Gynochthodes truncata is an endemic liana of Grande Terre in New Caledonia. This species is only known from 3 subpopulations (Tiébaghi, Kaala, and Contrefort Mt. Nemmara). Gynochthodes truncata is found in shrubland and humid forest on ultramafic substrates at an altitudinal range 400-750 m asl. The main threat is linked to ongoing mining activities on Tiébaghi and Mount Kaala areas. A further threat is from bushfires at Kaala and Mt. Nemmara, which contribute to the decline of habitat quality. Mining extraction projections for the coming 25 years could lead to a 50% reduction in the impacted subpopulation. Gynochthodes truncata is assessed as Endangered (EN) under criterion A4c with an inferred population reduction of more than 50 % over three generations (75 years) starting in 1970 and projected to 2045; and under criteria B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v) with the number of threat-defined locations estimated to be four, a continuous decline of all concerned subcriteria and extent of occurrence (EOO) of 534 km² and area of occupancy (AOO) of 40 km².

Geographical area

Gynochthodes truncata is an endemic liana of Grande Terre in New Caledonia. This species is only known from 3 subpopulations (Tiébaghi, Contrefort Mt. Nemmara and Kaala).

Population

Population size is unknown. Field surveys emphasize mostly isolated plants. However the mining extraction projections for the coming 25 years could lead to a 50% reduction in the impacted subpopulation and thus contribute to the potential reduction of the total population size.

Habitat

Gynochthodes truncata is found in shrubland and humid forest on ultramafic substrates at an altitudinal range of 400-750 m asl.

Threats

The main threat is linked to ongoing mining activities in the Tiébaghi and Mount Kaala areas. New Caledonia contains 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 (there was rise in nickel production from 60,000 to 200,000 tons per year between 2013 and 2015). A further threat is from bushfires at Kaala and Mt. Nemmara, which contribute to the decline of habitat quality. 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).

Conservation

Unprotected by legislation, Gynochthodes truncata does not occur in any protected area. 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 and Mount Kaala). It is moreover advised to conduct propagation tests in order to design a replanting programme, and to prospect actively in nearby areas.

Bibliography

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.

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

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.

Experts

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.