that the park could maintain
                       a free-roaming herd of about 200-250 bison without jeopardizing the
                       genetic viability of the herd. However, park officials say they are
                       considering public comments on the draft suggesting that the herd should
                       be maintained at 400 animals. To sustain the herd at the levels suggested,
                       the park has considered alternative management measures, which we
                       discuss at the end of this statement.

                       The condition of Yellowstone’s northern range2 has concerned the public,
The Controversy Over   land managers, and scientists for more than 70 years. Critics of the Park
the Impact of Bison    Service’s wildlife management policies—including some scientists, state
and Elk Herds on       officials, and representatives of livestock interests—believe large
                       populations of elk and bison have overgrazed Yellowstone’s available
Yellowstone’s Range    grasses and, in some cases, destroyed grasses that were once natural to
and Riparian Areas     the northern range. They contend that many of the natural grasses have
                       been replaced by nonnative agricultural grasses that better withstand
                       heavy use by wildlife. In addition, critics say that the large elk and bison
                       herds have damaged riparian areas. For example, the critics often cite
                       declines in woody vegetation, especially willows, aspens, and several
                       species of sagebrush in the Lamar Valley of the northern range, as
                       indications of the herds’ negative impact on riparian areas. The critics
                       contend that the destruction of the willows and aspens has reduced beaver
                       populations and accelerated soil erosion in streambeds. Finally, the critics
                       maintain that the bison herds have grown so large that they are naturally
                       migrating out of Yellowstone in search of forage that is no longer available
                       in the park because of overgrazing.

                        The northern range includes the valleys of the Lamar and Yellowstone rivers.

                       Page 7                                                                          GAO/T-RCED-97-200
According to the Park Service’s recently published compilation of 28
reports on research studies of the northern range, Yellowstone’s
grasslands do not appear to be overgrazed by any definition of
overgrazing.3 The studies were conducted during a 6-year period that
began in 1986 and concluded in 1991. The studies were researched and
written by a variety of scientists from several universities and agencies.
The researchers found that the production of grasses either was not
reduced or was enhanced by the grazing of ungulates (hoofed animals) in
all but drought years. The research shows that the decline in the range and
riparian areas’ vegetation was due to a number of factors, including
changing climatic conditions as well as grazing by elk. According to park
staff, the riparian plants are smaller in size but in no danger of
disappearing. Furthermore, the park report states the supposed declines in
beaver and white-tailed deer populations were based on inaccurate
historical interpretations. Park officials point out that beaver populations
persist in low levels on the northern range, while larger colonies live in
suitable habitat elsewhere in the park.

Park officials do not attribute the migration of bison out of the park to
overpopulation but to a combination of factors. First, bison migrate
because they are nomadic. Second, severe winter conditions can make
forage inaccessible beneath deep snow and ice, forcing bison to search for
forage elsewhere. Finally, park officials point out that except in the
northern range, Yellowstone has “groomed” or packed the snow on roads
for snowmobiling in the park since the early 1970s. These trails facilitate
the migration of bison out of the park and enable the animals to conserve
a great deal of energy by avoiding travel through deep snow. Park officials
said that access to more winter range for bison outside the park would
enhance their chances of survival in severe winters, but opponents think
that the herds should be reduced to numbers that can be supported within
the park. The park is currently reevaluating its policies on the use of
snowmobiles because of their effects on the environment and wildlife.

Both supporters and critics of the Park Service’s policies have scientific
evidence that supports their points of view. For example, the 6-year study
of the northern range addressed the population dynamics and ecological
effects of elk, bison, moose, deer, and other ungulates on the soil,
vegetation, and watersheds of the northern range. The research found that
the bunchgrass, swale, and sagebrush grasslands of the northern range did
not appear to be overgrazed. In riparian areas, willows were much taller in

  Effects of Grazing by Wild Ungulates in Yellowstone National Park, Department of the Interior,
National Park Service (Technical Report NPS/NRYELL/NRTR/96-01, 1996).

Page 8                                                                          GAO/T-RCED-97-200
some parts of the northern range in the late 1800s than currently, and
virtually no aspen have reached tree height since the 1930s. A study of
historical aspen growth found that there was only one period, between
about 1870 and 1895, when young aspen were not eaten by ungulates and
grew as tall as trees on the northern range. According to the park’s
summary report,4 the discovery that aspen reached full height during only
one period in the park’s history suggests that the failure of aspen to grow
into trees should not be regarded as proof that elk are overabundant.
Rather, the summary continued, several factors are involved in aspen
growth, including the number of elk, changes in climate, dry or wet
weather, fires, and the number of predators feeding on elk. Park officials
have called for more research on woody vegetation.

Critics of Yellowstone’s wildlife management policy disagree that factors
other than wildlife grazing are to any significant degree responsible for the
lack of robust woody vegetation on the northern range. They contend the
research program undertaken by the Park Service did not look for
evidence of overgrazing and was incomplete. They maintain, for example,
that park scientists have not documented a cause-and-effect relationship
between climate and the decline of willows. In addition, some critics
assert that independent research on range and riparian areas in the park
has been restricted by the park, which controls funding for research and
access to the park. For example, in February 1997, a researcher with the
Biological Resources Division of the U.S. Geological Survey testified
before the House Subcommittee on National Parks and Public Lands that
the park would not approve or fund his proposed research on woody
vegetation in the northern range or grant him a permit to work in the park.
Park officials said they denied the work assignment because of concerns
over the research design and the relevancy of the proposal to the work
priorities of both the park and the Biological Resources Division—then
known as the National Biological Service.

To support their position, critics often cite a 1990 dissertation by a Utah
State University researcher that linked the decline of riparian vegetation
directly to growth in the elk population. Park officials, however, state that
this study was based on a number of key assumptions about conditions in
the park during pre-European times. Park officials say they disagree with
the researcher on issues such as the number of Native Americans that
lived in Yellowstone and the impact they had on wildlife. Park officials

 Yellowstone’s Northern Range: Complexity and Change in a Wildland Ecosystem, National Park
Service, Yellowstone National Park (1997).

Page 9                                                                     GAO/T-RCED-97-200
                       added, however, that there is no scientific evidence available on either

                       Critics familiar with the principles of commercial range management for
                       the production of livestock believe that the number of grazing animals in
                       Yellowstone should be reduced to balance the available forage. They cite a
                       1963 survey of Yellowstone’s northern range conducted by what was then
                       the U.S. Department of Agriculture’s Soil Conservation Service. This
                       survey concluded that the range could support no more than 5,000 elk and
                       350 bison. According to the survey, populations of bison and elk in excess
                       of these numbers would cause severe damage to the range and riparian
                       areas. However, park officials said that the 1963 survey used commercial
                       standards for domestic livestock to assess the park’s carrying capacity.
                       According to park officials, they and other leading wildland ecologists
                       believe these standards should not be applied to wildlife.

                       A Forest Service official at Gallatin National Forest, which borders
                       Yellowstone on the north and west sides of the park, also believes that a
                       commercial carrying capacity cannot be set for wildlife. According to this
                       official, Gallatin National Forest does not develop carrying capacity limits
                       for wildlife because the Forest Service cannot control when wildlife come
                       or go on the land. Gallatin National Forest does develop carrying capacity
                       limits for cattle because the Forest Service can control where and when
                       cattle graze on its land. The official noted that cattle use only that portion
                       of the forage that is not required to support wildlife.

                       To help resolve the rangeland controversy, the House Committee on
                       Appropriations, in its July 1997 Committee Report on Interior’s 1998
                       appropriation, directs the Park Service to initiate a review by the National
                       Academy of Sciences of all available science related to the management of
                       ungulates and their ecological effects on the rangeland of Yellowstone.

                       The extent to which domestic cattle risk infection through exposure to
The Controversy Over   diseased bison and elk—either from mingling directly with infected wild
the Risk of            animals or from using rangeland where infected wild animals have
Transmitting           previously grazed—is the subject of intense controversy between the Park
                       Service, wildlife management agencies, wildlife conservation groups,
Brucellosis From       livestock interests, Native Americans, and others. Yellowstone National
Bison and Elk to       Park, under its interpretation of natural regulation, allows natural
                       processes to control wildlife populations and opposes efforts to manage
Cattle                 wildlife in a way that conflicts with natural regulation or restricts wild

                       Page 10                                                      GAO/T-RCED-97-200
animals’ free-roaming nature. APHIS, however, is committed to eradicating
brucellosis in the United States and believes that wildlife should be tested
and, if infected, slaughtered to prevent the disease from spreading further.
APHIS maintains that the techniques developed through its 63-year-old
eradication program for domestic livestock can be applied to eliminate
brucellosis in wildlife.

In Yellowstone, blood tests indicate that 40 to 54 percent of the bison and
about 1.5 percent of the elk from the northern range carry antibodies to
Brucella abortus. Some of the elk from the northern range migrate to
Montana for the winter. Other elk migrate to Wyoming for the winter and
use the federal National Elk Refuge or the state’s 22 feedgrounds to
supplement their food base. On average, about 38 percent of the mature
cow elk using the National Elk Refuge’s feedground have had positive
blood tests for brucellosis antibodies. Positive blood tests indicate that an
animal is infected with or has been exposed to brucellosis. On the one
hand, a positive test does not necessarily indicate that an animal is
infectious; on the other hand, a negative test does not exclude the
possibility of infection, because the blood of some animals that are
infected does not react positively to the test.

In addition to blood tests, tissue cultures are performed to detect the
presence of brucellosis. Although tissue cultures are a much more reliable
method of identifying active infection, they also will not identify all
infected animals. The rate of current infection as determined by tissue
cultures is always lower than the rate of positive blood tests because
Brucella abortus cannot always be cultured from infected animals. For
example, an ongoing analysis of samples from 41 bison killed during the
winter of 1996-97 showed that the blood tests for 30 females were positive.
For 18 of these 30, tissue cultures have been completed and the results
were positive for only 7. According to Wyoming officials, research with elk
have suggested a higher correlation between positive blood tests and
positive tissue cultures.

According to Park Service officials, in the scientific literature, there is no
documentation of brucellosis transmission from elk or bison to cattle in a
wild, uncontrolled setting. Furthermore, although the risk of such
transmission has never been quantified, the Park Service maintains that it
is likely to be very low. Hence, park officials believe that testing and
slaughtering infected wildlife to eradicate a potential source of infection
for cattle is not necessary in Yellowstone and could result in the
unnecessary slaughter of bison and negatively affect the genetic viability

Page 11                                                      GAO/T-RCED-97-200
of the herd. Park officials also object to the use of vaccines that were
developed and tested for cattle but have not been proven effective for
bison. They contend that the untested vaccines may be ineffective and/or
unsafe for the herds and other wildlife that may come into contact with
them. Park officials also question whether the disease can be eliminated
from wildlife. For example, they note that the disease may be impossible
to eliminate from bison because elk and other mammals can carry
brucellosis, which could then find its way back into bison. Unless
brucellosis is eliminated from all of these mammals, park officials and
others have stated, some chance remains that the disease will be
transmitted back to the bison.

According to APHIS officials, in several cases of brucellosis, wild elk or
bison have been identified as the source of transmission. These officials
believe that any risk is unacceptable in an eradication program. In
addition, they refer to several other parks where the disease has been
eliminated from bison and elk. However, APHIS officials agree that vaccines
need to be tested and proven to be safe and effective before being used on
elk and bison.

During our review, we visited two of the three states that surround the
park—Montana and Wyoming. Both states are concerned about the
potential for the transmission of brucellosis between wildlife and cattle.
However, each state approaches this problem differently. For example, the
state veterinarian in Montana believes that no risk is acceptable because
transmission would threaten the states’ brucellosis-free certification from
APHIS. In December 1994, APHIS wrote a letter to Montana setting forth its
intention to downgrade the brucellosis-free classification of the state if the
state failed to take action against bison within its borders that were known
to be infected with or had been exposed to the disease. As a result,
Montana officials believe that they have no alternative but to slaughter
bison that move into the state. Montana officials stated that they are not
addressing the disease in elk because the rate of infection in elk is low. In
the long term, Montana officials said, they plan to take action to eradicate
the disease in elk. Wyoming, which has fewer bison than Montana but a
much higher incidence of brucellosis in elk, has tried to manage the risks
of exposure to the disease while implementing a long-term program to
eradicate it. For example, in the Jackson area, Wyoming has worked with
federal agencies and private landowners to develop policies for separating
cattle from bison and elk to minimize the risk of transmission. Also, many
of the ranchers in the Jackson area voluntarily vaccinate their cattle.

Page 12                                                     GAO/T-RCED-97-200
                             Both Montana and Wyoming officials believe that the vaccines they have
                             used successfully with domestic cattle could be applied to the park’s bison
                             and elk herds. They and APHIS noted that the vaccine, combined with
                             efforts to test and slaughter infected animals, has been used successfully
                             on bison herds on private and other public lands. Finally, some experts
                             believe that even if brucellosis remains in “other mammals,” the disease
                             would naturally decline and be eliminated from other wildlife because the
                             carriers would not be able to transmit it to other animals.

                             Scientific data on both sides of the brucellosis debate are limited.
                             According to the Park Service, neither it nor APHIS has performed or
                             sponsored many scientific studies on the transmission of brucellosis
                             among elk and bison or on the development of vaccines against the
                             disease. Recently, however, the park, APHIS, and others have initiated an
                             ambitious series of studies on brucellosis in bison to obtain answers
                             needed for making future management decisions.

                             Critics of the park’s position on brucellosis derive support for their views
                             from the biological similarities between bison and cattle and data
                             developed through APHIS’ program for eradicating the disease in domestic
                             livestock, including bison. Some critics do not believe that they are
                             responsible for conducting additional research on brucellosis in wild
                             bison. However, since the late 1970s, Wyoming, with technical and
                             financial assistance from APHIS, has sponsored a number of studies on the
                             disease in elk. For example, the state sponsored research to determine the
                             effectiveness of a reduced dosage of one type of cattle vaccine in elk and
                             is testing the effectiveness of injecting the vaccine through the use of a
                             “biobullet” shot from an air gun.

Current Efforts to Control   Various federal, state, and private groups are conducting many research
Brucellosis                  studies and planning efforts to control or eradicate brucellosis in
                             Yellowstone wildlife. In discussing the controversy surrounding this issue,
                             one official described it as a war. Another official stated that the federal
                             and state representatives are so entrenched in their positions that no one
                             wants to be the first to compromise. He added that meetings on this issue
                             have become so heated that a fight once broke out between participants.

                             Recognizing the need to coordinate the work on brucellosis in the region,
                             in July 1995, the states and responsible federal agencies established the
                             Greater Yellowstone Interagency Brucellosis Committee. This interagency
                             committee includes representatives of the states surrounding the park, the

                             Page 13                                                    GAO/T-RCED-97-200
four federal land management agencies, and APHIS. The committee has
agreed on the objective of planning for the elimination of brucellosis by
the year 2010. However, the states and agencies disagree on the current
feasibility of eliminating the disease, the actions needed to eliminate it,
and the effect of the disease on wildlife or on the livestock industry if it is
not eliminated. Although members are generally very supportive of the
committee’s efforts, they agree that achieving results has been difficult
even when issues are generally agreed upon. For example, a paper
summarizing generally accepted information on brucellosis underwent 12
revisions over 22 months before it received final approval.

Despite these difficulties, members of the interagency committee believe
they are slowly making strides towards coordinating policies and
addressing scientific data needs. For example, the committee has
completed a policy on elk feedgrounds, produced an informational report
on the potential for brucellosis transmission by bull bison, developed a
bison quarantine protocol, and conducted a national symposium on
brucellosis in the Greater Yellowstone Area. Among its current activities,
the committee is coordinating a joint effort by the park, the state of
Montana, APHIS, and the Forest Service, as well as three cooperative efforts
in Wyoming.

Since 1989, Montana and the Park Service have been meeting to develop a
long-term plan for managing the brucellosis-exposed, free-roaming bison
that move primarily during the winter from the park to public and private
lands in Montana along the northern and western boundaries of the park.
The first goal of this effort was to issue a long-term plan and an
environmental impact statement (EIS) by December 1991. In a May 1992
Memorandum of Understanding, the Forest Service and APHIS joined this
effort. However, as negotiations have continued on ways to better manage
brucellosis in bison, many deadlines for completing this effort have come
and gone. In the interim, Montana filed a complaint in January 1995 in
federal district court contending that the conflicting policies of APHIS and
the Park Service threaten Montana’s brucellosis-free certification. To
settle the lawsuit, Montana, the park, and APHIS agreed to develop interim
bison management procedures to prevent the potential spread of
brucellosis from bison to domestic cattle. The August 1996 interim plan
was implemented over the last winter and remains in effect. Where cattle
graze in Montana, the interim plan has no tolerance for bison. As a result,
about 1,100 bison were shot or captured and slaughtered last winter. The
procedures do allow bison to use adjacent federal lands where cattle
either do not graze or are not present when bison are in the area. Early

Page 14                                                       GAO/T-RCED-97-200
this year, to move forward on the long-term plan, the Park Service
committed staff from its field area office to assist in preparing both
documents. The park and the state are committed to issuing a draft
management plan and an EIS for public comment in July 1997 and to
completing final products by March 1998. In June 1997, the state, APHIS, the
Forest Service, and the Park Service agreed upon a preferred alternative
for managing brucellosis and Yellowstone’s bison population. Generally,
the alternative provides for the capture and shipment to quarantine of
animals testing negative for brucellosis. These animals would then be
made available to Native American tribes to help establish herds. The
alternative also provides for the capture of bison to control their
movement onto private lands; the hunting of bison in certain situations;
the vaccination of bison when a vaccine is developed for them; and the
acquisition of additional winter range outside the park when such range
becomes available for purchase from willing sellers.

Three separate ongoing cooperative efforts are addressing brucellosis
issues in the area south of Yellowstone Park. First, Wyoming has been
working with APHIS, the Park Service, the Fish and Wildlife Service, and the
Forest Service since December 1995 to develop an interim brucellosis plan
for elk and bison. The goal is to design a plan that will maintain the state’s
brucellosis-free classification, reduce damage to private property, and
sustain the free-roaming bison and elk herds. Last November, the agencies
received public comments on a draft plan, which they are now analyzing.

A second effort is being conducted by Grand Teton National Park and the
National Elk Refuge, in cooperation with the Wyoming Game and Fish
Department and Bridger-Teton National Forest, to develop a long-term
management plan for the Jackson bison herd. The plan’s goal, in part, is to
minimize the potential for transmitting brucellosis among bison, elk, and
domestic livestock. A draft plan and environmental assessment were
published in September 1996, public comments were received, and a final
plan is expected in August 1997. To reduce the risk of transmission among
bison, elk and cattle, the draft plan proposes measures such as baiting or
feeding the bison for a limited time to keep them from migrating onto the
National Elk Refuge, separating bison from elk and cattle when the
potential for transmission is greatest, vaccinating cattle, using a vaccine on
bison when one is developed for them, and developing disease
transmission risk assessments to use as the basis for wildlife management
programs. The plan would also allow small public bison hunts outside the
park and make some bison available to Native Americans.

Page 15                                                     GAO/T-RCED-97-200
               A third effort, led by the Wyoming Game and Fish Department, is to
               develop brucellosis management action plans for each of the state elk
               herds and the surrounding range used by cattle. The objective is to
               develop plans that minimize the potential for transmitting brucellosis
               among elk, and from elk to cattle, by reducing the animals’ overlapping
               use of rangeland and conducting other actions designed to ultimately
               eliminate the disease.

               Finally, at the request of the Secretary of the Interior late last winter, the
               National Academy of Sciences’ Commission on Life Sciences agreed to
               review the scientific data on brucellosis contained in published studies in
               the fields of wildlife ecology, epidemiology, zoonotic diseases,5 infectious
               disease control, animal physiology and health, and veterinary science. The
               review is to examine the scientific issues surrounding the transmission of
               brucellosis among wild and domestic animals, especially among bison and
               cattle; determine the extent of infection in wild herds; and identify the
               additional research that is needed on these subjects. Specific questions
               include, among others, the relationship between blood tests and the ability
               of animals to transmit the disease, the effectiveness and safety of vaccines,
               and the impact of various risk reduction measures. The study is due to be
               published by October 1997.

               The impact of Yellowstone’s bison and elk herds on the park’s range and
Observations   riparian areas and the potential for these animals to transmit brucellosis to
               cattle are highly controversial, sensitive, and emotional issues for the
               affected parties. Scientific and historic data on some aspects of these
               issues are limited, and when agreement does exist, the data are often
               interpreted differently, reflecting differences in people’s values and in
               agencies’ mandates and missions. Many questions will need to be
               answered before these concerns can finally be resolved. For example, how
               will the reintroduction of the wolf in Yellowstone affect the size of the elk
               herd and, subsequently, the park’s woody vegetation?

               This past winter, the slaughter of bison that migrated out of the park,
               combined with the winter kill, reduced the bison herd to about half of its
               size the previous year. In the short term, this reduction may limit the
               migration of bison from the park, relieve some of the immediate pressure
               on the Park Service to take management actions, and create an
               opportunity for the Park Service and its critics to complete and assess the
               results of studies such as the National Academy of Sciences’ review of

                These are animal diseases that can be communicated to humans.

               Page 16                                                          GAO/T-RCED-97-200
brucellosis issues. The results of these studies are needed to make
informed management decisions.

This concludes my statement, Mr. Chairman. I would be happy to respond
to any questions you or other Members of the Subcommittee may have.

Page 17                                                   GAO/T-RCED-97-200
Appendix I

Winter Ranges and Migration Routes of the
Greater Yellowstone Area’s Elk Herds



                                                    Herd                          NATIONAL


                                                                          Gardiner              FOREST
                                                                                                               Cooke City

                                                                                                                              Clark’s Fork
                     NATL. FOREST

                                                                              Madison-                                           North Fork
                                                                              Firehole                                           Shoshone Herd

                                             TARGHEE               YELLOWSTONE
                                                                   NATIONAL                                     NATIONAL
                                                                   PARK                                                                      Carter Mt.
                      Sand Creek                                                                                                             Herd
                      Herd                                     NATIONAL

                                           St. Anthony

                                 Rexburg                                  NATL.
                                                                                               Jackson Herd


                      20 km
                     (12.4 mi)

                         Winter range
                         Elk northern range
                         Migration route

               Source: Yellowstone Center for Resources, Yellowstone National Park, National Park Service.

               Page 18                                                                                                         GAO/T-RCED-97-200
Appendix II

Winter Ranges and Migration Routes of the
Greater Yellowstone Area’s Bison Herds

                                                                                  GALLATIN                        CUSTER
                                                                                  NATIONAL                        NATIONAL
                                                                                  FOREST                          FOREST
                                                                            ➤     Gardiner
                                                                             ➤                    Montana
                                                                                          ➤          LamarValley
                                                           Hot Springs
                                                               YELLOWSTONE NATIONAL


                                             West        ➤
                                                                                                                    East Entrance



                                                            Old                            Yellowstone
                                                            Faithful                                                SHOSHONE


                                                                                   South Entrance

                                                              GRAND TETON
                                                              NATIONAL PARK

                                                                                   NATIONAL ELK          N
                                                                                                  W          E

                                                                                    10            0          10    20 Miles

                           Bison winter range
                           Migration route

               Source: Spatial Analysis Center, Yellowstone National Park, National Park Service.

(141012)       Page 19                                                                                                        GAO/T-RCED-97-200
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