New Zealand Journal of Botany abstracts
The importance of dispersal, disturbance, and competition for exotic plant
invasions in Arthur's Pass National Park, New Zealand
LINLEY JESSON*
DAVE KELLY
ASHLEY SPARROW
Department of Plant and Microbial Sciences
University of Canterbury
Private Bag 4800
Christchurch, New Zealand
* Present address: Department of Botany, University of
Toronto, 25 Willcocks St, Toronto, Ontario, Canada, M5S 3B2.
email: ljesson@botany.utoronto.ca
Abstract This study investigated the effects of disturbance,
dispersal, and plant competition on exotic plant invasion. An assessment of the
change in species distributions in the Mingha Valley, Arthur's Pass National
Park, over five years showed that many species had increased in range,
suggesting that dispersal had limited the distribution of these species. The
dispersal barrier was removed experimentally by transplanting plants and seeds
of Anthoxanthum odoratum, Holcus lanatus, Cerastium
fontanum, and Hieracium pilosella into undisturbed areas.
Although transplants of A. odoratum, H. lanatus, and H.
pilosella could survive without disturbance, it was essential for the
establishment from seed in all four species. These species were therefore
limited by the absence of disturbance. A survey of the plant distribution in
the Mingha and Edwards Valleys found many exotic species associated with hut,
track, and river disturbance regimes. The association of exotic plants with
disturbances may be due to the role of disturbance as a window through the
barriers of competition, dispersal, and abiotic barriers. The success of these
exotic plants in New Zealand seems largely due to success of seedlings of
exotic species establishing in areas disturbed by human activity.
Keywords Anthoxanthum odoratum; Hieracium
pilosella; Holcus lanatus; Cerastium fontanum; weeds;
disturbance; exotic plants; biological invasion
B99034
Received 20 July 1999; accepted 14 February 2000
PDF file of entire paper: medium quality (1283K); (scanned from paper original: notes about this process)
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