|
Seagrasses live in the coastal waters of most of the world’s continents. They are the main diet of dugongs and green turtles and provide a habitat for many smaller marine animals. They also absorb nutrients from coastal run-off and stabilise sediment, helping to keep the water clear.
Seagrasses are commonly found on tidal mudflats in estuaries, on shallow sandy areas close to the coast, in coral reef lagoons and around sand cays. In Australia they grow in temperate and tropical waters, from the Torres Strait to southern Tasmania.
The importance of the Great Sandy Strait cannot be overstated. Its extensive areas of mangroves and seagrass provide the habitat for many types of crustaceans, fish, dolphins, turtles and dugong. The area contains 5,554 hectares of seagrass meadows growing on intertidal sand and mud flats, with a tidal range of up to 4.1 metres.
The fern-like Halophila Spinulosa and Halophila Ovalis are the predominant species. Zostera Capricorni (pictured) and Halodue Uninervis are also common. In the Great Sandy Strait seagrass beds occur largely in the Kauri Creek/Tin Can Bay area. Monospecific stands of Cymodocea Serrulata (dugong-grass) are common here and there is only one other place in Queensland where this occurs. Cymodocea Serrulata is usually found as part of mixed communities in northern waters. The monospecific stands in the Sandy Strait may be botanical relics from periods when warmer waters occurred in the area.
Coastal seagrass habitats are dominated by physical disturbance caused by periodic events such as cyclones, storms and floods. Major floods in the Hervey Bay area have caused the temporary loss of the extensive seagrass meadows and the subsequent death of hundreds of dugong.
The strait is also experiencing unprecedented levels of coastal development with an associated rise in recreational and commercial pressures from tourism and boating, as well as recreation and commercial fishing. The Mary River Catchment consists of both sewered and unsewered residential and urban areas fringing the coastline. Leakage from septic tanks into nearby drains and creeks and storm water run-off threaten the viability of near-shore seagrass ecosystems. Extensive land clearing for cane production and dryland grazing has also altered the catchment, contributing to erosion and increased freshwater run-off into near-shore ecosystems.
Great Sandy Strait Fauna & Flora Watch An active Seagrass monitoring group exists in the region. The Great Sandy Strait Fauna & Flora Watch (GSSFFW) was established in the area in 1999 and remains one of the longest ongoing coastal data sets in the area. The group recently won an award for its efforts—the Burnett Mary NRM (Natural Resource Management) Coastal Community Award for 2007. The award is for excellence in activities that have contributed to the significant improvement of local coastal and/or marine environments, including estuaries, dune systems, wetlands and saltmarsh ecosystems.
Congratulations to all the team!
For more information about seagrass in general go to: www.seagrasswatch.org
Return to Threatened Flora & Fauna
|
|
Seagrass—Meadows in the Sea |
|
Since the time of the dinosaurs, three groups of flowering plants (angiosperms) colonised the oceans. Known as ‘seagrasses’, they are the only flowering plants that can live underwater.
Seagrasses grow like backyard grasses with roots, leaves and rhizomes (horizontal underground stems that form extensive networks below the surface), but they are not true grasses and are more closely related to water lilies and terrestrial plants such as lilies. |
|
Zostera Capricorni |
|
PROPOSED MARY RIVER DAM
IMPACTS ON THE GREAT SANDY
ABOUT THE GREAT SANDY |
|
ourgreatsandy.com Celebrating and Defending the Great Sandy Strait
|
|
Help Save Fraser Island’s Unique Marine Environment! |
|
Website created by Elisabeth Berry for 2Berries Communications. Copyright © 2008 ourgreatsandy.com. All rights reserved. |