Hydrological landscape settings of base‐rich fen mires and fen meadows: an overview

Abstract

Question: Why do similar fen meadow communities occur in different landscapes? How does the hydrological system sustain base‐rich fen mires and fen meadows? Location: Interdunal wetlands and heathland pools in The Netherlands, percolation mires in Germany, Poland, and Siberia, and calcareous spring fens in the High Tatra, Slovakia. Methods: This review presents an overview of the hydrological conditions of fen mires and fen meadows that are highly valued in nature conservation due to their high biodiversity and the occurrence of many Red List species. Fen types covered in this review include: (1) small hydrological systems in young calcareous dune areas, and (2) small hydrological systems in decalcified old cover sand areas in The Netherlands; (3) large hydrological systems in river valleys in Central‐Europe and western‐Siberia, and (4) large hydrological systems of small calcareous spring fens with active precipitation of travertine in mountain areas of Slovakia. Results: Different landscape types can sustain similar nutrient poor and base‐rich habitats required by endangered fen meadow species. The hydrological systems of these landscapes are very different in size, but their ground water flow pattern is remarkably similar. Paleoecological research showed that travertine forming fen vegetation types persisted in German lowland percolation mires from 6000 to 3000 BP. Similar vegetation types can still be found in small mountain mires in the Slovak Republic. Small pools in such mires form a cascade of surface water bodies that stimulate travertine formation in various ways. Travertine deposition prevents acidification of the mire and sustains populations of basiphilous species that elsewhere in Europe are highly endangered. Conclusion: Very different hydrological landscape settings can maintain a regular flow of groundwater through the top soil generating similar base‐rich site conditions. This is why some fen species occur in very different landscape types, ranging from mineral interdunal wetlands to mountain mires.

Topsoil removal in degraded rich fens: Can we force an ecosystem reset?

“…As discussed in Section 4.1, higher groundwater levels lead to rewetting, which correlates with higher concentrations of base cations and HCO 3 À . A continuous supply of both HCO 3 À (ensuring a high alkalinity and a buffered pH) and base cations is essential for rich fen species, which are vulnerable to acidification and base leaching (van Diggelen et al, 1996;Grootjans et al, 2006;Cusell et al, 2013). In this respect, a slight increase in concentrations of potassium may be of particular importance as K leaches relatively easily from degraded peat soils, thereby hampering fen restoration (van Duren et al, 1997).…”

Organic soils in Germany, their distribution and carbon stocks

“…The underlying concept is based on the correlation between hydrogeomorphic setting, site specific genesis and thus resulting soils. Wetland classifications based on the hydrogeomorphic setting are well known and widely accepted (Brinson, 1993;Cole et al, 1997;Grootjans et al, 2006Grootjans et al, , 2014Semeniuk and Semeniuk, 1995;Succow, 1988). As well, the hydrogeomorphic setting can be derived systematically and in comparable quality from nationwide available geodata on hydrology, geomorphology, topography, geology and pedology.…”

Mountain Fen Distribution, Types and Restoration Priorities, San Juan Mountains, Colorado, USA

“…Because most mountain fens are sloping and supported by ground-water discharge, watershed geology exerts a strong influence in ground-water chemical content (Vitt and Chee 1990;Cooper and Andrus 1994;Bedford and Godwin 2002;Bragazza et al 2003), which strongly influences fen plant community composition (Vitt and Chee 1990;Cooper and Andrus 1994;Cooper 1996;Bedford and Godwin 2002;Bragazza et al 2003). Hydrogeomorphic landform can also control fen plant community composition (Bridgham et al 1996;Grootjans et al 2006). We used well known geochemical fen categories to organize the plant communities into rich, intermediate, and iron fen types.…”