Island Invasion by a Threatened Tree Species: Evidence for Natural Enemy Release of Mahogany (Swietenia macrophylla) on Dominica, Lesser Antilles

Norghauer, Julian M.; Martin, Adam R.; Mycroft, Erin E.; James, Arlington; Thomas, Sean C. (2011). Island Invasion by a Threatened Tree Species: Evidence for Natural Enemy Release of Mahogany (Swietenia macrophylla) on Dominica, Lesser Antilles. PLoS ONE, 6(4), e18790. Lawrence, Kans.: Public Library of Science 10.1371/journal.pone.0018790

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Despite its appeal to explain plant invasions, the enemy release hypothesis (ERH) remains largely unexplored for tropical forest trees. Even scarcer are ERH studies conducted on the same host species at both the community and biogeographical scale, irrespective of the system or plant life form. In Cabrits National Park, Dominica, we observed patterns consistent with enemy release of two introduced, congeneric mahogany species, Swietenia macrophylla and S. mahagoni, planted almost 50 years ago. Swietenia populations at Cabrits have reproduced, with S. macrophylla juveniles established in and out of plantation areas at densities much higher than observed in its native range. Swietenia macrophylla juveniles also experienced significantly lower leaf-level herbivory (~3.0%) than nine co-occurring species native to Dominica (8.4–21.8%), and far lower than conspecific herbivory observed in its native range (11%–43%, on average). These complimentary findings at multiple scales support ERH, and confirm that Swietenia has naturalized at Cabrits. However, Swietenia abundance was positively correlated with native plant diversity at the seedling stage, and only marginally negatively correlated with native plant abundance for stems ≥1-cm dbh. Taken together, these descriptive patterns point to relaxed enemy pressure from specialized enemies, specifically the defoliator Steniscadia poliophaea and the shoot-borer Hypsipyla grandella, as a leading explanation for the enhanced recruitment of Swietenia trees documented at Cabrits.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS)
08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS) > Vegetation Ecology (discontinued)

UniBE Contributor:

Norghauer, Julian Martin

ISSN:

1932-6203

Publisher:

Public Library of Science

Language:

English

Submitter:

Peter Alfred von Ballmoos-Haas

Date Deposited:

04 Oct 2013 14:27

Last Modified:

07 Dec 2014 10:33

Publisher DOI:

10.1371/journal.pone.0018790

Web of Science ID:

000289458800043

BORIS DOI:

10.7892/boris.10018

URI:

https://boris.unibe.ch/id/eprint/10018 (FactScience: 215843)

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