Taxonomy
Synonyms
Sphaerocionium subobtusum Copel.Red List Status -
Endangered (EN) , assessed in 28/11/2018
Hymenophyllum subobtusum is an endemic saxicolous fern from New Caledonia, where it is only known from three summits in the northeastern mountain range of Grande Terre. It occurs in dense humid forest on volcano sedimentary soil between 750 and 1,550 m asl. Known from three localities, its extent of occurrence (EOO) and area of occupancy (AOO) are 70 and 16 km², respectively. The main threat is posed by invasive species (feral pigs (Sus scrofa) and rusa deer (Rusa timorensis)), causing habitat degradation. Therefore, H. subobtusum is listed as Endangered (EN) under criteria B1ab (iii)+B2ab(iii).
Geographical area
Hymenophyllum subobtusum is endemic to New Caledonia where it is known from three summits in the northeastern mountain range of Grande Terre: Mt. Colnett, Mt. Ignambi and Mt. Panié.
Population
Population size is unknown. Based on field prospections, this species is non-common species.
Habitat
Hymenophyllum subobtusum is a saxicolus fern which occurs in dense humid forest (mainly on shaded and humid areas) from 750 to 1,550 m asl.
Threats
The main threats identified are invasive species (Rusa deer (Rusa timorensis) and feral pigs (Sus scrofa)) which contribute to the decline of habitat quality.
Conservation
Hymenophyllum subobtusum is not protected by legislation in New Caledonia but it does occur in one protected area: Mont Panié. Prospections on other northeastern massifs is needed to collect more biological material and better estimate its population size.
Bibliography
Munzinger J., Morat Ph., Jaffré T., Gâteblé G., Pillon Y., Rouhan G., Bruy, D., Veillon J.-M., & M. Chalopin. 2019. FLORICAL: Checklist of the vascular indigenous flora of New Caledonia..
Ebihara A.,Iwatsuki K., Ito M., Hennequin S., Dubuisson J.Y. 2007. A global molecular phylogeny of the fern genus Trichomanes (Hymenophyllaceae) with special reference to stem anatomy. Botanical Journal of the Linnean Society,(155(1)) , p.1-27.
Ebihara A., Dubuisson J.-Y., Iwatsuki K., Hennequin S., Ito M. 2006. A taxonomic revision of Hymenophyllaceae. Blumea(51(2)) , p.221-280.
Endemia.nc 2016. Faune et Flore de Nouvelle-Calédonie.
Del Rio, A. & al. 2017. Origins of the fern genus Hymenophyllum (Hymenophyllaceae) in New Caledonia: Multiple independent colonizations from surrounding territories and limited in situ diversification. Taxon(66(5)) , p.1041-1064.
Experts
Assessor(s): Amice, R., Butin, J., Garnier, D., Veillon, J., Fleurot, D., Laudereau, C., Suprin, B., Mandaoué, L.
Reviewer(s): Tanguy, V.
Contributor(s): Perrie, L., Rouhan, G.
Facilitator(s): Warimavute, G., Meyer, S.