Tasmania in spring shows off a multitude of colours. Standing in the Mole Creek valley and gazing at the Great Western Tiers the first impression is the dense gold blossom of the black wattles against the sombre darkness of the native wet sclerophyll forests. The brilliant green of the mosaic farming landscape before the escarpment of the Tiers is stunning. The villages and farmhouses are brilliant with spring gardens in flower. But delve beneath the surface, into the caves, and the picture of our valley is complete. In spring, when we get plenty of rain, the caves’ formations are vibrant with colour as well; enhanced by the mineral rich water flowing and dripping over stalactites and flowstone.
Rivers are flowing strongly through the caves. Cave passages are the river systems here, and in summer and autumn when the cave streams are quieter, you can still sense how much water must flow at other seasons. You can sense that the underground world awaits the next seasonal flush with mountain water.
People at a cave entrance
Doorway to discovery
The rich colours of the calcite-streaked dark blue-grey cave walls in the stream passages contrast with the rich enhanced colours of the formations emerging from the ceilings. The waterfalls which rejoin stream branches in the lower cave system show dramatic white water when we turn our lights onto them. The roar of the churning water in the confines of the passages is very exiting. Much photography has been the rage here this spring. I hope all the photos turn out really well.
Most of the large cave spiders seem to have hatched their broods, and are able once more to roam for food after their long vigil, guarding their egg sacs for up to 5 months. They can be hard to spot now when they are so lively, and I must be careful not to linger with the lights as it disturbs them. The constant influx of fresh food from the forest on the rushing streams excites the glow-worms, which now appear to be increasing in numbers or brilliance, especially if you linger in a river cave long enough to gain complete night vision. The blind white shrimps are making a comeback into the main passages after each high water event when they hide in quieter nooks. I have seen two “calling cards” of platypus so far this spring in the caves, indicating these animals are finding fresh food in the caves.
Our exploration has sometimes been restricted largely to the upper levels of caves while streams are rising after heavy rainfalls or snow melt. Mostly we’re out of the rain in there, but don’t stand under that cluster of straw stalactites! There have been two days only when there was too much water to explore caves at all. At those times even the show cave, Marakoopa, was closed.
But spring is full of surprises. It’s great to enter the caves during rain and emerge to warm sunshine or shafts of sun between dramatic clouds. I’ve noticed more northern Australians coming to Tasmania to see the seasons they can’t experience at home.
As one of my responsibilities, I coordinated a Search and Rescue exercise in one of the river caves this week. A tremendous success all round, and a necessary public service to keep in practice with. We reckon it’s fortunate if we don’t have need to use our skills. These practice days are a lot of fun and stimulate discussion and awareness of the problems of evacuation in caves generally. They are supported by Parks, Police and our local caving club, the Mole Creek Caving Club.
More later. See you underground (again?).