POLICY IMPLICATIONS OF UNGULATE HERBIVORY IN MANAGING THE WEST’S
FOREST-DOMINATED ECOSYSTEMS
Robert A. Riggs
Wildlife and Range Scientist, Boise Building Solutions
1917 Jackson, La Grande, Oregon 97850, phone (541-962-2046), fax (541-962-2002),
email robertriggs@boisebuilding.com
John G. Cook
Research Scientist, National Council for Air and Stream Improvement
1401 Gekeler, La Grande, Oregon 97850, phone (541-962-6536), fax (541-962-6540),
email cookjg@eou.edu
Larry L. Irwin
Wildlife Program Manager, National Council for Air and Stream Improvement
3816 Salish Trail, Stevensville, Montana 59807, phone (406-777-7215), fax (541-777-7213),
email llirwin@bitterroot.net
Elk (Cervus elaphus), deer (Odocoileus spp.) and livestock are sympatric across the West. High
livestock numbers early in the 20th century and growing big game populations focused
management’s attention on livestock-wildlife relationships. This focus largely pertained to
rangelands and the dry transition zones where big game populations wintered. Relatively little
attention was devoted to understanding these relationships and their consequences in the
productive forest zones, or in understanding how forestry-herbivore interactions could influence
forest-ecosystem processes. Nevertheless, coniferous forests above the transition zone are
critically important to herbivore production, and particularly to many of the more notable big
game herds. Much of the West’s forest-zone game range had its genesis in periodic or
“episodic” disturbances, such as fire and logging. These episodic disturbances set in motion a
series of secondary forest successions that “underwrote” big game production for decades, and in
so doing formed the foundation for agency and public expectations for herbivore production.
Big game production has always been considered a valuable by-product of forestry and its
economic benefits used to influence land management, but it has never been a compelling factor
in forestry planning beyond that for roads and cover. The relevance of forage-based
relationships to processes involving forest succession and forest planning has been almost totally
ignored. Nevertheless, natural forest succession, and management policies involving fire,
reforestation, and timber harvest have profound influences on herbivore-vegetation relationships,
and in many settings will contribute to development of mature forest rather than early
successional stages. As these game ranges return to mature forest, herbivory effects will
intensify, and density-dependent feedbacks are likely to increasingly limit animal production,
thereby undercutting socio-economic values of the wildlife resource. Several of the region’s
flagship elk and deer herds are now in serious decline, precipitating a growing disparity between
public expectations for game production and the reality imposed by carrying capacity. Among
the most vexing by-products of this dynamic to the professions are a systemic inability to predict
the influences of multi-species herbivory on ecosystem dynamics, and an inability to predict how
various forest-management schemes have and are apt to alter landscape carrying capacities over
time.