American Bison - Buffalo Field Campaign

Chapter 10 Guidelines for Ecological
Restoration of Bison
Lead Authors: C. Cormack Gates, Robert O. Stephenson, Peter J.P. Gogan, Curtis H. Freese, and Kyran Kunkel
10.1 Introduction
During Pre-Columbia times, bison had the widest distribution
of any large herbivore in North America, ranging from the
arid grasslands of northern Mexico to the extensive meadow
systems of Interior Alaska (Chapters 2 and 7). Following the
arrival of Europeans, the species experienced unparalleled range
contraction and collapse of populations in the wild, primarily
during the late 19 th Century (Isenberg 2000). Wild bison persisted
in only two locations, south of Great Slave Lake in what is now
Wood Buffalo National Park (about 300 individuals), and in the
remote Pelican Valley in the Absaroka Mountains in the interior
of Yellowstone National Park (YNP) (fewer than 30 individuals).
The species was extirpated from the wild throughout the
remainder of its original range. The American bison has achieved
a remarkable numerical recovery, from approximately 500 at the
end of the 19 th Century to about half a million animals today, of
which 93% now exist under captive commercial propagation
(Chapter 7). However, Sanderson et al. (2008) estimate that bison
occupy less than 1% of their original range.
Rarely do wildlife populations in North America achieve the
full range of ecological interactions and social values existing
prior to European settlement. The bison remains extirpated as
wildlife and in the ecological sense from much of its original
continental range. This is particularly true of the plains bison,
for which few populations interact with the full suite of other
native species and environmental limiting factors (Chapters 6
and 7). In the absence of committed action by governments
(including aboriginal governments), conservation organisations,
and perhaps the commercial bison industry, the conservation of
bison as a wild species is far from secure. The main challenges
were described in earlier chapters of this volume and are
summarised by Freese et al. (2007). They include anthropogenic
selection and other types of intensive management of captive
herds, small population size effects, issues related to exotic
diseases, introgression of cattle genes, management under
simplified agricultural production systems, and associated with
this, widespread ecological extinction as an interactive species.
Contemporary biological conservation is founded on the
premise of maintaining the potential for ecological adaptation
in viable populations in the wild (IUCN 2003; Secretariat of
the Convention on Biological Diversity 1992; Soulé 1987), and
maintaining interactive species (Soule et al. 2003). Viability
relates to the capacity of a population to maintain itself without
significant demographic or genetic manipulation by humans
for the foreseeable future (Soulé 1987). For limiting factors,
such as predation and seasonal resource limitation, adaptation
requires interactions among species, between trophic levels,
with physical elements of an ecosystem. These, and other
interactions among individuals within a population (e.g., resource
and mate competition), contribute to maintaining behavioural
wildness, morphological and physiological adaptations, fitness,
and genetic diversity. These factors enable a species to adapt,
evolve, and persist in a natural setting without human support in
the long term (Knowles et al. 1998).
Viable, wild populations of bison, subject to the full range
of natural limiting factors, are of pre-eminent importance to
the long-term conservation, global security, and continued
evolution of the species as wildlife. However, the availability
of extensive ecosystems capable of sustaining large, free-
roaming, ecologically interactive bison populations is limited.
This is particularly true in the original range of plains bison in the
southern agriculture-dominated regions of the continent, given
the historical post-European settlement patterns of industrial and
post-industrial society. Social and political systems that provide
space and environmental conditions where bison can continue
to exist as wildlife and evolve as a species, are severely limited.
Innovative approaches need to be instigated in some locations
to emulate, to the extent possible, the original ecological
conditions, and to prevent domestication and small population-
related deleterious effects such as those experienced by the
European bison (Hartl and Pucek 1994; Prior 2005; Pucek et
al. 2004). Currently, there is only one population of plains bison
(YNP) and three populations of wood bison (Greater Wood
Buffalo National Park, Mackenzie, and Nisling River) in North
America that can be considered ecologically restored (thousands
of individuals, large landscapes, all natural limiting factors
present, minimal interference/management by humans).
The conservation of American bison as wildlife would be
significantly enhanced by establishing additional large
populations to achieve landscape scale ecological restoration.
This will require effective collaboration among a variety of
stakeholders, whereby local actions, based upon social and
scientific information, are coordinated with wider goals for
species and ecosystem conservation. The bison was an
American Bison: Status Survey and Conservation Guidelines 2010 103