SEED DISPERSAL OF HALOPHYTES IN TIDAL SALT MARSHES

1 Dispersal of halophyte propagules by tidal currents was studied in t ransects along the tidal gradient in a salt marsh in the Netherlands u sing standing nets fixed to the soil surface and floating nets. 2 Sign ificant interspecific differences were found in propagules caught in s tanding or in floating nets. 3 The transport of propagules was mainly determined by the tidal currents: neither wind direction or speed nor the height of the high tide played a significant role. 4 In the vegeta ted marsh a net upward transport of propagules with the flood currents was found. Comparatively few propagules were transported into the mar sh from elsewhere with the incoming tide; a significantly higher numbe r of propagules was transported out of the marsh with the ebb currents . 5 There was substantial exchange of propagules within the marsh. Exp ort of propagules especially of species growing in the lower parts of the marsh indicate a potential exchange between different salt marshes .