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Ancistrachne numaeensis 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Liliopsida Poales Poaceae

Scientific Name: Ancistrachne numaeensis (Balansa) S.T.Blake

Assessment Information [top]

Red List Category & Criteria: Endangered A2ce; B1ab(ii,iii,iv)+2ab(ii,iii,iv) ver 3.1
Year Published: 2010
Date Assessed: 2007-05-15
Assessor(s): Hequet, V.
Reviewer(s): Pollock, C.M. & Hilton-Taylor, C.
Justification:
Ancistrachne numaeensis is endemic to dry forests in New Caledonia. Its habitat is among the most threatened in the country; dry forests have been reduced dramatically, both in size and in quality. They have been severely cleared for agricultural purposes over the last century and what remains today are highly fragmented patches. This species probably used to be common around Noumea where intense urbanization, developing human activities and repeated fires around the city have considerably reduced its potential available habitats. It is suspected that most of Noumea's historical locations to have now disappeared. The last collection of this species dates back to 1988. Ancistrachne numaeensis also suffers intense predation by the introduced Rusa Deer (Cervus timorensis russa) (de Garine 2005). The reduction of its habitat has been estimated at 95% over the last 150 years (Bouchet 1995) and is probably close to 100% in Noumea and its suburbs. From this it is suspected that a population reduction of at least 50% has occurred over this period; the actual generation length for this species is not known, but with evidence of dramatic declines in dry forest habitat over the last 150 years it is likely that there has been a decline of at least 50% over the last three generations.

Geographic Range [top]

Range Description:This species must once have been common all along the west coast of New Caledonia. Historically, individuals have been collected from 10 locations between Noumea and Paita. Another collection has been made 63 km further north on "Ile Isié", a small island of La Foa region. The only other collection was made 108 km north from Nepoui in the Poya region. Ancistrachne numaeensis has also been mentioned from Ile des Pins. However, it is suspected that the species has now disappeared from most of these locations, especially those between Noumea and Paita, because of human activities. There may be no more than five living subpopulations remaining today.
Countries occurrence:
Native:
New Caledonia
Additional data:
Estimated area of occupancy (AOO) - km2:14Continuing decline in area of occupancy (AOO):Yes
Estimated extent of occurrence (EOO) - km2:2327
Number of Locations:5Continuing decline in number of locations:Yes
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:When present, this species forms dense small bushes that can be common or scarce but are usually confined to small surfaces. This pattern can be due to poor long distance dispersal or to vegetative reproduction by suckers. Considering the distances between locations (respectively 63 and 108 km), there might not be much genetic exchange. Most collections date from the 1970s and 1980s; the last herbarium collection was made in 1993 from the subpopulation in Pindai. It is probable that some, if not most, of the subpopulations recorded in the 1980's have disappeared, especially those located around Noumea.
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This species is endemic to New Caledonian dry 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.

Dry forests used to be common around Noumea. In fact, numerous old herbarium collections of A. numaeensis are from Noumea and its suburbs. However, intense urbanization, developing human activities and repeated fires have probably eradicated all potential habitats for this species.
Systems:Terrestrial
Continuing decline in area, extent and/or quality of habitat:Yes

Threats [top]

Major Threat(s): This species probably used to be common around Noumea where intense urbanization, developing human activities and repeated fires around the city have considerably reduced its potential available habitats. It is suspected that most of the historically recorded locations have now disappeared. Away from the city, 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: No conservation measures are in place for this species at present.

Citation: Hequet, V. 2010. Ancistrachne numaeensis. The IUCN Red List of Threatened Species 2010: e.T177818A7464217. . Downloaded on 12 December 2017.
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