Alpine Short Tussock Grasslands
High Altitude Environments
Alpine short tussock grasslands have been induced from tall Chionochloa grasslands, in response to burning and/or grazing. In the drier eastern ranges, where extensive pastoral farming has taken place over the last 150 years, it has been common practice for the tall tussocks to be repeatedly burnt, to open the country up for stock access, and encourage the growth of more palatable herbs and grasses between the tussocks. Burning of tall tussocks promotes the redistribution of mineral reserves from the plant's roots to the new tillers, which are hence more nutritious and palatable to stock. Subsequent grazing of these tussocks puts undue stress on the plant, which can subsequently die. In addition, where stock and feral animal grazing pressure is moderate, young tussock seedlings are eaten, thereby hindering tussock regeneration.
As the tall tussocks die out, the more grazing tolerant plants such as blue tussock and alpine fescue tussock become dominant, together with herbs such as Celmisia viscosa and Gentiana sp. Some remnant tall tussock individuals may be evident.
In the western ranges, overgrazing of tall tussocks such as C. pallens by feral animals has resulted in a similar formation of an induced blue tussock grassland.
References:
Payton, I.J.; Lee, W.G.; Dolby, R.; Mark, A.F. 1986: Nutrient concentrations in narrow-leaved snow tussock (Chionochloa rigida) after spring burning. New Zealand journal of Botany. 16: 529-537
Mills, J.A.; Lee, W.G.; Lavers, R.B. 1989: Experimental investigations of the effects of takahe and deer grazing on Chionochloa pallens grassland, Fiordland, New Zealand. Journal of Applied Ecology, 26: 397-417.
Mark, A.F. 1994: Effects of burning and grazing on sustainable utilisation of upland snow tussock (Chionochloa spp) rangelands for pastoralism in South Island, New Zealand. Aust. J. Bot. 42: 149-161.
Mark, A.F. 1974: Old Man Range, New Zealand's Nature Heritage 2: 524-531, Hamblyn, Sydney.
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