What is so special about the red tussock (Chionochloa rubra) on the Gouland Downs you might ask as you plod past them on the way to the next hut? Harry Broad, DOC writer in residence, explains why this “dull and boring” plant is worthy of admiration.
They have a lovely appealing quality, best appreciated en masse when there is wind and sun to highlight their reddish brown and green sheen and typically arching formations as they wave around in the breeze. They can be a spectacular sight if they are flowering because the whole Downs looks like a landscape of golden sprays. On a dull and rainy day they do look much more subdued but there is much to admire in their life cycle.
They can live for hundreds of years because they continually regenerate themselves on their own accumulated dead matter. There are always new tillers (plant shoots) initiated where growth happens at the base of the tussock. A tiller might have seven or eight leaves and when it is big enough it will send up a flowering stem and die after the seed is shed, adding to the dead biomass of the tussock. By the turnover of old and new tillers and the accumulation of biomass, each tussock creates its own living environment.
They can mast just like beech trees in certain years (masting being an excessive production of seed) but it is not certain whether they have the same temperature triggers and the masting isn’t as pronounced as beech or other snow tussock species.
Red tussock typically lives in places where it’s too wet and/or cold for woody vegetation, such as frosty hollows, valley floors and the peneplains like the Downs. It’s very much a tussock species of gentle topography. That is its niche and as soon as the slope increases, other things come in like woody vegetation or other species of snow tussocks. Like other snow tussocks, red tussock can colonise after forest clearance if it’s already somewhere in the landscape.
There are over 2000 hectares of red tussock on the Gouland Downs which makes for a really strong population considering that there are only 72,000 hectares of red tussock throughout the whole country. There are three subspecies of red tussock and they are part of the snow tussock genus Chionochloa of which New Zealand has 23 of the known 25 species.
Red tussock really are the clothes of the downs! They are like a protective cloak, with the leaves intercepting the force of the rain and mitigating the erosion of the peneplain. They also act like a huge sponge and so are terrific water collectors. Because red tussock are on often misty valley floors, the mist condenses on the leaves and the water flows down them and into the fibrous tussock base where it is absorbed and held. Extensive red tussock lands have a lot of biomass which can soak up large volumes of water and release it slowly and so act as an important buffer against flooding.
Although red tussock doesn’t have very high nutritional value, cattle can eat them where they have access and so will takehe. They eat the sweet new growth at the base of the tillers. We know from work in the Murchison Mountains in Fiordland, where takehe were rediscovered in 1948, that red tussock is less nutritious than their most preferred food plants.
These notes were written by Harry Broad in response to a recent trip on the Heaphy Track in which fellow trampers dismissed red tussocks on Gouland Downs as being “dull and boring” and there is nothing to tell them otherwise! Acknowledgement to Shannel Courtney for his botanical wisdom.