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Establishment of the introduced kelp Undaria pinnatifida in Tasmania depends on disturbance to native algal assemblages


Valentine, JP and Johnson, CR, Establishment of the introduced kelp Undaria pinnatifida in Tasmania depends on disturbance to native algal assemblages, Journal of Experimental Marine Biology and Ecology, 295, (1) pp. 63-90. ISSN 0022-0981 (2003) [Refereed Article]

DOI: doi:10.1016/S0022-0981(03)00272-7


Despite recent rapid increases in the occurrence of nonindigenous marine organisms in the marine environment, few studies have critically examined the invasion process for a marine species. Here we use manipulative experiments to examine processes of invasion for the Asian kelp Undaria pinnatifida (Harvey) Suringar at two sites on the east coast of Tasmania. Disturbance to reduce cover of the native algal canopy was found to be critical in the establishment of U. pinnatifida, while the presence of a stable native algal canopy inhibited invasion. In the first sporophyte growth season following disturbance of the canopy, U. pinnatifida recruited in high densities (up to 19 plants m -2) while remaining rare or absent in un-manipulated plots. The timing of disturbance was also important. U. pinnatifida recruited in higher densities in plots where the native canopy was removed immediately prior to the sporophyte growth season (winter 2000), compared with plots where the canopy was removed 6 months earlier during the period of spore release (spring 1999). Removal of the native canopy also resulted in a significant increase in cover of sediment on the substratum. In the second year following canopy removal, U. pinnatifida abundance declined significantly, associated with a substantial recovery of native canopy-forming species. A feature of the recovery of the native algal canopy was a significant shift in species composition. Species dominant prior to canopy removal showed little if any signs of recovery. The recovery was instead dominated by canopy-forming species that were either rare or absent in the study areas prior to manipulation of the canopy. © 2003 Elsevier B.V. All rights reserved.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Control of pests, diseases and exotic species in marine environments
UTAS Author:Valentine, JP (Dr Joseph Valentine)
UTAS Author:Johnson, CR (Professor Craig Johnson)
ID Code:27609
Year Published:2003
Web of Science® Times Cited:118
Deposited By:Zoology
Deposited On:2003-08-01
Last Modified:2004-12-06

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