Hydrophyten in der Petite Camargue Alsacienne Elsass (Frankreich)

Abstract

Hydrophytes, which are submersed and floating aquatic plants, are adapted to dynamic processes of the formerly widespread alluvial floodplains. Nowadays the waterbodies are mostly isolated from the river system and differ substantially regarding environmental conditions and dynamics. In this study the distribution of hydrophytes in the nature reserve Petite Camargue Alsacienne situated on the former floodplain of the river Rhine was recorded and compared with earlier records. Also the effect of environmental factors and isolation on composition and number of hydrophyte species were examined and discussed. 28 vascular hydrophytes and 7 Chara species were recorded. No correlation can be shown between hydrophyte species composition or number of species and environmental variables. Biotic factors like competition, herbivory and dispersal must therefore play an important role in structuring hydrophyte communities. Different dispersal mechanisms are discussed, particularly the importance of dispersal by animals and man. Due to differences in dispersal abilities isolation has different effects on distribution of hydrophytes. More information on dispersal mechanisms is needed in order to protect these species.