Taxonomy
Synonyms
Trisema emarginatum Bureau ex Beauvis.Red List Status -
Vulnerable (VU) , assessed in 27/04/2015Protected species -
in Southern Province
H. emarginata is an endemic tree of New Caledonia restricted to the south half of the main island Grand Terre with Mont Ménazi as a north border. It is found in humid forest and in shrubland on ultramafic substrate at an altitudinal range 700-1300 asl. A continuing decline of the number of mature individuals is inferred by mining activities on Mont Ménazi and Camp des sapins and the lack of regeneration observed. In any sub-population, only isolated tree are found and the total population is estimated to be less than 10,000 mature individuals. Using criteria C, H.emarginata does qualify for Vulnerable (VU) C2a(i).
Geographical area
H. emarginata is an endemic tree of New Caledonia restricted to the south half of the main island Grand Terre with Mont Ménazi as a north border.
Population
In any sub-population, only isolated tree are found and a lack of regeneration is observed. Total population is estimated to be fewer than 10,000 mature individuals.
Habitat
It is found in humid forest and in shrubland on ultramafic substrate at an altitudinal range 700-1300 asl.
Threats
On the basis of available data, the lack of regeneration observed for all sub-populations can not be linked to threats clearly identified. Nevertheless for the sub-populations of Mont Ménazi, Camp des sapins, Prokomeo and Me Aiu, mining activities could be the reason of decline on those stations. Fire may also affect H.emarginata.
Conservation
H.emarginata is not protected by legislation. It occurs in some protected areas (réserve naturelle du massif du Kouakoué, réserve naturelle du Mont Humboldt, réserve intégrale de la Montagne des Sources, réserve naturelle du Mont Do, réserve naturelle de la Haute Pourina). In the known stations, it is recommended to extend prospection on slopes and rock slides to check the species presence.
Bibliography
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.
Endemia.nc 2016. Faune et Flore de Nouvelle-Calédonie.
Veillon J.-M.; Müller I.H.; Goldblatt P. 1990. Flore de la Nouvelle-Calédonie et dépendances. Volume 16 : Dilléniacées, Goodéniacées, Iridacées, Campynématacées.
Morat, P.; Jaffré, T.; Tronchet, F.; Munzinger, J.; Pillon, Y.; Veillon, J.-M. and Chalopin, M. 2012. The taxonomic database « FLORICAL » and characteristics of the indigenous flora of New Caledonia. Adansonia(334) , p.177-219.
Hély-Alleaume 2012. INC : Incendies et biodiversité des éco-systèmes en Nouvelle-Calédonie.
L'Huillier L.; Jaffré T. and Wulff A. 2010. Mines et Environnement en Nouvelle-Calédonie : les milieux sur substrats ultramafiques et leur restauration.
Experts
Assessor(s): Veillon, J., Amice, R., Butin, J., Cazé, H., Garnier, D., Lannuzel, G., Leborgne, T., McCoy, S.
Reviewer(s): Tanguy, V.
Facilitator(s): Chanfreau, S.