The ecology and conservation of Kunzea sinclairii (Myrtaceae), a naturally rare plant of rhyolitic rock outcrops

Kunzea sinclairii is a local endemic on Great Barrier Island, northeastern New Zealand. While variously ranked as vulnerable and endangered in the past, we show that this species is naturally uncommon and under no threat of extinction. Previous assessments of its conservation status have been based on inadequate knowledge of its ecology. K. sinclairii is a rupestral species whose optimum habitat is low shrubland on rhyolitic rock outcrops and cliffs. Because of past logging and burning of forest adjacent to the habitat to which it is adapted, K. sinclairii expanded its range. However, in regeneration back to forest, K. sinclairii is being excluded as it is overtopped by other species. This has led to the impression that it is declining. Similarly, a suggestion that K. sinclairii could be threatened by hybridisation with the more abundant closely related K.ericoides is not supported as the hybrids are confined to the disturbed sites created by logging and fire. This case study highlights the importance of having a good understanding of the ecology of uncommon plant species before making decisions on their conservation. Natural rarity does not itself necessarily equate with increased extinction risk and these taxa should not be classified as threatened.