American Bison - Buffalo Field Campaign

northern bison herds, managers should review relevant literature
and consult with biologists in boreal regions that support wood
or plains bison populations. To enhance and conserve regional
biological diversity, bison managers will need to consider local
and regional issues, cultural and economic issues, and land
use patterns. For example, if the conservation of prairie dogs
and other species associated with short vegetation structure is
desired, plains bison stocking rates should be higher than those
recommended by the NRCS field guides.
The following guidelines can help promote conservation of
biodiversity to a higher degree than is achieved in most livestock
production systems.
1) Promote the movement and distribution of bison across
the landscape in as-natural-a-fashion as possible,
including the existence of sub-herds;
2) Manage for a mosaic of seral conditions and grazing
intensities across a landscape. If particular conditions or
seral stages are regionally rare, they should be favoured
through management. This may contrast with traditional
livestock grazing management that attempts to impose
relatively uniform grazing pressure across an entire
management unit and avoid areas of “overgrazing”;
3) Manage fire using the best available information on natural
fire patterns for the region. Leave unburned areas as
refugia for invertebrates and small mammals;
4) Restore and/or conserve prairie dogs and other grazers
that interact with bison;
5) Where possible, restore or maintain native predators of
bison, i.e., wolves and bears;
6) If mineral, food, or water supplements are necessary
they should be provided in a way that creates habitat
heterogeneity (as a point attractant rather than being
distributed uniformly across the landscape);
7) Manage so that bison do not graze naturally inaccessible
areas, for example isolated buttes and steep slopes, which
increases landscape heterogeneity;
8) Leave carrion in situ.
9.5 Disease Guidelines: Considerations
for Infected and Uninfected Herds
As all wildlife populations are hosts to a wide variety of natural
pathogens, and these pathogens form an integral component of
ecosystem health, we limit the focus of this section to:
Pathogens that limit bison population recovery
directly by reducing survival and/or reproduction,
(demonstrating a bison population impact), and/or
Pathogens that indirectly prevent bison recovery as
they form threats to existing livestock and wildlife
populations (e.g., so-called economic diseases).
In general, pathogens that fit the above categories are exotic
(i.e., have spilled over from domestic livestock populations),
such as bovine tuberculosis, brucellosis, bovine viral diarrhoea
(BVD), and malignant catarrhal fever (MCF).
Wobeser (2002) outlined four general disease management
philosophies: (1) prevention, (2) control, (3) eradication, and (4)
the laissez-faire approach (do nothing). Preventative measures
are those designed to inhibit the spread of disease to uninfected
individuals or populations. For example, the Bison Control Area in
the Northwest Territories is managed to prevent the movement of
diseased bison from Wood Buffalo National Park (WBNP) to the
Mackenzie Bison Sanctuary (Nishi et al. 2002c). Control measures
reduce the frequency of occurrence or the effects of a disease
within a population or contain the spread of the disease. Under
this regime, a disease will normally persist indefinitely, requiring
continued management. The Yellowstone National Park (YNP)
cooperative bison management plan incorporates numerous
control measures including test-and-slaughter of diseased
bison, hazing of bison back into the park, vaccination, and radio
telemetry of pregnant bison (NPS-USDOI 2000). Total eradication
of a disease is difficult and, in some cases, may not be possible
given current technology and resources. Test-and-slaughter
programmes, in concert with vaccination, may eradicate a
disease from a captive population (Nishi et al. 2002c); however,
these techniques are difficult to apply to free-ranging wildlife
(Wobeser 2002). In larger populations, or over larger areas,
intensive management, emphasising treatment and vaccination,
may be inappropriate, unsustainable, or simply impractical
(Woodruff 1999). In these circumstances, managing population
size, structure, area of occupancy, or the risk of contact between
host species or adjacent populations, could offer alternatives
to more intensive interventions. Depopulation (=eradication) of
an infected herd is a potential option; however, there may be
considerable logistical challenges and conservation and policy
issues including genetic conservation or salvage, cascading
ecological effects, and public opposition (Nishi et al. 2002c;
Wobeser 2002). Selection of a disease management approach
depends on the rationale for management, whether the disease
is already present in a population, the availability of funding,
and the likelihood of success (Wobeser 2002). Managers should
also understand the ecology and pathology of the disease,
the dynamics of the pathogen-host relationship (Bengis et al.
2002; Wobeser 2002) and the risk to adjacent uninfected host
populations, including bison.
Our disease recommendations focus on four disease control
strategies: prevention, surveillance, management, and research.
We recommend development of a disease management plan
under the umbrella of a restoration programme plan that is
American Bison: Status Survey and Conservation Guidelines 2010 95