Seagrass viviparous propagules as a potential long-distance dispersal mechanism
journal contribution
posted on 2023-05-18, 07:59authored byThompson, ACG, York, PH, Smith, TM, Sherman, CDH, Booth, DJ, Keough, MJ, Donald RossDonald Ross, Macreadie, PI
Resilience of seagrass meadows relies on the ability of seagrass to successfully recolonise denuded areas or disperse to new areas. While seed germination and rhizome extension have been explored as modes of recovery and expansion, the contribution of seagrass viviparous propagules to meadow population dynamics has received little attention. Here, we investigated the potential of seagrass viviparous propagules to act as dispersal vectors. We performed a series of density surveys, and in situ and mesocosm-based experiments in Port Phillip Bay, VIC, Australia, using Zostera nigricaulis, a species known to produce viviparous propagules. Production of viviparous propagules was higher at sites with high wind and current exposure, compared to more sheltered environments. A number of propagules remained buoyant and healthy for more than 85 days, suggesting the capacity for relatively long-distance dispersal. Transplanted propagules were found to have improved survivorship within seagrass habitats compared to bare sediment over the short term (4 weeks); however, all propagules suffered longer-term (<100 days) mortality in field experiments. Conditions outside of meadows, including sediment scouring, reduced the likelihood of successful colonisation in bare sediment. Furthermore, sediment characteristics within meadows, such as a smaller grain size and high organic content, positively influenced propagule establishment. This research provides preliminary evidence that propagules have the potential to act as an important long-distance dispersal vector, a process that has previously gone unrecognised. Even though successful establishment of propagules may be rare, viviparous propagules show great potential for seagrass populations given they are facing global decline.
History
Publication title
Estuaries and Coasts
Volume
38
Pagination
927-940
ISSN
1559-2723
Department/School
Institute for Marine and Antarctic Studies
Publisher
Springer New York LLC
Place of publication
United States
Rights statement
Copyright 2014 Coastal and Estuarine Research Foundation