Vegetation characteristics and eco-hydrological processes in a pristine mire in the Ob River valley (Western Siberia)

Abstract

Relations between vegetation characteristics and eco-hydrological processes were assessed in a pristine mire in the valley of the Ob River (Western Siberia). Along a transect from the terrace scarp to the river, field data were collected on vegetation composition, peat stratigraphy, peat chemistry, hydrology and hydrochemistry. Based on floristic composition, eight vegetation communities were distinguished. Hydraulic head measurements were used to obtain an indication of groundwater flow directions. The water balance of the mire was calculated with a two-dimensional steady-state numerical groundwater model. Water types were defined based on cluster analysis of hydrochemical data. The results revealed that the dominant hydrological factor in the Ob mire is the discharge of groundwater, which supplies about threefold more water than net precipitation. Although the discharge flux decreases with increasing distance from the terrace scarp, high water levels and a ''groundwater-like'' mire water composition were observed in the major part of the study site. Precipitation and river water play only a minor role. Despite dilution of discharging groundwater with rainwater, spatial differences in pH and solute concentrations of the surficial mire water are small and not reflected in the vegetation composition. Although small amounts of silt and clay were found in the peat in the proximity of the river, indicating the occurrence of river floods in former times, no river-flood zone could be recognized based on hydrochemical characteristics or vegetation composition. A comparison of the Ob mire with well-studied and near-natural mires in the Biebrza River valley (Poland) revealed substantial differences in both vegetation characteristics and the intensity and spatial pattern of eco-hydrological processes. Differences in the 123Plant Ecol (2007) 193:131-145 DOI 10.1007 origin and ratios of water fluxes as well as a dissimilar land use history would seem to be key factors explaining the differences observed.

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)

“…In the natural Siberian percolation fens of the Ob valley where occasionally occurring floods used to be a natural phenomenon, P-limitation was also found (Schipper et al 2007).…”

“…Michaelis 2002). Undisturbed percolation mires have recently been found and studied in Siberia (Schipper et al 2007) and China (Schröder et al 2007). The Rospuda fen in north-east Poland is one of the few remaining well-preserved percolation mires in temperate Europe (cf.…”

Importance of water level dynamics for vegetation patterns in a natural percolation mire (Rospuda fen, NE Poland)

“…Similarly, Schipper et al (2007) proved that differences in peat and surficial mire water chemistry occur in the Ob river valley, but are small and not reflected in vegetation characteristics. The vegetation characteristics of the study site can largely be explained by hydrological processes.…”

“…In the Rospuda mire, highest Fe content was recorded in the middle part of the open fen vegetation, whereas the lowest concentration was found along the mire margin and close to the river. Schipper et al (2007) studied preconditions of vegetation zonation in a natural percolation mire in Fig. 4 Mire surface level along two transects (TR II and TR IV), water level dynamics in sampling points along the transects and vegetation types along the transect (1 brown moss-small and slender sedge fens, 2 Sphagnum-small sedge fens, 3 brown moss-tall sedge fens, 4 tall sedge-reed fens, 5 pine-birch fen woodlands and shrublands, 7 inundated alder woodlands, 8 alder spring fen woodlands) the Ob river valley (western Siberia) and found a similar relation to iron concentration pattern as in the Rospuda mire.…”

Biomass production of the last remaining fen with Saxifraga hirculus in Switzerland is controlled by nitrogen availability

“…The Polish site was recorded in 1987, it was located in a dwarf shrub community Betuletum humilis (Wassen et al 1990). The Russian sites were located in the valley of the Ob river in Siberia (Schipper et al 2007) in a Carex lasiocarpaParnassia palustris community (Tanneberger and Hahne 2003). Site 1 was recorded in 2001, sites 2, 3 and 4 were recorded in 2003.…”