Taxonomy
Synonyms
Dendrobium delumbe Kraenzl. • Dendrobium crispatum sensuRed List Status -
Vulnerable (VU) , assessed in 11/09/2015Protected species -
in Southern Province , in Northern ProvinceDendrobium polycladium is an endemic orchid of New Caledonia, distributed in île des Pins and discontinuously from the north to the south of Grande Terre. D. polycladium occurs in shrubland on ultramafic substrate at an altitudinal range 80-1,000 m asl. Due to nickel mining activities, invasive animals and bushfire, a continuous decline is estimated. Its population size is estimated to be fewer than 10,000 mature individuals Using criteria C, D. polycladium qualifies as Vulnerable (VU) C2a(i).
Geographical area
D. polycladium is an endemic orchid of New Caledonia, distributed in île des Pins and discontinuously from the north to the south of Grande Terre. D. polycladium exists as two varieties : D. polycladium var. atractoglossum and D. polycladium var. polycladium. Boakène location seems to the geographical boundary between those two varieties (norh boundary for D. polycladium var. polycladium).
Population
Population is currently not monitored but based on informations from experts, population is estimated to be fewer than 10,000 mature individuals. Subpopulations are fewer than 1,000 individuals.
Habitat
D. polycladium occurs in shrubland on ultramafic substrate at an altitudinal range 80-1,000 m. asl.
Threats
On Kaala, Kopéto, Boulinda and Canala, Koniambo, Poum and Negropo, nickel mining constitutes the major threat. Elsewhere bushfire and habitat degradation linked to wild pig and rusa rusa deer (Rusa timorensis) (Rusa timorensis) are involved in the continuous decline of D. polycladium and its quality of habitat.
Conservation
D. polycladium is protected by legislation in Province Nord and Province Sud. This species is found in three protected areas : réserve naturelle du barrage de Yaté, réserve naturelle du Pic du Pin, Parc provincial de la Rivière Bleue. Due to the high impact of mining activities on D. polycladium, it is recommended for sub-population on mining concession to fence viable population and to work on its propagtion in order to elaborate a consistent program of plantation (diversity rate to maintain, number of sub-population required to protect this species). Then, a monitoring of natural and planted sub-population should be provided.
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., Cazé, H., Fleurot, D., Frayssinet, I., Garnier, D., Goxe, J., Gâteblé, G., Veillon, J., Villegente, J.
Reviewer(s): Tanguy, V.
Contributor(s): Faria, E.
Facilitator(s): Chanfreau, S.