Dalbergia oligophylla 


Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Fabales Leguminosae

Scientific Name: Dalbergia oligophylla
Species Authority: Baker ex Hutch. & Dalziel
Taxonomic Notes: The species as assessed here is probably a species complex comprising multiple species. The true Dalbergia oligophylla may be a highland species which dries a distinctive black. Specimens from lower altitudes and lowland forest habitats probably represent different species.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2015
Date Assessed: 2015-07-14
Assessor(s): Cheek, M.
Reviewer(s): Onana, J.-M.
Facilitator/Compiler(s): Hilton-Taylor, C.
This species was overlooked as threatened in Cable and Cheek (1998). It was assessed as Endangered under criterion A2c+3c in Harvey et al. (2004) and in Cheek et al. (2004) on the basis that more than 50% of the population of this long-lived species had been lost in the last 100 years (see threats below). This assessment was maintained in Onana and Cheek (2011). However, once specimens from other herbaria are included, the species (if correctly determined) has a much wider range with an enormous extent of occurrence of almost two million km² and is known from more than 20 locations in a variety of habitats from close to sea level to montane forest at 2,000 m asl. The range as shown probably comprises more than one species, but until the taxonomy is resolved and all the specimens redetermined, it is treated here as a species-complex. As a result, given the wide range, the large number of locations and lack of information on threats across the whole area, the species is listed here as Least Concern. If the true D. oligophylla is found to have a much more restricted range with the core of its distribution in the highlands of Cameroon, it will need to be reassessed as it would most likely fall into a threatened category.
Previously published Red List assessments:
2004 Endangered (EN)

Geographic Range [top]

Range Description: Has a wide range across western Central and West Africa occurring in Congo, Gabon; Equatorial Guinea (mainland and Bioko); Cameroon: Mt Cameroon, Bafut-Ngemba, Bali-Ngemba, Mt Kupe and Mwanenguba; Nigeria (Obudu Plateau); Côte d'Ivoire; Liberia and Guinea. Specimens at Wageningen supposedly identified as this species from eastern Democratic Republic of the Congo and Burundi have been excluded from this assessment as they probably represent a different species. Likewise, collections of supposedly this species from Palau are excluded (these may be cultivated plants).
Countries occurrence:
Cameroon; Congo; Côte d'Ivoire; Equatorial Guinea (Bioko, Equatorial Guinea (mainland)); Gabon; Guinea; Liberia; Nigeria
Estimated area of occupancy (AOO) - km2: 176
Number of Locations: 23
Lower elevation limit (metres): 80
Upper elevation limit (metres): 2000
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: There is no information on population size, but if it is really so widespread it may be relatively common, whereas if it is confined more to the Cameroon highlands it could be very scarce.
Current Population Trend: Decreasing
Additional data:
Population severely fragmented: No

Habitat and Ecology [top]

Habitat and Ecology: In Cameroon, Nigeria and Bioko (Equatorial Guinea)  this species occurs in submontane and montane forest edge; (900-)1,500-2,000 m alt. But else where the species appears to occurs in a variety of habitats from mangrove forest to riverine forest and at elevations as low as 80 m asl. The species also grows in degraded forest. It is described as a liana, a shub or even as a small tree.
Systems: Terrestrial

Threats [top]

Major Threat(s): In Cameroon forest clearance for agriculture and wood are the main threats: the subpopulations at Bafut-Ngemba, Obudu Plateau and Mwanenguba have quite possibly been lost due to this already. The Bamenda Highlands may once have been the main range of this species (judging by records at Bali-Ngemba and Bafut-Ngemba) but forest loss here has been as high as 25% between 1987-1995 in one area studied (Moat in Cheek et al. 2000). In the Dom area, 50% of forest cover has been lost in the 15 year period  prior to 2003 (Baena in Cheek et al. 2010). Overall, over 50% habitat loss is postulated over the last 100 years, and at least 50% of that which remains could be lost in the next century. However, it is not clear that the same rate of forest loss would apply to the rest of the species' range.

Conservation Actions [top]

Conservation Actions: In Cameroon, unless Bali-Ngemba Forest Reserve is protected from incursion more vigorously, the only hope for the survival of this species is the summit area of Mt Kupe and the upper tree line of Mt Cameroon both of which are reasonably secure from threat. The species occurs in a number of protected areas across its range.
Further research is required to determine if the records are all one species or if there are multiple species involved. Once the identity of all the specimens is correctly determined, then then species should be reassessed.

Citation: Cheek, M. 2015. Dalbergia oligophylla. The IUCN Red List of Threatened Species 2015: e.T45882A3003483. . Downloaded on 29 November 2015.
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