Red List Status -Critically Endangered (CR) , assessed in 08/09/2017
Oxera microcalyx is a shrub endemic to New Caledonia, restricted to the center of Grande Terre, on Plateau de Dogny. An old herbarium specimen (1965) was collected at Ouipouin, but the species couldn't be found during recent prospection. It occurs in forest undergrowth on volcano-sedimentary between 260 and 900 m asl. It is known from a single location, and its area of occupancy (AOO) and extent of occurrence (EOO) are both equal to 8 km². The main threats are feral pigs (Sus scrofa) and rusa deer (Rusa timorensis russa), that cause habitat degradation. Deer also harm mature individuals by scratching or destroying the stems. Therefore, O. microcalyx is listed as Critically Endangered (CR) under criteria B1ab(iii,iv,v) with an estimated reduction of the concerned sub-criteria.
O. microcalyx is endemic to New Caledonia, restricted to the center of Grande Terre. This species is currently known only from the Dogny Plateau. An old herbarium specimen (1965) was collected at Ouipouin, but the species couldn't be found during recent field prospection.
Population size is unknown but the species seems to be locally abundant. However, no regeneration was observed.
O. microcalyx occurs in forest undergrowth on volcano-sedimentary substrate between 260 and 900 m asl.
The main threats are bushfires and invasive species, namely feral pigs (Sus scrofa) and Rusa deer (Rusa timorensis). Both impact habitat quality, but deer also harm mature individuals by scratching or destroying the stems.
This species is not protected by any legislation and it doesn't occur in any protected areas. This species would benefit from ex situ and in situ emergency conservation actions. It is proposed to monitor known populations and to preserve a viable population on limited areas, where invasive species are under control. Field prospection on the Dogny Plateau is important to estimate the size of the population and better understand potential threats. It is also recommended to inform the local authority responsible for the coordination of the firefighting effort about the presence of the species in the concerned areas. Finally, knowledge improvement on the species (multiplication tests) would also be needed for ex situ conservation.
Mabberley DJ, de Kok RPJ. 2004. Labiatae. In: Morat P,ed. Flore de la Nouvelle-Calédonie et dépendance.
Endemia.nc 2016. Faune et Flore de Nouvelle-Calédonie.
Gâteble G. 2016. Flore ornementale de Nouvelle-Calédonie.
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.
Gâteblé G. and Munzinger J. 2011. Réhabilitation d'Oxera pancheri Dubard (Lamiaceae), espèce menacée de la Nouvelle-Calédonie. Adansonia(34 (2)) , p.377-388.
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.
Assessor(s): Gâteblé, G., Barrabé, L., Fleurot, D., Amice, R., Cazé, H., Bruy, D., Hequet, V., Vandrot, H., Butin, J., Mandaoué, L., Haverkamp, C., Dumontet, V., Laudereau, C.
Reviewer(s): Meyer, S.
Facilitator(s): Warimavute, G., Tanguy, V.