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Conservation and management of ungulates in North America



The North American Model of Wildlife Conservation had its genesis, in part, with the conservation of native ungulates. Thus, it is important to understand what these species are and how they have been and are, currently, managed. Ungulates are hooved quadrupeds that include those that are odd-toed (e.g. tapirs [Tapirus bairdii]) and even-toed (e.g. deer). Contemporary management of the ungulates evolved through three stages: exploitation, concern for survival and conservation through wise use. The success of conservation of ungulates has been attributed to the merger of biology, an understanding of habitat and the role of human dimensions. This triad of wildlife management has been effective. Most ungulate populations in North America have been restored; viable populations exist. Challenges to the conservation of large mammals remain, however, including increased human population growth, climate change and sources of funding.
Conservation and management of ungulates in
North America
yBoone and Crockett Program in Wildlife Conservation, Wildlife Biology, University of Montana,
Missoula, MT 59812, USA; zDepartment of Biological Sciences, Idaho State University, Pocatello,
ID 83029, USA
The North American Model of Wildlife Conservation had its genesis, in part, with the conservation
of native ungulates. Thus, it is important to understand what these species are and how they have
been and are, currently, managed. Ungulates are hooved quadrupeds that include those that are
odd-toed (e.g. tapirs [Tapirus bairdii]) and even-toed (e.g. deer). Contemporary management of the
ungulates evolved through three stages: exploitation, concern for survival and conservation through
wise use. The success of conservation of ungulates has been attributed to the merger of biology, an
understanding of habitat and the role of human dimensions. This triad of wildlife management has
been effective. Most ungulate populations in North America have been restored; viable populations
exist. Challenges to the conservation of large mammals remain, however, including increased
human population growth, climate change and sources of funding.
Keywords: Conservation; Management; North America; Ungulates
North American ungulates
Ungulates are hooved quadrupeds belonging to two Orders: Perissodactyla, which are
odd-toed ungulates (e.g. horses [Equus spp.], rhinoceroses [Rhinoceros spp.], and tapirs
[Tapirus bairdii]), and Artiodactyla, which are even-toed ungulates (e.g. pigs, deer and
pronghorn (Antilocapra americana). Only one native ungulate of the Order Perissodactyla,
the tapir, occurs in North America (i.e. Mexico). Other native ungulates in North America
are in the Order Artiodactyla, which includes 10 recent families, 86 genera and 221 spe-
cies throughout the world. Although Artiodactyls are not native to the West Indies, New
Guinea, Australia, New Zealand, Antarctica or most oceanic islands [1], some ungulates
have been translocated to these areas. Groups of the living Artiodactyla are provided by
Nowak [1] and include pigs, peccaries (Pecari spp.), hippopotamuses (Hippopotamus
spp.), llamas (Lama spp.) and camels (Camelus spp.), mouse deer (Tragulus spp.), giraffes
(Giraffa spp.), musk deer (Moschus spp.), deer, pronghorn, antelopes, bison, cattle, goats
and sheep.
Artiodactyls native to North America include collared peccaries (Pecari tajacu),
white-lipped peccaries (P. pecari), elk (Cervus canadensis), mule or black-tailed deer
*Corresponding author. Email:
International Journal of Environmental Studies, 2013
Vol. 70, No. 3, 372382,
Ó2013 Taylor & Francis
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(O. hemionus), white-tailed deer (O. virginianus), moose (Alces alces), caribou (Rangifer
tarandus), brown brocket deer (Mazama gouazoupira), red brocket deer (M. americana),
pronghorn, American bison (Bos bison), mountain goat (Oreamnos americanus), muskox
(Ovibos moschatus), mountain sheep (Ovis canadensis) and Dalls sheep (O. dalli). Exotic
species (i.e. those that are non-native) that have been introduced to North America include
feral ass (Equus asinus) and feral horse (E. caballus), which are odd-toed ungulates.
Additional exotic ungulates are members of the Order Artiodactyla, including feral pigs
(Sus scrofa), axis deer (Axis axis), sika deer (C. nippon), sambar deer (C. unicolor), nilgai
(Boselaphus tragocamelus), gemsbok (Oryx gazelle), blackbuck (Antilope cervicapra),
Himalayan thar (Hemitragus jemlahicus), ibex (Capra ibex), European mouon sheep
(O. aries), Barbary sheep (Ammotragus lervia) and others. Many of these exotics from
Asia and Africa have established free ranging populations in the southwestern USA and
As a result, there are numerous problems for native species including competition for
natural and nancial resources, the transfer of diseases, displacement of native species,
alteration of habitats, altered genetic makeup of native species via interbreeding, and crop
damage. Additionally, exotic species often promote commercialization, which can jeopar-
dize conservation of native species [2].
Pronghorn are the only ungulate endemic to North America and numbers once were
similar to, or even exceeded, those of the American bison (e.g. millions). All native Artio-
dactyla, however, have received considerable attention from biologists and wildlife manag-
ers in North America for numerous reasons. Those ungulates were hunted and used for
food and clothing by the early Europeans that settled North America, and the early Euro-
peans also used ungulates to pay debts to the Crown for their journey to the New World
by sending hides to Europe as payment. Ungulates were also conspicuous among the spe-
cies that North Americans saw disappearin their lifetimes due to unregulated market
hunting and a lack of management. They were also the group of animals that led early
conservationists to initiate actions to prevent the further demise of all wildlife [3], which
was the beginning of wildlife management in the USA and led to the beginning of the
North American Model of Wildlife Conservation.
Pre-european status of ungulates in North America
Although modern wildlife management began in North America, the roots of the profes-
sion can be traced back to the Old World with chronicles indicating that big game (i.e.
large mammals, which includes ungulates) were particularly important [4] to human beings
for food, clothing and other necessities of life. Numerous practices and policies of modern
management can be traced back to founding European cultures but none of them included
the ‘… organized efforts to protect, wisely use, or deliberately control wildlife populations
and habitats for the societal benets now associated with wildlife conservation and man-
agement[4:293]. There were efforts to protect and wisely use wildlife but the use of wild-
life was for societys leaders instead of for the general population.
Our current management system evolved through three general stages that began with
the arrival of European immigrants in North America. As Europeans entered the New
World, they were met with abundant resources that they exploited with no concern for
conservation. Over time, unregulated harvesting led to concern, outrage and the demands
by sportsmen and other visionaries to stop overexploitation of wildlife and protect the
Conservation and management of North American ungulates 373
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remaining stocks. The nal stage was the rise of conservation and associated efforts to pro-
tect and conserve big game and the habitats they depended on. This effort led to conserva-
tion and management for all wildlife [4].
North America was vastly different prior to the arrival of Europeans and their inuence
on big game was dramatic. Prior to the arrival of settlers, the exact numbers of big game
were not known but chronicles and estimates by early naturalists placed numbers up to 10
times higher than today. For example, in pre-settlement times, there were estimated to be
13 million mule and black tailed deer, 500,0002,000,000 mountain sheep and up to mil-
lions of bison, elk and pronghorn [5,6] in North America. Recent estimates place numbers
at <5,000,000 mule deer, >14,000,000 white-tailed deer, 71,000 mountain sheep, 500,000
bison (including bison-livestock hybrids) and 1,000,000 elk and pronghorn [5,6]. Current
numbers are the result of aggressive conservation and management over the past century.
Changes with the arrival of Europeans
There are three general stages of conservation that occur for most imperiled species:
exploitation, concern for their survival and nally conservation through wise use. Several
examples of a species moving through the three stages of conservation exist, and perhaps
the best-known example is the American bison. Bison occurred throughout most of the
USA and the slaughter began east of the Mississippi River and led to the extermination of
the bison in that area by 1830. From 1720 to 1830, the large herds on the plains were
essentially untouched until a variety of factors led to increased human use of the Great
Plains: the gold rush of 1849, the homestead laws of 1862 and the incursion of railroads
in the 1860s attracted more people to the west. The additional human population created
large commercial opportunities to provide fresh and dried meat, tallow, tongues, robes,
chips (manure), sinews and an overwhelming market for bison hides [7].
The bison was attractive for human use: it was large (<1,000 kg), had excellent meat,
was easily killed with ries, provided an excellent robe and hide and the hair was useful
for insulation. They were nearly extirpated over a short period. Their decimation proceeded
rather slowly at rst but the real destruction began around 1830 and was complete in
50 years.
The near extirpation of bison was much more rapid in the western USA when com-
pared to that in eastern North America. Bison hunting expeditions began in 1820 using
Native Americans. In 1840, a single expedition included 1,210 transport carts, 620 Native
Americans and hunters, plus women and children. When the railroads came they adver-
tised the game, split the herds and began the rapid elimination of large populations. From
1872 to 1874, white hunters killed 3,158,730 bison. Native Americans killed about
390,000 and settlers an estimated 150,000 bison. Five thousand hunters and skinners
shipped about 200,000 hides in 1882, but went out of business the following year when
they shipped only 300 hides. By 1889, there were only remnants left of the North Amer-
ican population and only 200 bison in Yellowstone National Park, USA [8]. When the
Cree and white hunters moved up the Cannon Ball River in North Dakota to hunt the
last large herd of bison they ended a chapter of American history started only a few
years before [8]. It was at this time that private individuals, and later visionaries, like
Theodore Roosevelt, George Bird Grinnell, and Gifford Pinchot, and budding conserva-
tion organizations such as the Boone and Crockett Club, intervened and prevented the
total elimination of bison [9]. That effort began with the conservation of the species,
374 P.R. Krausman and V.C. Bleich
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which continues with plans to expand their range throughout Canada, the USA and
Mexico [10,11].
Pronghorn are another very good example of an ungulate that declined sharply and rap-
idly as a result of habitat alteration and human exploitation, but has recovered substantially
as a result of intensive efforts to conserve and manage them [12]. White-tailed deer and
mule deer similarly have recovered from low-levels resulting from overexploitation or hab-
itat modication [13,14]. Management and conservation have led to recovery of most spe-
cies of big game in North America, the majority of which went through similar reductions
in numbers; recovery was only possible with scientic management that started with the
elimination of outright slaughter.
Beginnings of wildlife conservation in North America
Wildlife conservation had its beginnings in Canada and the USA in the late 1800s [9], but
Mexicos conservation efforts began later. There is a diversity of ungulates in Mexico
including mule and white-tailed deer, brown and red brocket deer, collared and white-
lipped peccaries, tapirs, mountain sheep and pronghorn. Mexico had a longer history of
land exploitation than either Canada or the USA. Prior to the arrival of Spaniards in 1521,
the Mayan Indians practised intensive agriculture, cleared forests, and harvested plants and
animals, all of which destroyed wildlife habitats and locally depleted wildlife populations
[15]. Environmental impacts increased with the arrival of Spaniards as they mined precious
metals, harvested timber, introduced livestock and ranching, enhanced intensive agriculture
and continued with the largely unregulated exploitation of wildlife and sh [16]. With the
introduction of livestock, rangelands were overused and wildlife habitat was transformed,
which continues today [15]. In addition, there has been a continuous alteration of land use
laws in Mexico, resulting in limited incentives for conservation and a national attitude that
did not consider wildlife an economically sustainable resource until recently. Conservation
efforts are rapidly gaining ground in Mexico, and the Wildlife Conservation and Produc-
tion Diversication in the Rural Sector, initiated in 1997, is the most ambitious wildlife
management initiative in Mexico to date [15]. Mexicos new conservation ethic is bene-
cial to all wildlife in North America.
Objectives of conservation
The term conservation was popularized by Theodore Roosevelt, who proposed that
renewable natural resources, such as wildlife, forests, ranges and waterpower, if harvested
sustainably and not faster than they can reproduce, could last indenitely [17:17].
Conservation is, perhaps, best dened as what Roosevelt referred to as wise useof those
natural resources [9:20], a denition that has persisted in the eld of wildlife management
for many decades. Gabrielson [18] identied three primary obstacles to conservation: short-
sightedness of the human race; the tendencies to seek panaceas rather than real remedies;
and lack of knowledge and understanding. Much progress has been made in overcoming
these obstacles in North America but many challenges remain. Indeed, six North American
ungulates (i.e. Sonoran pronghorn (A. americanus sonoriensis), peninsular pronghorn
(A. a. penninsularis), Nelsons bighorn sheep (O. canadensis nelsoni) in the Peninsular
Ranges of California, USA, Sierra Nevada bighorn sheep (O. c. sierrae), woodland caribou
Conservation and management of North American ungulates 375
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(R. tarandus caribou) and Columbian white-tailed deer (O. virginianus leucurus) have been
afforded protection by the Endangered Species Act (ESA) in the USA, and woodland cari-
bou is afforded protection under Canadas Federal Species at Risk Act (SARA). Further,
land use changes including urbanization, agricultural conversion, oil or gas development,
and alternative energy projects continue to destroy, modify or fragment habitats upon which
ungulates depend for their existence [19]; habitat conservation must be a primary objective
if large mammals are to persist as sustainable populations. A constantly expanding human
population, both in North America and worldwide, will continue to create challenges to
the conservation of ungulates and all wildlife, and particularly large mammals, that are
dependent upon vast expanses of suitable habitat and the ability to travel long distances
unencumbered between seasonal ranges.
Understanding life history characteristics of ungulates is critical to their successful manage-
ment. Even the earliest steps towards maintaining viable populations via sustainable use
programmes required a solid education in the biological sciences. At the birth of the scien-
tic discipline of wildlife management, Aldo Leopold [17] identied ecology, ornithology,
mammalogy, botany, entomology, herpetology, parasitology, bacteriology, meteorology,
agronomy, geology, land economics, general zoology, physiology and biometry as the core
science-related disciplines wildlife managers should have some knowledge of. Understand-
ing the natural history of big game and their evolutionary relationships with the landscape
and other species is the foundation upon which all management of large mammals
depends. Over the years, additional knowledge of the habitat for ungulates, information
about their life history characteristics (e.g. birth rates, survival, numbers, density, relation-
ships with other animals and humans), and advanced ways of measuring these characteris-
tics through modelling and statistics, understanding the inuences of human beings on
ungulates, and how they are affected by public opinion, cooperative management between
all parties interested in ungulates, structured decision making (that allows for alternate
management) and a host of other topics have been added to the techniques ungulate scien-
tists work with. None, however, replaces an understanding of natural history, basic biology
and evolutionary processes that are so critically important to wildlife conservation [20].
Managing habitat for ungulates
Wildlife management in North America progressed through six stages that elevated
ungulates from the status of unmanaged and overexploited to successfully managed and
conserved: (1) the creation of laws and regulations; (2) appropriate predator control; (3)
the creation of reservation land refuges; (4) articial replenishment, mainly through reintro-
ductions; (5) environmental controls (i.e. control of disease); and (6) habitat management
[5,7,9,17,18]. Habitat has been dened in numerous ways but it constitutes the resources
and conditions present in an area that produce occupancy, provide for reproduction and
allow survival for a given organism. Habitat is species-specic and is the sum of the
resources needed by a particular organism. These resources include food, cover, water and
special factors that are necessary for reproduction and survival, and habitat includes the
corridors and migratory routes that are necessary for those processes even if they are only
used during short periods annually.
376 P.R. Krausman and V.C. Bleich
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The third step in the evolution of game management (i.e. reservations of lands) was
the rst attempt to establish refuges and manage habitats in the western USA, speci-
cally for ungulates (e.g. Yellowstone National Park in 1872) [9]. Early conservationists
realized that wildlife would not exist without habitat. The National Forest Reserves
Act of 1897 followed the establishment of refuges and provided administration, con-
servation and use of large areas of federal lands, which became national forests in
1905. Most of these lands were habitat for big game, including ungulates, in the
USA [4].
In subsequent years, conservation observers reported the poor condition of these lands
due to overuse by livestock. The western USA was open and grazing by domestic live-
stock was uncontrolled prior to the establishment of the US Forest Service in the early
1900s and the US Bureau of Land Management in 1946. Decades of unrestricted use had
negative consequences for landscapes and the wildlife that depended on them, and so
restrictions were put in place to maintain and enhance some ranges (e.g. Gallatin National
Forest, Montana; Kaibab National Forest, Arizona). These measures were the rst recorded
instances of habitat management for ungulate species by resource managers in North
America [4]. As wildlife science progressed, it became apparent that available forage was
one of the most important factors limiting populations of deer. This became the basis of
the idea of density dependence and carrying capacity, or the number of deer or other wild-
life a unit of range could sustain. As a result, many early ungulate habitat investigations
centred on forage conditions and range management practises to improve quality and avail-
ability of forage [4]. As new data and results of studies accumulated, the management of
native ungulates evolved around three major objectives: management of ungulates in con-
cert with other land uses and available habitat, provision for sustainable use of annual sur-
pluses of ungulates (i.e. hunting) and provision of maximum recreation possible for the
public (i.e. photography and viewing). The application of science was primarily directed to
white-tailed deer, mule deer and elk. Rising abundance of ungulates demanded manage-
ment attention and although habitat management programmes for most species were slow
to develop in North America [21], they were established in many state and federal agen-
cies in the USA by the 1950s. Studies of ungulate range and forage production (including
habitat use strategies), use, and condition of animals and their forage became increasingly
common as methods to evaluate range carrying capacity, animal population levels and
human harvest recommendations. As ungulate species were restored to their native land-
scapes, however, the moderntheory that they were controlled by forage supplies did not
always work. Questions arose about the ‘… ability of existing knowledge of deer-habitat
relationships to explain population trends, plus the lack of close or consistent correlation
between population characteristics and trend and measures of browse utilization and condi-
tion, resulted in reduced emphasis on browse and other range surveys as bases for estimat-
ing carrying capacity and determining harvest and other management needs by the late
1970s and 1980s …’ [4:315]. As more data were accumulated, biologists realized that
ungulates had complex relationships with predators, which led to increased interest in
predatorprey relationships.
Understanding ungulate-habitat relationships was greatly enhanced in the 1960s and
1970s with the advent of radiocollar transmitters, telemetry receivers and computers. This
technology increased our understanding of how ungulates use habitat, and how anthropo-
genic inuences alter the use of landscapes by ungulates. As technology continues to
increase, investigators will continue to understand these relationships better. This will be
instrumental in allowing human beings and big game to coexist.
Conservation and management of North American ungulates 377
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Predator management
Predation can be an important limiting factor for ungulate populations, although it infre-
quently is viewed in the context of environmental carrying capacity (K; [22]). Predator
control sometimes is desirable, or even necessary, to ensure the establishment, recovery or
persistence of populations of large mammals. It is important, however, to be mindful of
the inuence of ungulate population size relative to Kwhen assessing the potential benets
of removing predators to achieve management objectives. Indeed, determination of whether
a top-down (i.e. predation) or bottom-up (i.e. nutritional resources) process is limiting a
population is important to any decision regarding predator removal. For example, removal
of predators to protecta population of ungulates that demonstrate the life-history charac-
teristics associated with ungulate populations that are regulated from the bottom up (i.e. by
nutrient availability; [22]) would yield little in terms of allowing such a population to
escape from a low-level equilibrium [23].
Conversely, in populations that exhibit life-history characteristics typical of those regu-
lated by bottom-up processes [22] some benet(s) to the population under consideration
may be achieved [23]. When invoking predator removal(s) specically to achieve ungulate
management objectives, an understanding of the role of predation and the prey population
relative to Kis critically important, and holds greater promise than simple consideration of
predatorprey ratios or kill rates [22]. Even in the absence of such knowledge, however,
predator removal programmes sometimes have been invoked, and some have been success-
ful in helping to speed recovery of endangered taxa [24] or to achieve other management
objectives. Predator management programmes will remain an important option for conser-
vationists to have available for their use in the future.
Human dimensions in ungulate management
For many years, managers were mainly concerned with the animal and its habitat as the
two main legs of wildlife management, but by the 1970s the issues faced by managers
were increasingly complex. Indeed, most ungulate populations were stable or were increas-
ing. White-tailed deer increased dramatically altering ecosystems and encroaching into
urban areas, exotic feral horses and burros in the western USA expanded their range and
competed with native ungulates. After the passage of the ESA in the USA and the SARA
in Canada, a wide range of threatened and endangered species had to be considered, and
management moved away from single-species emphases towards management at the eco-
system level. This obviously involved a wider range of public opinion and society became
more vocal with respect to the management of wildlife; hunters were no longer the only
group with a stake in the management of the ungulate resources.
Because wildlife in the USA and Canada belongs to the citizens of each country, it
became important to understand better how those citizens viewed the management of these
large mammals. Thus, human dimensions (i.e. views and attitudes of humans towards
wildlife and wildlife policy) became the third leg of the wildlife management triad, with
the result that interests of non-hunters were incorporated into ungulate management, there
was a new emphasis on non-hunted wildlife, and there was recognition that broad public
interest existed for wildlife, habitats, and most aspects of management. As a result,
throughout the USA and Canada the viewpoints of more and diverse stakeholders were
378 P.R. Krausman and V.C. Bleich
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considered in the management of ungulates, resulting in broad public involvement. Public
hearings, surveys and meetings with interested parties have become integral to twenty-rst
century wildlife management.
Wildlife was assumed to be a part of the human environment, and major wildlife and
habitat management issues, including the impacts of changes in grazing management, log-
ging and road development, and mineral development, were subjected to intense public
and professional management scrutiny. Many sportsmens groups and others became
more involved in management decision making and challenge[d] programmes or data
supporting programmes. Analysis and reporting of habitat and population impacts or the
reviewing of environmental impact statements rapidly became a major task of biologists,
especially in federal agencies [4:316].
Current status of ungulates in North America
The current status of most ungulates in North America is encouraging, and the literature is
replete with examples of programmes that have resulted in the successful restoration or
recovery of many species [5]. Indeed, many species including bison and pronghorn, which
at one time were on the verge of extirpation or even extinction, have recovered substan-
tially in numbers and distribution as a result of intensive conservation efforts. Other spe-
cies, including white-tailed deer and elk, continue to increase in numbers and expand in
distribution as a result of changes in habitat quality or availability; in some cases reaching
numbers that make their management with habitat constraints almost impossible. In the
case of white-tailed deer, this has led to signicant overbrowsing of extensive ranges, and
highly problematic ecosystem damage. Most subspecies of caribou, and musk ox, moose
and Dalls sheep have not yet been impacted greatly by anthropogenic forces and continue
to thrive in large numbers. Their distributions include vast tracts of habitat not currently
subject to intensive human exploitation and, as a result, those ungulates will likely con-
tinue to thrive.
Some other ungulates, however, have required special protection and intensive efforts to
recover them from the threat of extinction. Among these are two subspecies of pronghorn
(A. americana sonoriensis,A. a. penninsularis), one distinct population segment of
bighorn sheep (O. canadensis nelsoni in the peninsular ranges of California) and one
subspecies (O. c. sierrae) of mountain sheep, one subspecies of the mountain ecotype of
woodland caribou (R. tarandus caribou) and a population segment of Columbian white-
tailed deer. All of these are listed as endangered by the US Fish and Wildlife Service and
subject to provisions of the ESA. In Canada, the woodland caribou is a nationally
threatened species and subject to provisions of the Federal SARA.
Challenges for the future
Mahoney and Cobb [19], recently identied a variety of threats to wildlife conservation in
North America. Among these are an increasing human population, climate change, global
economics, urbanization, the creation of novel ecosystems, abundance and superabundance
of certain species, the human-nature divide, the perception that wildlife are vermin,
changes in public perceptions, commercialization of wildlife, funding, and lack of public
Conservation and management of North American ungulates 379
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education in conservation. All of these are important to understand for the conservation of
ungulates in North America, especially funding and climate change.
Regulated hunting, for consumption and sport, has played an important role in these
success stories directly (through the manipulation of populations; [25]) and indirectly
(through the provision of funding for wildlife conservation; [3]), but hunters alone can no
longer assure a sustainable future for wildlife in the USA [26,27] and North America in
general. In the absence of funds to augment the direct use of wildlife as a result of an
interest in hunting for food or sport, funds available for conservation will decline. Indeed,
the continued viability of wildlife populations requires new and additional levels of fund-
ing, and it is appropriate that all citizens contribute to the cost of wildlife conservation
[27]. The limited funds available will be stretched further as increased human population
growth and climate change create new challenges to management.
Predictions have been made that modern climate change will alter habitats and life his-
tory characteristics of ungulate species across North America, yet only limited data are
available that document its inuence. Managers and scientists are actively studying climate
change and its effect on wildlife to enhance and predict management and conservation for
the future. Even though research in the arena of climate change effects is in its infancy,
the predicted inuences are serious. Climate change has the potential to alter habitats, food
availability, energy expenditure, physical condition, reproduction, parasite loads and sur-
vival for some species [28]. Indeed, caribou are likely to be impacted by a variety of fac-
tors associated with climate change [2939]. Further, musk ox, moose and Dalls sheep
can be negatively inuenced by increased parasitism caused by increases in temperature
[4042], and shifts in habitat and populations among some species (e.g. elk, collared pec-
caries and mountain sheep) can be expected with changing climate [43].
Changes in temperature alone are signicant for ungulates. Muskox respond negatively
to warm, snowy winters, which have resulted in population declines [44]. Moose popula-
tions have declined due to increased thermoregulatory costs, lower survival and depressed
fecundity with increases in mean summer temperatures [41]. Parturition in some moose
populations is tied to long-term climatic trends and shifts in climate could impact calf sur-
vival [45]. Furthermore, mountain sheep populations at lower elevations with lower precip-
itation and higher temperatures appear more likely to go extinct than those occurring at
higher elevations [46]. Clearly more work needs to be done to understand how climate
change will inuence migration, the use of corridors, winter and summer ranges, competi-
tion with livestock and a host of other biological factors.
Healthy and viable populations of native ungulates exist in North America because of
active and visionary management. The ax, plow, rie and cow contributed signicantly to
the demise of ungulates in North America [17] and those are the same tools being used to
reverse the downward trend. The difference has been science-based management. In the
late 1800s, there were few game laws and less enforcement, which resulted in unregulated
harvesting. Visionaries like Theodore Roosevelt and concerned sportsmen saw ungulates
disappearin their lifetimes (much as we are seeing habitat disappeartoday) and took
action to reverse the trend. The result was the beginning of scientic wildlife management,
which led to the North American Model of Wildlife Conservation. Initially, the charge for
conservation and management was led by sportsmen but as the human population
380 P.R. Krausman and V.C. Bleich
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increased more and different segments of society demanded a voice in wildlife issues.
Sportsmen still contribute signicantly to the active management of ungulates in North
America but other segments of society need to step up and contribute to the funding
efforts. Human population growth, limited funding, climate change and other challenges
will continue to force managers to reevaluate and alter management of big game in North
America. With the wildlife management triad of biological understanding, knowledge of
habitats and human dimension studies, ungulates in North America will continue to thrive.
Earlier drafts of this paper were reviewed by J.A. Bissonette and R.D. Brown. Support for
writing the paper was provided by the Department of Biological Sciences, Idaho State
University, the Boone and Crockett Program in Wildlife Conservation, University of
Montana, and the Eastern Sierra Center for Applied Population Ecology (ESCAPE). This
is Professional Paper 098 from the Eastern Sierra Center for Applied Population Ecology.
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382 P.R. Krausman and V.C. Bleich
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... Therefore, while for regions such as Europe, Oceania and South America, a higher amount of data are available, there are regions that are not well represented, such as Africa. For the USA, we integrated the information in GRIIS with additional data extracted from Feldhamer et al. (2003) and Krausman and Bleich (2013). ...
... In Argentina, New Zealand and Cuba 19, 17 and 15 invasive alien mammals with impacts on health are reported (Fig. 10.2). Feldhamer et al. (2003) and Krausman and Bleich (2013).) Fig. 10.2. ...
... (From and Feldhamer et al. (2003) and Krausman and Bleich (2013).) Australia, Brazil, Mexico, the Bahamas and the Czech Republic are characterized by the highest proportions of alien mammals impacting human health out of the total number of invasive mammals reported in the country (range from 93% to 96%). ...
... Plant-herbivore interactions in Texas are unique within the Great Plains due to relatively high ungulate diversity following several introductions of exotic game species. While many native ungulate populations in North America have been restored since their initial extirpation (Krausman & Bleich, 2013) (Demarais et al., 1990). While one of the most common introduced ungulates in Texas, the Indian axis deer Axis axis, does appear to eat much more grass than native white-tailed deer Odocoileus virginianus, other components of interspecies competition likely preclude the long-term coexistence of axis deer and white-tailed deer within the same range (Faas & Weckerly, 2010). ...
Full-text available
Questions Fire regime alterations are pushing open ecosystems worldwide past tipping points where alternative steady states characterized by woody dominance prevail. This reduces the frequency and intensity of surface fires, further limiting their effectiveness for controlling cover of woody plants. In addition, grazing pressure (exotic or native grazers) can reinforce woody encroachment by potentially reducing fine‐fuel loads. We investigated the effects of different fire energies on the herbaceous plant community, together with mammalian wildlife herbivory (exotic and native combined) exclusion, to inform best management practices. Location Texas semi‐arid savanna, southern Great Plains, USA. Methods We conducted an experiment in which we manipulated fire intensity and herbivore access to herbaceous biomass in a split‐plot design. We altered fire energy via fuel addition rather than applying fire under different environmental conditions to control for differences in standing biomass and composition attributable to differential plant physiological status and fire season. Results High‐energy fire did not reduce herbaceous biomass or alter plant community composition, although it did increase among‐plot variability in composition and forb biomass relative to low‐energy fire and non‐burned controls. Grazing pressure from native and non‐native mammalian herbivores reduced above‐ground herbaceous biomass regardless of fire treatments, but did not alter community composition. Conclusions Managers seeking to apply high‐intensity prescribed fire to reduce woody encroachment will not negatively impact herbaceous plant productivity or alter community composition. However, they should be cognizant that repeated fires necessary for greatly reducing woody plants in heavily invaded areas might be difficult to accomplish due to fine‐fuel reduction from wild herbivores. High fencing to restrict access by wildlife herbivores or culling might be necessary to build fuels sufficient to conduct high‐intensity burns for woody‐plant reduction.
... A downward trend in numbers of both species likely began with Euro-American settlement of western North America, and much attention has focused on unregulated market hunting, habitat loss or modification, and diseases contracted from domestic livestock as causes of that decline (Buechner 1960;Smith et al. 1991;Singer et al. 2000); some of these concerns remain. Primary challenges to conserving North American wild sheep on a continent-wide basis are maintaining habitat quality, reducing habitat loss, and managing disease (Krausman 2000;Bleich 2009b;Krausman and Bleich 2013). In this chapter, we discuss these mountain ungulates in areas where they overlap rangelands of western North America. ...
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Bighorn sheep (Ovis canadensis), and to a lesser extent mountain goats (Oreamanos americanus), historically occupied much of the mountainous rangelands of western North America. Both ungulates inhabit rugged terrain and feed on grasses, forbs, and browse. Bighorn sheep and mountain goats are widely recognized for their consumptive and non-consumptive value. Indigenous peoples valued these species for cultural and subsistence purposes. Populations of these ungulates have declined since the latter part of the nineteenth century—for mountain goats, this decline has occurred particularly in the southern portion of their distribution. Historical declines have been attributed to unregulated harvest, habitat loss, competition with non-native ungulates, and disease contracted from domestic livestock. Regulated hunting has played an important role in the conservation of bighorn sheep, and recent reintroductions of these ungulates have bolstered current populations in rangelands of western North America. Although competition for habitat is minimal for bighorn sheep and mountain goats with domestic livestock (compared with other wild ruminants or feral equids), diseases of domestic sheep and domestic or exotic goats have long posed challenges to the conservation of bighorn sheep. In parts of their distributions, mountain goats and bighorn sheep are sympatric, and both species may encounter domestic livestock on grazing allotments on public or private rangelands. If management of bighorn sheep and mountain goats is the goal, spatial and temporal separation is recommended between these species and domestic sheep and goats; doing so will improve the conservation of populations of bighorn sheep and mountain goats and their habitat on rangelands of western North America.KeywordsGrazingMountain sheep Oreamnos americanus Ovis canadensis Rangelands
... Many may view with irony the essential role that hunting has played in the restoration of bighorn sheep and other large mammals in North America. Thus far, funds from hunting that have helped with restoration have been a remarkable conservation success, as a result of efforts by wildlife and land management agencies, conservation organizations, concerned members of the academic community, private landowners, and other stakeholders Krausman and Bleich, 2013;Hurley et al., 2015;Bleich, 2018). Among those stakeholders have been individuals that hunt "big game, " and numerous conservation organizations that support the scientific management and legal harvest of bighorn sheep (Hurley et al., 2015). ...
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Mammals are imperiled worldwide, primarily from habitat loss or modification, and exhibit downward trends in their populations and distributions. Likewise, large-bodied herbivores have undergone a collapse in numbers and are at the highest extinction risk of all mammals. Bighorn sheep (Ovis canadensis) are among those large-bodied herbivores that possess a slow-paced life history, suffer from debilitating diseases, and have experienced range contractions across their historical distribution since the late 1800s. Translocations and reintroductions of these mountain ungulates are key aspects of restoration and often are used to re-establish populations in historical habitat or to supplement declining herds. Millions of US dollars and much effort by state and federal natural resource agencies, as well as public and private organizations, have been expended to restore bighorn sheep. Despite those efforts, translocated populations of bighorn sheep have not always been successful. We assessed restoration of bighorn sheep to provide insights in the context of conservation of populations of bighorn sheep, because this management tool is a frequently used to re-establish populations. We focused briefly on past efforts to restore bighorn sheep populations and followed with updates on the value of habitat enhancements, genetic issues, the importance of ecotypic or phenotypic adaptations when restoring populations, predation, and disease transmission. We also raised issues and posed questions that have potential to affect future decisions regarding the restoration of bighorn sheep. This information will help conservationists improve the success of conserving these iconic large mammals.
... Today, the artiodactyl fauna of much of eastern North America is limited to only whitetailed deer (Odocoileus virginianus), though it was once home to the now extirpated elk (Cervus elaphus) (88) and bison (Bison bison) (89). Since the arrival of humans, large mammals shifted geographically and climatically into areas with less human presence (43,90), leaving behind areas depauperate in fauna. In these faunally depauperate areas, we were unable to calculate variance associated with community-level trait values, so we did not include these communities in our models. ...
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We are in a modern biodiversity crisis that will restructure community compositions and ecological functions globally. Large mammals, important contributors to ecosystem function, have been affected directly by purposeful extermination and indirectly by climate and land-use changes, yet functional turnover is rarely assessed on a global scale using metrics based on functional traits. Using ecometrics, the study of functional trait distributions and functional turnover, we examine the relationship between vegetation cover and locomotor traits for artiodactyl and carnivoran communities. We show that the ability to detect a functional relationship is strengthened when locomotor traits of both primary consumers (artiodactyls, n = 157 species) and secondary consumers (carnivorans, n = 138 species) are combined into one trophically integrated ecometric model. Overall, locomotor traits of 81% of communities accurately estimate vegetation cover, establishing the advantage of trophically integrated ecometric models over single-group models (58 to 65% correct). We develop an innovative approach within the ecometrics framework, using ecometric anomalies to evaluate mismatches in model estimates and observed values and provide more nuance for understanding relationships between functional traits and vegetation cover. We apply our integrated model to five paleontological sites to illustrate mismatches in the past and today and to demonstrate the utility of the model for paleovegetation interpretations. Observed changes in community traits and their associated vegetations across space and over time demonstrate the strong, rapid effect of environmental filtering on community traits. Ultimately, our trophically integrated ecometric model captures the cascading interactions between taxa, traits, and changing environments.
... Human-ungulate coexistence is challenged across a wide variety of land uses, with severe consequences to both the species and the human population such as the damage to commercial forestry plantations (Chadwick et al. 1996, Spake et al. 2020) and crops (Linnell et al. 2020); the transmission of zoonotic diseases to livestock and eventually humans (Gortázar et al. 2012); and collisions with vehicles (Langbein et al. 2011). Most management plans depend on regulating the populations through hunting quotas, which requires a robust assessment of population densities, locally and globally , Krausman and Bleich 2013, Richardson et al. 2020. However, despite the importance of having accurate estimates of population densities and distributions to inform management, survey methods are rarely coordinated or standardised, and most information comes from private stakeholders' efforts to survey local populations (Apollonio et al. 2010, Liu andNieuwenhuis 2014) or, at most, population estimates based on hunting returns (Apollonio et al. 2010, Nagy-Reis et al. 2021. ...
Full-text available
Using geospatial data of wildlife presence to predict a species distribution across a geographic area is among the most common tools in management and conservation. The collection of high‐quality presence–absence (PA) data through structured surveys is, however, expensive, and managers usually have access to larger amounts of low‐quality presence‐only (PO) data collected by citizen scientists, opportunistic observations and culling returns for game species. Integrated species distribution models (ISDMs) have been developed to make the most of the data available by combining the higher‐quality, but usually scarcer and more spatially restricted, PA data with the lower‐quality, unstructured, but usually more extensive PO datasets. Joint‐likelihood ISDMs can be run in a Bayesian context using integrated nested laplace approximation methods that allow the addition of a spatially structured random effect to account for data spatial autocorrelation. Here, we apply this innovative approach to fit ISDMs to empirical data, using PA and PO data for the three prevalent deer species in Ireland: red, fallow and sika deer. We collated all deer data available for the past 15 years and fitted models predicting distribution and relative abundance at a 25 km2 resolution across the island. Model predictions were associated to spatial estimate of uncertainty, allowing us to assess the quality of the model and the effect that data scarcity has on the certainty of predictions. Furthermore, we checked the performance of the three species‐specific models using two datasets, independent deer hunting returns and deer densities based on faecal pellet counts. Our work clearly demonstrates the applicability of spatially explicit ISDMs to empirical data in a Bayesian context, providing a blueprint for managers to exploit unexplored and seemingly unusable data that can, when modelled with the proper tools, serve to inform management and conservation policies.
... Most immediately, North American bovids contend with alteration of existing suitable habitat (Krausman & Bleich, 2013), limitations on movement between seasonal ranges (Courtemanch et al., 2017;Stoellinger et al., 2020), and introduction of zoonotic disease (Clifford et al., 2009). These threats are difficult to predict, and changes in their distribution and magnitude should be considered while crafting management and conservation plans. ...
Full-text available
Assumptions about factors such as climate in shaping species' realized and potential distributions underlie much of conservation planning and wildlife management. Climate and climatic change lead to shifts in species distributions through both direct and indirect ecological pressures. Distributional shifts may be particularly important if range overlap is altered between interacting species, or between species and protected areas. The cattle family (Bovidae) represents a culturally, economically, and ecologically important taxon that occupies many of the world's rangelands. In contemporary North America, five wild bovid species inhabit deserts, prairies, mountains , and tundra from Mexico to Greenland. Here, we aim to understand how future climate change will modify environmental characteristics associated with North American bovid species relative to the distribution of extant protected areas. We fit species distribution models for each species to climate, topography, and land cover data using observations from a citizen science dataset. We then projected modeled distributions to the end of the 21st century for each bovid species under two scenarios of anticipated climate change. Modeling results suggest that suitable habitat will shift inconsistently across species and that such shifts will lead to species-specific variation in overlap between potential habitat and existing protected areas. Furthermore, projected overlap with protected areas was sensitive to the warming scenario under consideration, with diminished realized protected area under greater warming. Conservation priorities and designation of new protected areas should account for ecological consequences of climate change.
... In the context of increasing populations of wild ungulates throughout northern America and Europe (Krausman & Bleich, 2013;Ramirez et al., 2018;Rooney, 2001), how much could these populations impact the stoichiometry of forests and opened landscapes? Would this impact reinforce or buffer the general trend of Nsaturation observed in many forests of the northern hemisphere (Perakis & Hedin, 2002)? ...
Full-text available
Biological control of nutrient cycles is well documented in aquatic ecosystems, where consumer‐driven recycling by herbivores can significantly impact ecosystem stoichiometry. In contrast, little is known in terrestrial ecosystems, where there is evidence that herbivores can also impact ecosystem stoichiometry. I studied a stoichiometric model of the soil‐plant‐herbivore system. The model shows that herbivores influence the ecosystem stoichiometry mainly through the direct and indirect controls of ecosystem inputs and losses, in a more complex way than predicted by the classic consumer‐driven recycling theory. Overall, it shows that herbivores affect nutrient ratios in terrestrial ecosystems mostly independently of their own stoichiometric ratios, and that their impact may be different in forest versus grassland. The results highlight the sensitivity of terrestrial ecosystems to elusive actors, negligible in biomass but capable of modifying nutrient loss rates with major impacts on nutrient cycles and ecosystem stoichiometry. I addressed the impact of herbivores on nitrogen and phosphorus recycling in terrestrial ecosystems (forest and grassland) with a stoichiometric model. My results suggest that herbivores impact ecosystem stoichiometry mostly independently of their own stoichiometry, and may promote either N or P limitation depending on the propensity for loss of soil organic and mineral nitrogen relative to phosphorus, and on the N:P ratio exported by the herbivores from the ecosystem.
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Black-tailed and mule deer (both designated as Odocoileus hemionus; hereafter referred to as “deer” or “mule deer”) comprise an iconic species that is broadly distributed across western North America. This species occurs in all rangeland types including grasslands, desert shrublands, forests, savannah woodlands, and even portions of tundra. The distribution of mule deer has changed little since Euro-American settlement, but abundance has fluctuated in response to environmental variation and rangeland management practices. These deer are medium-sized, polygynous mammals classified as generalist herbivores (foregut fermenters). Population growth in this species is strongly influenced by survival of adult females and recruitment of young. The management of rangelands has direct influence on deer populations given the wide distribution of this species and measurable responses to rangeland management practices. Rangeland management practices including development of water, grazing by domestic livestock, prescribed fire, energy extraction, vegetation alteration, and others can have positive or negative influences or both on this species. Although mule deer are widely distributed and relatively abundant, conservation of this species is challenged by rapid changes currently occurring on rangelands of western North America. Altered fire regimes due to climate change and invasive plants, competition (with feral horses [Equus ferus caballus], livestock, and other wild ungulates), development of energy, ex-urban and urban expansion, and many other challenges threaten continued abundance of this species. Rangelands and their associated management will continue to play a disproportionally large role in the conservation of mule deer in the future.KeywordsBlack-tailed deerMule deerConservationHabitat Odocoileus hemionus RangelandsWildlifeManagement
Full-text available
The use of georeferenced information on the presence of a species to predict its distribution across a geographic area is one of the most common tools in management and conservation. The collection of high-quality presence-absence data through structured surveys is, however, expensive, and managers usually have more abundant low-quality presence-only data collected by citizen scientists, opportunistic observations, and culling returns for game species. Integrated Species Distribution Models (ISDMs) have been developed to make the most of the data available by combining the higher-quality, but usually less abundant and more spatially restricted presence-absence data, with the lower quality, unstructured, but usually more extensive and abundant presence-only data. Joint-likelihood ISDMs can be run in a Bayesian context using INLA (Integrated Nested Laplace Approximation) methods that allow the addition of a spatially structured random effect to account for data spatial autocorrelation. These models, however, have only been applied to simulated data so far. Here, for the first time, we apply this approach to empirical data, using presence-absence and presence-only data for the three main deer species in Ireland: red, fallow and sika deer. We collated all deer data available for the past 15 years and fitted models predicting distribution and relative abundance at a 25 km2 resolution across the island. Models' predictions were associated to spatial estimate of uncertainty, allowing us to assess the quality of the model and the effect that data scarcity has on the certainty of predictions. Furthermore, we validated the three species-specific models using independent deer hunting returns. Our work clearly demonstrates the applicability of spatially-explicit ISDMs to empirical data in a Bayesian context, providing a blueprint for managers to exploit unused and seemingly unusable data that can, when modelled with the proper tools, serve to inform management and conservation policies.
Full-text available
Enhancing the preparation of students for careers in wildlife conservation has been an objective of The Wildlife Society for many years. Among recent graduates, we have detected a general decline in knowledge of natural history and evolutionary biology. We suggest that additional formal training in those disciplines will result in personnel that are better prepared to contribute in meaningful ways to wildlife conservation in the future. Agency personnel and university faculty share responsibility for ensuring that adequately trained individuals are available to meet the needs of conservation agencies.
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Global warming will initiate a cascade of changes throughout the arctic ecosystems; predicting their magnitude and direction becomes more complex at the higher trophic levels. For top herbivores such as reindeer and caribou Rangifer tarandus, we have to consider the effects of climate change on lower trophic levels (forage), as well as the more direct effects on the animals themselves.
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Woodland caribou (Rangifer tarandus caribou) range occupancy and populations have declined in northwestern (NW) Ontario over the last 100 years primarily due to human-induced factors. Recovery efforts are underway to halt this decline by reducing risk factors. Climate forecasts suggest a 4—5 oC increase in May—August mean temperature over the next century with little change in precipitation. Resulting increases in extreme weather events and increased fire weather severity will likely increase the amount of forest burned, reduce the area of older forest, alter distribution and abundance of forest tree species and plant communities, and increase abundance of alternate prey. The reduced amount of older forest preferred by caribou will be in greater demand by the forest industry leading to more conflict over ecological and economic values. Most of these factors will increase risk to caribou survival. Although forests may experience enhanced productivity, forest management practices will try to adapt harvest, regeneration, silviculture and fire management practices to both maintain economic benefits and increase the ability of forests to sequester carbon. The interaction of climate-induced forest change and forest management practices adds uncertainty to caribou conservation efforts at the southern edge of its current range. This uncertainty reinforces the need for a precautionary approach to forest management, increased research and monitoring effort, sustained emphasis on caribou recovery, and careful rationalization of restoration efforts where greatest opportunities for success may be realized.