Hibbertia bouletii is an endemic tree known from two stations located in the Plaine des lacs area : north riverbank of lac de Yaté and at the confluence between the Riviere des Lacs and the Creek Pernod. Those two sub-populations are considered severely fragmented as they are separeted by the lake. It occurs in ligno-herbaceous shrubland on hydromorphic ferralitic soils on an altitudinal range 170-200 m asl. Its area of occupancy (AOO) as its extent of occurence (EOO) is 20 km². The threats to Hibbertia bouletii are more likely to be linked to habitat degradation due to water level fluctuations, erosion, fire and mining activities (exploration included). Since dam filling, a continuing decline of quality of habitat and number of mature individuals is observed. A count of two sub-populations highlighted a very small size of population : about 30 for the north station and 20 for the south one. Using criteria B and C, H. bouletii does qualify for Critically Endangered (CR) B1ab(iii,v); C2a(i).

Geographical area

Hibbertia bouletii is an endemic tree known from two stations located in the Plaine des lacs area : north riverbank of lac de Yaté and at the confluence between the Rivière des Lacs and the Creek Pernod.

Population

Population size is not precisely known but a count of two sub-populations highlighted a very small size of population : about 30 for the north station and 20 for the south one. We can confidently estimate that there are fewer than 250 mature individuals.

Habitat

It occurs in ligno-herbaceous shrubland on hydromorphic ferralitic soils at an altitudinal range 170-200 m asl.

Threats

The threats to Hibbertia bouletii are linked to habitat degradation due to water level fluctuations, erosion, fire and mining activities (exploration included). Since dam filling , a continuing decline of quality of habitat and number of mature individuals is observed. An important threat to biodiversity in New Caledonia comes from past, present and future mining activities. New Caledonia contains between 20 - 30% of the world’s nickel resources. Intense mining activities since the late 19th century has 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).

Conservation

H. bouletii is included in the area covered by the Ramsar Convention. In september 2014, 40 plants, multiplicated by the mining company Vale, were planted in two sectors of the Parc Provincial de la Rivière Bleue. To date (July 2015), only 10 individuals are still living. This species would benefit from in-situ and ex-situ emergency conservations actions, and protection of its rivarian habitat ( upriver,down-river). It is moreover recommended to prospect actively H. bouletii in the part of Creek Pernod, which is expected to be exploited, in the area downstream section between lac de Yaté and creek Pernod, and finally on the riverbank of Yaté river. Include this species in the list of protected species may be beneficial.

Bibliography

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.

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

Munzinger J., Morat Ph., Jaffré T., Gâteblé G., Pillon Y., Tronchet F., Veillon J.-M., & M. Chalopin 2016. FLORICAL: Checklist of the vascular indigenous flora of New Caledonia. vers. 22.IV.2016.

Experts

Assessor(s): Veillon, J., Amice, R., Butin, J., Cazé, H., Garnier, D., Lannuzel, G., Leborgne, T., McCoy, S.

Reviewer(s): Tanguy, V.

Contributor(s): Fogliani, B.

Facilitator(s): Chanfreau, S.