Taxonomy
Red List Status -
Vulnerable (VU) , assessed in 03/07/2017Protected species -
in Southern Province , in Northern Province
Field work over the last decade has indicated that this species should be regarded as threatened on the basis of a decline in the quality of habitat due to an increased frequency of fires (Montagne des Sources) and dieback in some subpopulations (Mt Humboldt and Mt Kouakoué). Despite its small area of occupancy (AOO), this species is confined to a little disturbed habitat in protected areas. Its AOO and extent of occurrence (EOO) are estimated to be 56 km2 and 809 km2 respectively. Araucaria humboldtensis is assessed as Vulnerable (VU) under criteria B1ab(iii,v)+2ab(iii,v) with six locations and an observed continuing decline in the number of mature individuals. It almost meets the criteria for listing as Endangered.
Geographical area
This species is known from the highest parts of four mountains in the southern massif - Mt Humboldt , Mt Kouakoué, Dzumac, Montagne des Sources and Mt Mou. A sixth area (Mamie) at much lower elevation has been confirmed recently. Occurs from 500 to 1,600 m asl.
Population
Subpopulations on the summits and ridges of Mt Humboldt, Mt Kouakoué and Montagne des Sources are quite extensive although dieback at Mt Humboldt has been observed over the last decade plus dieback has been recorded at Mt Kouakoué during field observations (B. Suprin pers. comm.) and from the notes on a specimen collected in 2006 held at the Royal Botanic Garden Edinburgh (Gaudeul 3993A). The subpopulation at Mt Mou is much smaller. At Mamie, in an area that represents an atypical habitat at an altitude of 400–500 m asl, a relatively extensive and healthy subpopulation has recently been identified as Araucaria humboldtensis. Although all subpopulations are geographically isolated from each other, they are not severely fragmented under the IUCN definition.
Habitat
Restricted to the higher ridges and summits on ultramafic soils in montane and lowland forest.
Threats
Recent dieback may have caused the death of at least 10% of the Mt Humboldt subpopulation. The extent of the dieback at Mt Kouakoué is not documented. The cause of the diebacks is unknown but may be related to drought induced stress or perhaps an unknown pathogen. Recent research partially explains dieback on some branches as being the result of infestation by native wood boring beetles (Beimforde et al. 2017), however, further on-going research is required to may clarify the causes of the diebacks. Wildfires are currently the main threat but they do not threaten the highest subpopulations. As subpopulations are restricted to a narrow altitudinal range with little possibility for upward expansion, this species may be very susceptible to the potential future impacts of climate change.
Conservation
The main subpopulations are within protected areas such as Montagne des Sources, Mont Mou, Massif du Kouakoué, Mont Humboldt and Haute Dumbéa. The species is recorded from ex situ collections (BGCI 2024). Fire prevention measures are being put in place with a "Plan de protection de massif forestier" by the province Sud from Montagne des Sources to Tontouta. Research works need to be continued to understand the causes of the observed dieback. Recent research partially explains dieback on some branches; this was the result of infestation by native wood boring beetles (Beimforde et al. 2017).
Bibliography
de Laubenfels, D.J. 1972. Flore de la Nouvelle-Calédonie et dépendances..
Ruhsam, M., Clark, A., Finger, A., Wulff, A.S., Mill, R.R., Thomas, P., Gardner, M.F., Gaudeul, M., Ennos, R.A. and Hollingsworth, P.M. 2016. Hidden in plain view: cryptic diversity in the emblematic Araucaria of New Caledonia.. American Journal of Botany(103(2)) , p.888-898.
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.
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].
Manauté, J., Jaffré, T., Veillon, J.-M. and Kranitz, M. 2003. Revue des Araucariaceae de Nouvelle-Calédonie. IRD, Nouméa..
Beimforde, C., Seyfullah, L.J., Perrichot, V., Schmidt, K.S., Rikkinen, J. and Schmidt, A.R. 2017. Resin exudation and resinicolous communities on Araucaria humboldtensis in New Caledonia.. Arthropod-Plant Interactions(11) , p.495-505.
Endemia.nc 2016. Faune et Flore de Nouvelle-Calédonie.
Jaffré, T., Munzinger, J. & Lowry, P.P. 2010. Threats to the conifer species found on New Caledonia’s ultramafic massifs and proposals for urgently needed measures to improve their protection.. Biodiversity and Conservation (19) , p.1485-1502.
Gaudeul, M., Ruhsam, G., Gardner, M.F. and Hollingsworth, P.M. 2012. AFLP markers provide insights into the evolutionary relationships and diversification of New Caledonian Araucaria species (Araucariaceae).. American Journal of Botany(99(1)) , p.68-81.
Experts
Assessor(s): Amice, R., Cazé, H., Dumontet, V., Fleurot, D., Garnier, D., Héquet, V., Lagrange, A., Lannuzel, G., McCoy, S., Suprin, B., Veillon, J.
Reviewer(s): Gardner, M., Munzinger, J., Jaffré, T., Thomas, P.
Contributor(s): Butaud, J., Gueugnier, C.
Facilitator(s): Maura, J., Tanguy, V.