Araucaria nemorosa | Threatened Conifers of the World (en-GB)

Araucariaceae

Araucaria nemorosa de Laub.

One of 13 species of Araucaria endemic to southern New Caledonia where it has a very restricted distribution on the main island of Grande Terre. It is threatened by fire, mining activities and tourism.

Description

Habit

A monoecious tree up to 20m tall, with a d.b.h. up to 70cm at maturity. Usually dome shaped at maturity, and pyramidal when young. The thick bark is grey, peeling in horizontal plates.

Foliage

Adult leaves subulate or narrowly lanceolate with an acute or obtuse apex, to 10 x 4mm. Foliage usually clustered on small branches at the end of primary branches. Stomata on adult leaves are on both surfaces, in rows from the base to the apex along the lower surface.

Cones

Female seed-cones, terminal on very short branches. Mature cones ovoid to subglobose, up to 12 x 10cm, ripening January and February; bracts have a prominent reflexed tip up to 15mm long. Male pollen-cones terminal, up to 12cm long and mature from July to October.

Distribution

Almost totally restricted to the immediate coastal areas around Port Boisé and Cap Reine Charlotte in southern New Caledonia. One small population (Forêt Nord) is slightly inland in the middle of a currently expanding nickel mine. This population is both geographically isolated and genetically distinct.

Habitat and Ecology

Six of the eight known population fragments occur within 2km of the coast around Port Boisé at around 20-40m above sea level on serpentine soils. They generally form small, emergent groups among low (to 10m) evergreen forest or scrub interspersed with black, stony areas (cuirasse) that are almost devoid of vegetation. In the more open areas that have been burnt, Baeckea ericoides is dominant. The remaining two populations (Forêt Nord and Cap Reine Charlotte) occur at slightly higher altitudes. Annual precipitation in the Port Boisé area is approximately 2,500–3,000mm.

Human Uses

No specific uses have been recorded for this species. It is very rare in cultivation and confined to botanical collections either under glass or in mild climates. Female cones bear several hundred seeds each although many are not viable. Cones release seed while on the tree. The fallen seed needs to be collected promptly as germination occurs within a few days.

Conservation Status

Global status

Critical Endangered B1ab(iii)+B2ab(iii)

Global rationale

There are eight known population fragments totalling less than 5000 trees; extent of occurrence of 9.8km² and an area of occupancy of 0.64km². The Forêt Nord fragment is isolated from the main distribution and is located in the centre of a currently expanding nickel processing plant. Levels of seed set and recruitment are extremely low in this species.

Global threats

The main threats are the small population size (< 5,000 trees), the very small extent of occurrence (9.8km² ), and the increased risk of fire associated with the fragmentation of the populations, the continuation and expansion of mining activities including road building and possibly tourism.

Conservation Actions

Most populations are on privately owned land outside of formally protected areas. Although the Forêt Nord area is in the heart of a mining development, the company has fenced off the area. Restoration of the Forêt Nord population is currently underway and in time, this may result in the establishment of a corridor between that fragment and those around Port Boisé. Genetic studies have indicated high levels of inbreeding and low diversity; it is recommended that wild seedlings are used rather than seeds from cones on individual trees.

References and further reading

de Laubenfels, D. J. (1972). Gymnospermes. In: Aubréville, A. & Leroy, J.-F. (eds.), Flore de la Nouvelle-Calédonie et Dépendances, 4. Paris: Muséum National d’Histoire Naturelle. 167 p.
Gaudeul, M., Rouhan, G., Gardner, M. F. & 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):68-81.
Jaffre, 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 & Conservation 19(5):1485-1502
Kettle, C. J.., Ennos, R. A., Jaffre, T., Gardner, M. F., Hollingsworth, P. M. (2008). Cryptic genetic bottlenecks during restoration of an endangered tropical conifer. Biological Conservation 141:1953-1961.
Kettle, C.J., Ennos, R. A., Jaffre, T., McCoy, S., Le Borgne, T., Gardner, M. F. & Hollingsworth, P. M. (2011). Importance of demography and dispersal for the resilience and restoration of a critically endangered tropical conifer Araucaria nemorosa. Diversity & Distributions 18(3):248-259.
Kettle, C. J., Hollingsworth, P. M., Jaffre, T., Moran, B. & Ennos, R. A. (2007). Identifying the early genetic consequences of habitat degradation in a highly threatened tropical conifer, Araucaria nemorosa de Laub. Journal of Molecular Ecology 16:3581-3591.
Thomas, P. (2010). Araucaria nemorosa. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.1.www.iucnredlist.org . Downloaded on 29 June 2012.

External links

Endemic Flora of New Caledonia