Biodiversity Sampling Using a Global Acoustic Approach: Contrasting Sites with Microendemics in New Caledonia Amandine Gasc 1,2 *, Je ´ro ˆ me Sueur 1 , Sandrine Pavoine 2,3 , Roseli Pellens 1 , Philippe Grandcolas 1 1 De ´partement Syste ´matique et E ´ volution, Muse ´um national d’Histoire naturelle, Paris, France, 2 De ´partement Ecologie et Gestion de la Biodiversite ´, Muse ´um national d’Histoire naturelle, Paris, France, 3 Department of Zoology, University of Oxford, Oxford, United Kingdom Abstract New Caledonia is a Pacific island with a unique biodiversity showing an extreme microendemism. Many species distributions observed on this island are extremely restricted, localized to mountains or rivers making biodiversity evaluation and conservation a difficult task. A rapid biodiversity assessment method based on acoustics was recently proposed. This method could help to document the unique spatial structure observed in New Caledonia. Here, this method was applied in an attempt to reveal differences among three mountain sites (Mandje ´lia, Koghis and Aoupinie ´) with similar ecological features and species richness level, but with high beta diversity according to different microendemic assemblages. In each site, several local acoustic communities were sampled with audio recorders. An automatic acoustic sampling was run on these three sites for a period of 82 successive days. Acoustic properties of animal communities were analysed without any species identification. A frequency spectral complexity index (NP) was used as an estimate of the level of acoustic activity and a frequency spectral dissimilarity index (D f ) assessed acoustic differences between pairs of recordings. As expected, the index NP did not reveal significant differences in the acoustic activity level between the three sites. However, the acoustic variability estimated by the index D f , could first be explained by changes in the acoustic communities along the 24-hour cycle and second by acoustic dissimilarities between the three sites. The results support the hypothesis that global acoustic analyses can detect acoustic differences between sites with similar species richness and similar ecological context, but with different species assemblages. This study also demonstrates that global acoustic methods applied at broad spatial and temporal scales could help to assess local biodiversity in the challenging context of microendemism. The method could be deployed over large areas, and could help to compare different sites and determine conservation priorities. Citation: Gasc A, Sueur J, Pavoine S, Pellens R, Grandcolas P (2013) Biodiversity Sampling Using a Global Acoustic Approach: Contrasting Sites with Microendemics in New Caledonia. PLoS ONE 8(5): e65311. doi:10.1371/journal.pone.0065311 Editor: David L. Roberts, University of Kent, United Kingdom Received August 23, 2012; Accepted April 29, 2013; Published May 29, 2013 Copyright: ß 2013 Gasc et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by a CNRS INEE PhD grant, the BIONEOCAL ANR (Agence National de la Recherche) and the FRB (Fondation pour la Recherche sur la Biodiversite ´) grant BIOSOUND. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: agasc@mnhn.fr Introduction New Caledonia has been classified as one of the 25 most important hotspots of biodiversity conservation regarding the number of endemic species and degree of threat [1]. Kier et al. [2] also ranked New Caledonia as the terrestrial region with the highest level of endemism. As an example, 19% of bird, 67% of mammal, 86% of reptile and 76% of plant species are endemic to this Pacific island at the regional scale [1]. The emphasis put on regional endemism and biogeography masks another remarkable feature of New Caledonia, the extremely high level of local endemism, hereafter called microendemism. The so-called micro- endemic species of plants, lizards or insects show a very short distributional range, limited to small mountains or rivers of New Caledonia. According to recent studies, this local endemism mainly originated through recent allopatric speciation with little ecological differentiation [3], with the notable exception of adaptation to metalliferous soils derived from ultramafic rocks covering one third of the island [4]. In this paradigm, the island can be considered as a wonderful natural laboratory for evolution, where many questions regarding speciation and endemism can be studied through a large time window of 37 million years (e.g., [3,5–8]). Microendemism also bears strong consequences for conserva- tion since very short distributional ranges increase the risk of species extinction, facing three principal threats that are nickel mining, fire and invasive species (reviewed in [9]). The origin and composition of this threatened biodiversity have to be quickly described and deciphered, both to allow theoretical studies of speciation and evolution to be conducted and to permit the establishment of conservation policies. It is therefore necessary to rapidly characterize sites and their communities. However, such a task is made complex because sites differ not only by distinct species combinations within the same local pool, but also by the fact that each mountain or river usually shows local endemics formed by allopatric speciation (e.g., [7–8,10]). Inventorying in New Caledonia has proved to be a fastidious and slow process due to a complex landscape, a small local scientific community, and long distance isolation from most academic centres. The level of species richness in New Caledonia is particularly high throughout the island. Comparing species richness of sites is not likely to be very informative [9]. Establishing complementarities of different sites in terms of species composition should help in establishing conservation priorities for the diversity evaluation and conserva- tion of New Caledonia [11–12]. PLOS ONE | www.plosone.org 1 May 2013 | Volume 8 | Issue 5 | e65311