Thanks, John. I agree that there will be little value in trying to define and name distinct units of space and time, but there may be value in defining units along the taxonomic axis. However, we should first come to a community consensus on what the maximum scope of each axis is.
My sense is that the maximum scope of space is "Earth" (at least until we begin documenting populations of extraterrestrial life).
My sense is that the maximum scope of time is effectively "any window of time during the past 4 billion years or so".
But I don't have a clear sense for what the maximum scope of "one or more organisms" ought to be. I'm content with extending it to "populations" as a unit of "organisms", because I see a smooth transition from two individual organisms all the way up to a population of organisms. But should we accept taxonConcept (which can be thought of as an implied set of populations) as an extension of "organisms"? If so, then "Animalia Occurred on Earth sometime during the past 2 billion years" is a legitimate Occurrence record (pretty damn useless...but still legitimate).
I think it matters, and is relevant to this exchange -- both because of Steve's point about more clearly defining what an "Occurrence" can be, and because we still don't have a good idea of how and where to score "nativeness" (for which there is clearly an expressed need).
I agree that fitness-for-use should be determined from the content of the records, but coming back to Donald's (and others') point about filtering "non-native" records, there needs to be a way to include this information in the content of the records in order to determine fitness-for-use. I believe that a controlled vocabulary for establishmentMeans will probably be all we have to do to satisy 95% of the user need. But before we can nail down what that controlled vocabulary would encompass, I think we need to come to some sort of consensus on the issues that Steve has articulated.
Aloha, Rich
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From: gtuco.btuco@gmail.com [mailto:gtuco.btuco@gmail.com] On Behalf Of John Wieczorek Sent: Tuesday, October 12, 2010 11:29 AM To: Richard Pyle Cc: Steve Baskauf; joel sachs; tdwg-content@lists.tdwg.org; tdwg-bioblitz@googlegroups.com Subject: Re: [tdwg-content] How to record "Nativeness"?
Occurrence is admittedly a problematic term. Its current definition is vague following in the grand tradition of Dublin Core term definitions. Rich's interpretation echoes what Steve wrote and comes closest in my mind to what an occurrence really is meant to be, namely "evidence of one or more organisms occurring at a place and time." This leaves open all of the vast continuum of scales - geographic, temporal, and taxonomic - at which occurrences can be described. I'm not sure exactly what is solved by trying to make named distinctions between different scales or levels of detail (on any of the three axes) of Occurrence. The core of the issue really boils down to fitness-for-use of records and a potential user's capacity to accurately determine that. These should be characteristics that can be determined from the content of the records.