| Responses of Tuatara (Sphenodon punctatus) to removal of introduced Pacific rats from islands. | |
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MedLine Citation:
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PMID: 17650252 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Invasive mammalian predators such as rats are now widespread on islands, but hypotheses about their effects have rarely been tested. Circumstantial evidence from New Zealand indicates that, when introduced to islands, Pacific rats (Rattus exulans) have negative effects on endemic plants, invertebrates, birds, and reptiles, including the tuatara (Sphenodon punctatus). We tested the effects of Pacific rats on tuatara by comparing the demographic structure and body condition of tuatara populations on three islands before and after removal of rats and on a fourth island where rats remained. In the presence of rats, juvenile tuatara constituted on average 0-5% of the sample tuatara populations. When Pacific rats were removed after at least 200 years' occupancy, the proportion of juvenile tuatara increased 3.5- to 17-fold and body condition of adult males and females also improved (sometimes dramatically). We predict that, unless Pacific rats are removed from Taranga Island, the tuatara population will collapse because of low population density and the lack of juvenile recruitment. Our results demonstrate that when invasive species exert subtle effects on recruitment and body condition, the effects on populations of long-lived endemic species may only become apparent long after the invasion. |
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Authors:
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David R Towns; G Richard Parrish; Claudine L Tyrrell; Graham T Ussher; Alison Cree; Donald G Newman; A Tony H Whitaker; Ian Westbrooke |
Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Conservation biology : the journal of the Society for Conservation Biology Volume: 21 ISSN: 1523-1739 ISO Abbreviation: Conserv. Biol. Publication Date: 2007 Aug |
Date Detail:
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Created Date: 2007-07-25 Completed Date: 2008-02-04 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9882301 Medline TA: Conserv Biol Country: United States |
Other Details:
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Languages: eng Pagination: 1021-31 Citation Subset: IM |
Affiliation:
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Terrestrial Conservation Unit, Department of Conservation, Private Bag 68-908, Newton, Auckland 1145, New Zealand and School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140, New Zealand. dtowns@doc.govt.nz |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Body Constitution Conservation of Natural Resources* Female Geography Male New Zealand Population Dynamics Rats Reptiles / physiology* Seasons Time Factors |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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