Mossy Mangroves in the Daintree

Moss does not usually grow on the ground in mangrove swamps. In fact there seems to be only one species of marine moss. Whilst, I lack the expertise to officially identify this moss, I have found mangrove forests in the Daintree, where the forest floor is carpeted with moss.

Mangrove moss, possibly Taxithelium merrillii

Moss-like algae is common in the mangroves but the sporangia show that this is really moss.

The mossy ground is in the back swamps, where the ground level is high and conditions are almost terrestrial. Only the tree species reveal that these areas are of mangrove character and not rainforest. The ground is more soil than mud and crabs are scarce. Buttress roots from Looking glass mangroves meander across the ground for several metres around each tree. Stands of these trees create a ground-level maze for the forest's smaller creatures. Scrub fowl scratch and poke around among the roots. Above in the canopy are giant basket ferns. It is like an alien ecosystem.

Scrub-fowl are as large as roosters and buttress roots are far larger

Some of the buttresses are as high as a man and twist across the forest floor for 10 m.

In peak condition, Looking glass mangroves are one of the tallest species.

This unique mossy habitat is only 50 m wide and perhaps a kilometre long. It is probably only found near the Daintree River although it may also be present in the coastal regions of our wetter northern neighbours.

This band of forest is the only mangrove forest where really large buttresses were the dominant root structure.

Almost a kilometre away, this intriguing stand continued.

Where the stand transitions into mangroves, a thick understorey of mangrove seedlings was present.

Further up the Daintree River is a freshwater mangrove swamp. Even though the water in this area would be fresh enough to drink for most of the year, it is still tidal. During droughts the freshwater dwindles and sometimes these areas are exposed to full seawater. These events are tolerated by the freshwater forests and their fauna. I suspect that the mud is always close to saturation and does not absorb much saltwater. Often the small amount of freshwater that persists also forms a protective film on the surface of the river. One consequence of not having seawater inundation is that the animals that feed on what the tide leaves behind are absent and creek banks are often smooth and almost devoid of crab holes. Only crabs that feed on fallen leaves are present and in very fresh areas, even these are usually absent. The fish are more exciting and I have previously written about the fish that choose to live in these habitats.

Freshwater tidal area with red Sonneratia mangroves and River Cherry trees.

River cherries, Barringtonia mangroves and sedges grow in a tidal forest.

On the river, the breathing roots can be as tall as a man.

Where the surrounding landscape has not been converted to agriculture, these brackish and tidal freshwater reaches are as extensive as the seaward edge of the mangroves. In most areas, only traces of this habitat remain.