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Oxera balansae

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Taxonomy [top]

Kingdom Phylum Class Order Family
PLANTAE TRACHEOPHYTA MAGNOLIOPSIDA LAMIALES VERBENACEAE

Scientific Name: Oxera balansae
Species Authority: Dubard

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(iii)+2ab(iii) ver 3.1
Year Published: 2010
Date Assessed: 2007-05-15
Assessor(s): Hequet, V.
Reviewer(s): Pollock, C.M. & Hilton-Taylor, C.
Justification:
Oxera balansae has an extent of occurrence (EOO) of 4,164 km² and an area of occupancy (AOO) of 20 km². The species is endemic to New Caledonian dry forests (including calcareous forests) where it is known from five locations. The locations on Grande Terre are 52 km apart; the others are on Pine Island and Lifou, and those subpopulations are considered to be severely fragmented with very few genetic exchange between them. Its habitat is among the most threatened in New Caledonia; dry forests have been reduced dramatically, in size as well as in quality. They have been intensively cut for agricultural purposes over the last century and what remains today are highly fragmented patches that suffer intense predation by the introduced Rusa Deer (Cervus timorensis russa) and uncontrolled fires. The reduction of the habitat has been estimated at 95% over the last 150 years (Bouchet 1995) and this degradation continues today.

Geographic Range [top]

Range Description: This species is endemic to New Caledonia. It is recorded from Noumea and Paita, then occurs 50 km north in Boulouparis. Its presence is also mentioned in Lifou and Pine island (Loyalty Islands). This fragmented distribution might be the illustration of a declining species that once was common on the west coast and surrounding islands. The species may have become extirpated at one location because of collection for its ornamental qualities. Its total extent of occurrence is 4,164 km², and its estimated area of occupancy within this range is 20 km².
Countries:
Native:
New Caledonia
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Population size is unknown but this species has mostly been collected as single individuals. In Noumea it is sympatric with Oxera pulchella ssp. grandiflora from which it is difficult to distinguish by appearance.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: This species is endemic to dry forests (including calcareous forests). 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 intensively cut for agricultural purposes for a century; what remains today are highly fragmented patches that have been estimated at 2% of the original area.
Systems: Terrestrial

Threats [top]

Major Threat(s): The major threat is lowland clearing for cattle grazing and agriculture, which began in the 1850s and is ongoing. Another threat comes from the Rusa Deer (Cervus timorensis russa), which was introduced in the 1880s and adapted extremely well to the Caledonian habitats. Its population may have reached 105,000–110,000 individuals in the wild. This deer consumes a wide variety of plant species and also causes severe damage to trees by rubbing antlers against tree stems. The third major threat is uncontrolled fires that sweep across lowlands of New Caledonia each year during the dry season and have slowly transformed remnant patches of dry forest into shrubland dominated by Acacia spirorbis and Leucaena leucocephala, or Niaouli (Melaleuca quinquenervia) savannas.

Conservation Actions [top]

Conservation Actions: Not present in any protected area in the wild but is cultivated ex situ and studied for its commercial potential as an ornamental.

Citation: Hequet, V. 2010. Oxera balansae. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 02 September 2014.
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