Understanding the Long Term Ecosystem Stability of a Fen Mire by Analyzing Subsurface Geology, Eco-Hydrology and Nutrient Stoichiometry – Case Study of the Rospuda Valley (NE Poland)

Abstract

We explored the background of differences in long-term stability between two parts in an undisturbed mire system (Rospuda fen, NE Poland). We re-constructed the Holocene history of the mire and compared it with current vegetation, water level dynamics, water chemistry and nutrient availability in two basins: A, where the mire terrestrialised a deep gyttja-filled lake, and B, where peatland developed directly on fluvial sands. The current vegetation of sedgemoss fens was described in 10 relevés from each basin, groundwater was sampled from piezometers and analysed for major ions, while its relative water level was recorded during three years. N and P content was measured in above ground vascular plant samples collected within the relevés. Fens in basin A were stable in the past, whereas fens in basin B switched between open and wooded or reed-dominated phases. In basin B, where trees are more abundant, we found higher water fluctuations, occurrence of river floods and a higher N:P ratio than in basin A. Our interpretation follows that the subsurface geology of fen basin may govern mire stability by determining its hydrological-buffering capacity, which may affect N:P ratios. Our results suggest that Plimited fens are more vulnerable for changes in water level.

Water and nutrient discharge to a high‐value terrace–floodplain fen: resilience and risk

“…PO 4 -P concentrations in terrace groundwater or in fen surface water did not vary appreciably ranging from approximately 0.04 to 0.1 mg/l, but concentrations in fen groundwater were significantly higher (1.2 mg/l; Table I). P release from fens has been linked to redox-status and P availability (Bailey Boomer and Bedford, 2008;Jablonska et al, 2014). Phosphorus will be released under hypoxic or anoxic conditions in the fen as a result of microbial Fe reduction process, which are known to have a dominant influence on P-dynamics (Sharpley, 1995).…”

“…These threats affect the long-term stability of fen ecosystems, changing a system that once was resilient over long periods of time to one that may be rapidly degraded and altered (Dise, 2009;Jablonska et al, 2014). Existing fens are often fragmented and degraded, and many have been lost all together (Bedford and Godwin, 2003).…”

“…Despite their high ecosystem value, fens are under threat from many directions including direct land use conversion (van Diggelen et al, 2006), hydrologic changes (van Belle et al, 2006;Duval and Waddington, 2011), eutrophication (Wassen and Olde Venterink, 2006;Lamers et al, 2014) and potential climate change (Herrera-Pantoja et al, 2012). These threats affect the long-term stability of fen ecosystems, changing a system that once was resilient over long periods of time to one that may be rapidly degraded and altered (Dise, 2009;Jablonska et al, 2014). Existing fens are often fragmented and degraded, and many have been lost all together (Bedford and Godwin, 2003).…”

Application of multisensoral remote sensing data in the mapping of alkaline fens Natura 2000 habitat

“…At present, the largest preserved mire fragments occur in Poland in the Biebrza River valley (Herbichowa and Wołejko, 2004) and in the Rospuda River valley (Jabłońska et al, 2014). The Biebrza valley is an excellent area to study alkaline fens preserved over a large area with a varied conservation status (Jarzombkowski, 2010;Koczur, 2010;Kotowski et al, 2013).…”

Can we effectively stop the expansion of trees on wetlands? Results of a birch removal experiment

“…The shift of peatland vegetation towards treedominated ecosystems may likely be accelerated by anthropogenic disturbances (i.e., drainage; Tousignant et al 2010), climate change (i.e., future warming; Heijmans et al 2013), external eutrophication (i.e., atmospheric deposition; Riemersma et al 2006;Jickells 2005;Smith et al 1999), and abiotic variables (i.e., water fluctuations, N:P ratio; Økland et al 2001;Jabłońska et al 2014). Thus, protecting open wetland ecosystems is a priority of nature conservation policy.…”