Taxonomy

endemique
protegee
UICN

Red List Status -

Endangered (EN) , assessed in 12/10/2015

Protected species -

in Northern Province

Xylosma tuberculatum is a shrub endemic to the north-western part of Grande Terre in New Caledonia. This species is known from 3 subpopulations: Ouazangou, Paéoua and Boulinda. It is found in shrubland and in high altitude humid forest on ultramafic substrates at an altitudinal range of 700-1,100 m asl. The main threat is presented by ongoing mining development in Ouazangou. In addition this species can be potentially threatened by future mining development in Paéoua and Boulinda and in the past has been affected by bushfires at Paéoua. Extraction projections for the coming 25 years could have a significant impact on the population. Therefore, Xylosma tuberculatum 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 five, a continuous decline of all concerned subcriteria and extent of occurrence (EOO) and area of occupancy (AOO) are respectively estimated to be of 493 km² and 40 km².

Geographical area


Xylosma tuberculatum is an endemic shrub of the north-western part of Grande Terre in New Caledonia. This species is known from 3 subpopulations: Ouazangou, Paéoua and Boulinda.

Population


Population size is unknown. 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


Xylosma tuberculatum is found in shrubland and in high altitude humid forest on ultramafic substrates at an altitudinal range of 700-1,100 m asl.

Threats


The main threat is presented by ongoing mining development in Ouazangou. In addition this species can be potentially threatened by future mining development in Paéoua and Boulinda. New Caledonia contains 20 - 30% of the world’s nickel resources and has experienced intense mining activities since the late 19th century which has 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 a rise in nickel production from 60,000 to 200,000 tonnes per year between 2013 and 2015). Paéoua and Boulinda are also under a heightened threat from bushfire. Uncontrolled fires 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).

Conservation


The Xylosma genus is protected by legislation in Province Nord, but does not occur in any protected area. It is recommended to conduct searches at Koniambo and, if possible, to collect an herbarium specimen to confirm if a subpopulation is present there. This species would benefit from ex-situ and in-situ emergency conservation actions. It is proposed to ensure the monitoring of the known populations and to preserve a viable population within delimited perimeters. It would be moreover advised to conduct propagation tests in order to assist future planting operations.

Bibliography


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.

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.

Experts


Assessor(s): Tanguy, V., Veillon, J., Amice, R., Barrière, R., Chambrey, C., Fleurot, D., Lannuzel, G.

Reviewer(s): Vandrot, H.

Contributor(s): Wulff, A.

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


Geographical distribution