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Question 3.

What is your opinion about how we determined the effective extinction date (EED)? Specifically, for your group, can an EED be adequately assigned to a species solely based on observational evidence, or would collected material be the only satisfactory evidence?

  • Comments by CREO Chairman, Ian Harrison, have been added to some of the responses below -- in underlined text.

    Amphibians Advisory Panel

    Comment 1: for amphibians, observational data will rarely be adequate and collected material is preferable.

    Comment 2: both observational and collected material should be acceptable. Observational data can include photographs and audio tapes of calls.

    Comment 4: collected material is clearly more reliable than observational evidence. However, basing extinction records on collected material is all very well if people actually look critically at the museum collections (the vast majority of old collections in some museums has notbeen looked at this century). There are cases for Asian fishes and amphibians where much of the museum material is misidentified and common species well known from the popular literature are in fact misidentified (in several cases, the museum specimen/s actually represent extinct species).

    Birds Advisory Panel

    Comment 1: observational evidence is acceptable, but it is necessary to be explicit as to the exact nature of the evidence (for effective evaluation).

    Comment 2: perhaps we should have separate categories according to the type of available evidence for the EED.

    Comment 3: observational evidence for birds has to be treated very carefully. What is a "competent observer?" The Raoul Island megapode is almost certainly valid — as the pigeon has since been found archaeologically, but there is no way that the taxonomic status can be resolved without specimens. Collected material can be the only way of securing an identification. Perhaps a "suspense list" may be a way around the problem of verifying observational data (ie., a list for taxa where the decision on their probable extinction is suspended pending further information). (This is partly in place with the fish and mammal lists, where taxonomically unverified species are put in their own category).

    Comment 4: collected specimens are the best evidence, but photographs and recordings of vocalizations would be acceptable for some species.

    Coleoptera Advisory Panel

    Comment 1: accumulate information from multiple sources: personal observations, memoirs, published observations, published data on distributions, and collections based info.

    Comment 2: collected material is required because species identification is too tentative without it.

    Comment 3: for invertebrates, at least the great majority of species, a combination of observational and collected material would be required because identity can usually only be established in comparison to related taxa, in a lab or collection and it would be helpful to have voucher specimens to confirm identifications.

    Comment 4: for beetles, let's use what we can get. Observation may be subjective.

    Fishes Advisory Panel

    Comment 1: for freshwater fishes, materials collected within 50 years give evidence for the EED.

    Comment 2: for most fish, collected evidence is the only acceptable evidence.

    Comment 3: because of obvious problems associated with identifying fishes in their habitats, collected material would provide the only satisfactory evidence.

     

    Lepidoptera Advisory Panel

    Comment 1: Observational evidence can be difficult to interpret because of taxonomic confusion in all but the most conspicuous groups, and collected material is necessary for confirmation of name applicability in almost all cases - not least, because recent taxonomic studies are leading to considerable changes even in putatively well known groups of butterflies and moths, and numerous sibling groups are coming to notice.

    Mammals Advisory Panel

    Comment 1: observational evidence is very important for some mammals, for example, Australian mammals -- especially where there has been a major extinction event with little scientific collecting prior to the event. Aboriginal oral history includes indication of species' presence some time after the last collected specimen.

    Comment 2: observational evidence is acceptable.

    Comment 3: accepts observational evidence or photographs for large species, but is less inclined to accept such evidence for small species.

    Molluscs Advisory Panel

    Comment 1: Effective Extinction Date in mollusks is best related to the last collected specimens. Observational data is dangerous. The data should be verified by an expert and the data (usually a specimen) be available for subsequent checking — i.e., a voucher in a public museum.

    Reptiles Advisory Panel

    Comment 1: observational evidence is adequate for some distinctive taxa, but many or most taxa would require specimens for confirmation.

    Comment 2: collected material for small lizards and snakes is highly recommended, as reliable identifications of many of the tropical species can be done and verified independently only with preserved material (alpha taxonomy of some lizards is confused). Photos and sight records may be adequate for nearly all crocodilians, many turtles, and the larger lizards and snakes.

    Comment 3: observational evidence is required.

    Comment 4: the EED can adequately be assigned to a species based on observational evidence.

    Comment 5: for reptiles, collected material will be very important, if not critical.

    Summary comments:

    (In the case of some groups, collected evidence seems to be the only acceptable evidence. However, for other groups, other evidence (e.g, acoustic) seems reliable enough. Perhaps the evidence can be classified according to what it was - 1) direct observation, 2) indirect observation (photos, calls, nests etc. Observational, or other evidence is acceptable so long as it is reputable; it should refer to some definitely diagnostic feature of the species.)

     

     

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