WP1 Seedling processing

Design of eelgrass seed and seedling processing for restoration purposes.
Well-established eelgrass meadows produce large numbers of seeds that can be harvested and
stored for later seed and seedling transplantation. However, a major bottleneck with the use of
seeds for eelgrass restoration is the transition of seeds to successful seedling establishment in
the field (Valdemarsen et al. 2010). Even in areas with adequate water quality germination
success is low, and only a small proportion (<10%) of seedlings typically survive their first months due to loss factors such as sediment conditions, hydrology and bioturbation (van Katwijk et al. 2004; Marion & Orth 2012). Methods and techniques will be developed to maximize seed viability and improve microhabitats for seed germination and seedling establishment by addressing loss factors identified in the selected transplant sites (WP 4). Suitable source populations and their reproductive phenology will be identified. Moreover, methods for harvest, sorting and storage of seeds will be tested in collaboration with the international partners. Seeds germinate following a period of dormancy depending on environmental conditions as well as climatic factors (Moore et al. 1993). The onset of seed germination under natural conditions will therefore be examined to evaluate environmental cues triggering germination and optimize the timing of seeding. Also, the effect of planting depth and seeding density will be examined. Techniques to facilitate seedling survival and growth will be developed and adapted to environmental conditions at the sites where eelgrass transplantations are attempted (WP 2 and 5). The experimental approaches include laboratory and microcosm studies with controlled chemical and physical conditions to isolate effects of loss processes acting on seeds and early-stage seedlings.