Applying Predator-Prey Theory to Large Mammal Systems: Predation Rates and Prey Selection of Wolves in Greater Yellowstone

Matthew S. Becker and Robert A. Garrott

One of the most pervasive human impacts on ecosystems is the removal of top predators and the reintroduction of large carnivores has recently become a viable conservation and management practice worldwide. Yet, owing to the paucity of data from existing, intact large mammal systems, the effects of such recolonizations on ecosystems remains both a scientific controversy and societal concern. Predator-prey dynamics has been a well-studied yet highly controversial topic for decades, with no consensus as to how systems behave. Most studies have been performed on smaller taxa, differing dramatically in life-history characteristics from large mammal systems. How applicable current predator-prey theory is to large mammal systems is thus questionable. The intent of this study is to identify the factors driving predation in large mammal systems, to clarify differences and commonalities between these systems and those of smaller taxa, and to incorporate these differences into traditional predator-prey models to better describe the dynamics of large mammal systems. The research will focus on the analysis of long-term wolf predation rate data from two study sites in the Greater Yellowstone area, one within central Yellowstone National Park, the other in the lower Madison valley of southwestern Montana (See Wolf-Ungulate Study Sites). Despite both sites being in close proximity within the Madison river drainage, elk density, herd size and movements, wolf use, pack sizes, environmental conditions, and the availability of alternative prey all differ between the two sites. Thus, by investigating how varying levels of these factors influence wolf predation rates and prey selection, this research has the potential to yield significant insights into factors driving predator-prey dynamics in large mammal systems.

Funding:  National Science Foundation