Sphenostemon tireliae is an endemic shrub/tree of New Caledonia, restricted to two distant areas (Paéoua/Boulinda and Montagne des Sources/Ni/Pourina). This species is only known from five subpopulations. It occurs in mainly in dense humid forest but alson at the margin of forests on ultramafic substrate at an altitudinal range 650-1,200 m asl. The main impact identified comes from potential mining activities on Paéoua and Boulinda and past bush fire events at Montagne des Sources, Paéoua and Haute Ni. Its area of occupancy (AOO) and extent of occurrence (EOO) being respectively estimated to 28 and 1,849 km², while the number of locations are estimated to be four. Sphenostemon tireliae is therefore assessed as Endangered (EN) under criteria B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v) with a continuing decline of all concerned subcriteria.

Geographical area

Sphenostemon tireliae is an endemic shrub/tree of New Caledonia, restricted to two distant areas (Paéoua/Boulinda and Montagne des Sources/Ni/Pourina).

Population

This species is known from five subpopulations. It is an uncommon species and based on feild observations it is composed of isolated individuals.

Habitat

This species is only known from 5 subpopulations. It occurs in dense humid forest on ultramafic substrate at an altitudinal range 650-1,200 m asl.

Threats

The area of distribution of Sphenostemon tireliae has declined significally due to past bushfires events on Paéoua (the summit (1300-1400 m) has been impact several times by past bushfires (pers.comm. Veillon, J.-M.), Montagne des Sources and potentially in Haute Ni. Other main impacts identified comes from potential mining activities on Paéoua and Boulinda.

Conservation

Unprotected by legislation, this species is known in protected areas: Rivière Bleue, Montagne des Sources, and Haute Yaté. It is proposed to ensure the monitoring of known sub-populations and to preserve viable populations within delimited perimeters on the mining areas (Paéoua and Boulinda). Plus Sphenostemon tireliae should be included in the regional legislation for a better protection of the species.

Bibliography

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

Munzinger J., Morat Ph., Jaffré T., Gâteblé G., Pillon Y., Tronchet F., Veillon J.-M. and M. Chalopin 2016. FLORICAL: Checklist of the vascular indigenous flora of New Caledonia. vers. 22.IV.2016.

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.

Jérémie, J.; Hoff, M.; Jonsell, B. 1997. Flore de la Nouvelle-Calédonie et dépendances. Volume 21 : Sphenostemonaceae, Anacardiaceae, Cruciferae.

Experts

Assessor(s): Veillon, J., Amice, R., Bruy, D., Butin, J., Fleurot, D., Garnier, D., Gâteblé, G., Goxe, J., Suprin, B.

Reviewer(s): Pillon, Y.

Facilitator(s): Maura, J., Warimavute, G., Tanguy, V.