Alyxia veillonii is an endemic shrub/liana restricted to the valley of Tontouta on Grande Terre in New Caledonia. It is only known from a two subbpopulations: Tontouta valley and the base of Mont Tonta. It is found in low elevation shrubland up to 600 m asl. on riverbanks on an ultramafic substrate. Recurrent bushfires and past and on-going mining activities in the valley (Tomo/Vulcain and Opoué) and road construction contribute to the degradation of the habitat, especially to soil erosion. Alyxia veillonii is particularly vulnerable to erosion because it is found close to riverbanks. Its extent of occurrence (EOO) and area of occupancy (AOO) are both estimated to be of 28 km² with an estimation of two locations. Alyxia veillonii is therefore assessed as Endangered (EN) with criteria B1ab(i,ii,iii,v)+2ab(i,ii,iii,v) with a continuing decline of all the sub criteria concerned.

Geographical area

Alyxia veillonii is endemic to New Caledonia where it is restricted to the valley of Tontouta on Grande Terre. It is only known from a two subbpopulations: Tontouta valley and the base of Mont Tonta.

Population

The population size is not known. Field observations indicate a species that is locally common.

Habitat

This species is found in shrubland on riverbanks on an ultramafic substrate up to 600 m asl.

Threats

Recurrent bushfires and on-going (and past) mining activities in the valley (Tomo and Vulcain and Opoué) and road construction contribute to the degradation of the habitat, especially to erosion. Alyxia veillonii is particularly vulnerable to erosion because it is found close to riverbanks.

Conservation

Alyxia veillonii is protected by the code de l'environnement in New Caledonia. It does not occur in any protected area. A few individuals of this species are cultivated at the IAC (Institut Agronomique de Nouvelle-Calédonie) nursery at Port-Laguerre. This species is recalcitrant to seed banks and anti-erosive works (banks reinforcement) has been realised on this species. Furthermore this species would benefit from emergency in situ conservation measures. In terms of protection, while it seems difficult to propose perennial measures as long as the valley will be exploited, it is proposed to carry and to protect the low valley of Tontouta (river forebank, dry forest).

Bibliography

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

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].

Boiteau Pierre avec collaboration de Lucie Allorge 1982. Flore de la Nouvelle Calédonie et dépendances. Volume 10 : Apocynacées.

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.

Lannuzel et al. 2024. Alyxia Banks ex R.Br. in New Caledonia: a clarification of several species complexes, nomenclatural notes, and a description of three new species. Phytotaxa(649 (1)) , p.1-43.

Experts

Assessor(s): Amice, R., Bruy, D., Butin, J., Cazé, H., Fleurot, D., Héquet, V., Bernard-Musmann, M., Goxe, J., Lagrange, A., Lannuzel, G., Laudereau, C., Vandrot, H.

Reviewer(s): Pillon, Y.

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