Small Mammals in Modified Pinyon-Juniper Woodlands, New Mexico

Abstract

The effects of pinyon (Pinus edulis)-juniper (Juniperus spp.) treatments on rodent abundance, 13 to 18 years after treatment, were studied in southwestern New Mexico from 1981 to 1983. Treatments included bulldozing, bulldozing/piling/burning, thinning, and untreated woodland. The area had not been grazed by livestock since time of treatment but was subjected to light and irregular use by wild ungulates. Total rodent numbers were significantly greater (P is greater than or equal to 0.05) on all treated areas compared to untreated woodlands but individual species and groups responded differently. Woodrats (Neotoma spp.) and brush mice (Peromyscus boylii) increased in abundance as slash accumulations increased, regardless of condition of overstory. Pinyon mice (P. truei) and rock mice (P. difficilus) numbers were also greater where slash was present, but only if the pinyon-juniper overstory was relatively intact. Grassland rodents, as a group, were more abundant on areas where the pinyon-juniper overstory and slash had been removed (bulldozed and bulldozed/piled/burned), but reduced numbers on bulldozed plots where slash was left suggested slash accumulations may have detrimental effects on numbers of these species. Treatments did not influence number of different rodent species. Data indicate that numbers of individuals and proportions of rodent species can be affected by manipulation of pinyon-juniper overstory and method of slash disposal.