Innovative Techniques for Large-scale Seagrass Restoration Using Zostera marina (eelgrass) Seeds (original) (raw)
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Buoy-deployed seeding: Demonstration of a new eelgrass (Zostera marina L.) planting method
Ecological Engineering, 2005
We describe an innovative method of dispersing Zostera marina L. (eelgrass) seed that has the potential to facilitate large-scale, citizen-based restoration programs. Mature reproductive shoots of eelgrass were collected during the second week of seed release and stocked into mesh pearl nets suspended from buoys set in 0.04 ha plots. As the seeds ripened, they were naturally released from the nets, fell to the bottom and germinated to form a distinct arc-shaped meadow under each buoy. A survey of seedling survival indicated that recruitment was at least 6.9% based on estimated seed abundance within each net. The advantages of this method are that (1) harvest and deployment of reproductive shoots takes place on the same day, eliminating the need to store reproductive shoots in an onshore storage facility, to obtain a sufficient number of seeds for large-scale restoration programs and (2) once trained, citizens can participate in both the collection and seeding phases, thereby, increasing awareness and value of Z. marina restoration programs. The technique presented allows for a low-cost, efficient, and simple method for successfully dispersing seed, which consequently has a significant impact on establishment of plants from seed. These attributes can also influence restoration programs for other species of aquatic plants for which the seeding of sites, historically degraded but now habitable, is possible.
Restoration Ecology, 2009
Selection of strategies to efficiently utilize limited seed supplies in efforts to restore the seagrass Zostera marina (eelgrass) requires a better understanding of the processes that limit seedling establishment at potential restoration sites. We investigated the effect of seed distribution timing on seedling establishment and tested for interactive effects of seed burial and distribution timing. We also investigated the effect of habitat type on seedling establishment by distributing Z. marina seeds inside and outside of established Ruppia maritima (widgeongrass) patches and examined mechanisms causing habitat differences by manipulating seed position (buried or unburied) and vulnerability to seed predators (unprotected or protected in packets). Seeds distributed on the sediment surface in the summer (July or August) produced fewer seedlings than seeds distributed in fall (October) in five of six trials over 3 years.
Aquatic Botany, 1999
Eelgrass (Zostera marina L.) restoration efforts have historically focused on the use of adult vegetative shoots because of generally low success using seeds, a propagule of potential, but littleknown utility, in restoration work. Previous work has shown that approximately 15% of seeds broadcast on unvegetated sediments survive to seedling stage, with losses in part resulting from predation, burial, or lateral transport. We conducted experiments using seeds in burlap bags under both laboratory and field settings to determine if protecting seeds increased survival or germination rates. Retention of seeds from preparation to initial sampling six months later was nearly 100%. Seedling survival at the field sites ranged from 41 to 56% in the burlap bag treatment, compared to 5-15% for seeds without burlap bag protection. Under laboratory conditions, seedling survival was identical in both treatments (50%). However, successful seedling growth noted in the protected treatment after 6 months was lost by 8 months because of significant sand accumulation over anchored seed bags. These preliminary results are encouraging for future restoration efforts that shift the focus to the use of seeds rather than adult plants, as greater survival of seeds in a protected environment can offer enhanced opportunities for addressing both basic and applied questions in restoration ecology. 0304-3770/99/$ -see front matter ©1999 Elsevier Science B.V. All rights reserved. PII: S 0 3 0 4 -3 7 7 0 ( 9 9 ) 0 0 0 0 8 -X
Sowing the Seeds of Seagrass Recovery Using Hessian Bags
Frontiers in Ecology and Evolution, 2019
Seagrass meadows are an important wetland habitat that have been degraded globally but have an important carbon storage role. In order to expand the restoration of these productive and biodiverse habitats methods are required that can be used for large scale habitat creation across a range of environmental conditions. The spreading of seagrass seeds has been proven to be a successful method for restoring seagrass around the world, however in places where tidal range is large such methods become limited by resultant water movements. Here we describe and test a method for deploying seagrass seeds of the species Zostera marina over large scales using a new, simple method "Bags of Seagrass Seeds Line (BoSSLine)." This method involved planting seeds and sediment using natural fiber hessian bags deployed along strings anchored onto the seabed. When deployed in a suitable environment 94% of bags developed mature seagrass shoots, unfortunately one site subjected to a large storm event resulted in sediment burial of the bags and no seed germination. Bags were filled with 100 seeds with each leading to the development of 2.37 ± 2.41 mature shoots (206 ± 87 mm in length) 10 months after planting. The method was proven successful however the experiments illustrated the need to ensure habitat suitability prior to their use. Low seed success rate was comparable to other restoration studies, however further trials are recommended to ensure ways to improve this rate. In conclusion, this study provides evidence for an effective, simple method "Bags of Seagrass Seeds Line (BoSSLine)" for deploying seeds of the seagrass Zostera marina over large scales.
Eelgrass (Zostera marina) restoration on the west coast of Sweden using seeds
MArine Ecology Progress Series, 2016
Along the northwest coast of Sweden, over 50% of Zostera marina L. (eelgrass) meadows have vanished since the 1980s. With the improvement of conditions, there is a growing interest to restore lost habitats, but methods are lacking for restoration of eelgrass beds at high latitudes where long winters create special challenges. We assessed if seed planting could be used for large-scale restoration, with the aim to identify the major causes of seed and seedling loss and to determine which planting method best increases restoration success. In the laboratory, we identified optimal conditions for long-term seed storage and demonstrated that eelgrass seeds can be successfully stored for 8 mo before being planted in the spring. However, field studies did not find an increased seedling establishment in seeds planted in the spring of 2013 compared to those planted in the fall of 2012. Field results suggest that the main causes for the seed loss were seed predation from crabs, seed transport by currents and bioturbation by lugworms, while the main processes affecting shoot development were light availability and physical disturbance. Covering the seeds with a layer of sand increased seedling establishment 2 to 6 times compared to uncovered seeds, probably through the reduction of seed predation and seed transport, and could potentially be developed as a method to reduce losses during restoration. In addition, positive feedback mechanisms (i.e. sediment resuspension and drifting macroalgae mats) may also prevent natural recovery and restoration success. However, high seed loss (on average 98.6%) and high shoot mortality pose a challenge that need to be addressed before restoration using seeds can be recommended for large-scale restoration.