This species is endemic to New Caledonia and much of its distribution is concentrated in the southern part of the island above 600 m. It has an estimated extent of occurrence (EOO) of 5,248 km². The southern subpopulation shows a good number of individuals, whereas the northern population seems particularly fragmented, suggesting they once joined showing a much larger range. The species has experienced historical population decline largely due to climate change but has been exacerbated by human agriculture, nickel mining and potentially fire. All of these factors still threaten the species but perhaps the main threat being fire. Recent fire in the Dzumac Range in 1991 burnt extensively consuming much Nothofagus codonandra forest, yet number of individuals lost to this fire is not known. Overall, this species has a broad range covering north to south of New Caledonia, but due to fire and speculative threats, it is suspected that it has experienced population decline. Considering it also has a small estimated EOO and occurs in 12 locations, this species has been globally accessed at Near Threatened as it nearly meets the criteria for Vulnerable B1ab(v).

Geographical area

This species is endemic to New Caledonia and much of its distribution is concentrated in the southern part of the island, from 150 m above sea level. The species extent of occurrence (EOO) of 5,248 km². Records indicate the species has 12 locations.

Population

Nothofagus populations, including that of this species, are largely made up of older individuals of a similar age. The overall population size is not known but population is considered to be in decline due to the growing occurrence of fire in the region which threatens the species.

Habitat

The species grows to 25–35 m in height and is usually found in wet riverine areas at low altitudes in the south of the island. It has been recorded infrequently on greywacke and schists but in these cases it is often confined to skeletal soils on ridge tops (Veblen et al. 1996). Within a Nothofagus forest, there is often little overlap between species stands. The under canopy of trees typically occur 5–10 m lower often containing species that comprise the upper canopy in mixed rain forest. This layer commonly includes several genera in the families Podocarpaceae, Araliaceae, Cunoniaceae, Lauraceae, Myrtacee, Sapindaceae, Euphorbiaceae and Apocynaceae along with many species (Veblen et al. 1996). Nothofagus species require large scale disturbance to the forest canopy and ideal growth conditions to encourage regeneration but some regeneration is being seen at some sites, for some species.

Threats

There is little literature available regarding threats to Nothofagus species specifically. The major threats of climate change, fire, nickel mining are having a devastating effect on much of New Caledonia’s flora including Nothofagus species. The species experiences a minor threat from agricultural expansion. The degree to which this impacts the species specifically is not known.

The region is experiencing rapid economic growth, rising population and the constant mining for nickel which is causing many species to become fragmented and extinct in parts of the island. Many of the species habituate to lower montane forests (600–800 m), which suggests that these species are unlikely to be able to shift in response to a changing climate due to poor wind dispersal and the need for specialised soil conditions. Pressure from nickel mining will inevitably affect the future of the species to varying degrees. Being usually confined to ridge tops, it is possible that this species is less harmed by human induced threats but this requires confirmation.

With temperatures beginning to rise coupled with sporadic rain, fires have become more common in parts of New Caledonia. Fires have burnt in to the boundaries of Nothofagus forests in many localities and are directly responsible for the sharp boundaries often formed between rainforest and woodland or maquis. A fire in the Dzumac Ranges in 1991 burnt extensively and damaged N. codonandra forest (Veblen 1996). The number of individuals lost to this fire is not known.

Conservation

According to the BGCI Plant Search (2017), there are currently two ex situ collections of this species. Some subpopulations of the species occur within protected areas for example in the reserves of Thy, Rivière Bleue and Mount Do).

Bibliography

Munzinger J., Morat Ph., Jaffré T., Gâteblé G., Pillon Y., Tronchet F., Veillon J.-M., & M. Chalopin 2016. FLORICAL: Checklist of the vascular indigenous flora of New Caledonia. vers. 22.IV.2016.

Endemia.nc 2016. Faune et Flore de Nouvelle-Calédonie.

Experts

Assessor(s): Baldwin, H.

Reviewer(s): Barrabé, L., Tanguy, V., Read, J.

Contributor(s): Rivers, M., Barstow, M.