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
Amphibians Advisory Panel
Comment 1: not
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
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).