Biogeographical and vegetation outlines of Valgrande National Park (Insubric Prealps – NW Italy).

In the present work Val Grande National Park (Verbania NW Italy) vegetation is investigated with phytosociological methods. Main synecological features and local distribution (according to altitude and insolation) of identified vegetation types are presented. Broad-leaved forests (chestnut-oaks and beech) dominate lower vegetation belts where forest degradation stages are also frequent. Towards the top, few shreds of coniferous woods are encountered. Above timberline, Alnus viridis and Rhododendron ferrugineum shrubs develop widely. Nardus stricta pastures and Festuca varia s.l. prairies are the main topmost herbaceous formations, since proper alpine pastures stands are sporadic. The altitude successional pattern outlined here is consistent with the one described in Canton Ticino and other rainy parts of Insubria. On the contrary, the study area strongly differs from other sections of Prealps which were partially exposed to quaternary glaciation because of floristic poorness including endemic species. The few endemic species found (Campanula excisa and Potentilla grammopetala) have distribution centred on inner Alps.