Taxonomy
Red List Status -
Critically Endangered (CR) , assessed in 02/05/2019
Acropogon horarius is an endemic monoecious shrub to small tree that grows up to 6 m tall. It was recently described in 2018. The plant is named after the last of New Caledonia’s scheduled roads or “route à horaire” along which it grows (Gâteblé and Munzinger 2018). A. horarius is only known from Petchécara Pass between Thio and Canala in the south-east of Grande Terre. It grows in low humid forest (200-270 m asl.) slopes on a soil of complex geological origin (Gâteblé and Munzinger 2018). The species is threatened by invasive deer (Rusa timorensis), which cause the habitat quality declines (erosion) and contribute to the poor regeneration of the species. The other threat is from rats eating immature fruits and seeds directly on the trees. It was recently reported that Black Rat (Rattus rattus) consumption of fruits represent a threat for most Acropogon species (Munzinger and Gâteblé 2017). The species is rare and the population size is estimated to be fewer than 50 mature individuals. Therefore, with an Extent of Occurrence and Area of Occupancy both estimated to be 4 km², Acropogon horarius qualifies as Critically Endangered B1ab(iii,v)+2ab(iii,v); C2a(i,ii); D with a continuing decline in habitat quality and mature trees.
Geographical area
A. horarius is endemic to New Caledonia where it is only known from Petchécara Pass between Thio and Canala in the south east of Grande Terre.
Population
The population size is estimated to be fewer than 50 mature individuals.
Habitat
A. horarius occurs in low humid forest slopes (200-270 m asl.) on a soil of complex geolocical origin (Gateble, 2018).
Threats
The species is threatened by invasive deer (Rusa timorensis) that caused the decline of habitat quality (erosion) and contribute to the poor regeration of the species. The other threats is rat predation of immature fruits and seeds directly on the trees. It was recently reported that black rat (Rattus rattus) predation of fruits represent a threat fos most of Acropogon species (Munzinger and Gâteblé 2017).
Conservation
A. horarius is not protected by legislation in New Caledonia and is not present in a protected area. This species would benefit from in-situ emergency conservation actions. It is recommended to inform the DSCGR (emergency services), responsible for the coordination of the firefighting effort on the presence of the species in the concerned areas. Young plantlets of Acropogon horarius are fairly easy to grow in nursery conditions. Shrubs have been grown in a private nursery (Eriaxis nursery) and at the research station of Institut Agronomique néo-Calédonien (IAC) located in Saint-Louis, Mont-Dore. It is therefore suggested to promote its growing in nurseries, to integrate it in future green space planning and to raise awareness on this species amongst local stakeholders.
Bibliography
Gâteblé G. & Munzinger, J. 2018. Novitates neocaledonicae X: A very rare and threatened new microendemic species of Acropogon (Malvaceae, Sterculioideae) from New Caledonia . PhytoKeys (110) , p.1-8.
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): Amice, R., Butin, J., Cazé, H., Garnier, D., McCoy, S., Veillon, J., Gâteblé, G., Fleurot, D., Laudereau, C., Suprin, B., Héquet, V., Bruy, D., Vandrot, H.
Reviewer(s): Lannuzel, G.
Facilitator(s): Warimavute, G., Meyer, S.