The Ganna Lake is located in northern Italy's Lombardia region and covers approximately 100 ha of the Valganna valley in Varese Province. The oligotrophic lake is protected at the regional level and is considered a Site of Community Importance within the Alpine biogeographical region. Peculiar weather conditions in the lake catchment area, characterised by low temperatures and high precipitation, favours the presence of six habitat types of Community importance, two of which are priorities for conservation: the alluvial forests with Alnus glutinosa and Fraxinus excelsior; and the Calcareous fens with Cladium mariscus and species of the Caricion davallianae.
These habitats host some 240 plants species, a number of which are very rare in Italy. Notable fauna include crustaceans, amphibians, bats and birds, seven of which are of Community importance. Ganna Lake represents the altitudinal limit for particularly interesting species such as Rana latastei. It is also home to Italy's only known breeding population of Pipistrellus nathusii. Notwithstanding the good quality of the water, mainly due to the absence of human settlements in the entire hydrographic basin, the habitats and species of the site are isolated from other water courses and have experienced a range of threats including silting, decreasing water levels and human disturbance.
The main aim of this LIFE-Nature project concentrated on improving and sustaining the environmental quality of Ganna Lake's habitats. Bog areas were to receive special attention. Hydraulic engineering actions would be implemented to restore natural water levels via removal and control of sediment flows, particularly from the lake's tributaries. These physical measures would be complemented by scientific monitoring to clarify and calibrate optimal water levels in different parts of the catchment vis-à-vis the conservation status of aquatic fauna (fish, amphibians and crustaceans) and the plants. Results would inform dedicated conservation works to: improve the vegetation status of habitats affected by lower water levels; and create or restore breeding areas for amphibian species and the white clawed crayfish (Austropotamobius pallipes).
Long term sustainability was to be achieved through the preparation of management documents tasked to integrate conservation actions for the lake area's flora and fauna. Visitor management facilities would be introduced to minimise trampling or erosion impacts on sensitive areas and raise awareness about the lake's natural heritage value.
The project achieved and exceeded its original intentions. Key conservation interventions included: excavating 4,122 m3 of sediment from the Pralugano bog to help restore its ecological integrity; constructing a weir to facilitate water level control and allow bog water levels to increase by 10 cm, as determined and verified by the project's monitoring activities; establishing physical works to control sediment flows within the peat bog tributaries.
These hydrogeological management measures involved sinking wells, creating stone pathways to regulate water flows and building wooden or stone hydraulic engineering devices along the Valeggio stream to reduce erosion threats; increasing amphibian breeding pond areas to 103 m2 by restoring three existing sites and introducing another three new ponds; restocking the smaller Lake Saint Gemolo with 91 Austropotamobius pallipesindividuals; and enhancing the water ecological corridor between Lake Ghirla and Lake Ganna.
A variety of visitor management features were implemented, such as: construction of a new two storey observatory; limiting vehicle access on areas prone to erosion; improving 1.334 meters of footpath; restoring Saint Gemolo's cellars and upgrading access by a new footbridge; preparation and installation of seven interpretation panels; plus a range of printed environmental education materials were published in both English and Italian.
The monitoring programme collated a large amount of new and useful information concerning local hydrology, water fauna and vegetation. This included the discovery of two previously unknown fish species in the area (Leuciscus souffia, Lethenteron zanandrei) and two new bird species (Dryocopus martius, Alcedo atthis) which allowed updating of the site's Natura 2000 attributes. Monitoring also identified a number of alien and invasive species which will be managed over a five year period within the project's "Action plan for the freshwater fauna" and "the rules for the birds of Community interest of the SCI lago Ganna".
Both documents are incorporated in a new overall management plan for the SCI/SPA "Lago Ganna", not foreseen as a deliverable of the LIFE project, which was approved by the Regione Lombardia and adopted by the Regional Park Authority. The plan proposes land purchase to enlarge the SCI/SPA, sylvicultural interventions on artificial conifer plantations, creation of underground passages for amphibians and restoration of old buildings, as well as on-going work on the LIFE-funded ponds, bioengineering features and visitor facilities.
Other legacies from the LIFE project include advanced hydroengineering skills for local contractors which are anticipated to be applied on new works in Varese Province during restoration of a further two bogs (Palude Brabbia and Torbiera di Biandronno).
The project also led to the beneficiary setting up an "Italian bogs network" that includes several protected areas from Piemonte, Liguria, Toscana, valle d'Aosta and Lombardia.