Great Basin Naturalist


In 1973 a timber harvest of ponderosa pine (Pinus ponderosa) was conducted in an area southeast of Monticello, Utah, that is inhabited by Abert squirrels (Sciurus aberti). Abert squirrel dietary habits, foraging patterns, and population densities were compared in the timber harvest area and in an adjacent nonharvested area. Squirrel feeding patterns and preferences were visually determined by physical evidence of past feeding. Live-trapping and field-marking of animals were used to determine population density and trends in the two areas. Squirrels fed in only 26.3% of sampled plots on the timber harvest areas, while 42.7% of the uncut area plots showed use (P < 0.001). Trap days per catch were higher on the harvested area (P < 0.01). Similar differences in hypogeous fungi feeding sites between the two study sites were also recorded (P < 0.01). Thus, clearcut timber harvest of ponderosa pine did negatively affect Abert squirrels. To minimize long-term effects on squirrels, timber should be harvested in small, selective blocks (< 20 acres) rather than in large-scale areas (>50 acres) by clear-cut methods commonly employed by management agencies.