Erfolgreicher Moorschutz braucht sowohl sorgfältige Pflege als auch regelmässiges Monitoring: Fallbeispiel Boniswiler-Ried 1976-2010
Krüsi, B.O.; (2011). Erfolgreicher Moorschutz braucht sowohl sorgfältige Pflege als auch regelmässiges Monitoring: Fallbeispiel Boniswiler-Ried 1976-2010. Vierteljahrsschrift der Naturforschenden Gesellschaft in Zürich, 156,, 3/4. 47-60. Peer reviewed.
Successful fen preservation requires both careful management and regular monitoring: a case study from the Swiss Plateau (Boniswiler-Ried) 1976-2010
In Switzerland, wetlands have been well protected by law for many years. Nevertheless, many fens and mires are still threatened by slow degradation due to desiccation, eutrophication, or inappropriate management. In the Boniswiler-Ried, the largest fen in the Canton of Argovie, the vegetation has been mapped three times during the past 35 years (1976, 1986 and 2010), in order to monitor both the fen vegetation and the impact of the management treatments applied. In 1976, the encroachment of shrubs and trees was considered to be the chief problem. Thanks to appropriate management, this problem has been solved already by 1986. Despite careful management, however, substantial changes in the fen vegetation were observed on more than two thirds (71%) of the protected area between 1976 and 2010. Most conspicuous were the substantial expansion of tussock-free tall sedge communities (Magnocaricion, Vegetation-unit 3b, +200%) and the massive loss of pure stands of the ecologically particularly valuable small sedge communities (Caricion davallianae, -75%). The reason for the in Switzerland unusual spreading of tall sedge communities may be due to a slowly increasing groundwater level. Because it is unlikely that the observed spreading of tall sedges can be reversed by purely mechanical means, a more detailed investigation of the hydrological situation is suggested. The present case study illustrates that even carefully managed wetlands may remain highly dynamic and that undesired changes can only be recognized in time if the area is monitored at regular intervals.