Ineffective enforced legislation for nature conservation: A case study with Siberian flying squirrel and forestry in a boreal landscape

Unsustainable use of forest resources is causing dramatic changes in the landscape and poses a serious threat to biodiversity worldwide. This threat is becoming increasingly tangible in boreal biomes, especially in regions where intensive production-oriented forestry is widely applied. Legislation is one of the key tools for preserving nature from anthropogenic damage, but rarely its effectiveness is evaluated. We assessed the effectiveness of guidelines enforcing Finnish legislation aimed at preserving sites occupied by the Siberian flying squirrel (Pteromys volans), a vulnerable species in Finland (and Europe), from destruction due to forest clear-cutting practices which often target its primary habitat, mature mixed forests. Using a before–after-control-impact design, we found that current protection measures for preserving breeding/resting areas do not maintain site occupancy (e.g. the proportion of years when a site was found occupied) by flying squirrel. We show that a dramatic reduction in occupancy after clear-felling was not paralleled by a similar change in occupancy at sites used as controls, where occupancy was stable through time. The collapse in occupancy at sites where the forest was clear-cut according to the guidelines can be explained by the reduction in suitable area by half of its original amount within 200 m, and by two thirds within 100 m as a consequence of tree harvest. The results provide clear evidence of the inefficacy of current guidelines to maintain suitable breeding/resting habitat to this species and thus, a revision is critically needed. We conclude that evaluating effectiveness is crucial for enhancing the impact of conservation measures at tackling the massive biodiversity crisis worldwide.

► We assess effectiveness of guidelines to protect Siberian flying squirrel habitat.
► We compared sites with and without clear-cutting according to guidelines.
► Flying squirrel disappeared from sites cut following guidelines.
► Guidelines are ineffective at preserving the species habitat from forestry impacts.
► More evaluations of enforced legal nature protection measures are needed.