Influence of rodent predation on antelope bitter-brush seedlings.

Abstract

Antelope bitterbrush (Purshia tridentata(Pursh) DC) is the most important browse species on many mule deer (Odocoileus hemionus) ranges. California-Nevada interstate mule deer herds are critically dependent on antelope bitterbrush stands, in which many of these stands have been and are currently exhibiting little recruitment. Lassen is the only established cultivar of antelope bitterbrush. Rodent predation on Lassen antelope bitterbrush seedlings was studied in burned and unburned antelope bitterbrush communities in northeastern California during 1993. Rodent population densities were 15/ha and 14/ha in the burned and unburned habitats, respectfully. Rodent compositions consisted of the Ord's kangaroo rat (Dipodomys ordii), deer mouse (Peromyscus maniculatus), and the Great Basin pocket mouse (Perognathus parvus). Rodents significantly decreased antelope bitterbrush recruitment through grazing and disturbance of antelope bitterbrush seedlings. Ord's kangaroo rats preyed on higher numbers of antelope bitterbrush seedlings than did the other 2 common rodent species.