CSIRO PUBLISHING Australian Systematic Botany, 2018, 31, 448–480 https://doi.org/10.1071/SB18016 One new endemic plant species on average per month in New Caledonia, including eight more new species from Île Art (Belep Islands), a major micro-hotspot in need of protection Gildas Gâteblé A,G, Laure Barrabé B, Gordon McPherson C, Jérôme Munzinger D, Neil Snow E and Ulf Swenson F AInstitut Agronomique Néo-Calédonien, Equipe ARBOREAL, BP 711, 98810 Mont-Dore, New Caledonia. BEndemia, Plant Red List Authority, 7 rue Pierre Artigue, Portes de Fer, 98800 Nouméa, New Caledonia. CHerbarium, Missouri Botanical Garden, 4344 Shaw Boulevard, Saint Louis, MO 63110, USA. DAMAP, IRD, CIRAD, CNRS, INRA, Université Montpellier, F-34000 Montpellier, France. ET.M. Sperry Herbarium, Department of Biology, Pittsburg State University, Pittsburg, KS 66762, USA. FDepartment of Botany, Swedish Museum of Natural History, PO Box 50007, SE-104 05 Stockholm, Sweden. GCorresponding author. Email:
[email protected] Abstract. The New Caledonian biodiversity hotspot contains many micro-hotspots that exhibit high plant micro- endemism, and that are facing different types and intensities of threats. The Belep archipelago, and especially Île Art, with 24 and 21 respective narrowly endemic species (1 Extinct,21Critically Endangered and 2 Endangered), should be considered as the most sensitive micro-hotspot of plant diversity in New Caledonia because of the high anthropogenic threat of fire. Nano-hotspots could also be defined for the low forest remnants of the southern and northern plateaus of Île Art. With an average rate of more than one new species described for New Caledonia each month since January 2000 and five new endemics for the Belep archipelago since 2009, the state of knowledge of the flora is steadily improving.