Old-growth and mature forests near spotted owl nests in western Oregon

We investigated how the amount of old-growth and mature forest influences the selection of nest sites by northern spotted owls (Strix occidentalis caurina) in the Central Cascade Mountains of Oregon. We used 7 different plot sizes to compare the proportion of mature and old-growth forest between 30 nest sites and 30 random sites. The proportion of old-growth and mature forest was significantly greater at nests sites than at random sites for all plot sizes (P less than or equal to 0.01). Thus, management of the spotted owl might require setting the percentage of old-growth and mature forest retained from harvesting at least 1 standard deviation above the mean for the 30 nest sites we examined

Habitat selection by female black bears in the central Cascades of Oregon

Public scrutiny over management of black bears (Ursus americanus) in Oregon resulted in the passing of a referendum to ban the use of dogs and bait to hunt bears in 1994. Challenges to bear management necessitate the application of regionally derived biological information to bear management. The overall objective of this research was to define habitat characteristics that influence the autecology of female black bears in Oregon. Because habitat-selection processes operating at finer resolutions (e.g., the home range) are inevitably the product of landscape characteristics, we chose to study selection at both the home range and landscape scale. We radio-tracked 14 adult female black bears from June 1993 to December 1995 in the central Cascades of Oregon to determine home-range size and analyze habitat selection. Locations were classified to one of six habitat classes based on stand structure, and digitally overlaid onto a habitat map produced from a LANDSAT Thematic Mapper scene of the study area. A geographic information system was used to determine habitat characteristics at known and random locations; chi-square and logistic regression techniques were used to analyze habitat use. Female black bears were associated with open-canopy sapling/pole and open canopy mature timber, apparently selecting for a combination of foraging opportunities and security cover. Furthermore, black bears were negatively associated with roads and positively associated with streams. Consequently, roads located along watercourses may inhibit the use of riparian areas by bears. Understanding how forest-management practices influence the availability and use of habitats for black bears, and applying this knowledge to bear-management strategies, will ensure that management plans are based on the best available science, and confer greater credibility to state agencies from an increasingly informed and involved publi

Diets and foraging behavior of northern Spotted Owls in Oregon

Volume: 38Start Page: 214End Page: 23