Aquatic plant dispersal in wetlands

Project summary

The Gippsland Lakes in Victoria are internationally recognised by the Ramsar Convention. They consist of a distinctive network of high-value wetlands that support large numbers of flora and fauna, particularly water birds. However, changes in hydrology have resulted in fragmentation and increased salinity in this system. Some wetlands occur along rivers or adjacent to Lake Wellington, while others within the Gippsland Lakes region have no physical connection with any rivers or lakes.

This project addresses a critical information gap in the relative importance of hydrology, waterfowl and wind for the interconnectivity of high-value wetlands. Seeds, pollen and plant fragments may be transported across the landscape to new sites. Wetlands can therefore be viewed as interconnected mosaics linked by plant dispersal, rather than as isolated sites.

The dispersal of plants is likely to be an important factor in maintaining the species richness and genetic diversity of aquatic vegetation, but little is known of the role of the various plant dispersal mechanisms. The degree of connectivity between wetlands and the dispersal mechanisms of seed and pollen have a direct effect on the pattern of genetic variation within wetland species. In addition, the dominant reproductive mode will influence both the amount and the structuring of genetic variation across the landscape.

Seed movement in and out of wetlands has been monitored using wind traps and water traps and also by sampling river flow throughout the year. Two plant species, Phragmites australis (Poaceae) and Triglochin procerum (Juncaginaceae) are being used to study the landscape genetic patterns of predominantly wind-dispersed and water-dispersed species.

Project team

• Elizabeth James (Royal Botanic Gardens Melbourne)
• Elisa Raulings (Monash University)
• Kay Morris (Monash University)
• Ross Thompson (Monash University)
• Ralph McNally (Monash University)

Support

• Australian Research Council
• Royal Botanic Gardens Melbourne
• Parks Victoria
• Department of Sustainability and Environment
• West Gippsland Catchment Management Authority
• East Gippsland Catchment Management Authority
• Gippsland Lakes Coastal Board
• Field and Game Australia
  
• Australian Ecosystems