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Question 5.

How should the EED criteria be changed if it was decided that these surveys should begin significantly earlier than AD 1500?

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

    Amphibians Advisory Panel

    Comment 1: not sure.

    Comment 2: the criteria would have to be changed. For example, do we accept all the words of Pliny? (Similar comments were made for assessing reliability of very old data for fishes: essentially, if Pliny's accounts are shown to be taxonomically invalid and/or not supported by collected material then it is reasonable to discount them.)

    Birds Advisory Panel

    Comment 1: work this out by further trial and error and see what circumstances become apparent. Try adding a few pre-1500 mammal extinctions to the list and see how the criteria fare.

    Comment 2: AD 1500 probably works well for birds on continents, and on islands reached later by Europeans without previous occupation, e.g. St. Helena. But the Pacific had a major extinction event that started before AD 1500 and continued after it. AD 1500 is an artificial date and the should simply be moved back to AD 1000 with the same criteria (specimens with direct [preferably] or close associating 14C dating), with calibrated age post AD 1000.

    Coleoptera Advisory Panel

    Comment 1: changing the EED to earlier than AD 1500 probably can't happen because our knowledge is still too limited in terms of taxa, present and past distribution etc.

    Fishes Advisory Panel

    Comment 1: the earlier than AD 1500 one goes, the more uncertain becomes the goal of the surveys. The large scale range extension of men starting from AD 1492 is specific to the modern EED brought about by human activities.

    Mammals Advisory Panel

    Comment 1: Any survey starting before AD 1500 requires wider criteria and must account for upper Pleistocene faunas.

    Comment 2: either the EED is made more flexible, or if the EED is maintained as strictly defined then species not meeting this are removed from the list.

    Molluscs Advisory Panel

    Comment 1: If the dates were earlier the criteria would remain much the same - although the evidence would be much harder to obtain.

    Reptiles Advisory Panel

    Comment 1: the evidence should include published or manuscript references regarded as unambiguously identifiable by modern specialists. Estimated dates should be based on standardized dating techniques in archaeology.

    Comment 2: N/A

    Comment 3: collected material is more important than observational evidence. Intensity of surveying for sub-fossil material should be considered (this would seem to come down to ensuring that sampling had been representative). Accuracy of radio-carbon dating needs to be considered. (Looking at data from Don McFarlane and Clare Flemming, relative accuracy of radio-metric dating (ie., %of total time frame since presumed loss) seems acceptable compared to recent dating which is itself vague in several instances; ie. when the standard error of radiometric dates are expressed as a percentage of the total time elapsed since the presumed fossil extinction, this value does not seem to be much greater than when the possible range in EED of a recent extinction is expressed as a percentage of the total time elapsed since that extinction).

    Comment 4: This would be very difficult for reptiles as the fossil remains (and perhaps more importantly those working on fossil remains) for reptiles are very difficult to label to a particular species, rather generic level placements are usually the best that is done. (The same is often true for fishes).

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