Mangroves, salt marshes and sea grass lock away carbon at up to five times the rate of tropical forests.
Tweed Heads Caravan Park is situated between Tweed River and Terranora Creek. There is a saltwater lagoon and it is here that the creek edges are lined with Mangroves.
The Creek is rich in wild birds…pelicans, pacific gulls, herons, egrets and ibis live here. The mangroves are home to crabs and people like to fish in the waters when the tide is in.
There are mangroves growing near the lookout and park as you come to Kingscliff. Then the area is developed and the mangroves lessen.
Mangroves are plants or plant communities between the sea and the land in areas inundated by tides, usually at the mean high water level. They can take the form of trees, shrubs or palms. All share the ability to live in saltwater, although they do not appear to need salt to thrive. Growing in a salty environment means the mangroves lack competition. Only a limited number of plants have adapted to intertidal conditions.
Worldwide there are about 65 recognised species of mangrove plants. Approximately 40 species and hybrids of mangroves are known to occur in Queensland, although figures can change due to updates in species descriptions, taxonomy and new discoveries.
Sixof the more common mangroves are described to help you recognise these marine plants.
Mangroves roots perform a number of functions for a plant, they support it and they obtain essential nutrients and oxygen.
In unstable, sometimes semi-fluid, soil an extensive root system is necessary to keep the trees upright. As a result, most mangroves have more living matter below the ground than above it. The main mass of roots, however, is generally within the top 2m—mangroves do not grow deep tap roots, probably because of the poor oxygen supply below the surface.
Roots have different functions and 3 different forms. Radiating cable roots, punctuated by descending anchor roots, provide support. From this framework sprout many little nutritive roots that feed on the rich soil just below the surface and collect oxygen.
Little oxygen is available in fine, often waterlogged, mud. Many mangroves adapt by raising part of their roots above the mud. These roots are covered with special breathing cells (lenticels) which draw in air. The lenticels are connected to spongy tissue within the roots. When the roots are submerged by water, the pressure within these tissues falls as the plant uses up the internal oxygen. The resulting negative pressure means that when the root is re-exposed when the tide drops, more air is drawn in through the lenticels. https://wetlandinfo.des.qld.gov.au/wetlands/ecology/components/flora/mangroves/
The breathing roots of mangroves can become covered as sediments accumulate. Under normal conditions sediments build up at the rate of 1.5–2cm a year. To avoid being buried, species have developed different ways of keeping their roots in the air.
Red mangrove (Rhizophora stylosa) is commonly found close to the seaward side of communities. It is therefore subjected to high wave energy and has developed a system of stilt or prop roots. These spread far and wide, providing anchors for the tree as well as a large surface area for oxygen-absorbing lenticels. In common with other species, this mangrove also grows aerial roots (extra stilts) which arise from the branches or trunk. Studies have shown that these aerial roots alter dramatically in structure when they reach the mud: above it they have about 5% air spaces in their tissues, but 50% below.
Grey mangrove (Avicennia marina) grows a series of snorkels or peg or pencil roots, (pneumatophores). Experiments with related Avicennia species have shown that plants growing in coarse coral sand, with a good air supply to the roots, were able to survive after their pneumatophores were removed. However, those living in poorly aerated soil died when the pneumatophores were covered. In one situation, where they were covered with oil, the plants responded by growing aerial roots.
Orange mangrove (Bruguiera gymnorrhiza) develops knee roots. These are cable roots that have grown above the surface of the mud and then down into it again.
Looking glass mangrove (Heritiera littoralis) produces buttressed roots that are flattened, blade-like stilt roots.
Cannonball mangrove (Xylocarpus granatum) is buttressed, but the cable roots also appear above the ground in the fashion of knee roots. https://wetlandinfo.des.qld.gov.au/wetlands/ecology/components/flora/mangroves/
Myora Springs has fresh water coming from inland. It also has tidal sea water coming in when the tide is high. The mangroves here are on the side of the sea water.
The mangroves are quite small and have spreading roots. This area may have people walking and boat activity so the mangroves may not grow as densely as in other places. The area also gets fresh water from the Spring as well as 2 tidal incoming water each day.
Mangroves have traditionally been used by Indigenous Australians as sources of food, including mangrove fruit, mud crabs, clams and fish such as barramundi. Mangrove timber has traditionally been used to make canoes, paddles and weapons such as shields, spears and boomerangs. Because mangroves are flowering plants, the flowers are a likely source for honey; native bees are found in the mangroves during the various flowering seasons, and these are exploited now by commercial apiarists with their exotic bees. An important bivalve which is found in dead and decaying mangrove wood is called “mangrove worm“, Teredo spp. The action of the shells moving together excavates a hole through the wood, and the wood shavings accumulate in the stomach which becomes a distended, worm-like bag. The mangrove worm is chopped from the wood using an axe and is eaten raw.
| Mangrove species | Food use | Medical use | Tool use |
| Acrostichium speciosum | stems eaten after roasting | ||
| Aegiceras corniculatum | nectar | smoke for making babies strong (Belyuen) | axe handles and digging sticks (Belyuen) |
| Aegialitis annulata | children’s toys as stingrays (Groote Eylandt, Tiwi), whistles (Belyuen, Tiwi) | ||
| Avicennia marina, white mangrove | fruit eaten after treatment, (Mornington Is; Tiwi; Boorroloola, Roper R; Belyuen; Bardi; Dampierland); flavour in cooking mussels (Groote Eylandt); nectar | sting-ray and stonefish ‘stings’ (Milingimbi); ringworms, sores and boils (Yirrkala); scabies (general); ‘cheeky’ mangrove worm medicine for coughs (Tiwi) | shields |
| Bruguiera exaristata | mangrove worm (Tiwi) | fishing boomerangs (Bardi) | |
| Bruguiera gymnorrhiza | mangrove worm (Tiwi); hypocotyls eaten after treatment (Cape York) | spear tips (Belyuen); throwing sticks for hunting magpie geese (Tiwi); boomerangs | |
| Bruguiera parviflora | mangrove worms (Milingimbi; Tiwi) | paddles (NQ) | |
| Brugiera rheedii | hypocotyls eaten after treatment (Cape York) | ||
| Camptostemon schultzii, kapok mangrove | skin sores and scabies; leprosy sores (Galiwin’ku, Ramingining; Milingimbi) | canoes and catamarans (Kimberley); canoes and floats (Milingimbi; Tiwi); floats (Ramingining) | |
| Ceriops australis | spear shafts (Tiwi) | ||
| Ceriops tagal | sores and infections (Yirrkala); scabies (Tiwi) | fishing boomerangs and spears (Bardi); sticks for hunting magpie geese (Tiwi) | |
| Diospyros compacta | fruit eaten | ||
| Excoecaria ovalis | nectar (Groote Eylandt) | toxic plant, latex causes skin to swell (Milingimbi); leprosy sores, marine stings, body pain | floats for turtle hunting, firewood (Groote Eylandt); cordage |
| Hibiscus tiliaceus | boils (Yirrkala, Galiwin’ku); washing wounds (NT); headaches, splints for fingers (Groote Eylandt) | woomeras, light spears, fire sticks, harpoon rope (Groote Eylandt); string from inner bark (Belyuen); string and rope from inner bark, spear shafts, fire-sticks (Tiwi) | |
| Lumnitzera littorea | nectar-rich flowers as sweets (Yirrkala) | digging sticks, throwing sticks (Belyuen) | |
| Lumnitzera racemosa | nectar | spears for hunting wallabies and stingrays (Tiwi); firewood, fire sticks, spears | |
| Nypa fruticans | mud mussels at base (Tiwi); unripe seeds eaten (NQ) | ||
| Osbornia octodonta | cooking herb | toothache, insect repellant | |
| Pemphis acidula | toothache (Groote Eylandt) | woomera peg, digging sticks (Groote Eylandt) | |
| Rhizophera apiculata | mangrove worm (Tiwi) | skin sores (Tiwi) | ceremonial armbands (Tiwi) |
The mangroves have mudcrabs the months with an ‘r’ in them….. I treat the flushing/flooding effect of the king tides as an ideal time for crabbing. Crabs caught during months with the letter ‘r’ (e.g.  March) tend to be much fuller than those caught during the winter months. This is generally due to the belief that mud crabs hide in their holes during winter and malt their shell. They tend to remain empty during these months until they get a chance to grow into their new larger shell. Partially full crabs tend to have a greenish ting to their shells and full crabs have a darker more browny-blue colour.Â
 .https://www.swanboathire.com.au/2009-Fishing-Reports/fishing-report-8-january-2009.html
I was so excited with my first catch of Mud crabs. A bit scared to take them out of the crab pot, I called a neighbour for help and together we dragged the pots up to the house, and using oven gloves and towels we extracted the crabs and returned the females back to the water… Being able to distinguish between male and female crabs is a very important way for anglers to play a role in sustainable fisheries. The mud and sand crabs though very different in appearance, both have the same protective cover on their under body. On male crabs this cover is in the shape of a long narrow, pointed flap. The females have a broad, more rounded flap that covers more than half of their underside. All female crabs must be returned to the water after capture. Male mud crabs must measure 15cm from spine to spine on the spines closest to the back swimmer legs. Male sand crabs have to measure 11.5cm from notch to notch on the notch closest to the spines. https://www.swanboathire.com.au/2009-Fishing-Reports/fishing-report-8-january-2009.html
We weren’t the only ones enjoying the fruits of the mangroves, birds walked among the sea grass
At the Bottom end of Russell island is Sandy Beach. As the name suggests, the beach here is sand, not mud flats and here too there are mangroves growing in the sands.
When the tide is low, birds come to feast on the oysters and shellfish and small fish in the water. The rocks are thick with oysters…but if you want any you have to beat the oyster catchers who are always here first.
The mangroves are different here. There is no mud to adhere to, and the roots spread out over the sand. Closer to the shore, the mangroves are more prolific but the root system is a flat spread out root rather than the curved thick roots of the mangroves growing in the mud. Here too many small crabs call this area home and at sunrise and sunset you can see soldier crabs marching across the sand like an army. This is also a good fishing place when the tide is in for squid as well as good sized fish.
When the tide is really low, usually during the New Moon, you can walk out in the bay wearing gumboots and the mud flats are rich in shellfish. You can see herons, ibis and spoonbill along with black swans and pelicans amidst the sea grass…
When its low tide in the islands, the water recedes and in certain places you can walk right onto the mudflats in the Bay. Here at low tide, Ooncooncoon Bay opens up and its also the time to place crab pots and also a fishing line.
The mangroves are prolific in this side of Russell island as there are only seven houses on the top, and only two properties further down the bay have a jetty and own a boat, leaving the mangroves people free and able to develop at their own pace creating amazing shapes and twists in the roots that have grown for many years.
The roots provide a safe haven for crabs. You see many small black crabs scuttering away here and the roots also provide a safe cave for huge mud crabs larger than the size of a plate. There homes are edged with sand and easily visible. As well as Crabs, the mangroves are rich with birds and when the blossom is here, the mangroves buzz with bees, mostly native.
The Lady Caroline Cruise went from Russell island to Calypso Bay then Back along the small Islands past Stradbroke Islands.
On the East Coast of Russell island where the Boat Ramp is located n Wahine Drive, there are still some mangroves. Most have been destroyed to make way for private jetties, but there are still mangroves next to the boat ramp and also along the shore edge. I went on a cruise with The Lady Caroline who is moored off Wahine Crescent, and below the private jetty are mangroves
The mangroves are mostly mud….
Mangroves Australia 