Vegetation and soil processes in a small mountain catchment

Abstract

Variation in the soil pattern in a small first order catchment within the Torlesse Catchment, Porters Pass, was described. Both soil chemical and soil physical properties were recorded. The soils were described as Tekoa soils with the main elements of variation being due to the activities of the drift regime and to differences in soil moisture.

The vegetation was described using a modified point-height method and the Braun-Blanquet cover-abundance method. Ordination and correlation analyses were conducted on all data. The point-height method gave an accurate picture of the structure of the vegetation while the Braun-Blanquet method was generally adequate for the ordination analysis. The principal environmental gradients determining species composition were soil maturity and soil drainage. The species distribution and site factors for 5 important species were described.

Variation in the vegetation and the soils across a riparian area was analysed. The vegetation was recorded using the point-height method and the soil morphological features were described. Schoenus pauciflorus and Bulbinella angustifolia were useful specie s for distinguishing the riparian zone while soil mottle and gley features gave an indication of the extent of soil saturation.

The concentrations in sheaths, green material and dead material and weight per tiller of P, N, K, Ca and Mg are reported for Festuca novae-zelandiae. These samples were taken from the sites upon which the previous vegetation and soil analysis had been undertaken. Species means were comparable to those reported by other authors.

Few significant correlations between tussock nutrient levels and soil element concentrations were found although significant differences between sections of the tiller were shown.