III. Ipotesi sugli esiti a medio-lungo termine della gestione forestale attuale sulla conservazione della biodiversità

Starting from the consideration emerged form the previous phases (MAIROTA et al. and MAIROTA and PIUSSI this volume) a posterior landscape ecological analysis was carried out in order to assess the consequences of an actual forest management plan. The same set of spatial scale was adopted, even though the focus was on the lower three levels of the hierarchy of the patchiness, birds were again used as bioindicators and a GIS was created on purpose for the management estate studied. The analysis was extended in time up to the year 2042 when the interventions, as scheduled and implemented by 2005, are likely to infl uence both the single stand and the resultant spatial mosaic. Landscape confi guration change was examined at the three levels of the hierarchy using data at the patch to compute a few landscape pattern indices. To compare the ex ante and the ex post situations descriptive statistics applied. Effects on biodiversity were qualitatively assessed by means of the verifi cation of the fulfi lment of the habitat needs, in terms of habitat availability, of a set of bird species specialised or dependent on forest habitat types, in both situations. A higher degree of landscape heterogeneity (due to the increase of both aggregation and contrast) at the management level is to be expected by the implementation of the forest management plan. As the management level is crucial for habitat selection for birds, speaking in general terms, such effects do not appear as detrimental for conservation purposes. However it has to be taken into an account that the implementation of this very management plan is also likely to produce a relatively homogeneous pattern as far as age of forest stands is concerned which does not seem to favour the viability of local populations of a few among the bird species considered. It is suggested that these and other issues emerging from this analysis are taken into an account when a new plan will be compiled in order to both avoid management anomalies and to better harmonise silviculture and conservation instances. The approach adopted is consistent with both the principles of “wise forest management in Europe” (ANDERSSON 2003) and of “adaptative management” (FEMAT).