Managing Boreal Forest Landscapes for Flying Squirrels

Abstract

Flying squirrel (Pteromys volans) populations have declined severely during the past few decades, and the species has beconme afocal species in forest management and the conservation debate in Finland. We compared land.scape structure around known flying squirrel home ranges with randomly chosen forest sites to determine which landscape patterns characterize the areas occupied by the species in northern Finland. We sought to identify the key characteristics of the landscape that support the remaining flying squirrel popu- lations. We analyzed landscape structure within circular areas with 1- and 3-knm radii around 63 forest sites occupied by flying sqtuirrels, and arotund 96 random sites. We applied stepwise analysis of the landscape structure where landscapes were built ul) step-by-step by adding patch types in order of their suitability for the flying squirret The land-use and forest-resource data for the analysis were derived from multisource na- tional forest inventory and imported to a geographical information systenm. Landscape patch types were di- vided into three suitability categories. breeding habitat (mixed spruce-deci.duous forests); dispersal habitat (pine atd young forests); and unsuitable habitat (young sapling stands, open habitats, water). Flying squir- rel landscapes contained more suitable breeding habitat patches and were better connected by dispersal hab- itats than random1 landscapes. Our results suggest that for the persistence of the flying squirrel, forest manag- ers should 1) maintain a deciduous mixtutre, particularly in spruce-dominatedforests; 2) maintain physical connectivity between optimal breeding habitats; and 3) impose coarse-grained structures on northeastern Finnish landscapes at cturrent levels of habitat availability.