Homalium rubiginosum is an endemic small tree restricted to the east coast of Grande Terre in New Caledonia (from Kouaoua to Touho). It is found in dense humid forest and shrubland on ultramafic or volcano-sedimentary substrate at an altitudinal range 50-450 m asl. Past mining activities in Kouaoua likely impacted one subpopulation.The habitat of H. rubiginosum is moreover degraded by bushfires and the invasive species Rusa Deer (Rusa timorensis). Its extent of occurrence (EOO) and area of occupancy (AOO) are respectively estimated to be of 657 and 16 km² while the number of locations is estimated to be 4. H. rubiginosum is therefore assessed as Endangered (EN) with criteria B1ab(iii,v)+2ab(iii,v) with a continuing decline of habitat quality and number of individuals.

Geographical area

Homalium rubiginosum is an endemic small tree restricted to the east coast of Grande Terre in New Caledonia (from Kouaoua to Touho).

Population

Population size is unknown.

Habitat

This species is found in dense humid forest and shrubland on ultramafic or volcano-sedimentary substrate at an altitudinal range 50-450 m asl.

Threats

Past mining activities in Kouaoua likely impacted one subpopulation.The habitat of H. rubiginosum is moreover degraded by bushfires and the invasive species Rusa Deer (Rusa timorensis). Uncontrolled bushfires sweep across lowlands of New Caledonia each year, especially during the dry season (an average of 20,000 ha of land is burnt each year, with dramatic peaks of 70,000 ha). Rusa rusa deer (Rusa timorensis) was introduced in 1870s and is now perfectly adapted to New Caledonian habitats. It affects native plants directly (killing plants by eating bark and seedlings) and indirectly (through habitat degradation).

Conservation

This species is protected by the Code de l'environnement of province Nord. It does not occur in any protected area. It is recommended to enhance prospection because of the lack of general observations.

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.

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

L'Huillier L.; Jaffré T. and Wulff A. 2010. Mines et Environnement en Nouvelle-Calédonie : les milieux sur substrats ultramafiques et leur restauration.

Wulff AS, Hollingsworth PM, Ahrends A, Jaffré T, Veillon J-M, L’Huillier L, et al. 2013. Conservation Priorities in a Biodiversity Hotspot: Analysis of Narrow Endemic Plant Species in New Caledonia.

Experts

Assessor(s): Tanguy, V., Veillon, J., Bruy, D., Dubreuil, M., Dumontet, V., Fleurot, D., Garnier, D., Lagrange, A., Lannuzel, G.

Reviewer(s): Amice, R.

Contributor(s): Wulff, A.

Facilitator(s): Tanguy, V., Chanfreau, S.