A case for controlling the distribution of the tree daisy Olearia lyallii Hook.F. in its type locality, Auckland Islands.
- Ecology Division, DSIR, P.O. Box 30466, Lower Hutt
Olearia Lyallii occurs on forested islands south of mainland New Zealand. It was apparently introduced accidentally to the Auckland Islands by sealers in the early 19th century. It is still spreading, but is not yet found beyond Port Ross, three of the Port Ross islands and the north-east shores of the main island. It supplants the dominant forest tree, Metrosideros umbellata, because it has greater tolerance to partial shade and salt spray; it grows faster and taller and is not browsed. Olearia forest is floristically simpler than Metrosideros forest. Seed can be dispersed by wind and possibly by visiting scientists. When the present juvenile plants mature the rate of spread will increase. The potential impact of Olearia lyallii on the indigenous vegetation should be considered in the management plans for the reserve.