The Importance of Vouchers: Even Molecular Workers Need Herbaria

Those of you who have seen the Monty Python movie The Meaning of Life may recall a scene near the beginning where a woman is brought into a hospital to have a baby, only to have attention to her condition overshadowed by the attention lavished by the hospital staff on their expensive equipment and machines going "ping". Part of the joke, of course, is that a lot of their flashy machinery is completely unnecessary under normal circumstances, considering that women have been successfully having babies without it for as long as there have been women to have babies. The other part is that while we all see the ridiculousness of the situation in the movie, we still all fall for the flashy expensive option in real life. If we go to hospital ourselves, we still damn want the machine that goes "ping".

The proposed closure of the Utrecht Herbarium is actually just another example of a general trend of recent years towards the downsizing and reduction in prestige of natural history collections everywhere. In these days of biochemical assays and gene sequencers, many people, unfortunately including many university and museum directors, seem to find specimen collections just a little antiquarian and hokey. Surely modern genomic and proteomic techniques have rendered such things obsolete? No, they haven't. Molecular investigations don't remove the need for physical specimen storage. Indeed, they make it even more important than before.

Yesterday, I wrote on the importance of conserving type specimens. Type specimens are a special type of voucher specimen, and I thought I'd enlarge today on the significance of voucher specimens in general. A voucher is a representative specimen of the organisms used in a study, such as the specimen used as the source of DNA for a molecular study or a specimen collected as part of an ecological survey. Like type specimens, voucher specimens allow for the confirmation of the identity of the species referred to in the study. They therefore provide a backup against misleading results due to such things as misidentification, changing species concepts, etc.

Apparently one of the projects that has been going on at the Utrecht Herbarium involves the identification of native medicinal plants used in Suriname, so I'll take that as a hypothetical example. Imagine that a researcher working on one of these medicinal plants, call it the "big-leaved bungleflower", manages to extract an active compound from it that he dubs "ifeelfantasticin", and which shows a great deal of promise in medical tests. The problem is that no-one else is able to extract that compound from the big-leaved bungleflower, despite much effort. Despair seems inevitable, until someone decides to check the voucher specimens that the original researcher deposited from his original study. At that point, it becomes clear that the original researcher was not using specimens of big-leaved bungleflower as he had thought, but actually the similar purple-leaved bungleflower. Focus switches to the latter species, ifeelfantasticin is recovered once more, and medical history is made.

Without the voucher specimens, the error would have never been corrected so easily. Griffiths and Bates (2002) report on a real life example of voucher specimens allowing the explanation of unusual results, when a molecular study on New World vultures was seemingly unable to distinguish between greater (Cathartes melambrotus) and lesser (C. burrovianus) yellow-headed vultures. Re-examination of the original specimens indicated that some had been misidentified, including one specimen that had been deposited in a collection before the two species were recognised as distinct.

Unfortunately, all too many researchers still fail to deposit vouchers for studies (Agerer et al., 2000; Wheeler, 2003). Dennis (1960, as quoted in Agerer et al., 2000) commented that "records that cannot be verified are mere waste paper". The need for proper natural history collections remains as strong now as ever.

REFERENCES

Agerer, R., J. Ammirati, P. Blanz, R. Courtecuisse, D. E. Desjardin, W. Gams, N. Hallenberg, R. Halling, D. L. Hawksworth, E. Horak, R. P. Korf, G. M. Mueller, F. Oberwinkler, G. Rambold, R. C. Summerbell, D. Triebel & R. Watling. 2000. Open letter to the scientific community of mycologists: “Always deposit vouchers”. Mycorrhiza 10 (2): 95-97.

Griffiths, C. S., & J. M. Bates. 2002. Morphology, genetics and the value of voucher specimens: an example with Cathartes vultures. Journal of Raptor Research 36 (3): 183-187.

Wheeler, T. A. 2003. The role of voucher specimens in validating faunistic and ecological research. Biological Survey of Canada (Terrestrial Arthropods) Document series no. 9. Ottawa.

The Significance of Type Specimens, and More on Utrecht

Last week I brought up the topic of the Utrecht Herbarium, which faces imminent closure as of June 1. Since then I have been in touch with Renske Ek, who started the petition against the closure. The closure of the herbarium is primarily a cost-cutting measure, and has been under consideration for some time, though it was not announced officially until the 26th of March. The most significant question you might be asking, though, is what is to become of the collection after the closure?

Let me remind you that, as well as over 800,000 specimens, the Utrecht Herbarium holds over 10,000 type specimens. What, some of you may ask, is a type specimen? When a new species is described, the author will select one of his/her specimens (or sometimes, a collection of specimens) of that species to act as the 'type'. That specimen then becomes the definitive example of that species. From that point, if the question ever arises, "What species does "species name X" refer to?", the answer essentially is, "The species that "type specimen X" belongs to". The type specimen also allows the identification of the species if the original published description turns out to be inadequate somehow. Imagine that a taxonomist working on ants describes a new species. He describes the new species' colour, ornamentation of the body, shape of its head, and calls it "species 1". Many years later, another ant taxonomist discovers that the area where the earlier taxo got his specimens from is actually home to two very similar species. One is the earlier author's "species 1", the other is a new "species 2". The problem is, the two species are identical in colour, body ornamentation and shape of the head. They can be distinguished by the shape of the antennae, but the earlier taxonomist, not realising that the shape of the antennae was going to turn out to be significant, never included it in his original description. How is the later taxonomist to work out which of the two species he has on hand is "species 1"? That is where the type specimen comes into play - even if the original description didn't include the appearance of the antenna, the later taxonomist can always look at the type specimen and fill in the missing details.

The type specimen means that a species name is not just a vague philosophical concept, but is tied to a real tangible object. As a result, it is critical that any type specimen is preserved and remains accessible to future researchers. If a collection is locked away from visitors, the specimens are unable to serve their purpose. Also, a locked collection does not simply sit intact until such a time as it is ever opened. Biological collections require constant maintenance and monitoring. After all, these are pieces of dead plant and animal matter we're talking about - their natural tendency is to decay. Alcohol and other preservatives can evaporate, dried insects or plants may be eaten by beetles, and when the collection finally gets opened up again, all that is left is unrecognisable dust and mush. The collected specimens, and type specimens in particular, have failed in their purpose.

Unfortunately, at present there seems to be no clear plan for what is to happen to the Utrecht herbarium collection after closure. Plans to transfer it to the Universiteit Leiden appear to have been shelved due to lack of funding. It seems to have been hoped that the Nederlands Centrum voor Biodiversiteit (Dutch Centre for Biodiversity) currently being put together would offer a permanent home for the collection, but it is unlikely that the Centre will be up and running before the herbarium closes.

Whatever is to become of the Utrecht Herbarium itself, it is imperative that the collection, particularly the type specimens, remains curated and accessible somewhere. Failure to ensure this would be an unforgivable tragedy.

Postscript: David Shorthouse of iSpiders has also commented on the situation.

An Endangered Herbarium

A message that came through yesterday on the TAXACOM mailling list informs us that the University Board of Utrecht University in the Netherlands has announced plans to close the university herbarium as of the 1st of June, with access to the collections by researchers to cease immediately as of that date.

The Utrecht Herbarium holds a collection of over 800,000 specimens, including more than 10,000 type specimens. The central focus of research at the university is on plant biodiversity in tropical South America, particularly Suriname. Among the current research projects is investigation of the taxonomic identity of medicinal plants used in Suriname, information that will be vital in developing wider applications of the species involved.

The Utrecht Herbarium is part of the Nationaal Herbarium Nederland, which also includes branches at the Universiteit Leiden and the Wageningen University, and would have also been an significant part of the integrated Netherlands Centre for Biodiversity currently being developed. There are currently four PhD students among the staff at the herbarium.

For more information on the significance of the Utrecht Herbarium, and a petition against its closure and, go here. The website of the Utrecht Herbarium is here, and that of the Nationaal Herbarium Nederland is here. Other blog reactions to the closure can be found at Myrmecos and The Other 95%. I will endeavour to keep you all abreast of further developments.