Gmelina tholicola is a shrub endemic to the north-west of Grande Terre in New Caledonia. This species is only known from five subpopulations (Poum, Tiebaghi, Koumac, Ouaco, Néhoué). Gmelina tholicola is found in shrubland on ultramafic or schist substrates at an altitudinal range of 30-578 m asl. This species is rare and based on experts knowledge, the population size is estimated to be fewer than 2,500 mature individuals with a number of mature idividuals estimated to be less than 250 mature individuals in each subpopulation. Due to the threats of nickel mining at Tiebaghi, invasive animals (Rusa timorensis) and the high impact of uncontrolled bushfires, a continuous decline is estimated. Using criteria C, Gmelina tholicola qualifies as Endangered (EN) C2a(i);C2a(ii).

Geographical area

Gmelina tholicola is endemic to New Caledonia where it is restricted the north-west of Grande Terre in New Caledonia. It is only known from five subpopulations (Poum, Tiebaghi, Koumac, Ouaco, Néhoué).

Population

This species is rare and based on experts knowledge, the population size is estimated fewer than 2,500 mature individuals with an estimated number of less than 250 mature individuals in each subpopulation.

Habitat

This species occurs in shrubland on ultramafic substrates at an altitudinal range of 30-578 m asl.

Threats

The main threat is linked to ongoing mining activities on Tiebaghi, along with impacts of uncontrolled bushfires and Rusa deer (Rusa timorensis). Uncontrolled bushfires sweep across New Caledonia each year, especially during the dry season (an average of 25,000 ha of land is burnt each year, with dramatic peaks of 70,000 ha). These fires contribute significantly to habitat degradation and hence a dramatic decline in the quality of habitat.

Conservation

Gmelina tholicola is protected by legislation in Province Nord but it does not occur in any protected area. It is recommended to inform the DSCGR (emergency services), responsible for the coordination of the firefighting effort. This species would benefit from in-situ and ex-situ emergency conservation actions. It is recommended to monitor existing populations and to preserve viable populations within delimited areas on mining zones (Tiébaghi). It is moreover advised to conduct propagation tests in order to design a replanting programme, and to pursue the search in the Néhoué area in Koumac (Vallée de la Rade).

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.

Mabberley DJ, de Kok RPJ. 2004. Flore de Nouvelle-Calédonie. Volume 25. (2004) Labiateae.

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].

Experts

Assessor(s): Amice, R., Bruy, D., Cazé, H., Garnier, D., Laudereau, C., Mandaoué, L., Eltabet, N., Vandrot, H.

Reviewer(s): Gâteblé, G.

Facilitator(s): Warimavute, G., Fourdrain, A.