Talk, 36. Jahrestagung der GFÖ, Bremen: 2006-09-11 - 2006-09-15
Abstract:
Springs and their vegetation have been subject of studies on bioindication of environmental stress (e.g. acidification due to deposition of airborne pollutants) for decades. At larger scales, such as catchments or landscapes, a strong correlation between acidity and vegetation composition was found in previous surveys. This study deals with the spatial heterogeneity of vegetation and hydrological parameters at the within-spring scale, aiming at a comparison of phenomena between different scales.
In total 15 springs in the Frankenwald (NE-Bavaria) were investigated, using an equidistant hexagonal sampling design. Vegetation data and hydrological parameters were recorded in 706 subplots in total, using a piezometer technique for gaining water from the rhizosphere. Ordination techniques and GIS were used for the data analysis.
Surprisingly, springs are characterized by a remarkable small-scale differentiation of hydrological conditions and vegetation composition, with the most distinct patterns found at the springs’ margins. These findings contradict the wide-spread assumption that springs are very homogeneous systems with an abrupt shift to their surrounding ecosystems. At the within-spring scale patterns of hydrology and vegetation are strongly interrelated. Consequently, at all investigated scales (within-spring to inter-landscape) analogue relations between hydrology and vegetation can be shown, with pH being the main driving factor for vegetation composition.