Conservation of Zostera marina: Evaluating the effectiveness of seed storage conditions for restoration

Abstract

Zostera marina is a seagrass species that acts as an ecosystem engineer, creating biodiversity-rich habitats that offer important ecosystem services. The species is, however, in decline across its range owing to environmental change and anthropogenic impacts. Conservation work includes the use of seeds and shoots to restore seagrass meadows, although ex situ storage of Z. marina seeds is a small area of research and there is no one set protocol. This study investigated the effects of salinity and temperature on the maintenance of dormancy and viability of Z. marina seeds during cold storage. Seeds were stored at 1 °C and 4 °C, in a range of salinity solutions (20, 30, 40, 50, 60 and 70 psu) over a period of 112 days. Results were collected by a velocity-based viability test at 28-day intervals, with seeds categorised as either viable, non-viable or germinated. Over the course of the storage period, results indicated that low salinities (20, 30, 40 and 50 psu) would exhibit premature germination during storage as well as loss of viable seeds at either temperature, while 60 and 70 psu groups have zero germinations and the highest viable seed number is found in 70 psu groups. Analysis revealed that overall temperature was only statistically significant in relation to viable seeds at 1 °C, suggesting that this is the better temperature to maintain viability. The study indicates that low salinity should be avoided for Z. marina seed storage; instead, a salinity solution of 70 psu at 1 °C storage for up to 4 months could ensure seed dormancy is unbroken and few seeds become non-viable. Overall, results from this study were used to create a simple storage protocol that could contribute to community-based restoration projects.