Vegetation/soil relationships and distribution of selected macroelements within the shoots of tall-tussocks on the Murchison Mountains, Fiordland, New Zealand

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Abstract
The vegetation/soil relationships of six tall-tussock (Chionochloa) species are described for the high rainfall environment of the Murchison Mountains in Fiordland. Soil profile features, bulk densities, and chemical properties including inorganic phosphorus fractions are described for the soils at a range of sites. Field collections of the tall-tussock shoots were divided into three components and analysed for selected macro-elements. For shoot dry weight the species are in the order: C. flavescens (3.77 g) > C. pallens > C. rubra > C. crassiuscula, C. teretifolia, C. acicularis (0.53 g). Variability in concentration of elements within the shoot is similar for all six species: Ca and Mg are consistently higher, N and S usually higher, K and Na consistently lower, in the green blades than in the sheaths. All elements except Ca and Mg are lowest in the dead tips of the shooots. Variability in element concentration between tussocks of the same species at one site is: Na > K, Mg, Ca, S > P, N. Significant differences exist in element concentration between sites and species. The highest concentrations of P, N, K, Mg, and Ca are in C. pallens in the alpine zone, on youthful soils with high levels of total inorganic P and high proportions of Ca-bound-P, developed on talus cones. Shoot concentrations of these elements are lower, but Na is higher, where C. pallens grows on order soils. C. acicularis, C. teretifolia, and C. crassiuscula are associated with the most organic soils which have low levels of inorganic P and Ca-bound-P. Here the shoots of these species have low P, N, K, Mg, and Ca concentrations, but C. crassiuscula shoots have high Na and S concentrations. Concentrations and weights of elements per shoot are higher in C. crassiuscula where it grows with C. pallens. These results are discussed in relation to the processes of vegetation/soil system development in the alpine zone. Low levels of all elements are found in C. rubra growing in wet alluvial soils in the subalpine zone. C. flavescens in the alpine zone is associated with soils having low levels of Ca-bound-P, and a low concentration of Ca in the shoots. These results are discussed in relation to the present taxonomic status of the species.

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