Habitat Modelling as a Tool for Landscape-Scale Conservation: A Review of Parameters for Focal Forest Birds

We propose how quantitative knowledge about specialised birds and spatially explicit land cover data describing the terrestrial vegetation can be used to build Habitat Suitability Index models for the assessment and planning of representative habitat networks at the scale of landscapes and regions. Using specialised forest-dwelling species listed in the EC Birds directive, we review the quantitative knowledge, and identify knowledge gaps, about the requirements of species at different spatial scales from individuals to local populations. We also assess to what extent the selected species cover different forest types and ecoregions associated with the drainage basin of the Baltic Sea. We then use this information to estimate the tentative size of planning units for the assessment of habitat networks aimed at maintaining biodiversity. The estimated mean minimum size of planning units where suitable habitat dominate the landscape was ca 40 000 ha, while in managed landscapes with minimum amount of habitat the unit size averaged 250 000 ha. By contrast, the size of individual conservation areas such as woodland key biotopes and protected reserves from which habitat network can be built in a managed matrix was ca 1-1000 ha. We conclude that when managing for the maintenance of forest biodiversity there is a need to extend the spatial and temporal scale from the stand scale to that of landscapes within large management units. Finally, we discuss perspectives and limitations in using ecological knowledge about birds, landcover information and GIS-modelling as an integrated tool for tactical conservation planning.