Similarity between seed banks and above-ground vegetation along a salinity gradient

Zonation of above-ground vegetation often occurs in salt marshes along salinity and moisture gradients. The above-ground vegetation and seed bank in four physiognomically different vegetation zones in a salt marsh were compared to determine their level of similarity using percent similarity as a distance measure. 10-m transects were established along a salinity gradient through four different vegetation zones; a Salicornia zone, a Salicornia-Atriplex zone, an Atriplex zone and an Atriplex-Hordeum zone. A UPGMA cluster analysis demonstrated that the above-ground vegetation was not usually highly correlated with the seed bank composition of zonal communities. Since seeds of these annual salt marsh species occurred in all zones, the levels of salt stress may be the main factor determining which species were found in the above-ground vegetation.