--QUESTIONS RELATING TO BASIC CRITERIA

Our first criterion is that the species name and status must be systematically valid.

This statement indicates that we are using standard rules of nomenclature, and that for this survey we are interested in counting organisms on the level of species. We have chosen "species" as the basic unit to count for practical reasons. It is the most widely accepted and recognized biological unit, particularly in terms of having the greatest acceptance and practical value to conservation policy. Thus, we are not counting subspecies or populations. If we include these units, we risk producing lists that are too confusing and complicated to be understood or used by relevant consuming groups. Do you agree or disagree with this rationale?

If you disagree, what species concept do you think works best for this kind of study, and why?

Responses

Our second criterion is that the effective extinction date (EED) must be confirmed as falling within recent times. The studies on recently extinct fish and mammals defined this time as covering from AD 1500 to the present. We felt that AD 1500 represented a justifiable start date for surveying recent extinctions for two reasons: following this date, human exploration of the globe became more prevalent, and reliable evidence for the loss of other species in association with human movement and activities began to be recorded widely. Do you agree that this is a sensible date from which to start a survey such as this? If not, how much further back in time do you think the survey should go?

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?

Responses

In reference to establishing the EED, we have stated that evidence of observation, identification, and date of collection of the specimen should be "reliable." We defined "reliable source" as someone with an intimate knowledge of the taxon in question. Do you consider this to be sufficiently precise and, if not, how would you change it?

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

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Question 6

Our third criterion involves using a 50-year rule as an insurance policy (albeit arbitrary) against prematurely declaring a species "extinct;" in other words, unless at least 50 years have passed since the species was last located in the wild, its extinction cannot be declared "resolved." We adopted this protocol because it provides a lengthy time period during which the species, if still extant, might be seen or collected, purely by chance. This can be particularly important when it is difficult to judge whether sufficient sampling has been conducted to confirm the species’ absence.

What is your opinion of the 50-year rule? (Realize that this rule in no way precludes listing species that are most likely extinct — it merely puts them in a different category to indicate that the species has met other criteria except for the 50-year rule.) Would you alter this time span or eliminate it altogether? If eliminated, how would you deal with the possibility that:

(1) the species is particularly difficult to collect regardless of sampling--for example, because it is cryptic or naturally rare.

(2) the habitat is particularly difficult to survey -- for example, marine environments.

(3) the species is temporally absent from its typical habitat, but not extinct; for example, when environmental change or ecological shift result in the movement of the species to a different, unexpected (and unsurveyed) habitat.

Responses

For some taxa it may be necessary to apply a more detailed analysis of absence after the species’ reported EED in order to accurately account for its status. In our survey of freshwater fish, for example, it was determined that because they are so elusive, extant species could easily be overlooked and wrongly considered extinct unless these additional criteria were applied:

a) significant but unsuccessful attempts had been made to relocate the species after its noted absence (either in a search targeted toward that species or in a sampling exercise that covered the expected range of that species),

b) there had been a decline of that particular species, or an environmental threat to it, before the EED.

To what degree would it be necessary to apply these additional criteria to your group in order to be more certain that an extinction took place?

Responses

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?

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Question 9

Can you think of other sub-criteria that would be helpful for your group for analyzing absence after the EED?

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--GENERAL QUESTIONS

In general, can you think of any other criteria or sub-criteria that would be helpful for assessing extinctions in your group?

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Any additional comments about criteria, categories, or the CREO project in general?

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