The influence of tidal creek networks on wetland vegetation

Abstract

Six years of research and experience with restoring Bay of Fundy (Nova Scotia) salt marshes have shown that salt marsh plant species can colonize readily without planting, if the barriers to tidal flow are removed and suitable abiotic conditions (i.e. elevation) are present. Reactivated hybrid creek networks are potentially highly important to the restoration process, as they may represent the primary transport mechanism for seeds and vegetative material for re-colonization. It is unknown how important the hybrid creeks are for the colonization of target species (Spartina alterniflora; S. patens; Salicornia europaea; Suaeda maritima; Atriplex spp.). Utilizing the Cogmagun River salt marsh restoration site (Hants County), restored in 2009, this research set out to discover if there was a relationship between proximity to creeks and the colonization rates of target salt marsh species. We were also interested in finding out if seedling coverage of Suaeda maritima in the previous year had a relationship with colonization rates in the following year. The results showed that colonization rates were positively related to proximity to the main tidal creek for four out of five target species (S. alterniflora, S. europaea, S. maritima, and Atriplex spp.). The presence of S. maritima in the previous year did increase the colonization rates of newly established communities. These results provide a fine-scale complement to existing and ongoing macro-scale studies and further clarify the relationships between abiotic properties of a recently restored tidal wetland and colonization.