Taxonomy
Acianthus halleanus
Synonyms
Acianthopsis halleana (Kores) M.A.Clem. & D.L.Jones • Acianthopsis halleana (Kores) Szlach.Red List Status -
Near Threatened (NT) , assessed in 26/10/2015Protected species -
in Northern Province
Acianthus halleanus is an endemic geophyte orchid of New Caledonia, distributed from Forêt Nord to Dumbéa for the southern part of Grande Terre, from Boulinda to Mont Kaala for the northern part of Grande Terre and on île des Pins. A. halleanus occurs in dense humid forest, in open shrubland on ultramafic substrate at an altitudinal range 20-400 m asl. With more than 10 locations, partly threatened by bushfire and mining activities, a continuous decline of habitat quality is estimated. Using criteria B, A. halleanus is assessed as Near Threatened (NT) close to Vulnerable (VU) B1ab(iii)+B2ab(iii).
Geographical area
Acianthus halleanus is an endemic geophyte orchid of New Caledonia, distributed from Forêt Nord to Dumbéa for the southern part of Grande Terre, from Boulinda to Mont Kaala for the northern part of Grande Terre and on île des Pins.
Population
Population size is not precisely known, but from field observations, sub-population size ranges from 10 to 100 mature individuals.
Habitat
A. halleanus occurs in dense humid forest, in open shrubland on ultramafic substrate at an altitudinal range 20-400 m asl.
Threats
The main threats to A. halleanus are the bushfires, especially for the populations located at the bottom of Pic N'ga and mont Kaala but also mining activities on Goro area.
Conservation
A. halleanus is protected by legislation in Province Nord and Province Sud and occurs in two protected areas : Parc provincial de la Rivière Bleue and Parc de la Dumbéa. From experts, its distribution is likely to be larger than what is figured by actual observations, field surveys are thus required to refine our knowledge on its distribution.
Bibliography
Endemia.nc 2016. Faune et Flore de Nouvelle-Calédonie.
Morat, P.; Jaffré, T.; Tronchet, F.; Munzinger, J.; Pillon, Y.; Veillon, J.-M. and Chalopin, M. 2012. Le référentiel taxonomique Florical et les caractéristiques de la flore vasculaire indigène de la Nouvelle-Calédonie [The taxonomic database « FLORICAL » and characteristics of the indigenous flora of New Caledonia]. Adansonia sér 3(34) , p.177-219.
Hallé N.; Aubréville A.; Leroy J. F.; 1977. Flore de la Nouvelle-Calédonie et dépendances. Volume 8: Orchidaceae.
Experts
Assessor(s): Butin, J., Laudereau, C., Amice, R., Fleurot, D., Frayssinet, I., Garnier, D., Letocart, D., Letocart, I.
Reviewer(s): Tanguy, V.
Contributor(s): Faria, E.
Facilitator(s): Chanfreau, S.