title: Seed germination in a southern Australian temperate seagrass.
abstract: In a series of experiments, seeds from a temperate seagrass species,Zostera nigricauliscollected in Port Phillip Bay, Victoria, Australia were exposed to a range of salinities (20 PSU pulse/no pulse, 25 PSU, 30 PSU, 35 PSU), temperatures (13 °C, 17 °C, 22 °C), burial depths (0 cm, 1 cm, 2 cm) and site specific sediment characteristics (fine, medium, coarse) to quantify their impacts on germination rate and maximum overall germination. In southern Australia the seagrassZ. nigricaulisis a common subtidal species; however, little is known about the factors that affect seed germination which is a potential limiting factor in meadow resilience to natural and anthropogenic disturbances. Overall seed germination was low (<20%) with germination decreasing to <10% when seeds were placed in the sediment. When germination ofZ. nigricaulisseeds was observed, it was enhanced (greater overall germination and shorter time to germination) when seeds were exposed to a 20 PSU pulse for 24 h, maintained at salinity of 25 PSU, temperatures <13 °C, in sediments with fine or medium grain sand and buried at a depth of <1 cm. These results indicate that germination ofZ. nigricaulisseeds underin situconditions may be seasonally limited by temperatures in southern Australia. Seed germination may be further restricted by salinity as freshwater pulses reaching 20 PSU are typically only observed in Port Phillip Bay following large scale rainfall events. As a result, these populations may be particularly susceptible to disturbance with only a seasonally limited capacity for recovery.
authors.affiliation: Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University , Waurn Ponds , Victoria , Australia.
authors.forename: Erin
authors.initials: E
authors.lastname: Cumming
authors.affiliation: Department of Biology and Marine Biology, Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC, United States; Centre for Tropical Water & Aquatic Ecosystem Research, James Cook University, Cairns, Queensland, Australia.
authors.forename: Jessie C
authors.initials: JC
authors.lastname: Jarvis
authors.affiliation: Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University , Waurn Ponds , Victoria , Australia.
authors.forename: Craig D H
authors.initials: CD
authors.lastname: Sherman
authors.affiliation: Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, Australia; Centre for Tropical Water & Aquatic Ecosystem Research, James Cook University, Cairns, Queensland, Australia.
authors.forename: Paul H
authors.initials: PH
authors.lastname: York
authors.affiliation: Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University , Waurn Ponds , Victoria , Australia.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Smith
keywords: Burial depth; Heterozostera tasmanica; Resilience; Salinity; Seagrass; Sediment; Temperature; Zostera nigricaulis