Diatoms from the Mire of Fiavé: Their contribution to a multidisciplinary study to assess the conservation biology problems of the mire

Peatlands are ecologically important sites for carbon sequestration, provide a valuable refuge for many sensitive threatened species of the Alpine foothills, and can be hotspots of biodiversity. The Fiavé Nature Reserve, a Natura 2000 site, is an alkaline fen (main occurring vegetation, Caricion davallianae), and includes the UNESCO World Heritage Site of the Bronze-Age pile dwellings of Fiavé. This study aims to assess the influence of surrounding farmlands on the quality of local biotopes using diatoms, chemistry, and vegetation (mapped with drones) as indicators and proxies. For this purpose, three 50-cm deep peat cores (in the Alps roughly representing the last 500 years), and surface and piezometer water samples were collected. Peat cores were cut while frozen into 3-cm samples, which were characterized from the physical and chemical point of view. Moreover, subsamples were processed to create permanent diatom mounts. Diatoms were identified, counted, and evaluated from the perspective of a link to the concentration of nutrients and a possible negative impact of eutrophication or chemical pollution in the studied area. The results will also be used to inform and support best management practices, such as the establishment of buffer zones.