Abstract

The habitats of national importance, including fens, raised bogs, dry grasslands, riparian areas, flood plains, and amphibian breeding sites, are a crucial element of the network of protected sites in Switzerland. In 2011, the Federal Office for the Environment (FOEN) and the Swiss Federal Research Institute WSL launched the joint project “Monitoring the effectiveness of habitat conservation in Switzerland (WBS)“ to observe whether these habitats are developing in line with their conservation targets and whether the area and quality of habitat is being maintained. The WBS is using remote sensing approaches as well as extensive floristic and faunistic field surveys to calculate various indicators, which evaluate the state and the development of the sites of national importance. First results show mainly negative trends: in the last 20 years raised bogs have become drier and richer in nutrients. Fens also became drier, cover by shrubs increased and the proportion of typical fen species decreased. Active drainage systems in raised bogs and fens, as well as land-use abandonment in fens appear to be the most important drivers. In dry grasslands woody cover increased, particularly in the southern Alps. Furthermore, the vegetation now indicates more nutrient-rich, moist, dense and darker conditions compared to previous observations. The national amphibian breeding sites have lost on average at least one amphibian species per site. Populations of the common toad and the midwife toad continued to decline sharply. Although developments were predominantly negative, positive changes were observed in particular regions or at least in individual sites. For example, in the raised bogs of the Swiss lowlands woody cover decreased and losses of frequent amphibian species (common toad, alpine newt, grass frog) in amphibian breeding sites have been mitigated or were even reversed by new discoveries. In addition, rare amphibian species showed a partial stabilization of their populations. These positive developments can be attributed to restoration and conservation measures by the cantons and other stakeholders, as well as to the appropriate management of the sites. This shows that these measures are effective and should be continued or even intensified in order to preserve the biodiversity of the habitats  of national importance in the long term. The continuously collected data within the framework of the WBS will provide information on the development of the habitats of national importance and will therefore allow to evaluate the success of the conservation measures in the future.