Taxonomy

Plerandra pouemboutensis Lowry & G.M.Plunkett, ined.
endemique
protegee
UICN

Red List Status -

Critically Endangered (CR) , assessed in 12/02/2015

Protected species -

in Southern Province

Plerandra pouemboutensis is an endemic tree of New Caledonia occurring in sclerophyllous dry forest. This species has suffered from dry forest reduction and fragmentation. This is particularly linked to agriculture on the west coast. Today's main additional threats for Plerandra pouemboutensis come from habitat degradation due to Rusa Deer (Rusa timorensis) and uncontrolled fires. Population size of mature individuals is estimated to be around 80 with a continuing decline and fewer than 50 individuals per subpopulation. Therefore, this species is Critically Endangered (CR) using C2a(i).

Geographical area


Plerandra pouemboutensis is an endemic tree of New Caledonia restricted on the west coast of Grande Terre from Pouembout to Koumac.

Population


Plerandra pouemboutensis is known from few individuals (approximately 80) scattered in 7-8 sites.

Habitat


Plerandra pouemboutensis is found essentially in sclerophyllous dry forest at an altitudinal range of 20-500 m, on black clay or calcareous substrates. A few individuals occur in humid forest. Tropical dry forests are probably among the world's most endangered of all lowland tropical forests. Because of their propensity to become pastures and their susceptibility to fire, dry forests have reduced dramatically, in both size as well as in quality. In New Caledonia, they have been extensively cleared for agricultural purposes for a century; what remains today are highly fragmented patches that have been estimated at 2% of the original area.

Threats


Tropical dry forests are probably among the world's most endangered of all lowland tropical forests. Because of their propensity to become pastures and their susceptibility to fire, dry forests have reduced dramatically in both size as well as in quality. In New Caledonia, they have been extensively cleared for agricultural purposes or urbanization for a century; what remains today are highly fragmented patches that have been estimated at 2% of the original area. Uncontrolled fires sweep across lowlands of New Caledonia each year, especially during the dry season (an average of 20,000 ha of land is burnt each year, with dramatic peaks of 70,000 ha). They have slowly transformed remnant patches of dry forest into scrubland dominated by Acacia spirorbis and Leucaena leucocephala, or into Niaouli (Melaleuca quinquenervia) savannahs. Another main threat comes from Rusa Deer (Rusa timorensis), which was introduced in the 1880s and adapted extremely well to Caledonian habitats. Its population may have reached over 100,000 individuals in the wild. This rusa deer (Rusa timorensis) consumes a wide variety of plant species and causes severe damage to trees, which results in very little regeneration.

Conservation


This species is not protected by local legislation. None of the subpopulations occur within a formal protected area, although dry forests derive some benefit from a conservation programme managed by the Conservatoire des Espaces Naturels.This species would benefit from further in situ and ex situ conservation actions (experimental nursery reproduction and in situ re-enforcement).

Bibliography


Lowry, P. P. II; G. M. Plunkett and D. G. Frodin 2013. Revision of Plerandra A. Gray (Araliaceae). I. A synopsis of the genus with an expanded circumscription and a new infrageneric classification. Brittonia(65) , p.42-61.

Lowry, P. P. II; G. M. Plunkett; D. G. Frodin; C. Rodrigues Vaz; M. Gostel and A. N. Nicolas 2016. Revision of Plerandra A. Gray (Araliaceae). III. A taxonomic treatment of Plerandra subg. Dizygotheca..

Bouchet, P.; Jaffré, T. and Veillon J.-M. 1995. Plant extinction in New Caledonia: protection of sclerophyll forest urgently needed. Biodiversity and Conservation(4) , p.415-428.

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

Experts


Assessor(s): Tanguy, V.

Reviewer(s): Schatz, G.

Contributor(s): Lowry, P., Vandrot, H., Fleurot, D., Barrière, R., Butin, J., Barrabé, L.

Facilitator(s): Schatz, G.


Geographical distribution