Hydro-ecological assessment of vegetation of Dutch river habitats.
Aggenbach, Camiel J. S.; Pelsma, Tim A. H. M.
Ecological models for floodplains predict vegetation development on regional scale, while non-river specific, hydro-ecological models can assess on a local scale. PREVIEW (Predicting Vegetation in Excavated Winterbeds) was developed in order to predict succession at a local scale for excavated river forelands in the Dutch Rhine system. The data underlying the model consisted of vegetation records linked with data on soil chemistry and physics, water levels and biomass production. From this data and literature sources, ecological ranges of phytosociological units, according to the Dutch classification system, were derived. Differences in such ranges between river courses were found. The time lapse within which a vegetation unit will occur after excavation was determined by literature and expert judgement. The minimal model input requirement includes clay fraction, inundation duration throughout the year and growing season, lowest groundwater level and vegetation management. The model's relevance to lowland river rehabilitation is: (1) the large data set underlying it, (2) its application on a local scale, which fits well to the practice of nature management, (3) its simple input, (4) its possibility to generate a better input for hydraulic models, and (5) its capacity to evaluate management scenarios.