Phyllanthus deciduiramus is a sub-shrub or shrub of 0.4-2 m high, endemic of New Caledonia. This species is only known from Mount Kaala, in the north west of Grande Terre. It occurs on shrubland on ultramafic substrates between 72 and 1,061 m asl. Its area of occupancy (AOO) and extent of occurrence (EOO) are both equal to 24 km². This species was assessed as Critically Endangered in 2017 and prospection efforts have since identified other subpopulations. It is now known to be in two locations (mining threats and bushfire threats). The main identified threats are linked to habitat damage by mining activities and bushfires. In 2019, a big bushfire event departed from Troulala at the base of Mont Kaala and went up to Mont Kaala at 1,000 m asl. P. deciduiramus is therefore listed as Endangered (EN) under criterion B1ab(i,ii,iii,v) +B2ab(i,ii,iii,v), with an estimated decline of all the concerned subcriteria.

Geographical area

Phyllanthus deciduiramus is endemic to New Caledonia where it is only known from Mount Kaala, in the north west of Grande Terre.

Population

Population size is unknown but field observations indicate that the species is not abundant.

Habitat

Phyllanthus deciduiramus occurs on shrubland on ultramafic substrates between 72 and 1,061 m asl.

Threats

The main identified threats are linked to habitat damage by mining activities and bushfires. In 2019, a bushfire events departed from Troulala at the base of Mont Kaala and went up to Mont Kaala at 1,000 m asl. (personal communication Fleurot, D).

Conservation

Phyllanthus genus is protected by legislation in Province Nord. Phyllanthus deciduiramus does not occur in any protected area. This species would benefit from ex situ and in situ emergency conservation actions. It is proposed to monitor known subpopulations, to preserve a viable population on a delimited site in the mining area. Moreover, it is advised to run multiplication tests in order to assist future planting operations. The local authority responsible for the coordination of the firefighting effort should also be informed about the presence of this species in areas concerned.

Bibliography

Munzinger J., Morat Ph., Jaffré T., Gâteblé G., Pillon Y., Rouhan G., Bruy, D., Veillon J.-M., & M. Chalopin 2020. FLORICAL: Checklist of the vascular indigenous flora of New Caledonia [continuously updated].

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

McPherson, G.; Schmid, M. 1991. Flore de la Nouvelle-Calédonie et dépendances. Volume 17 : Euphorbiaceae II Phyllanthaceae.

Experts

Assessor(s): Amice, R., Bruy, D., Butin, J., Cazé, H., Fleurot, D., Héquet, V., Lannuzel, G., Laudereau, C., Lagrange, A., Veillon, J., Garnier, D., Dumontet, V., Goxe, J., McCoy, S., Gâteblé, G.

Reviewer(s): Warimavute, G.

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