Nursery-propagated plants from seed: a novel tool to improve the effectiveness and sustainability of seagrass restoration

1. Seagrasses and the valuable ecosystem services they provide are threatened world-wide by impacts of human activity. Numerous revegetation efforts have attempted to restore seagrasses. Most restoration programmes use plants collected from the field because of limited seed availability, low seedling survival and difficulty in culturing plants. However, this practice risks damage to donor populations and has the potential to reduce genetic diversity, which may counteract the desired effects of restoration. 2. A novel aquaculture system for producing plants (mother plants and cuttings) from a limited number of seeds was tested using Cymodocea nodosa as model species. The ability of transplanted cuttings to survive and grow in the natural habitat was also evaluated. 3. Seed germination was high (48%) compared with field conditions, and most seedlings produced mother plants with up to 78 m of rhizome and 300 shoots within 4 years in culture. All cuttings from mother plants regenerated new plants. Up to 100 transplants were produced from two seeds, and most (85%) of them survived and initiated the colonization of substrate, 1 year after planting. 4. Synthesis and applications. This study provides a robust protocol that can reduce plant and/or seed collection pressure on donor populations and produce a high number of transplants which show lower mortality rates during the early transplantation phases. This method can also help to preserve genetic diversity in restored populations, which should be one of the major goals of ecological restoration. This novel tool can be applied to other seagrass species with low or unpredictable reproductive success, therefore the development of nurseries should be incorporated in future restoration programmes. This is currently the only sustainable methodology to produce material for transplanting programmes for protected species.