You are here: Tussock Grasslands MIS  Site Contents Mixed short/tall tussock grassland Habitat Other spp. present Vegetation history Background management information Management options |
|
|
Mixed short/tall tussock grassland e.g. Chionochloa rigida with Festuca novae-zelandiae
Diagnostic features for identification in the field
| Descriptions of narrow-leaved snow tussock are complicated by the fact that this species is now considered to form a complex with broad-leaved snow tussock (C. flavescens). There are five recognised taxa (including three broad-leaved ones which are described under C. flavescens), which vary in locality and habitat. However, the general description below will differentiate the narrow-leaved members of this complex from the other Chionochloa tussock species. A large green or tawny green tussock, usually less than 150cm tall. Tussocks may be smaller with narrow leaves, where soil fertility is reduced or at higher altitudes. Leaves are relatively broad, which droop. They are tough and glossy, and lack a conspicuous midrib above or beneath. The leaves tend to trail on the ground, so that the exposed soil shows a swept effect. The sheaths are a lighter colour than other species, being pale green to light brown to orange, often purple tinted. Young sheaths are white-hairy, while dead sheaths break crosswise. The flower heads are borne well above the leaves. |
|
References:
- Jane, G. 1995. Field guide to grasses. 1. Alpine grasses.
- Mark, A.F. and Adams, N. 1996. New Zealand alpine plants, Methuen.
- Wilson, H.W. 1996. Wild plants of Mount Cook National Park, Manuka Press, Christchurch.
Description of community and habitat
Narrow-leaved snow tussock grassland is the dominant vegetation cover at mid altitude on mountain slopes south of the Rakaia River, and the hill tops of Banks Peninsula. It's current distribution is a shadow of it's extent prior to European settlement. Tussock size is influenced by the harshness of the climate in which it grows. Where present near sea-level in south-east Otago, tussocks are up to 1.5m tall, but reduce to 0.3m tall at high altitudes. The abundance and composition of species growing in narrow-leaved snow tussocks is influenced by the degree of disturbance that the grassland has experienced. Mixed short/tall tussock grasslands develop where tall tussock grasslands have been severely opened up by grazing disturbance, resulting in low tall tussock cover, interspersed with short tussocks and an abundance of intertussock herbs and grasses. In Canterbury, mountain cotton daisy (Celmisia spectabilis) is a common associate, especially in more modified grasslands. These open canopied mixed short/tall tussock grasslands are widespread today, especially at mid-altitude, where extensive pastoral development has also taken place. North Island
Mixed short/tall tussock grasslands (with narrow-leaved snow tussocks) are not present in the North Island.
Other species present
These open canopied mixed short/tall tussock grasslands often support a diverse array of intertussock herbs and grasses. Mat daisies (Raoulia subsericea) are common, while grasses often include Deyeuxia avenoides, Elymus solandri, and the exotic brown top (Agrostis capillaris) and sweet vernal (Anthoxanthum odoratum). Mouse-eared hawkweed (Hieracium pilosella) is the most widespread hawkweed, although tussock hawkweed (H. lepidulum) and king devil hawkweed (H. praealtum) can also be common. Matagouri (Discaria toumatou) is the most common shrub associated with mixed short/tall tussock grassland, especially where soil fertility has been increased through the aerial application of fertiliser. Native broom (Carmichaelia spp), and Leucopogon colensoi can be locally important. In mid Canterbury, mountain cotton daisy is a common sight in open short/tall tussock grasslands, and is a sign of overgrazing.
Vegetation History