Red List Status -Endangered (EN) , assessed in 10/09/2015
Protected species -in Northern Province , in Northern Province
Gmelina tholicola is a narrow endemic shrub restricted to the north-west of Grande Terre in New Caledonia. This species is only known from four sub-populations (Poum, Tiébaghi, Ouaco,Néhoué).Gmelina tholicola is found in shrubland on ultramafic substrate at an altitudinal range 30-500 m asl. The main threat is linked to on-going mining activities on Tiébaghi, Poum and Ouaco areas. Extraction projections over the coming 25 years leads to the extinction risk of all sub-populations. Fire and rusa rusa deer (Rusa timorensis) are further threats to this species. Its area of occupancy is equal to 20 km² and its area of occurrence to 428 km² for a total of 4 populations. Gmelina tholicola is therefore assessed as Endangered (EN) with criteria B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v) with a continuing decline of all concerned sub-criteria.
Gmelina tholicola is a narrow endemic shrub restricted to the north-west of Grande Terre in New Caledonia. This species is only known from four sub-populations (Poum, Tiébaghi, Ouaco,Néhoué).
Population size is unknown. Field surveys emphasize mostly isolated plants.
Gmelina tholicola is found in shrubland on ultramafic substrate or schist at an altitudinal range 30-500 m asl.
The main threat is linked to on-going mining activities on Tiébaghi, Poum and Ouaco areas. Extraction projections over the coming 25 years leads to the extinction risk of all sub-populations. New Caledonia contains between 20 - 30% of the world’s nickel resources. Intense mining activities since the late 19th century have generated soil erosion (1.2% of bare ground mapped by SPOT5 in 2007). Based on the distribution of metal-rich soils and site accessibility, these threats are predictable and planned (rise in nickel production from 60,000 to 200,000 tons per year between 2013 and 2015). Moreover, a fire outbreak could affect the entire population in a single event. Uncontrolled bushfires sweep across 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). These fires contribute significantly to habitat fragmentation and hence a dramatic decline in the quality of habitat. Two sub-populations (Ouaco, Néhoué) are threatened by rusa rusa deer (Rusa timorensis). Introduced in the 1880's, rusa rusa deer (Rusa timorensis) are now perfectly adapted to New Caledonian habitats.
Protected by legislation in Province Nord however Gmelina tholicola does not occur in any protected area. This species would benefit from in-situ and ex-situ emergency conservation actions. It is recommended to ensure the follow-up of existing populations and to preserve viable populations on delimited areas on mining zones (Tiébaghi, Poum and Ouaco). It is moreover advised to realize multiplication tests in order to design a replant program and to prospect actively Néhoué area in Koumac (Vallée de la rade).
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.
Morat, P.; Jaffré, T.; Tronchet, F.; Munzinger, J.; Pillon, Y.; Veillon, J.-M. and Chalopin, M. 2012. The taxonomic database « FLORICAL » and characteristics of the indigenous flora of New Caledonia. Adansonia(334) , p.177-219.
L'Huillier L.; Jaffré T. and Wulff A. 2010. Mines et Environnement en Nouvelle-Calédonie : les milieux sur substrats ultramafiques et leur restauration.
Endemia.nc 2016. Faune et Flore de Nouvelle-Calédonie.
Assessor(s): Tanguy, V., Veillon, J., Amice, R., Barrière, R., Fleurot, D., Gailhbaud, P., Garnier, D., Suprin, B.
Reviewer(s): Vandrot, H.
Contributor(s): Wulff, A.
Facilitator(s): Chanfreau, S., Tanguy, V.