Modeling a regime shift in a kelp-forest ecosystem caused by a lobster range expansion


Show simple item record Blamey, Laura K Plagányi, Éva E Branch, George M 2016-02-25T11:15:25Z 2016-02-25T11:15:25Z 2013
dc.identifier.citation Blamey, L. K., Plagányi, É. E., & Branch, G. M. (2013). Modeling a regime shift in a kelp forest ecosystem caused by a lobster range expansion. Bulletin of Marine Science, 89(1), 347-375. en_ZA
dc.identifier.issn 0007-4977 en_ZA
dc.description.abstract The South African West Coast rock lobster, Jasus lalandii (H. Milne-Edwards, 1837), has expanded its range to the southeast, where its abundance has increased radically. The ecological consequences of this “invasion” are likely to be considerable. We employed a minimally realistic model to simulate the “invasion” and to explore interactions of J. lalandii with the sea urchin, Parechinus angulosus (Leske, 1778), and the abalone, Haliotis midae Linnaeus, 1758, juveniles of which shelter beneath this urchin. Model fits to empirical data were good, although species-interaction terms were difficult to estimate. Base-case trajectories indicated: (1) Lobster biomass peaked at about 1000 t in 1994 and was then reduced by fishing to a stable value approximately 50% lower by 2008. (2) Urchins remained close to carrying capacity in “noninvaded” areas but collapsed to local extinction by 1997 in the invaded area. (3) Abalone declined over 2000–2008 in noninvaded areas because of illegal fishing and collapsed to near zero in the “invaded” area because of illegal fishing combined with increased lobster abundance. Sensitivity analyses favored the hypothesis that the invasion was due to adult immigration rather than larval recruitment. Modeled 50-yr projections indicated that urchins will remain locally extinct in the invaded area, even 50 yrs into the future. The abalone collapse in the invaded area would persist >50 yrs, even if lobsters were absent. We argue that the lobster “invasion” triggered an alternative stable state, making a return to pre-invasion conditions unlikely. en_ZA
dc.language eng en_ZA
dc.publisher University of Miami, Rosenstiel School of Marine and Atmospheric Science en_ZA
dc.source Bulletin of Marine Science en_ZA
dc.title Modeling a regime shift in a kelp-forest ecosystem caused by a lobster range expansion en_ZA
dc.type Journal Article en_ZA 2016-02-25T09:03:08Z
uct.type.publication Research en_ZA
uct.type.resource Article en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Marine Resource Assessment and Management Group en_ZA
uct.type.filetype Text
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