Pittosporum muricatum is an endemic shrub of New Caledonia known from Col de Mouirange and Port-Boisé in Province Sud. Found in dense humid forest on ultramafic substrate patches at an altitudinal range 15-350 m asl, P. muricatum is considered as a rare species. The latest field observations on both well known localities suggest an estimated population size fewer than 250 mature individuals (each sub-population not exceeding 50 individuals). Primary threats are fire, fruit predation by rats and effects of mining activities, as such a continuous decline of habitat quality and number of individuals is projected. Using criteria C, P. muricatum qualifies as Critically Endangered (CR) C2a(i).

Geographical area

P. muricatum is an endemic shrub of New Caledonia known from Col de Mouirange and Port-Boisé in Province Sud.

Population

Due to its distribution and density observed by station, population size is estimated to be fewer than 250 mature individuals.

Habitat

P. muricatum is found in dense humid forest on ultramafic substrate patches at an altitudinal range 15-350 m asl.

Threats

Main threats for this species are fire, mining activities and induced drying up under cuirasse on ferralitic soil. Some case of fruit predation by rats on Vale mine have been observed and could thus be also a threat in the wild.

Conservation

A protected species In Province Sud, P. muricatum has also been noticed in réserve naturelle de la Forêt Nord. In order to maximize protection efforts of P. muricatum, it is essential to count the population in réserve naturelle de la Forêt Nord, to monitor this population, and survey surrounding areas to determine area of occurrence. Propagation of wild collected fruits trials done by Vale showed a good germination rate. However, of growing concern is the predation on fruits by rats, which are able to reach fruits in spite of fixation of metal net. Vale company stopped field collecting of fruits for 2 years but continue monitoring 6 individuals. Finally to improve taxonomic knowledge of New Caledonian species of Pittosporum, further phylogenetic studies are needed to clarify the relationship between P. muricatum and P.leratii.

Bibliography

L'Huillier L.; Jaffré T. and Wulff A. 2010. Mines et Environnement en Nouvelle-Calédonie : les milieux sur substrats ultramafiques et leur restauration.

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

Morat, P.; Jaffré, T.; Tronchet, F.; Munzinger, J.; Pillon, Y.; Veillon, J.-M. and Chalopin, M. 2012. Le référentiel taxonomique Florical et les caractéristiques de la flore vasculaire indigène de la Nouvelle-Calédonie [The taxonomic database « FLORICAL » and characteristics of the indigenous flora of New Caledonia]. Adansonia sér 3(34) , p.177-219.

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

Tirel, C. & Veillon J.-M. 2002. Flore de la Nouvelle-Calédonie et dépendances. Volume 24 : Pittosporaceae.

Gomez C.; Mangeas M.; Curt T.; Ibanez T.; Munzinger J.; Dumas P.; Jérémy A.; Despinoy M. and Hély C. 2014. Wildfire risk for main vegetation units in a biodiversity hotspot: modeling approach in New Caledonia, South Pacific. Ecology and Evolution(5) , p.377-390.

Experts

Assessor(s): Gemmill, C., Veillon, J., Amice, R., Cazé, H., Dumontet, V., Fleurot, D., Garnier, D., Gâteblé, G., Maggia, L.

Reviewer(s): Tanguy, V.

Contributor(s): McCoy, S.

Facilitator(s): Chanfreau, S.