Thiollierea dagostinii is an endemic shrub of New Caledonia, known from Boulinda (Poya) in Grande Terre. It occurs in shrubland or in the riparian zone on ultramafic substrate at an altitude of 100 m asl. The main threats impacting this species come from habitat degradation linked to invasive species (Rusa Deer, Rusa timorensis, and feral pigs), uncontrolled bushfires and land clearing due to agriculture and farming. Its area of occupancy (AOO) and extent of occurrence (EOO) are both equal to 4 km², while the species is known to exist at only a single location. Thiollierea dagostinii is therefore assessed as Critically Endangered (CR) with criteria B1ab(iii,v)+2ab(iii,v) with a continuing decline of all concerned sub-criteria.

Geographical area

Thiollierea dagostinii is an endemic shrub of New Caledonia, known from Boulinda (Poya) in Grande Terre.

Population

Population size is unknown. Only two herbarium specimen have been made in this area.

Habitat

Thiollierea dagostinii occurs in shrubland or in riparian zone on ultramafic substrate at an altitude of 100 m asl.

Threats

The main threats impacting this species come from habitat degradation linked to invasive species (Rusa rusa deer (Rusa timorensis) and wild pigs), uncontrolled bushfires and land clearing due to agriculture and farming. Uncontrolled bushfires sweep across New Caledonia each year, especially during the dry season (an average of 20,000 ha of land is burnt each year, with dramatic peaks of 70,000 ha). Lowest parts of ultramafic areas are particularly exposed to such risk.

Conservation

Thiollierea dagostinii is unprotected by legislation and it does not occur in any protected area. This species would benefit from ex-situ and in-situ emergency conservation actions. It is proposed to ensure the follow-up of known sub-populations, to preserve a viable population on delimited perimeters. It is recommended to inform the DSCGR (emergency services) on the presence of the species in the concerned areas. Prospections in Boulinda, Kopéto, Paéoua and Mé maoya, specially in riparian areas, are recommended.

Bibliography

Barrabé L., Mouly A., Muzinger J. 2011. Deux espèces nouvelles de Thiollierea (Rubiaceae) restreintes aux sols hypermagnésiens du massif du Boulinda (Nouvelle-Calédonie). Adansonia(33) , p.135-148.

Barrabé L., Mouly A., Lowry II P.P. & Muzinger J. 2011. Reinstatement of the endemic New Caledonian genus Thiollierea Montrouz. (Rubiaceae) necessitated by the polyphyly of Bikkia Reinw. as currently circumscribed. Adansonia(33) , p.115-134.

Endemia.nc 2016. Faune et Flore de 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.

Experts

Assessor(s): Barrabé, L., Amice, R., Bruy, D., Butin, J., Fleurot, D., Garnier, D., Gâteblé, G., Goxe, J., Héquet, V., Lannuzel, G., Suprin, B., Veillon, J.

Reviewer(s): Cazé, H.

Contributor(s): Mouly, A.

Facilitator(s): Tanguy, V., Maura, J., Warimavute, G.