Australian National Herbarium
and
Centre for Plant Biodiversity Research

New distributions of
Leptospermum namadgiensis and Olearia rhizomatica
on Yaouk Peak (Southern Tablelands, NSW)

with contributions from: M. Ballantine, S. Boulton, L. Buza, D. Cunningham, L. Halasz, M.Humphreys, I. Ermayanti, C. Keller, F. Knight, N. Lam, R. Last, N. Leist, J. Matarczyk, B. Mitchell, B. Mumbuila, S. Smith, G. Toohey, V. Torrisi, T. Wardill, R Wilkey.

Introduction

A field trip to Yaouk Peak was undertaken by students participating in the Australian National Herbarium's (CANB) Botanical Internship Programme. The twenty interns assisted by Herbarium staff visited the Peak on the 9th January 1996 to make collections. The range of habitats on the treeless ridge-top was sampled haphazardly in order to find as much floristic diversity as possible. As such, the species list in Table 1 must be considered a preliminary one. Most of the collections were made on the treeless ridge top above 1700 m, although some collections were from the lower, woodland margins.

Heath vegetation, predominantly Leptospermum namadgiensis Lyne, L. micromyrtus Miq. and Kunzea muelleri Benth. partially covers the ridge top area, between many exposed rocky surfaces. The surrounding woodland is dominated by Eucalyptus pauciflora Sieber ex Sprengel with E. debeuzevillei Maiden also present. Eucalyptus pauciflora and Hakea lissosperma R.Br. are occasionally emergent on the higher areas. The flora of this peak was previously poorly known, as only a few collections had been made there (Table 1).

Leptospermum namadgiensis and Olearia rhizomatica Lander ms were found on Yaouk Peak. These collections increase the known geographic ranges of both species (Fig. 1). As very few collections have been made of both of these species, the distributions may still be incomplete.

The collections made on the trip have been determined, databased and incorporated into the CANB collection. The flora known to date of Yaouk Peak is listed in Table 1, and predominantly reflects the flora of the treeless ridge top.

Discussion

BIOCLIM generates climate estimates based on meteorological data and topographical information (Busby 1991). User input of the distribution of taxa is used to create climatic profiles, which can subsequently allow predictions of further distributions of these taxa (Busby 1991). BIOCLIM requires precipitation and temperature information, but does not take substrate into account. Leptospermum namadgiensis has only been found on a limited number of substrates, namely porphyritic and muscovitic leucogranite (Yaouk Peak), undifferentiated leucogranite (Scabby Range) and granodiorite (The Sentry Box and Mt Namadgi). As L. namadgiensis has not been found on nearby peaks of similar climate and altitude (Mt Morgan-as predicted by BIOCLIM), it appears that L. namadgiensis may be restricted to certain substrates. Further experimentation would be needed to properly test this hypothesis.

Fig. 1. Distribution of Leptospermum namadgiensis Lyne O
and Olearia rhizomatica Lander ms X

Olearia rhizomatica is found on the same substrates as Leptospermum namadgiensis but in addition it is found on Mt Morgan (adamellite and granodiorite). Olearia rhizomatica appears not to be as restricted by substrate as L. namadgiensis.

Conservation implications

Olearia rhizomatica has been recorded from Namadgi and Kosciuszko National Parks, and Scabby Range Nature Reserve. Olearia rhizomatica is listed by Briggs & Leigh (1996) and has been given a conservation code of 2RCit. Again, this should be amended to 2RCi. The citation of 0. rhizomatica in the Tinderry Nature Reserve (Briggs & Leigh 1996) is incorrect, as the specimen from there is not conspecific (I.R. Telford pers. comm.) The populations of Leptospermum namadgiensis and Olearia rhizomatica on Yaouk Peak do not appear to be threatened, as the area is unsuitable for agricultural purposes.

Acknowledgments

References

Busby, J.R. (1991) BIOCLIM - A bioclimatic analysis and prediction system. In: Margules, C.R. & Austin, M.P. (eds.), Nature conservation: cost effective biolgical surveys and data analysis. CSIRO, Australia.

Helman, C.E. & Gilmour, P.M. (1985) Treeless vegetation above 1000 metres altitude in the A.C.T. Conservation Council, Canberra.

Lyne, A.M. (1993) Leptospermum namadgiensis (Myrtaceae), a new species from the Australian Capital Territory-New South Wales border area. Telopea 5 (2): 319-324.

Snelling, N.J. (1960) The geology and petrology of the Murrumbidgee batholith. The Quarterly Journal of the Geological Society of London 116 (2): 187-217.

Thompson, J. (1981) A key to the plants of the subalpine and alpine zones of the Kosciusko region. Telopea 2 (3): 219-297.

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