Vouchering, integrative taxonomy and natural history collections: a case study with the amphibians of Madagascar

Natural history collections have played an important role in the origin of natural history museums. Over the time these institutions have become places where “voucher specimens” and other kinds of natural history objects were preferably deposited. In this paper we further highlight the importance to consider collecting biological specimens as a useful / needed action for the expansion and diffusion of scientific collections, as well as for advancing sciences and, indirectly, conservation. We also report on a recent trend of underestimating the need of voucher specimens and provide evidences that the collection of a selected number of individuals as voucher specimens is necessary to contribute to such a goal and duty of cataloguing the world biodiversity and promote its conservation. Voucher specimens play the crucial function – among the others - to confirm the presence of a species at a locality at a given time, document the original ecological and biological diversity before change, can enable long-term studies and comparisons (i.e., using for example morphological or molecular tools) and can serve as a basis for ecological studies. Specifically, we used the amphibians of Madagascar as a case-study to highlight the need to continuing the collection activities, showing that their collection has been crucial to the cataloguing of Malagasy biodiversity and thus moving towards their conservation. The use of ancillary data alone (including photographs, videos, acoustic recordings, and genetic analysis carried out on tissue samples), frequently considered in alternative to vouchering, although useful, remains insufficient.