Taxonomy

Podonephelium cristagalli Munzinger, Lowry, Callm. & Buerki
endemique
protegee
UICN

Red List Status -

Critically Endangered (CR) , assessed in 20/02/2015

Protected species -

in Northern Province

Podonephelium cristagalli is an endemic tree of New Caledonia occurring in sclerophyllous forest. This species has suffered sclerophyllous forest reduction and fragmentation. This is particularly linked to agriculture on the west coast and urban development around Nouméa. Other threats come from habitat degradation due to Rusa Deer (Rusa timorensis) and uncontrolled fires. The population size reduction cannot be assessed because of a lack of data. Its area of occupancy is estimated to be 5 km² while its extent of occurrence is around 1,530 km². The number of locations, based upon urban development as the main threat is estimated to be two. The two known subpopulations are small, isolated and distant of 300 km with a really reduced probability of natural recolonization. There is moreover an apparent lack of regeneration. Podonephelium cristagalli is therefore in a situation of severe fragmentation.A continuing decline has been observed or estimated in its extent of occurrence, area of occupancy, quality of habitat, number of subpopulations and number of mature individuals. Using criteria B, P. cristagalli is assigned a status of Critically Endangered B2ab(i,ii,iii,iv,v). The population size is not precisely known but it would be highly recommended to get a better estimation in both sub-populations. Under criteria D, P. cristagalli would be VU D2.

Geographical area


Podonephelium cristagalli is an endemic tree of New Caledonia which sparsely occurs on the west coast of the main Island (Grande Terre) from Nouméa to Koumac.

Population


Population size is not precisely known. The type collection was made in an area near Koumac, in the northeastern part of Grande Terre, where the vegetation has been highly impacted by introduced deer. The other recently visited subpopulation, located at Nakutakoin, comprises only adult trees, with a total absence of young individuals, likewise suggesting the presence of deer.

Habitat


Podonephelium cristagalli occurs in sclerophyllous and mesic forests at low elevation (10-250 m). Sclerophyllous forests in New Caledonia are the most heavily impacted native vegetation type in New Caledonia, of which just 1–2% of the original cover remained as of the mid-1990s (Bouchet et al. 1995) and even less today. Because of their propensity to become pastures and their susceptibility to fire, dry forests have reduced dramatically, in size as well as in quality. In New Caledonia, they have been extensively cleared for agricultural purposes for a century; what remains today are highly fragmented patches.

Threats


Tropical dry forests are probably among the world's most endangered of all lowland tropical forests. Because of their propensity to become pastures and their susceptibility to fire, dry forests have reduced dramatically, in size as well as in quality. In New Caledonia, they've been extensively cleared for agricultural purposes or urbanization for a century; what remains today are highly fragmented patches that have been estimated at 2% of the original area. Uncontrolled fires sweep across lowlands of 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). They have slowly transformed remnant patches of dry forest into shrubland dominated by Acacia spirorbis and Leucaena leucocephala, or Niaouli (Melaleuca quinquenervia) savannahs. Another main threat comes from Rusa Deer (Rusa timorensis), which was introduced in the 1880s and adapted extremely well to Caledonian habitats. Its population may have reached over 100,000 individuals in the wild. This rusa deer (Rusa timorensis) consumes a wide variety of plant species and causes severe damage to trees and very little regeneration.

Conservation


This species is not protected by local legislation. None of the subpopulations occur within a protected area while dry forests benefit from a conservation programme managed by the Conservatoire des Espaces Naturels. Dry forests are a patrimonial ecosystem protected by the Code de l'Environnement of the Province Sud.This species would benefit from in-situ and ex-situ emergency conservation actions. It is moreover recommended to estimate number of individuals in Koumac and Nakutakoin and study its ecology.

Bibliography


Bouchet, P.; Jaffré, T. and Veillon J.-M. 1995. Plant extinction in New Caledonia: protection of sclerophyll forest urgently needed. Biodiversity and Conservation(4) , p.415-428.

Munzinger J. et al. 2013. A Taxonomic Revision of the Endemic New Caledonian Genus Podonephelium Baill. (Sapindaceae). Systematic botany(38) , p.1105-1124.

Experts


Assessor(s): Tanguy, V.

Reviewer(s): Schatz, G.

Contributor(s): Cazé, H., McCoy, S., Isnard, S., Wulff, A., Munzinger, J.


Geographical distribution