Tuesday, 29 July 2014

Miniature Forests of the Salt

The salt pans and samphire flats of South East Queensland receive a lot of attention.  Yet the salt pans of Cape York Peninsula have a strange flora that is barely described on the internet or even in scientific reference sites such as the Atlas of Living Australia.  On a saltpan that is within  bike riding distance of Cooktown I found a veritable rainforest of succulents.  Within this miniature forest, the canopy was almost closed, the understorey was dark and humid and a thriving crab population.
Samphire flat with Batis argillicola near Cooktown
Batis argillicola mini tree
Being on a salt pan is to experience open space.  If you value open space and enjoy the visual intensity of colour and detail, being on a salt pan is like freedom to breath.  In this particular salt pan, it is also about being a giant that needs to tread carefully through a forest that reaches as high as our knees.

Tropical samphire flat
Should I even call this a salt pan?
Batis (Batis argillicola) is the main plant although approximately six succulents were present in total. Grass which is ususally present was not to be seen. Batis is quite large for a succulent and stands about half a metre tall.  The leaves are bright green and of similar shape and size to grains of rice and the seed pods are like green peas.  I am not sure how old the Batis are and I don't know if any one does but their stout trunk suggest they are old.  As there are no good photos on the net, here are a few more (yes it is true, stacks of stuff is still not on the net).

Batis argillicola shrubs near Cooktown
Batis argillicola is big enough to compete with young mangroves
Batis argillicola leaves and flowers
Leaves and flowers of Batis argillicola - the flower are tiny and only stamens are clearly visible
In the salty margins are some red and pink Halosarcia succulents, which come from the salt bush family.  The red is a protective pigment (a carotene) that allows plants to avoid damage caused by intense sun.  It is a sunscreen and a way of dissipating excess energy.  In such a dry landscape, plants cannot open their stomates to get CO2, so the energy captured by the photosynthetic pigments cannot be used and would generate free radicals that would corrode the plants cells if it the energy was not passed to pigments which reradiates the energy.  The pigments also have a sunscreen effect by blocking some of the incoming energy.  Back in the days of the ozone hole, it was predicted that many plants would go orange or red as they increase pigment levels to protect themselves as UV light also creates free radicals.  Breeding programs were established to put protective pigment genes into crops as many crops are badly damaged by intense UV.  The succulents on the salt pans also experience high UV from the sky and reflected UV from the salty surface.

Red succulents dominate very salty areas
Thinking of fauna, the crabs were in hiding and all I could find were mud whelks.  It seems that mud whelks thrive in a narrow band of ground around the margins of the saltpan.  Here shallow pools exposed to the sun provide better grazing than the surrounding mangrove forest.  However on this flat terrain, a mud whelk can easily move in the wrong direction and by after as little a five metres, it can find itself lost in the miniature forest with fatal consequences.
Mud whelk - telescopium
Hundreds of mud whelks clustered seeking shade under an isolated mangrove
There is a sad fate for those that crawl a few metres in the wrong direction

1 comment: