Vegetation succession and soil cover transformation after extreme flood :a case study from the Sázava river floodplain

Abstract

The goal of this study was to assess impact of flood on soil and vegetation cover in the Sázava river floodplain after an extreme spring flood in 2006. The impact on soil cover resulted mainly in vast erosion and sedimentation leading to differentiation of three fluvisol subtypes according to sediment coarseness. The impact on vegetation resulted in regeneration of herbaceous alluvial vegetation buried under a thin layer of sediments, succession of vegetation on eroded sites and succession of vegetation on new sediments. The regeneration of alluvial vegetation, expressed by vegetation cover, reached the same level as vegetation on undisturbed sites after 8 months. The succession of vegetation on new sites, studied within 25 m2 sampling plots and tested by using multivariate statistical methods, was primarily dependent on diaspores left on sites by the flood and on site type as well. The vegetation cover reached 100 percent at the end of the first vegetation season in both cases. There was a significant difference in species‘ composition between eroded sites and sites on thick layers of sediments each year as hypothesized. There was also significant difference in vegetation succession between site types