Begonia oxyanthera 


Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Cucurbitales Begoniaceae

Scientific Name: Begonia oxyanthera
Species Authority: Warb.
Taxonomic Notes: Includes B. jussiaecarpa Warb. of Flora of West Tropical Africa. This species, of sect. Tetraphila A.DC. is closely related to B. preussii and can be regarded as an altitudinal vicariant (information on these species provided by Marc Sosef and Hans De Wilde, Wageningen).

Assessment Information [top]

Red List Category & Criteria: Vulnerable A4bc ver 3.1
Year Published: 2015
Date Assessed: 2011-03-25
Assessor(s): Cheek, M.
Reviewer(s): Onana, J.-M.
Facilitator/Compiler(s): Lopez Poveda, L.
This is an epiphytic, montane forest tree-dependent Begonia with fleshy, scandent stems and sausage-like fruits. In previous assessments (Cable and Cheek 1998, Cheek et al. 2000) this taxon was listed as Lower Risk/near threatened.  The upgraded conservation assessment of this species as Vulnerable in Cheek et al. (2004) is maintained here since no additional data are available apart from its discovery at Lebialem, where its habitat is very severely threatened. It was reassessed as Vulnerable because of habitat destruction in what appears to be its main subpopulation in the Bamenda Highlands from which most of the c. 30 specimens listed by de Wilde (2002) derive. Moat (in Cheek et al. 2000) records forest loss in the Kilum-Ijim  area itself as 25-30% over eight years. Since the 'generation' duration of this taxon might easily be five years (and possibly far longer), it is estimated that habitat loss for the species over its area of occupancy as a whole is likely to have been over 30% in the last 15 years. The increasing density of this species, moving northwards (Mt Cameroon and Bioko only c. two sites each; Bamenda Highlands numerous sites and collections) is perhaps a reflection of a longer dry season requirement. Forest loss continues unabated in the Bamenda Highlands, even inside some protected areas (M. Cheek pers. obs.), so future declines of this species are expected.
Previously published Red List assessments:
2004 Vulnerable (VU)
2000 Lower Risk/near threatened (LR/nt)

Geographic Range [top]

Range Description: Nigeria (Obudu; Mambilla); Equatorial Guinea, Bioko (six collections from two sites); Cameroon (Mt Cameroon (four collections), Mt Kupe and the Bakossi Mts (five collections), Rumpi Hills (one collection), Mwanenguba (one collection), Lebialem Highlands/Bamboutos Mts (two collections), Bamenda Highlands (17 collections)). The range data are taken from the account of the species in the recently published revision of Begonia sect. Tetraphila (de Wilde 2002).

Records from the Centre and South Regions are excluded from this assessment as their identification may not be correct, but even if included, the area of occupancy would still be under 500 km2.
Countries occurrence:
Cameroon; Equatorial Guinea (Bioko); Nigeria
Estimated area of occupancy (AOO) - km2: 136-499
Lower elevation limit (metres): 1200
Upper elevation limit (metres): 2400
Range Map: Click here to open the map viewer and explore range.

Population [top]


Population size is not known but is probably declining.

Current Population Trend: Decreasing
Additional data:
Population severely fragmented: No

Habitat and Ecology [top]

Habitat and Ecology: Grows in submontane and montane forest; 1,200-2,200(-2,400) m alt.
Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Yes
Generation Length (years): 5

Threats [top]

Major Threat(s): Forest clearance for wood and agriculture (mainly in the Lebialem/Bamboutos/Bamenda Highlands of Cameroon). Most of the sites for this species in the Northwest Region of Cameroon, where the species has been most frequently recorded, are outside of protected areas and it appears likely that the forest habitat has since been lost. In Cheek et al. (2000), it was calculated that 96% of the original forest cover of the Bamenda Highlands had been lost. In Nigeria, in Mambilla at Mai Samari, the forest reserve where this species was recorded in the 1970s, still exists with a few trees, but most trees have been cleared and the ground is intensively cultivated (Google Earth imagery of May 2010).

Conservation Actions [top]

Conservation Actions: Subpopulations in the Southwest Region (Cameroon), and probably also in Bioko (Equatorial Guinea), are fairly secure, lacking severe threats except those in the Buea area where submontane forest has been cleared upslope. In the Northwest Region the substantial subpopulation in the well protected Kilum-Ijim site (Mt Oku and the Ijim Ridge) may be the only locality where the taxon will survive, unfortunately, thus protection here is important. However, only one record occurs in the only formally protected forest at Kilum-Ijim, which is around Lake Oku, other sites not having formal protection. Similarly at Mt Kupe, only one of several records occurs in the National Park at the summit.At Mt Cameroon, four sites occur inside the National Park and can be considered secure. Finally, in Nigeria, there are single records from both the Gashaka Gumti National Park, and the Obudu Plateau Forest Reserve.

Citation: Cheek, M. 2015. Begonia oxyanthera. The IUCN Red List of Threatened Species 2015: e.T39502A2927906. . Downloaded on 30 November 2015.
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