My comment about the meaning of "voucher" is based on having the experience of being scolded for collecting digital images of plants without "collecting vouchers" along with the images. In that case, it was clear that "voucher" was intended to mean "a piece of the plant or the whole plant itself". I don't know if there is a technical definition definition of "voucher" but I'm pretty sure that most botanists use "voucher" to mean "PreservedSpecimen". The use of "voucher" may be different outside of botany.
I take the broader view that it is important to document Occurrences with evidence which may or may not include PreservedSpecimens. In some cases, it is virtually impossible to collect PreservedSpecimens. For example in National Parks in the USA, you can get in big trouble for collecting specimens without a permit and even with a permit the specimens remain the property of the park, not the collector. Camera traps and images of highly mobile animals such as whales may be the only practical way to document some organisms. In cases such as these, digital images of the organisms are about the best that you can do. That is why I feel it is very important that Darwin Core be broadened in ways such as we are discussing here to allow for characterizing forms of evidence beyond preserved specimens.
Steve
On 7/12/2011 3:16 AM, Gregor Hagedorn wrote:
For many endangered species the normal evidence is that an expert visits the place and gives testimony. This testimony can be recording sheet, etc. Digital images are desirable, but that depends. I think evidence and vouchers have not much to do with the process of collecting. At least not if you work outside a museum.
Gregor