Restoration of peat‐forming vegetation by rewetting species‐poor fen grasslands

Abstract

Questions: Does succession of rewetted species‐poor fen grasslands display similar trends when different water levels, sites and regions are compared? Will restoration targets as peat growth and waterfowl diversity be reached? Location: Valley fen of the river Peene (NE‐Germany) and the Hanság fen (Lake Neusiedler See, NW‐Hungary). Methods: Analysis of permanent plot data and vegetation maps over a period of up to seven years of rewetting. The general relations between newly adjusted water levels and changes in dominance of helophytic key species during early succession are analysed considering four rewetting intensities (water level classes) and eight vegetation types (Phalaris arundinacea type, Carex type, Glyceria maxima type, Phragmites australis type, Typha type, aquatic vegetation type, open water type and miscellaneous type). Results: The initial period of balancing the site conditions and vegetation is characterised by specific vegetation types and related horizontal vegetation structures. Most vegetation types displayed similar trends within the same water level class when different sites and regions were compared. A significant spread of potentially peat forming vegetation with dominance of Carex spp. or Phragmites as desired goal of restoration was predominantly restricted to long‐term shallow inundated sites (water level median in winter: 0–30 cm above surface). Open water patches as bird habitats persisted mainly at permanent inundated sites (water level median in winter > 60 cm above surface). Conclusions: Site hydrology appeared as a main force of secondary succession. Thus the rewetting intensity and restoration targets have to be balanced adequately.

Fens and floodplains of the temperate zone: Present status, threats, conservation and restoration

“…Conservation of existing fens and floodplains and restoration of degraded ones, therefore, is a high priority ( Establishing and safeguarding necessary abiotic conditions in affected wetlands almost always involves raising the water table (Timmermann et al 2006, this issue), (re-)establishing the major water source (rainwater, groundwater and surface water) for the wetland under consideration and creating the necessary productivity level regime (van Belle et al 2006, this issue). Rewetting is in itself technically not so difficult to achieve (Timmermann et al 2006, this issue;Bodegom et al 2006, this issue), but conserving and/or restoring the two other parameters may be much more difficult.…”

Hydroecological model predictions indicate wetter and more diverse soil water regimes and vegetation types following floodplain restoration

“…[33] Hydrological degradation can lead to decreased diversity [Tockner and Stanford, 2002], and a typical goal of restoring hydrology in wetlands is to reverse this trend [Osland et al, 2011;Timmermann et al, 2006;Zedler, 2005]. However, the anticipated increase in site-scale diversity is usually assumed to occur following a uni-directional shift in the distribution of vegetation types toward a more wetland obligate community.…”

Restoration of floating mat bog vegetation after eutrophication damages by improving water quality in a small pond

“…neziki Hara, and Vaccinium bracteatum Thunb., may be irreversible or show slow recovery, even if the nutrient loading is removed (Kitamura and Murata 1981a;Tabata 2008). Although generalization of successional trends from case studies is often problematic due to the extensive ecological factors involved in wetland ecosystems (Timmermann et al 2006), we suggest that the improvement of water quality can be effective for the conservation of Sphagnum bog vegetation, as demonstrated by the Mizorogaike wetland, in which the vegetation has been restored and invading plants have been prevented from flourishing in the nutrient-poor conditions (Koshikawa et al 2005). However, some effects of past eutrophication such as flourishing nitrophilic plants remain and may be irreversible.…”