Araucaria bernieri J.Buchholz

Araucariaceae

One of 13 species of Araucaria endemic to New Caledonia where it occurs on the main island of Grande Terre. It has become much reduced due to logging but present-day threats include fire and mining activities.

Description

Habit

Monoecious tree to 50m tall (sometimes bifurcating), to 1m d.b.h. at maturity; trunk straight or curved. Crown In mature trees columnar but open, branched along the greater part of the trunk, apex rounded or truncated, often wider than the lower crown. Bark on trunks of mature trees to 3cm thick, exfoliating in horizontal strips, forming horizontal bands or ridges; inner bark dark reddish brown; outer bark grey or brown.

Foliage

Adult leaves broadly ovate, 2.5–4.7 × 1.5–2.5mm, 3-edged and incurved with acute or obtuse apex, leathery and smooth, prominently keeled beneath. Stomata on adult leaves, on the underside restricted to the proximal part of the leaf in depressions either side of the keel; on upper surface the stomata are numerous in rows from just above the base to the apex.

Cones

Male pollen-cones 35–45 × 8.5–10mm, terminal, initially erect but pendulous when shedding pollen, light brown with glaucous bloom, cylindrical, confined to higher parts of tree on primary branches. Female seed-cones 8–10 × 6.5–8cm, terminal on short, usually solitary, sometimes 2–3 together, erect, green when mature, subglobose. Bracts 25–30 × 20–25mm including rounded, thin membranous wings, ending in a caudate, slightly curved, 6–8mm long bract tip.

Taxonomic note

A. bernieri var. pumilio Silba was described in 2000 based on specimens collected from the Tiebaghi massif in the northern part of New Caledonia. These specimens have since been redetermined as Araucaria scopulorum. Other specimens from Poum and Tiebaghi that are cited in the Flore de la Nouvelle-Calédonie et dépendances (de Laubenfels, 1972) have also been re-identified as Araucaria scopulorum.

Distribution

Araucaria bernieri is mainly confined to areas of moist evergreen forest on the slopes of the lower mountains in the southern part of the island. Records from Poum and Tiebaghi in the north of the island have been re-identified as A. scopulorum. The most northern population currently known is at the Col de Petchécara.

Habitat and Ecology

This species is commonly found in evergreen rainforest on slopes of lower mountains. It does not form dense stands but rather scattered individual trees that emerge well above the closed canopy of the forest, sometimes in association with A. subulata. It is limited to soils derived from ultramafic rock (peridotite and serpentine) with a high content of heavy metals such as iron, manganese and nickel. Where the forest has been disturbed A. bernieri may survive in stream beds with permanent (underground) water.

Conservation Status

Global assesment and rationale

Vulnerable C1

Although the extent of occurrence and the area of occupancy fall within the threshold for Endangered, the number of locations (defined in the IUCN sense) is 15, beyond the thresholds for listing under either Endangered or Vulnerable. Additionally, although subpopulations (Thio, Mount Kouakoué/ Rivière Bleue and the Plaine des Lacs area) are discontinuous and separated by significant areas of unsuitable habitat, the majority of fragments lie within a 50km radius of the main subpopulation at Rivière Bleue. For this reason, they are not considered severely fragmented and criterion B is not applicable under any category of threat.

The total population is estimated to be less than 10,000 mature individuals. A decline of 10% over the next ten years is projected based on the likelihood of losses through fire and activities associated with mining. On this basis an assessment of Vulnerable under criterion C1 is reasonable.

Global threats

In the past, this species was under some pressure from logging. Currently the major threats are various activities associated with mining such as road building and waste storage and fires whose frequency prevents the regeneration or expansion of remnant stands.

Conservation Actions

This species is represented in protected areas including Rivière Bleue Provincial Park and Montagne des Sources Nature Reserve. Northern subpopulations are all outside of protected areas and vulnerable to mining activities. All subpopulations are vulnerable to fire.