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Question 8.

We did not stipulate quantitative measures for defining when significant attempts had been made to relocate the species, or for defining when there had been a species decline or environmental threat (see above), because quantitative measures proved difficult to develop and apply. Do you think it is necessary to develop a more quantitative system? If so, do you have any suggestions for how it could be developed?

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

    Amphibians Advisory Panel

    Comment 1: no

    Comment 2: it is not necessary at this time to develop quantitative methods. Quantitative methods for amphibians have been developed and attempted to be applied at the US national level. This generated controversy. Only need to find one individual to disprove current extinction.

    Comment 3: this is a very difficult issue to address.

    Birds Advisory Panel

    Comment 1: no, quantitative measures are difficult to assign and often spurious.

    Comment 2: you have to have a narrative that makes sense, and it would be good to fit the key elements into a database. For example, is the glaucous macaw extinct? We have maybe 10 widely scattered localities in Brazil, Uruguay, Paraguay and Argentina. How carefully has the range been covered? Pretty well, but we cannot be sure that it isn't somewhere. But it is big and blue and you'd think it would have been seen... But we're dealing with negative evidence - and uncovering the existence of negative evidence is hard work. We need to piece together habitat information and a plausible explanation for the taxon's loss before we determine with defensible authority the current status."

    Comment 3: "significant attempts" should have been made. Perhaps 5 organized attempts, in appropriate habitat at appropriate season? Other criteria, such as percent of habitat still available (if known), presence of adverse factors/influences should be factored in. In New Zealand, species thought to be critical have been searched for, but for those thought 'extinct', such as laughing owl and South Island kokako, efforts have been reactionary, relying on reported sightings to initiate effort. The problem might be resolved by scoring such factors as environmental damage, presence of predators, years since last report, and having a cut-off score for acceptance.

    Comment 4: there is no reason for additional quantification at this time. However, evidence would have to be assessed with the habitat and potential distribution ranges of the species in mind.

    Coleoptera Advisory Panel

    Comment 1: in most cases, available and published collection material will not afford a very quantitative set of critieria beyond simply inspecting recency of records. The records themselves are the most compelling sources of historical context.

    Comment 2: Yes. The panelist providing this comment has databased all captures for selected Hawaiian taxa and can quantify past survey days, localities by latitude/longitude references etc. This allows comparison of effort by decade, century etc., Quantification of the decrease in representation within comparable samples can be used to imply factors unfavorable to the species. Prolonged absence from samples (>50 years, >100 years) lends credence to an extinction explanation. Think of it as an extinction "out-group" analysis.

    Comment 3: quantitative measures would be especially difficult to develop and apply for invertebrates.

    Fishes Advisory Panel

    Comment 1: no, fish are the least applicable animals to estimate a species decline or environmental threat by quantitative measures, because of migration and movement.

    Comment 2: the concept of 'quantitative measures' is a good one, but it will unavoidably remain somewhat subjective. Perhaps a review committee established under the auspices of the ASIH could provide the necessary degree of reliability and confidence.

    Mammals Advisory Panel

    Comment 1: see question 9.

    Comment 2: quantification is a problem.

    Comment 3: quantification not necessary.

    Molluscs Advisory Panel

    Comment 1: Quantitative measures would be desirable but are probably not practical.

    Reptiles Advisory Panel

    Comment 1: it is impractical to define some minimum level of significant attempt. However, it would be useful to document, as far as possible, what the nature of such attempts have been in each case; for example, person-hours of night searches, pit-trap days etc.

    Comment 2: a quantitative procedure is highly desirable in order to make the listing more scientifically accurate, but an absolutely quantitative system (given the ecological diversity) may be difficult to develop.

    Comment 3: quantitative measures are not necessary

    Comment 4: quantitative measures for certain taxonomic groups will be important, but the same measures are not broadly applicable to all groups or all questions.