Are vouchers always necessary?

We live in times with a heightened sense of urgency to confirm the return of animals thought to be extinct, or to confirm the presence of newly discovered species. Global climate change and rapidly disappearing habitat is endangering species and we become increasingly concerned about the consequences of their disappearance. The standard approach in biology is to go out and collect specimens either to confirm that they do still exist in the wild or to discover new species. However, sometimes this field work may actually pose a risk to vulnerable animal populations already on the brink of extinction:

Cases such as the extinction of the great auk remind us what is at stake in taking animals from small and declining populations. The last wild great auk (Pinguinus impennis) was sighted in 1844 on Eldey Island, Iceland. Centuries of exploitation for food and feathers, and, to some degree, a changing climate, had stressed the species, but overzealous museum collectors also played a role in its extinction. As the bird's numbers dwindled in the 19th century, ornithologists and curators increasingly prized great auk skins and eggs, with museums and universities sending out collection parties to procure specimens. On Eldey, fishermen killed the final breeding pair of the flightless birds and sold them to a local chemist, who stuffed the specimens and preserved them in spirits. Their internal organs now reside at the Zoological Museum in Copenhagen.

The great auk's disappearance predates the rise of a robust societal ethic of conservation and the emergence of a scientific concern for global biodiversity decline in the late 20th century. Yet, there is still a strong and widespread impulse to procure specimens of rare or rediscovered species for scientific purposes.

Researchers at Arizona State University and Plymouth University in the United Kingdom want to change the way biologists think about the current state-of-the-art of collecting a voucher specimen for species description and often identification. They say using modern technologies can be just as effective in identifying an organism and will also avoid increasing the extinction risk for small and isolated populations. The researchers suggest using a combination of modern, non-lethal techniques to confirm a species' existence including high-resolution photography and audio recordings of sounds or mating calls. Also, using DNA sampling by taking swabs of the mouth or skin offer ways to identify an animal without taking a specimen from the field. Especially this suggestion has DNA Barcoding written all over it and I am convinced that the barcoding community will wholeheartedly support this request:

For this system to work, the DNA of relict populations and newly discovered species must be sequenced and the data made publicly available. This would, for example, make future population rediscoveries easier to document.

The discussion about replacing non-lethal identification techniques with less-invasive ones is part of a more complex issue. Balancing ecological impact against value of improved scientific understanding of threatened species for conservation is a touchy subject. However, I concur with the authors stating that a change of our standard practices for scientific description would have more advantages than we might think:

The multivariate description of a species that results from combining high-resolution photographs, sonograms (as appropriate), molecular samples, and other characteristics that do not require taking a specimen from the wild can be just as accurate as the collection of a voucher specimen without increasing the extinction risk. Clearly there remains a long-running debate over the appropriate standards for scientific description absent a voucher specimen. The benefits and costs of verification-driven specimen collection, however, should be more openly and systematically addressed by scientific societies, volunteer naturalist groups, and museums. Sharing of specimen information, including obligations to store genetic information from voucher specimens in widely accessible digital repositories, can also help to reduce the future need to collect animals from the wild.

h/t Claudia Kleint-Steinke