Effects of salinity and temperature on the germination of Phragmites australis, Juncus kraussii, and Juncus acutus: Implications for estuarine restoration initiatives

We describe effects of salinity and temperature on germination characteristics of three dominant macrophytes, Phragmites australis, Juncus acutus, and J. kraussii, located in wetlands along the Hunter River, New South Wales, Australia. These wetlands were altered, from estuarine to freshwater habitats, by flood mitigation activities initiated during the 1970s. Tidal restoration to approximately 300 hectares of the marsh is planned to occur by 2008, with the goal to reduce freshwater vegetation in favor of salt marsh species. We determined if timing restoration projects to coincide with natural germination cycles or seasonal conditions of high salinity would be disadvantageous to P. australis or J. acutus germination. Germination trials lasted 25 days under two temperature range treatments (l0–25 and 15–30°C) and a salinity gradient (0–30 ppt). Many P. australis seeds commenced decomposition after three days (up to 58%). Increased salinity lowered germination in all species; however, only P. austr...