Gillian L. Holloway

Nest-Tree Use by Northern and Southern Flying Squirrels in Central Ontario

Abstract Little is known about nest use by flying squirrels (Glaucomys) in partially harvested forests, especially for northerly populations where cavity use is prevalent. We used radiotelemetry to examine nest use by 24 southern flying squirrels (G. volans) in 2003 in logged and unlogged hardwood forests, and by 18 northern flying squirrels (G. sabrinus) in 2004 in conifer forests, in Algonquin Provincial Park, Ontario, Canada. Of 76 nest trees used by G. volans, 71% were in declining trees and 22% were in snags. Sixty tree nests used by G. sabrinus included 28% snags, 46% declining trees, and 25% healthy trees, although nearly one-half of nests of G. sabrinus that were used on more than 3 occasions were in snags. G. volans used larger-diameter trees and American beech (Fagus grandifolia) more often than expected by chance, whereas G. sabrinus used trembling aspen (Populus tremuloides), white birch (Betula papyrifera), and yellow birch (B. alleghaniensis) more than expected by chance. Both species used a high proportion of cavity nests, few external nests, and trees that were decayed or diseased. We found indications that nest supply was limited in recently harvested sites, where there were fewer cavity trees and snags; however, G. volans may compensate by using abandoned yellow-bellied sapsucker nests and by nesting in aggregations. Hardwood snags and decaying trees appear to provide crucial nesting habitats for both squirrel species, particularly for females.

Sciurid habitat relationships in forests managed under selection and shelterwood silviculture in Ontario

Abstract Although partial forest harvesting is practiced over large areas, managers know little about its impacts on sciurid rodents, particularly on northern (Glaucomys sabrinus) and southern flying squirrels (G. volans) in the northeastern United States and Canada. We examined habitat relationships of sciurid rodents (northern flying squirrels, southern flying squirrels, red squirrels [Tamiasciurus hudsonicus], and eastern chipmunks [Tamias striatus]) at 2 spatial scales in managed and unmanaged coniferous and hardwood forests of Algonquin Provincial Park, Ontario, Canada. We live-trapped rodents in 26 northern hardwood stands and in 16 white pine (Pinus strobus) stands from 2002 to 2004. Northern flying squirrel and red squirrel densities were significantly lower in recently harvested (3–10 yr since harvest) shelterwood stands than in unmanaged stands. In contrast, southern flying squirrel densities were higher in selection-harvested stands than in old-forest areas. The densities of northern flying squirrels and red squirrels had a strong relationship with the density of large spruce (Picea sp.) and hardwood trees and snags in conifer sites. Southern flying squirrel numbers had a positive association with the density of mast trees at the landscape level but not at the stand level in hardwood forests. Eastern chipmunk density had a positive correlation with the volume of old downed woody debris and the stems per hectare of declining trees. We recommend forest managers retain more large spruce and hardwood trees to mitigate the impacts of shelterwood harvesting on northern flying squirrels and red squirrels, and that they maintain high mast availability at the landscape level to ensure the persistence of southern flying squirrels.

Planning forwards: biodiversity research and monitoring systems for better management.

The world is currently facing a suite of complex and dynamic issues that threaten the diversity and processes sustaining humanity. Ecologists have long debated how to best study these issues, resulting in ‘friendly fire’ between different camps of thought. The most recent casualties, the Alberta Biodiversity Monitoring Institute (http://www.abmi.ca), and the PPBio Program in Brazil (http://ppbio.inpa.gov.br/Eng/public/) and Australia (http://www.griffith.edu.au/ppbio), results from Lindenmayer and Likens’ [1] supposition that these programs lack rigorous questions, a factor that has ‘undermined the credibility of long-term research and monitoring’.

A meta‐analysis of forest age and structure effects on northern flying squirrel densities

ABSTRACT Research on the impact of clearcut logging and partial harvesting practices on northern flying squirrels (Glaucomys Sabrinus) has shown inconsistent and contrary results, limiting the use of this species as a management indicator species. Much of this variability in study results is due to the labor intensive nature of studying flying squirrels, resulting in small sampling sizes (average = 5.2 sites, n = 14) and high variation (CV = 0.59) across studies. We conducted a meta-analysis of relevant studies from North America to determine how forestry practices affect flying squirrel abundance. Mean effect size was -1.18 [P < 0.001; n = 14) for all studies, indicating a strong difference between control stands and those regenerating postclearcut or following partial harvesting. Our results support the association of northern flying squirrels with mature, uncut forest and their suitability as ecological indicators of these vegetation types.