American Bison - Buffalo Field Campaign

and elk herds migrate across several jurisdictions including
the NER, GTNP, YNP, Bridger-Teton National Forest, Bureau
of Land Management, State of Wyoming, and private lands.
The NPS and FWS coordinated the extensive involvement of
the associated agencies, organisations, and private interests
affected by this new management plan and Environmental
Impact Statement (EIS). The U.S. Department of Interior
(USDOI) published a record of decision in April 2007, selecting a
management alternative that emphasises adaptive management
of elk and bison populations while reducing their dependence
upon feed grounds. The plan also calls for a brucellosis
vaccination programme for elk and bison conducted by the
State of Wyoming. Recent hunting programmes, modification
of feeding programmes and disease management have
reduced the number of bison to 700 animals and the long-term
management of this herd is now prescribed in a long-term plan.
Several legal challenges were mounted and the implementation
of the plan remains controversial.
5.3 An Occurrence of Reportable
Diseases in Wood Bison
Wood bison herds in and around WBNP, including SRL, are
infected with BTB and brucellosis (Gates et al. 1992; Gates et
al. 2001c). These diseased herds account for about 50% of the
total wood bison conservation population. Joly and Messier
(2001a) reported the sero-prevalence of the diseases to be 31%
for brucellosis and 49% for tuberculosis. With the exception of
free-ranging bison in the WBNP and GYA, aggressive eradication
programmes in both the U.S. and Canada have reduced the
probability of brucellosis and BTB in domestic cattle and bison
herds to extremely low levels. The wild diseased wood bison
herds in and near WBNP are the only known reservoirs of
BTB among all bison conservation herds (Gates et al. 2001c;
Reynolds et al. 2003; Shaw and Meagher 2000).
BTB and brucellosis were likely introduced to wood bison
populations with the transfer of plains bison from Wainwright
Buffalo Park in the 1920s (Fuller 2002). In 1925, the Canadian
government implemented a plan to move 6,673 plains bison
from the overcrowded Wainwright Buffalo Park to WBNP. The
transfer proceeded despite opposition from mammalogical
and biological societies in the U.S. and Canada, who warned
of transmission of BTB to the resident wood bison population
(Anonymous 1925; Ogilvie 1979). BTB was first reported in
WBNP in 1937 (Fuller 2002; Gates et al. 1992; Geist 1996).
Although it is not known whether BTB was endemic among
wood bison prior to the transfer (Reynolds et al. 1982),
evidence indicates that the disease was introduced to wood
bison with the transfer of plains bison (Fuller 1962). Brucellosis
was also present in the plains bison herd and was reported in
WBNP in 1956 (Gates et al. 1992).
The presence of BTB and brucellosis threatens the recovery
of wood bison in several ways. First, the infected animals are
subject to increased mortality, reduced fecundity, and increased
vulnerability to predation (Gates et al. 1992; Joly and Messier
2001a). In 1934, the bison population in WBNP was estimated
at 12,000 animals (Soper 1941). The population decreased from
approximately 11,000 in 1970 to 2,151 in 1999 (Joly 2001).
This decrease has been attributed to the interactive effects of
diseases and predation (Carbyn et al. 1998; Fuller 1991; Joly and
Messier 2001a). Recently, the WBNP population increased to
4,050, although the reasons for this increase are unclear (Bradley
2002, personal communication).
Second, the potential exists for the infected herds to transmit
the diseases to healthy herds, most notably the Mackenzie,
Nahanni, and Hay-Zama herds (Animal Plant and Food
Risk Assessment Network (APFRAN 1999). Since 1987, the
Government of the Northwest Territories has managed a
39,000 km 2 Bison Control Area south of the Mackenzie River
to prevent movement of diseased bison into the MBS (Nishi
2002). Recent analysis and modelling of bison movements on
the landscape have demonstrated considerable risk potential
for transmission of diseases to healthy wood bison herds and
bison ranches in the vicinity of the diseased herds (Gates et al.
2001a; Mitchell 2002). The Government of Alberta announced
a new hunting season for the Hay Zama herd in 2008. The
purpose of the hunt is to maintain the wood bison population at
approximately 400 and limit distribution of these animals until
the diseased bison issue, in and around WBNP, is successfully
resolved. In particular the hunt will be used to control expansion
of the Hay-Zama herd eastward, preventing contact with bison
emigrating from WBNP that may be infected with brucellosis or
BTB. Although preliminary, results of serological tests and post
mortem examination of about 100 bison harvested from the
Hay-Zama population in the winter of 2008 were negative for the
two bovine diseases (D. Moyles, Alberta Sustainable Resource
Development, personal communication).
Much research and debate has been focused on trying to
resolve the diseased bison issue in northern Canada. In 1990,
the Federal Environmental Assessment Panel released its
report on its analysis of the disease issues (FEARO 1990).
The panel concluded that eradication of the diseased wood
bison populations is the only method for eliminating the risk of
transmission of brucellosis and BTB from bison to domestic
cattle, non-diseased wood bison, and humans. The panel further
recommended that healthy wood bison be reintroduced to the
area following depopulation of the diseased herds. Sources of
healthy bison for reintroduction could include the EINP wood
bison herd and other captive herds supplemented by disease-
free animals salvaged from the Northern Bison herds (FEARO
1990). One such salvage operation, the Hook Lake Wood Bison
Recovery Project in Fort Resolution, Northwest Territories, was
American Bison: Status Survey and Conservation Guidelines 2010 35