Late holocene history and vegetation dynamics of a floodplain alder carr: A case study from eastern Bohemia, Czech Republic

Vegetation development in the lowland floodplain alder carr "Na bahne" (eas tern Bohemia, the Czech Republic) has been studied by means of pollen and m acrofossil analyses and combined with vegetation analysis performed over th e last 70 years. Local successional changes started with an oxbow lake (160 cal BC) which has later terrestrialised (630 cal AD). Then it changed from a typical alluvial fen into a Sphagnum- dominated spring mire (950 cal AD) supplied by water arising from a river terrace surrounding the locality fr om three sites. In the centre of this wetland a small patch of alder carr d eveloped (100 cal. AD), showing some tendency towards cyclic succession. Th e alder carr alternated several times with an open Carer fen (1100 cal AD t o recent). The last fen-to-alder carr transition has been documented by dir ect observation during this century. Possible autogenic and allogenic facto rs driving the succession are discussed. The model of autogenic cyclic succ ession corresponds well with direct field observations and can be used to i nterpret alder carr structure, its dynamics, and function.