Taxonomie
Statut liste rouge -
Vulnérable (VU) , évaluée le 27/04/2015
Description
Description Générale
Sous-arbrisseau prostré ou arbuste de 1 m buissonnant; branches issues de la base du tronc, courtes, sinueuses et bien ramifiées.Répartition en Nouvelle-Calédonie
Cette espèce est connue sur la Grande Terre de 3 secteurs: Tontouta-Humboldt-Mt d. Sources, Thio-Ninga, Boulinda-Kopéto-Paéoua.Habitat
Dans le maquis ligno-herbacéSubstrat
Sur sol érodé d'origine ultramafique.Feuille
Feuilles petites, groupées au sommet des axes, courtement pétiolées, étroitement elliptiques, râpeuses sur les 2 faces.Phénologie (Fleur)
Fleurs jaunes (3-3.5 cm de diam.), 1-5 siur des inflorescences terminales, scorpioïdes, dépassant un peu les feuillesFruits
Follicules âgés et graines mûres non observées.Reproduction
Floraison répartie sur l'ensemble de l'année.Particularité
Espèce de rocailles à vocation horticole.H. heterotricha is an endemic tree of New Caledonia spread on five sectors on the main island, Grande Terre, with Boulinda-Paéoua-Koépto as the north limit and Montagne des sources as the south one. Tree of open vegetation, H. heterotricha is found in sclerophyllous ligno-herbaceous shrubland on ultramafic soils at an altitudinal range 800-1200 m asl. Part of population is under threat of mining activities, so a continuing decline is estimated because of the resulting degradation of habitat. Total population is estimated to be fewer than 10,000 mature individuals and each sub-population fewer than 1,000. Using criteria C, H. heterotricha does qualify for Vulnerable C2a(i).
Aire géographique
H. heterotricha is an endemic tree of New Caledonia spread on five sectors on the main island, Grande Terre, with Boulinda-Paéoua-Koépto as the north limit and Montagne des sources as the south one.
Population
On the basis of 10 known sub-populations, population size of H. heterotricha is estimated to be fewer than 10,000 mature individuals and each sub-population fewer than 1,000.
Habitat
H. heterotricha is found in sclerophyllous ligno-herbaceous shrubland on ultramafic soils at an altitudinal range 800-1200 m asl.
Menaces
An important threat to biodiversity in New Caledonia comes from past, present and future mining activities. New Caledonia contains between 20 - 30% of the worlds nickel resources. Intense mining activities since the late 19th century generated soil erosion (1.2% of bare ground mapped by SPOT5 in 2007). Based on the distribution of metal-rich soils and site accessibility, these threats are predictable and planned (rise in nickel production from 60,000 to 200,000 tonnes per year between 2013 and 2015). Three out of five sectors which host Hibbertia heterotricha are actively mined. Perturbations caused by mining activities could also lead to a greater sensitivity to drought.
Conservation
H. heterotricha is not protected by legislation but occurs in some protected areas (réserve naturelle du Pic Ningua, réserve naturelle du Mont Humboldt, réserve naturelle du Mont Mou, réserve intégrale de la Montagne des Sources). In case of reopening of the mine, it would be necessary to carefully prospect the area.
Bibliographie
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. The taxonomic database « FLORICAL » and characteristics of the indigenous flora of New Caledonia. Adansonia(334) , p.177-219.
Veillon J.-M.; Müller I.H.; Goldblatt P. 1990. Flore de la Nouvelle-Calédonie et dépendances. Volume 16 : Dilléniacées, Goodéniacées, Iridacées, Campynématacées.
L'Huillier L.; Jaffré T. and Wulff A. 2010. Mines et Environnement en Nouvelle-Calédonie : les milieux sur substrats ultramafiques et leur restauration.
Endemia.nc 2016. Faune et Flore de Nouvelle-Calédonie.
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.