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Tuhinga 32: 52-63
ABSTRACT: The Australian tree Lomatia fraseri was recently reported as naturalised on ‘Mowlem Ridge’, near Wainuiomata in the Wellington region of the North Island of New Zealand. Here, we provide more details about this discovery and the presence of the species in New Zealand. The identification of these plants as L. fraseri is supported by the abundant hairs on the underside of the leaves (although these are absent in some plants), hairy flower tepals (also absent in some plants) and the narrowly ovate or narrowly elliptic, dentate leaves of the adults. Occasional juveniles have pinnatifid rather than the usual unlobed leaves, a variation consistent with Australian reports. Lomatia fraseri clearly fulfils the criteria for the Naturalised category in New Zealand. It is intensively established on Mowlem Ridge, where many thousands of plants extend over more than 2 km on a ridgeline firebreak through regenerating forest dominated by Leptospermum scoparium (mānuka). Scattered plants have also been found at least 2.5 km to the east. In addition, self-sown seedlings of L. fraseri have been reported near Christchurch in the South Island. Currently, the Wainuiomata population of L. fraseri is not being actively controlled. We suggest this may be regretted given that L. fraseri has the potential to establish widely throughout New Zealand, based on its demonstrated invasiveness and its broad indigenous distribution in southeastern Australia. Furthermore, that L. fraseri remained undetected for long enough to become so well established, despite being so close to a major population centre and being an utterly distinctive tree, raises the question of whether governmental agencies should be doing more biosecurity surveillance.
KEYWORDS: Biosecurity, exotic plants, Lomatia ilicifolia, Lomatia myricoides, weeds.