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Rollo H. Beck's Visits to Isla Guadalupe, Mexico, with Additions and Corrections to the Island's Avifauna

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William Everett at Endangered Species Recovery Council
William Everett
  • Endangered Species Recovery Council
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... The Guadalupe Storm-Petrel was recorded on Guadalupe Island, Mexico, during the late 19th and early 20th centuries until it was last seen in 1912 [52]. The hypothesis of its global extinction is supported by (1) it not having been sighted despite surveys carried out over several years; (2) potential threats posed by the introduction of cats, goats, and feral dogs; and (3) its restricted geographical range [53,54]. ...
An integrated system to assess marine extinctions
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More than 20 global marine extinctions and over 700 local extinctions have reportedly occurred during the past 500 years. However, available methods to determine how many of these species can be confidently declared true disappearances tend to be data-demanding, time-consuming, and not applicable to all taxonomic groups or scales of marine extinctions (global [G] and local [L]). We developed an integrated system to assess marine extinctions (ISAME) that can be applied to any taxonomic group at any geographic scale. We applied the ISAME method to 10 case studies to illustrate the possible ways in which the extinction status of marine species can be categorized as unverified, possibly extinct, or extinct. Of the 10 case studies we assessed, the ISAME method concludes that 6 should be categorized as unverified extinctions due to problems with species’ identity and lack of reliable evidence supporting their disappearance (periwinkle—Littoraria flammea [G], houting—Coregonus oxyrinchus [G], long-spined urchin—Diadema antillarum [L], smalltooth sawfish—Pristis pectinata [L], and largetooth sawfish—P. pristis [L]). In contrast, ISAME classified the Guadalupe storm-petrel (Oceanodroma macrodactyla [G]) and the lost shark (Carcharhinus obsolerus [G]) as possibly extinct because the available evidence indicates that their extinction is plausible—while the largetooth sawfish [L] and Steller’s sea cow (Hydrodamalis gigas [G]) were confirmed to be extinct. Determining whether a marine population or species is actually extinct or still extant is needed to guide conservation efforts and prevent further biodiversity losses.
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