The First Managed Salt Marsh Restoration in New Brunswick, Canada: Lessons Learned

Ollerhead, J.; Abbandonato, H., and McLellan, N., 2024. The first managed salt marsh restoration in New Brunswick, Canada: Lessons learned. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 705-709. Charlotte (North Carolina), ISSN 0749-0208. In Maritime Canada, there is significant opportunity to conserve salt marshes, to preserve accommodation space into which salt marshes can migrate, and to undertake salt marsh restoration projects. The purpose of our study was to monitor the progress of a managed salt marsh restoration project at Musquash, NB, Canada. In 2005, a dyke (abandoned railway bed) was removed to allow salt water to once again flood an area of agricultural land that was reclaimed salt marsh. Prior to 2005, there was very limited hydrologic connectivity between the site and the macrotidal Musquash Estuary. Most of the vegetation was terrestrial. Since dyke removal, the hydrologic connections have restored and the site is regularly flooded with sea water. Between 2005 and 2022, the terrestrial vegetation died (e.g., Betula sp. trees) and was replaced by salt marsh species (e.g., Sporobolus sp.). Sediment has been deposited at a rate of 9.8 ± 4.0 mm/a, a rate greater than the estimated rate of relative sea level rise of 8.5 ± 3.5 mm/a (2010-2030). In 2021, 25 cores were collected from the site and analyzed using loss-on-ignition (LOI) to quantify amount of organic carbon compounds (Corg) with depth. Corg density was found to be 0.021 g/cm3 ± 0.004 g/cm3. Mean total carbon stock calculated from Corg values for the whole site was 51.9 Mg/ha. These values compare well to, and are higher than, values measured at other Bay of Fundy sites. The project is judged to be a success. Important salt marsh ecosystem services have been restored, nature-based protection is being provided for the adjacent highway, and Corg is being sequestered. Lessons learned have been subsequently applied to the successful restoration of other sites within the Bay of Fundy over the past 15 years.