Northern Flying Squirrel Glaucomys Sabrinus Research Articles

Gliding locomotion of Siberian flying squirrels in low-canopy forests: the role of energy-inefficient short-distance glides

Short glides of less than 20 m seem energy inefficient for the Siberian flying squirrel Pteromys volans as with the northern flying squirrel Glaucomys sabrinus. However, Siberian flying squirrels in low-canopy forests frequently use short glides. Therefore, we sought to clarify the gliding patterns of Siberian flying squirrels for energy-efficient gliding transport in low-canopy forests (mean tree height, 15.3 m) in Hokkaido, Japan, based on records of 66 glides and 35 launch and landing trees. Mean launch height, landing height, and horizontal glide distance were 14.4, 2.7, and 21.4 m, respectively. For short distances, horizontal glide distance was strongly correlated with launch heights but not with launch tree height. For glides of more than 20 m, horizontal glide distance was significantly correlated with both launch height and launch tree height. The mean heights of launch and landing trees for short glides were 15.6 and 19.5 m, respectively. For long glides, these heights were 22.7 and 19.2 m. For short glides, mean launch tree height did not differ from overall mean tree height. However, for long glides, the mean launch tree height was greater than the overall mean tree height. Also, for short glides, the height of the landing tree was greater than that of the launch tree. Launch trees used for long glides were as high as the landing trees used in short glides. From these results, we conclude that Siberian flying squirrels in low-canopy forests save energy by gliding initially from a tree with sufficient height to permit a glide to a taller tree. This taller tree then permits long-distance glides that are energetically more efficient.

Locomotor performance and cost of transport in the northern flying squirrelGlaucomys sabrinus

We assess locomotor performance by northern flying squirrelsGlaucomys sabrinus Shaw, 1801 and test the hypothesis that gliding locomotion is energetically cheaper than quadrupedal locomotion. We measured 168 glides by 82 northern flying squirrels in Alaska. Mean glide distances varied from 12.46 m to 14.39 m, with a maximum observed glide distance of 65 m. Mean glide angles varied from 41.31° to 36.31°, and mean air speed ranged from 6.26 m/s to 8.11 m/s. There were no differences in the performance of male and female flying squirrels. We used models of transport cost to provide an initial assessment of the hypothesis that gliding locomotion is energetically less expensive than quadrupedal locomotion. For glides of average length, cost of gliding was less than cost of quadrupedal locomotion except when the animals climbed to the launch point very slowly or ran quickly. Thus the hypothesis that gliding is less expensive than quadrupedal locomotion is supported.

Home range and habitat use of the Vulnerable Virginia northern flying squirrel Glaucomys sabrinus fuscus in the Central Appalachian Mountains, USA

The Virginia northern flying squirrel Glaucomys sabrinus fuscus is a Vulnerable sciurid that has experienced a 90% reduction of suitable high elevation boreal montane forest habitat over the last century in the central Appalachians of West Virginia and Virginia, USA. Using radiotelemetry and GIS analyses we examined the species' home range size and habitat use in the Monongahela National Forest, Kumbrabow State Forest and the MeadWestvaco Ecosystem Research Forest in West Virginia during the summers of 2000–2003. The mean home range sizes of male and female squirrels were 54.2 and 15.3 ha, respectively, based on the adaptive kernel method. Euclidean distance analysis indicated the squirrels used spruce, mixed spruce-northern hardwood, and open habitats more than was available across the landscape. Selection of spruce and mixed spruce-northern hardwood habitats indicates that forest management activities designed to restore and increase these types in the central Appalachian landscape are required to conserve and increase this Vulnerable species.

Using GIS to relate small mammal abundance and landscape structure at multiple spatial extents: the northern flying squirrel in Alberta, Canada

Summary It is common practice to evaluate the potential effects of management scenarios on animal populations using geographical information systems (GIS) that relate proximate landscape structure or general habitat types to indices of animal abundance. Implicit in this approach is that the animal population responds to landscape features at the spatial grain and extent represented in available digital map inventories. The northern flying squirrel Glaucomys sabrinus is of particular interest in North American forest management because it is known from the Pacific North‐West as a habitat specialist, a keystone species of old‐growth coniferous forest and an important disperser of hypogeous, mycorrhizal fungal spores. Using a GIS approach we tested whether the relative abundance of flying squirrel in northern Alberta, Canada, is related to old forest, conifer forest and relevant landscape features as quantified from management‐based digital forest inventories. We related squirrel abundance, estimated through live trapping, to habitat type (forest composition: conifer, mixed‐wood and deciduous) and landscape structure (stand height, stand age, stand heterogeneity and anthropogenic disturbance) at three spatial extents (50 m, 150 m and 300 m) around each site. Relative abundances of northern flying squirrel populations in northern and western Alberta were similar to those previously reported from other regions of North America. Capture rates were variable among sites, but showed no trends with respect to year or provincial natural region (foothills vs. boreal). Average flying squirrel abundance was similar in all habitats, with increased values within mixed‐wood stands at large spatial extents (300 m) and within deciduous‐dominated stands at smaller spatial extents (50 m). No relationship was found between squirrel abundance and conifer composition or stand age at any spatial extent. None of the landscape variables calculated from GIS forest inventories predicted squirrel abundance at the 50‐m or 150‐m spatial extents. However, at the 300‐m spatial extent we found a negative, significant relationship between average stand height and squirrel abundance. Synthesis and applications. Boreal and foothill populations of northern flying squirrel in Canada appear unrelated to landscape composition at the relatively large spatial resolutions characteristic of resource inventory data commonly used for management and planning in these regions. Flying squirrel populations do not appear clearly associated with old‐aged or conifer forests; rather, they appear as habitat generalists. This study suggests that northern, interior populations of northern flying squirrel are probably more related to stand‐level components of forest structure, such as food, microclimate (e.g. moisture) and understorey complexity, variables not commonly available in large‐scale digital map inventories. We conclude that the available digital habitat data potentially exclude relevant, spatially dependent information and could be used inappropriately for predicting the abundance of some species in management decision making.

Plant Community Characteristics Associated with the Endangered Northern Flying Squirrel, Glaucomys sabrinus, in the Southern Appalachians

-Overstory and understory vegetation and physical parameters were sampled at sites where two endangered subspecies of the northern flying squirrel Glaucomys sabrinus are known to occur in the southern Appalachians. The 13 sites were disjunct, occurring at high elevations in mesic communities. Picea rubens was always present in the canopy (191173 trees/ha); the northernmost sites had greater densities of P. rubens and Betula lutea, while the southern sites had greater densities of Abies fraseri and Fagus grandifolia. Cluster analysis of overstory importance value data indicated the more southern sites and the more northern sites differed in species composition. In comparison the understory was highly variable among sites, both in species composition and percent cover and was therefore considered to be a poor indicator of suitable habitat for populations of G. sabrinus. Site characteristics indicate that the endangered populations of G. sabrinus may be restricted to patches of suitable habitat which remain at only a limited number of sites at high elevations in the southern Appalachian Mountains.