Taxonomy
Red List Status -
Near Threatened (NT) , assessed in 08/09/2017
Oxera crassifolia is an endemic sub-shrub of New Caledonia. This species is rare, being restricted to the high mountain massifs of southern Grande Terre and only known from three locations (Mt. Humboldt, Kouakoué and Montagne des Sources). It is found in altitudinal shrubland on ultramafic substrates between 900 and 1,550 m asl. The population size is unknown. Its Area of Occupancy (AOO) and Extent of Occurrence (EOO) are estimated at 20 and 84 km², respectively. This species does not seem directly threatened because of its altitudinal habitat. However, evidence of past and ongoing recurrent bushfires has been observed in Montagne des Sources and therefore constitutes a potential threat, as well as feral pigs, which impact habitat quality. These threats could quickly drive the species to Endangered in the future. Therefore, Oxera crassifolia is listed as Near Threatened (NT) close to Vulberable under criterion D2.
Geographical area
O. crassifolia is endemic to New Caledonia. It is restricted to the southern high mountain massifs of Grande Terre, and only known from three locations: Humboldt, Kouakoué and Montagne des Sources.
Population
Population size is unknown but field observations indicate that populations are small.
Habitat
O. crassifolia occurs in altitudinal scrubland on ultramafic substrate from 900 to 1,550 m asl.
Threats
This species does not seem directly threatened because of its altitudinal habitat. However, evidence of fires has been observed in Montagne des Sources and therefore constitutes a potential threat, as well as feral pigs (Sus scrofa), which impact habitat quality.
Conservation
This species is not protected by any legislation in New Caledonia but it does occur in four protected areas: Massif du Kouakoué, Mont Humboldt, Haute Yaté and Montagne des Sources. It is proposed to monitor known populations and to inform the local authority responsible for the coordination of the firefighting effort about the presence of the species in the concerned areas. Searches at Boirou, Néaoua and Katrikoin-Kouaoua are also recommended to determine the size of the population and better understand potential threats. Finally, improved knowledge of the species (e.g propagation tests) would also be needed for ex situ conservation.
Bibliography
Endemia.nc 2016. Faune et Flore de Nouvelle-Calédonie.
Gâteblé, G. 2016. Flore ornementale 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.
Barrabé L, Karnadi-Abdelkader,G, Ounemoa,J,de Kok RPJ., Robert N, Gâteble,G. 2015. Recircumscription of Oxera (Lamiaceae: Ajugoideae) ta include Faradaya based on molecular and anatomical data. Botanical Journal of the Linnean Society(179) , p.693-711.
Mabberley DJ, de Kok RPJ. 2004. Labiatae. In: Morat P,ed. Flore de la Nouvelle-Calédonie et dépendance.
Experts
Assessor(s): Gâteblé, G., Barrabé, L., Fleurot, D., Amice, R., Cazé, H., Bruy, D., Héquet, V., Vandrot, H., Butin, J., Mandaoué, L., Haverkamp, C., Dumontet, V., Laudereau, C.
Reviewer(s): Meyer, S.
Facilitator(s): Warimavute, G., Tanguy, V.