Metrosideros humboldtiana is an endemic shrub or small tree from New Caledonia, where it is known from several summits (Mts. Humboldt and Kouakoué, Montagne des Sources) and the Ouinné basin, in the south of Grande Terre. It occurs in high elevation shrubland on ultramafic substrate above 850 m asl. This species is currently threatened by bushfires and feral pigs, which degrade its habitat, and could also be impacted by climate change in the future. Its extent of occurrence (EOO) and area of occupancy (AOO) are estimated at 86 and 36 km², respectively, and the number of locations is estimated to be five. Therefore, M. humboldtiana is listed as Endangered (EN) under criteria B1ab(iii,v)+2ab(iii,v).

Geographical area

This species is endemic to New Caledonia, where it is known from three summits (Mt. Humboldt, Mt. Kouakoué, Montagne des Sources) and the Ouinné basin, in the south of Grande Terre.

Population

Population size is unknown.

Habitat

This shrub or small tree occurs in high elevation shrubland on ultramafic substrate, above 850 m asl.

Threats

Main threats to this species include bushfires and feral pigs, which degrade its habitat. Besides, like other high elevation species, this one could be impacted by climate change in the future.

Conservation

M. humboldtiana is protected by legislation in Province Nord and occurs in four protected areas: Mt. Humboldt, Massif du Kouakoué and Montagne des Sources natural reserves, as well as the Côte Oubliée provincial park. This species would benefit from ex situ and in situ emergency conservation actions. It is proposed that monitoring should occur to ensure the persistence of known subpopulations. It is recommended to inform the DSCGR (government department overseeing firefighting actions) on the presence of the species in the concerned areas.

Bibliography

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.

Dawson J.W. 1992. Flore de la Nouvelle-Calédonie et dépendances. Volume 18 : Myrtacées Leptospermoïdées.

Endemia.nc 2016. Faune et Flore de Nouvelle-Calédonie.

Experts

Assessor(s): Amice, R., Bruy, D., Butin, J., Cazé, H., Dumontet, V., Fleurot, D., Gâteblé, G., Goxe, J., Henry, B., Héquet, V., Lagrange, A., Lannuzel, G., Mandaoué, L., Pillon, Y., Veillon, J.

Reviewer(s): Vandrot, H.

Facilitator(s): Meyer, S., Warimavute, G.