Flood meadows represent semi-natural vegetation by the great rivers in northern Finland. Physical forces acting on the river

banks such as ice, fl oods and annual sedimentation create temporarily oxygen-free conditions as well as open space for the

growth of grasses and herbs. Besides fl ood dynamics, clearing and mowing for winter forage maintained fl ood meadow

series representative for centuries. When the regular management for winter forage ceased by the end of 1950 ’ s, fl ood

meadows started to overgrow by trees and shrubs, and thus change back to their virgin state.

Diff erent meadow types are traditionally arranged into a grassland continuum on the basis of their soil moisture

gradient: from dry to wet meadows, from which dozens of vicariating associations emerge. Fine-featured vegetation types

may be categorized into six functional groups according to their vicinity to riverside and fl ooding frequency.

Th e aim of this study was to defi ne the state of fl ood meadows in Finland by studying the data collected during the

nationwide inventory (NWI) of traditional rural biotopes in Finland 1992 – 2001, and by comparing NWI with the vast

material collected by 14 diff erent researchers starting from the beginning of the 1900 ’ s and reaching into fi rst decade of

present millennia. First, the NWI and the researchers ’ data were studied alone and thereafter the material was pooled and

compared.

Results show that management cessation have had only minor eff ect on wet fl ood meadows close to mean water level.

Equisetum fl uviatile -, tall Carex - and moist grass fl ood meadows remain largely open without human infl uence. However,

combined eff ect of ceased mowing and decreased sedimentation due, e.g. to watercourse regulation and hydraulic engineering,

changes also the wet types into open- and shrub-covered swamps. In contrast, without management the uppermost tall

herb-, moist grass- and small herb fl ood meadows turn quickly into thickets. As a consequence, today moist grass-, tall- and

small herb fl ood meadows are critically endangered habitat types in Finland.