LEMIEUX, Ben – 2010

The Influence of the Soil Seed Bank and Hydrochory on the Early Re-Colonization Dynamics on Two Salt Marsh Restoration Projects

Salt marsh restoration efforts in Nova Scotia have thus far taken a self-designed approach where recruitment of target vegetative community members into the restoration site is left to occur by natural means. Previous research in the province has shown that salt marsh re-colonization is dependent on distances to internal creek structures or by transport on ice blocks. The relative contribution of seeds to marsh re-colonization has not been studied thus far on Nova Scotia salt marshes. The aim of the research was to determine the relative contribution of the remnant portion of the soil seed bank prior to restoration as well as sample water dispersed seeds, hydrochory, being deposited within the restoration site post dyke breach on two restoration projects with the Avon Estuary of Nova Scotia.

This research took place on two dykelands in Nova Scotia whose dyke walls were breached in the summer of 2009. Buffer zones of 2m, 7m, 20m, 54m, and 148 m away from the Higher High Water Mean Tide level were created using ArcGIS version 9.3. Within each buffer zone 3 soil seed bank samples were taken by using a metal core measuring 4.5 cm with a 10 cm depth from the site prior to restoration. These samples were then germinated under greenhouse conditions to determine the viable portion of the soil seed bank. Hydrochory was sampled post-restoration using artificial turf traps that were placed using the same buffer zones as were used for the soil seed bank. The hydrochory samples were cold stratified for a one month period before the germination survey began. There were some difficulties in the greenhouse to grow all plans to maturity. However, when comparing results with the above ground vegetation it becomes apparent that the soil seed back may be reflective of the above ground vegetation community membership. Hydrochory traps showed that seed dispersal may also be a short range phenomenon as no major target species were found on the artificial turf traps within the restoration area.