Plerandra elegantissima is an endemic tree of New Caledonia occurring essentially in dense humid forest (occasionnaly in dry forest). Based on herbarium specimens, it is known from seven subpopulations. This species has declined as a result of urban development around Nouméa. Another threat comes from habitat degradation due to Rusa Deer (Rusa timorensis), which was introduced in the 1880s and adapted extremely well to Caledonian habitats. Population size reduction cannot be assessed because of a lack of data. Its area of occupancy (AOO) and extent of occurrence (EOO) are respectively 44 km² and 545 km². The number of locations, based on urban development as the main threat is estimated to be four. A continuing decline has been estimated/observed in its extent of occurrence, area of occupancy, quality of habitat, number of subpopulations and number of mature individuals. Using criteria B, P. elegantissima qualifies for Endangered (EN) B1ab(i,ii,iii,iv,v)&2ab(i,ii,iii,iv,v).

Geographical area

Plerandra elegantissima is an endemic tree of New Caledonia restricted to the south-west of Grande Terre, ranging from Nouméa to Bourail. Based on herbarium specimens, it is known from seven subpopulations although some subpopulations have not been seen recently (Bourail).

Population

Population size is unknown.

Habitat

Plerandra elegantissima is found in dense humid forest (occasionnaly in dry forest) at an altitudinal range of 0-500 m.

Threats

The main threat is linked to the intense urbanization and developing human activities around Nouméa which have occurred in the last 30 years and are still ongoing. Natural habitats are at best very fragmented when they have not been eradicated. Another threat comes from habitat degradation due to 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 and results in very little regeneration.

Conservation

This species is not protected by local legislation and does not occur in any protected areas (one subpopulation is however close to the Réserve naturelle du Mont-Mou but specimens have not been noticed inside the reserve). Dense humid forests are a patrominial ecosystem protected by the Code de l'Environnement of Province Sud.This species would benefit from in situ and ex situ conservation actions.It is recommended to investigate the sub-populations of Yahoué, Tonghoué and Forêt de Mécou.

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.

Hély-Alleaume 2012. INC : Incendies et biodiversité des éco-systèmes en Nouvelle-Calédonie.

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..

Experts

Assessor(s): Tanguy, V.

Reviewer(s): Schatz, G.

Contributor(s): Vandrot, H., Fleurot, D., Garnier, D., Lowry, P., Cazé, H., Butin, J., Barrabé, L., Amice, R., Birnbaum, P., Gâteblé, G., Anquez, M.

Facilitator(s): Schatz, G.