Effect of hydrogeomorphic setting on calcareous fen hydrology

Abstract

Calcareous fens are species-rich peatlands that are dependent on minerotrophic water sources for wetland functioning, with current conceptual models suggesting the water source is ubiquitously groundwater upwelling. By quantifying the water balance and subsurface water flow paths and fluxes over 3 growing seasons for calcareous fens in 3 different hydrogeomorphic settings (Riparian, Trough, and Basin), we show evidence that challenges this conceptual model. The Riparian Fen received an order of magnitude more water inputs than the Trough or Basin Fens and was dominated by stream recharge inputs and groundwater outputs. Precipitation and evaporation dominated the water balance of the Trough Fen whereas only the Basin Fen received sizeable groundwater inputs. Indeed, subsurface water fluxes were low at all fens due to weak hydraulic gradients and low saturated hydraulic conductivity in some areas of each wetland, though variations in growing season precipitation led to subsurface flow reversals in all 3 fens. Our results demonstrate the importance of understanding landscape position, or hydrogeomorphic setting, on calcareous fen hydrology for improving conservation, management, and restoration efforts of these important ecosystems.

Variations in the water storage capacity of a mountain peatland with complex stratigraphy

“…Carlson-Mazur et al (2013) reported a linear decrease in Sy to 3 m depth, whereas Bourgault et al (2016Bourgault et al ( & 2018 reported a logarithmic decrease in Sy until 1m depth. Duval & Waddington (2018) found one well location which followed a pattern similar to the Sy increase at depth observed in this study. However, they did not state a cause for the increase in Sy at depth.…”

“…The inclusion of mineral sediment within the peat profile changes the soil hydrologic properties (Duval & Waddington, 2018).…”

Plant distribution, stature, rarity, and diversity in a patterned calcareous fen: tests of geochemical and leaf‐height models

“…Calcareous spring‐fed fens (extremely rich fens, sensu Sjörs, ) are globally rare and of great interest to conservationists in Europe and North America because they harbor many endangered plant species (Amon et al., ; Nekola, ; van Diggelen et al., ; Jímenez‐Alfaro et al., ; Seer and Schrautzer, ; Duval and Waddington, ; Horsáková et al., ). Such fens often show internal patterning, with short, sparse, species‐rich vegetation near springheads grading into taller, denser, less diverse vegetation on less calcareous substrates (Boyer and Wheeler, ; Carpenter, ; Bowles et al., ).…”

Hydrogeochemical Conditions of the Development of Anthropogenic Carbonate Swamps: A Case Study of an Abandoned Polish Sandpit

“…Their importance for the conservation of the biodiversity of the region and the country is significant because of the participation of species that are deemed to be endangered in the country as well as the abundance of Liparis loeselii -a species that is of European importance [23], especially because the natural swamp communities in the Silesian Upland are very rare and endangered vegetation components. The particular importance of Ca 2+ and pH is highlighted for the communities of alkaline swamps [31]. Communities that include Liparis loeselii and other calciphilic species that have been found by the Rospuda River grow on a substrate where the water has the following parameters: pH -7.0, conductivity -466 (max 694), Mg +2 -15.9, Ca +2 -21.7 [32].…”