Moose and Winter Ticks in Western Wyoming

Moose are an important game species in Montana, Idaho and Wyoming but hunter opportunities have been reduced in many areas over the last two decades as populations have declined at this southern limit of the species’ geographic range. In the Jackson, Wyoming area moose populations have declined by an estimated 80% since the early 1990s. Rising temperatures, pathogens, and parasites represent some of the hypothesized mechanisms behind the declines. Specifically, concerns have increased about the abundance of winter ticks (Dermacentor albipictus), a widespread parasite associated with moose that increases in abundance with shorter winters and longer growing seasons. The winter tick has been associated with drastic moose declines in the northeastern U.S. Consequently, understanding how winter tick loads may be affecting moose in western Wyoming is an important issue for natural resource managers as climate conditions are shifting in the region. The goal of this project is to determine the potential role of winter ticks (and other parasites and pathogens) on moose declines in western Wyoming, an area that is experiencing warming temperature trends and changing seasonal conditions. We propose to study the interaction of ticks and climate variables and their impact on moose health in western Wyoming using a combination of field work and mechanistic modeling at local and regional scales. This information will help natural resource managers better understand where winter ticks are likely to be most prevalent in the future so appropriate management actions can be implemented.