Plerandra baillonii is a tree occurring in dense humid forest on non-ultramafic substrate. It is known from only a single (sub)population located in a rather isolated forest patch (due to recurring fires) in the Central Chain of New Caledonia at an altitudinal range of 550-600 m.There is an evident threat due to uncontrolled fires that lead to forest reduction. The population size reduction cannot be assessed because of a lack of data.Its area of occupancy (AOO) and extent of occurrence (EOO) are no more than 4 km². It is considered as one single location as a fire could rapidly affect all the individuals. A continuing decline is estimated for its AOO, EOO, quality of habitat and number of mature individuals.Using criteria B, P. baillonii qualifies for Critically Endangered (CR) B1ab(i,ii,iii,v)+2ab(i,ii,iii,v). Population size cannot be estimated. Using criteria D, P. baillonii would qualify for Vulnerable (VU D2) but the threat (fire) is more than plausible.

Geographical area

Plerandra baillonii is restricted to the Col d'Amoss, north of Ouegoa in New Caledonia.

Population

The number of individuals is not precisely known. The forest patch in which the population is located has not been inventoried but ca 30 mature individuals have been noticed. It is difficult to infer the total number of individuals. Regeneration has been noticed.

Habitat

Plerandra baillonii occurs in dense humid forest on non-ultramafic substrate. It has been located in a rather isolated forest patch (due to recurring fires) in the Central Chain at an altitudinal range of 550-600 m.

Threats

The main threat identified is linked to habitat degradation and reduction due to uncontrolled fires that sweep across New Caledonia. The forest patch hosting Plerandra baillonii may be reducing as this area is regularly surrounded by fires. A study to detect changes of forest cover from 1989 to 2009 covering the communes of Hienghène, Pouébo and Ouégoa in northeastern New Caledonia showed a forest decline of 29.8% (Schroers and Tron 2009) linking mainly deforestation to bushfires. Grazing by the invasive species Rusa rusa deer (Rusa timorensis) has not been noticed.

Conservation

Plerandra baillonii is not protected by legislation and does not occur in a protected area.

Bibliography

Ibanez et al. 2012. Rainforest and Savanna Landscape Dynamics in New-Caledonia: Towards a mosaic of stable Rainforest and Savanna states?.

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..

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

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.

Experts

Assessor(s): Tanguy, V.

Reviewer(s): Schatz, G.

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

Facilitator(s): Schatz, G.