Thirty years later: How successful was the restoration of a raised bog in the Swiss Plateau?

Abstract

Raised bogs as huge carbon stocks are of worldwide importance, but they have been severely decreased and degraded globally. To stop this development, restoration measures are being carried out in many countries. The recovery of raised bogs is, however, slow and the success of restoration projects is uncertain. Long-term monitoring is thus needed. The Hagenmoos raised bog in the Swiss Plateau was restored by logging within former peat-cutting pits and by blocking drainage pathways. The vegetation in the bog was recorded 3 times within 72 permanent plots: immediately before, 10 years after and 30 years after restoration. Based on these vegetation surveys, changes in habitat conditions (ecological indicator values) and in species richness and single species were analysed. Overall, the restoration measures proved to be successful. Mean indicator values for light and moisture both increased over time. The increase of these indicators was strongest during the first 10 years after restoration and weakened afterwards. Within former peat-cutting pits, both indicator values reached values from a reference dataset composed of 21 plots from Swiss raised bogs representing typical bog communities. However, 30 years after restoration, mean light and moisture indicator values were still significantly lower outside former peat-cutting pits than within them, indicating a need for further restoration measures.

Keywords

• bryophyte
• conservation
• ecological indicator value
• long-term monitoring
• vegetation