Investigation of the priority forest habitats of Val di Mello Natural Reserve

Alice Grandi ¹, Marina Borgatti ¹, Marco Caccianiga ¹, Leonardo Malvezzi ¹, Barbara Valle ²

Department of Biosciences, Università degli Studi di Milano, Milan, Italy ¹, Università degli Studi di Siena; NBFC – National Biodiversity Future Center, Palermo ²

Val di Mello represents the eastern extension of Val Masino (Sondrio province, Italian Alps), a major lateral valley on the right hydrographic side of Valtellina. Since 2009 Val di Mello is almost entirely included in “Val di Mello Natural Reserve”, becoming the largest protected reserve in Lombardy. The aim of our work consists in monitoring the priority natural habitats of the valley as defined by the Habitat Directive (Council Directive 92/43/EEC) using a phytosociological approach. We performed phytosociological relevés to examine the following habitats: - 91E0* - “Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae)” - 9180* - “Tilio-Acerion forests of slopes, screes and ravines”. Our sampling design was partly defined according to the plots already marked by a group of forestry experts, which was involved in parallel for the forestry assessment of the habitats. Further plots have been determined on the field consulting the map of habitat types, also trying to assess the presence of additional areas which could deserve higher protection. Furthermore, our work was paralleled by a sampling aimed at verifying the occurrence of the two bryophyte species included in the Annex II of the Habitat Directive, namely Orthotrichum rogeri Brid. and Buxbaumia viridis (Lam. & DC.) Moug. & Nestl., confirming most of the earlier reports and discovering a new site for the latter specie. The data collected have been processed with a cluster analysis in order to investigate the phytosociological characterization of the forest vegetation. Surveys from areas earlier reported as 9180* habitat turned out to be differentiated into two clusters: the first one belongs to Arunco-Aceretum Moor 1952 association, thus confirming the habitat 9180* attribution, while it wasn’t possible to define the second cluster’s phytosociology even at the order level, because of the simultaneous occurrence of typical species relevant to Quercetalia roboris Tüxen 1931 and Fagetalia sylvaticae Pawłowski in Pawłowski, Sokołowski et Wallisch 1928. On the other hand, the assignation of habitat 91E0* finds confirmation in the results of our analysis, which lead to the attribution of the Aceri-Alnetum incanae Beger 1922 association. Ultimately, our preliminary results confirm the far from easy categorization of the 9180* habitat, often subject to floristic depletion, and underline some discrepancies with respect to the map of habitat types, expressing the necessity of further investigation.

Main author career stage: Master student

Contribution type: Talk

First choice session: 2. Ecology

Second choice session: 3. Biodiversity and global change