Mineke Wolters

Soil seed bank and driftline composition along a successional gradient on a temperate salt marsh

Abstract This study focuses on the relationship between vegetation succession and soil seed bank composition on the Schiermonnikoog (The Netherlands) salt marsh over 100 yr. The importance of driftline material in seed dispersal and the relationship with succession is also investigated. The results indicate that the majority of species have a transient or short-term seed persistent bank. Seeds of most species are able to float over the salt marsh and become concentrated in the driftline higher up the marsh. After plants have established a seed bank forms, which disappears when vegetation is replaced by later‐successional species. Exceptions are Spergularia maritima which is still present in the seed bank of late successional stages, and Juncus gerardi and Glaux maritima which appear in the seed bank of early successional stages, but are absent in the vegetation. Based on the results of this study constraints and possibilities for salt‐marsh restoration by de‐embankment are discussed. Nomenclature:van der Meijden (1990).

The natural regeneration of salt marsh on formerly reclaimed land

ABSTRACT Question: Does the vegetation of restored salt marshes increasingly resemble natural reference communities over time? Location: The Essex estuaries, southeast England. Methods: Abandoned reclamations, where coastal defences had been breached in storm events, and current salt marsh recreation schemes were surveyed giving a chronosequence of salt marsh regeneration from 2 to 107 years. The presence, abundance and height of plant species were recorded and comparisons were made with adjacent reference salt marsh communities at equivalent elevations. Results: Of the 18 paired sites surveyed, 13 regenerated marshes had fewer species than their adjacent reference marsh, three had an equal number and two had more. The plant communities of only two de-embankment sites matched that of the reference community. 0–50 year old sites and 51–100 year old sites had fewer species per quadrat than the 101+ year sites and the reference salt marshes. There was a weak relationship between differences in species richness for regenerated and reference marshes and the time since sites were first re-exposed to tidal inundation. Cover values for the invasive and recently evolved Spartina anglica were greater within regenerated than reference marshes. Conclusions: Salt marsh plants will colonise formerly reclaimed land relatively quickly on resumption of tidal flooding. However, even after 100 years regenerated salt marshes differ in species richness, composition and structure from reference communities. Nomenclature: Rodwell (2000) for plant communities, Stace (1997) for vascular plants and Hardy & Guiry (2003) for algae.