Mangroves and sea grass are important for marine biodiversity
Mangroves and Saltmarshes: Why are they important?
A significant proportion of the estuarine coastline of the 900 km2 Great Sandy Straits supports mangroves and / or saltmarshes.
Mangrove and saltmarsh habitats support ecologically diverse communities of plants and animals that include fish, crustaceans, molluscs, insects, mammals, birds and reptiles.
Mangroves and saltmarshes are particularly important as they form ecosystems that link the marine and terrestrial environments and provide habitat for both marine and terrestrial organisms including some endangered and vulnerable species.
Mangroves in Snapper Creek
For further information on the importance of mangroves in our region please follow this link. About mangroves - Tin Can Bay Dolphins
For information generally on mangroves and their importance go to the Mangrove Watch web site.
Bird feeding in a seagrass meadow exposed at low tide off Fraser Island
References and links
- Great Barrier Reef Marine Park Authority, 'Environmental Status: Mangroves and Saltmarshes', GBRMPA, June 2006
- Seagrass Educators Handbook by Len McKenzie: Seagrass-Watch | seagrass education
- Seagrass-Watch web site: www.seagrasswatch.org
What are the main threats to mangrove forests, saltmarshes and seagrass from the proposed marina developments?
- Construction impacts include direct removal, altered hydrology
- Disturbance of acid sulphate soils, also linked to fish mortality and disease, as well as toxic algal blooms
- Pollution
- Dredging impacts, including direct destruction of seagrass beds as well as increased sediment runoff and water turbidity
- Large, fast displacement hull power boats are also likely to lead to loss of seagrass in relatively shallow waters.
- Damage to seagrass from boat propellers and anchors when away from the marina
- These threats in turn directly impact on the fauna that rely on the overall health of the ecosystem - reducing its carrying capacity.
Mangrove wetland area adjacent to Carlo Point - the site of one of the proposed marinas
The importance of Seagrass
Seagrass can easily be seen to be critical to the Dugong and Green Turtle populations as it is a significant part of their diet. Any reduction in seagrass has a direct impact on these species.
However, it is more important to the rest of the marine environment than it may appear at first glance. In fact it impacts on the biodiversity of the entire marine ecosystem including marine mammals, turtles and fish.
The following are some of the ways the seagrass works for the health of the marine environment:
- Fish nursery
- Provides food for benthic (bottom dwelling) aquatic life, which in turn provides food for juvenile fish
- Interaction with mangroves to stabilise the environment
Watch this video from SeagrassWatchHQ for more information about the importance of seagrasses.
The Great Sandy Strait has over 5000 hectares of seagrass beds making it a very productive marine ecosystem. The local community are actively involved in the monitoring of this seagrass as part of the global Seagrass-Watch program.
For a perspective on the importance of seagrasses to fish see this Fishing World article by Dr Ben Diggles with a focus on seagrasses in Moreton Bay and Pumicestone Passage / Bribie Island areas.
For further information on seagrass please head to the following sites
- Seagrass Watch Great Sandy Strait
- SSSMeg About Seagrass