Fragmentation patterns and protection of montane forest in the Cantabrian range (NW Spain)

We analysed the composition and configuration patterns of the forested landscape in the Cantabrian range (NW Spain) determining how different forest communities are currently affected by long-term fragmentation process. We also evaluated the regional reserve network in relation to forest fragmentation and forest heterogeneity at the landscape level. The current landscape scenario is characterised by low forest habitat cover (22%) and a fragment size distribution strongly skewed towards small values (<10 ha). Forest classes differ strongly in fragment size, internal heterogeneity, shape, dispersion and isolation. Beech forests were less fragmented than other types, being the dominant class in terms of surface and fragment occurrence. Fragmentation was heavier in forests occurring in agriculture-suitable areas (i.e. valley bottoms, southern exposures), such as ash-maple and oak forests, as well as in second-growth forests developed after tree-line deforestation for pastures (i.e. holly and rowan forests). The current reserve network in the Asturias region covers preferentially bigger and less isolated forest fragments. This was a consequence of protection biased towards beech forests, to the detriment of an adequate representativeness of most other forest types, some of them with high ecological value. Future expansion of the reserve network should be based on landscape information, to promote both the protection of well-conserved, less-fragmented forests as well as the inclusion of under-represented target forest types.