Threatened herbaceous species dependent on moderate forest disturbances: A neglected target for ecosystem-based silviculture

Abstract

Biodiversity conservation should be considered in forest management. Most forests have a long history of moderate human disturbances. In the temperate region this coevolution has resulted in high species diversity since many threatened herbaceous species depend on moderate forest disturbances. This study considered these species in Estonia. One-third of Estonian threatened herbaceous species were estimated to be dependent on moderate forest disturbances. All of these species are favoured by small-scale gaps through partial cutting or allowing natural uprooting of trees to occur. Several species are favoured by moderate soil disturbances (paths, horseriding, etc.) and clearing of undergrowth. A smaller number of species are favoured by grazing or by prescribed fires. Disturbance-dependent species ranked high in the national Red Data Book and they were particularly characteristic in dry forests. Disturbance-dependent herbaceous species should be considered as a target group for ecosystem-based forest management. Moderate disturbances are required in both managed and protected forests to conserve forest biodiversity.

Keywords:

• Biodiversity conservation
• boreal forest
• forest conservation
• forest disturbance
• forest management
• small-scale gapping
• soil disturbances
• threatened species

Acknowledgments

We thank Aino Kalda, Nele Ingerpuu, Zigmantas Gudžinskas and two anonymous reviewers for valuable comments. Financial support was provided by the Estonian Science Foundation (grants no. 4726, 5503, 5815, 5849 and 6229) and EU 6FP project ALARM (GOCECT-2003-506675).