Re‐establishing a saltmarsh vegetation structure in a changing climate

Abstract

Summary A major management decision in an ecological restoration or rehabilitation project is whether supplementary planting or natural vegetation regeneration is the better alternative or if a combination can be applied. Management decisions are further complicated when the project involves saltmarsh as tidal cycles, the effects of salinity and sea level rise add to the complexity of decisions. The ecological values of the saltmarsh community in Australia were only recognized relatively recently but the endangered ecological community listing in 1994 (under the New South Wales Threatened Species Conservation Act 1995) highlighted the need to protect, rehabilitate and restore saltmarsh.This project measured vegetation change after soil profile reconstruction in saltmarsh surrounding Sponsors Lagoon, Fingal Peninsula in north coastal New South Wales, Australia. Restored sites (planted and non‐planted) were compared with nearby disturbed (control) and reference sites. The dominant species in the community to be restored were Saltwater Couch (Sporobolus virginicus), Suaeda (Suaeda australis), Sarcocornia (Sarcocornia quinqueflora ssp. quinqueflora and Sea Rush (Juncus kraussii ssp. australiensis). Changes in percentage cover of the species in the first three years after soil reconstruction work showed that the dominant Saltwater Couch established only from vegetative growth arising from remnant vegetation but there was strong seedling regeneration of several other species. It was concluded that planting is important for species that are less vagile, in larger, denuded parts of this site where their resilience is lower and natural regeneration potential is limited. An understanding of the biology of the individual species is therefore likely to be essential in saltmarsh restoration projects. A combination of techniques, incorporating planting of slower establishing species and encouragement of seed‐germinated colonizers is useful for initial site stabilization and progressive ecological recovery at this site. The inclusion of migration zones in the planning phase will allow for the long‐term viability of this restoration project.