PARENT SESSION
Oral Session # 42: Mammal Ecology: From Mice to Elephants.
Presiding: H Howe
Wednesday, August 6. 8:00 AM to 11:30 AM, SITCC Meeting Room 104.

Ecological correlates of flying squirrel microhabitat use and density in temperate rainforests of southeastern Alaska.

Smith, Winston^*,, Gende, Scott, Nichols, Jeffrey,

ABSTRACT- The northern flying squirrel was proposed as an indicator of biological diversity in coniferous forests of the Pacific Northwest. We studied habitat relations of the Prince of Wales flying squirrel (Glaucomys sabrinus griseifrons), an endemic of temperate, coniferous rainforest of southeastern Alaska, because of concerns over biological diversity from extensive clearcut logging in the region. We used stepwise logistic regression (SLR) to examine relationships between microhabitat use and individual habitat features (measured variables) and habitat factors, which were independent linear combinations of individual habitat variables identified in factor analysis. Seasonal (spring, autumn) models were created for upland, old-growth (upland-OG) western hemlock (Tsuga heterophylla)/Sitka spruce (Picea sitchensis) and peatland mixed-conifer forests (peatland-MC). Density of trees with diameter-at-breast-height (dbh) >74 cm and abundance of Vaccinium were positively correlated with microhabitat use in peatland-MC during both seasons with the odds of capturing a flying squirrel increasing by factors of 2.7 and 16.9 during spring and autumn, respectively, with an increase in density of 10 trees/ha. Microhabitat use of upland-OG during autumn was related to Vaccinium ground cover and density of snags with a dbh of 50-74 cm; microhabitat use during spring was inversely correlated with percent surface cover of water. SLR models with multivariate factors performed poorer in predicting capture sites than models of individual habitat variables, indicating that habitat factors were not more thorough in explaining variation in habitat use than individual habitat elements within the scope of conditions examined. At the stand level, large (>74 cm) trees explained 65% of the variation in density between habitats; percent cover of moss and downed wood in decay classes I-IV explained 70% and 63-77% of the variation, respectively. Our results corroborate some general patterns reported for western coniferous forests, but suggest that northern flying squirrels in temperate rainforests of southeastern Alaska differ ecologically from populations in the Pacific Northwest in important ways that likely influence their suitability as management indicators.

Key words: Glaucomys sabrinus griseifrons, temperate rainforest, ecological correlates, southeastern Alaska