Dalbergia humbertii 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Fabales Fabaceae

Scientific Name: Dalbergia humbertii R.Vig.
Dalbergia hutibertii R.Vig. [orth. error]
Taxonomic Notes: Flowers of Dalbergia humbertii indicate affinity with D. greveana, which can be easily distinguished by its much smaller fruits and leaves with 7-9 leaflets which are thicker in texture (DuPuy et al. 2002).

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(iii)+2ab(iii) ver 3.1
Year Published: 2012
Date Assessed: 2010-04-30
Assessor(s): Contu, S.
Reviewer(s): Hilton-Taylor, C.
Contributor(s): Members of the IUCN SSC Madagascar Plant Specialist Group
Dalbergia humbertii is endemic to Madagascar, where it is severely fragmented in its distribution range. The extent of occurrence (EOO) has been estimated to be less than 5,000 km² and area of occupancy is estimated to be about 72 km², which along with the number of locations (three) and the continuing decline of the extent and quality of the habitat qualify the species for the Endangered category. Even though some subpopulations are known to occur within the protected areas network, it is still believed that the species is of conservation concern, as it is also used for timber, although at present it is not clear how much impact this is having on the population. Therefore it is listed as Endangered until further research and field work clarify status and trends for this species.
Previously published Red List assessments:

Geographic Range [top]

Range Description:Dalbergia humbertii is endemic to north and west Madagascar where it is recorded mainly from the Ankarana massif to the Bemaraha massif (Antsiranana and Mahajanga province).
Countries occurrence:
Additional data:
Estimated area of occupancy (AOO) - km2:72
Number of Locations:3
Upper elevation limit (metres):500
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:D. humbertii appears to be severely fragmented in its distribution range, in fact at present only three localities are known for this species, and they are really far apart one to the other (the Mantamena subpopulation is in northern Madagascar, Antsiranana province, and the other two (Antsalova and Bemaraha) are in western Madagascar, Mahajanga province; there are ca. 800 km between the populations in Diana and Melaki region; and the population in the Boeny region needs to be confirmed). Moreover no precise data about population size and trends is currently available for this species, but D. humbertii has been described as declining (Du Puy et al. 2002) as a result of the dry forests' decline.
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:Yes

Habitat and Ecology [top]

Habitat and Ecology:D. humbertii is a deciduous tree up to 20 m tall which grows in deciduous seasonally dry forest and woodland, along stream margins, on limestone
Continuing decline in area, extent and/or quality of habitat:Yes

Use and Trade [top]

Use and Trade: The wood of this species is used for construction materials and there may be some international trade.

Threats [top]

Major Threat(s): The species in found in the Madagascar dry deciduous forests, which is a habitat type that has been severely destroyed, it is in fact estimated that the western dry forest has reduced by approximately 40% since the 1970s (Moat and Smith 2007) and that since human settlement of this region, an estimated 97 per cent of the island’s dry deciduous western forests have been destroyed, and those remaining are extremely localized and isolated (Crowley 2001). The major threat to the dry, deciduous forests is destruction and fragmentation through intentional burning to clear land for grazing and agricultural lands, and through wildfires sparked by burning adjacent secondary grasslands. With an expanding rural population and increasing degradation of existing arable lands, the pressure on the remaining forest is extremely high. Selective logging and the removal of large trees pose additional threats of forest habitat degradation. As the distance between the subpopulations is very large (ca. 800 km) it is unlikely that genetic material is being exchanged. This could lead to a possible erosion of genetic variability by bottlenecks, genetic drift or inbreeding, meaning that as a result of the loss of genetic diversity, the populations might became more susceptible to ecological or anthropogenic perturbation.

Conservation Actions [top]

Conservation Actions: There are no known conservation measures specifically for D. humbertii, but some of the species' populations are currenly known to occur within the protected areas network, as they occur in Ankarana Special reserve and Tsingy de Bemaraha National Park. Samples of seed of D. humbertii should be collected and stored in the Millennium Seed Bank or any other gene bank as an ex situ conservation measure. D. humbertii has been previously listed as Endangered (IUCN 2.3) in the Red List of Threatened Species and in The World List of Threatened Trees (Oldfield et al. 1998). And it is listed as Vulnerable (A1cd+2cd) in the Leguminosae of Madagascar (Du Puy 2002).

Citation: Contu, S. 2012. Dalbergia humbertii. The IUCN Red List of Threatened Species 2012: e.T36221A20056067. . Downloaded on 27 May 2018.
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