eCite Digital Repository

Interactions and impacts of two introduced species on a soft-sediment marine assemblage in SE Tasmania

Citation

Ross, DJ and Johnson, CR and Hewitt, CL and Ruiz, GM, Interactions and impacts of two introduced species on a soft-sediment marine assemblage in SE Tasmania, Marine Biology, 144, (4) pp. 747-756. ISSN 0025-3162 (2004) [Refereed Article]

DOI: doi:10.1007/s00227-003-1223-4

Abstract

Introduced species are having major impacts in terrestrial, freshwater and marine ecosystems worldwide. It is increasingly recognised that effects of multiple species often cannot be predicted from the effect of each species alone, due to complex interactions, but most investigations of invasion impacts have examined only one non-native species at a time and have not addressed the interactive effects of multiple species. We conducted a field experiment to compare the individual and combined effects of two introduced marine predators, the northern Pacific seastar Asterias amurensis and the European green crab Carcinus maenas, on a soft-sediment invertebrate assemblage in Tasmania. Spatial overlap in the distribution of these invaders is just beginning in Tasmania, and appears imminent as their respective ranges expand, suggesting a strong overlap in food resources will result from the shared proclivity for bivalve prey. A. amurensis and C. maenas provide good models to test the interaction between multiple introduced predators, because they leave clear predator-specific traces of their predatory activity for a number of common prey taxa (bivalves and gastropods). Our experiments demonstrate that both predators had a major effect on the abundance of bivalves, reducing populations of the commercial bivalves Fulvia tenuicostata and Katelysia rhytiphora. The interaction between C. maenas and A. amurensis appears to be one of resource competition, resulting in partitioning of bivalves according to size between predators, with A. amurensis consuming the large and C. maenas the small bivalves. At a large spatial scale, we predict that the combined effect on bivalves may be greater than that due to each predator alone simply because their combined distribution is likely to cover a broader range of habitats. At a smaller scale, in the shallow subtidal, where spatial overlap is expected to be most extensive, our results indicate the individual effects of each predator are likely to be modified in the presence of the other as densities increase. These results further highlight the need to consider the interactive effects of introduced species, especially with continued increases in the number of established invasions. © Springer-Verlag 2003.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and Estuarine Ecology (incl. Marine Ichthyology)
Objective Division:Environment
Objective Group:Natural Hazards
Objective Field:Natural Hazards in Marine Environments
Author:Ross, DJ (Dr Jeff Ross)
Author:Johnson, CR (Professor Craig Johnson)
Author:Hewitt, CL (Professor Chad Hewitt)
ID Code:31140
Year Published:2004
Web of Science® Times Cited:40
Deposited By:TAFI - Zoology
Deposited On:2004-08-01
Last Modified:2007-08-31
Downloads:0

Repository Staff Only: item control page