Isoglossa nervosa 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Magnoliopsida Scrophulariales Acanthaceae

Scientific Name: Isoglossa nervosa C.B.Clarke

Assessment Information [top]

Red List Category & Criteria: Vulnerable B2ab(iii) ver 3.1
Year Published: 2014
Date Assessed: 2011-03-25
Assessor(s): Cheek, M.
Reviewer(s): Onana, J.-M.
Previously assessed as VU D2 (Cheek et al. 2004: 140) when it was known only from Mann's Spring (Cameroon). Re-assessment of Cameroon montane Isoglossa by Pearce and Darbyshire (2011) has extended the range of this taxon - it is now known from eight locations along the Cameroon Highlands, and two from Bioko (Equatorial Guinea) with an AOO of 48 km². The extent of occurrence of 21,960 km² is just larger than the threshold for Vulnerable. The species remains listed as Vulnerable despite the increased number of locations as there is continuing decline in the extent and quality of its habitat in all the unprotected sites. Mt Cameroon remains the focal area for this taxon, with seven of the 14 known collections.
Previously published Red List assessments:

Geographic Range [top]

Range Description:Recorded from Equatorial Guinea: Bioko (Pico Basile and Pico de Sante Isabel); Cameroon: SW Region (Mt Cameroon - Mann's Spring, Bokwangwo), W Region (Bamboutos), NW Region (Mt Oku), Adamawa Region (Adamawa); and Nigeria (Mabile-Ngelyaki). The area of occupancy was estimated using 4 km2 cells.
Countries occurrence:
Cameroon; Equatorial Guinea (Bioko); Nigeria
Additional data:
Estimated area of occupancy (AOO) - km2:48
Number of Locations:10
Lower elevation limit (metres):2000
Upper elevation limit (metres):2950
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The population size is unknown, but it is declining.
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Grows in montane forest; 2,000-2,950 m alt.
Continuing decline in area, extent and/or quality of habitat:Yes

Threats [top]

Major Threat(s): While the Mann's Spring and Mt Oku sites appear secure from disturbance, those at Bokwango, Banboutos and Mabila are under great threat of clearance for agriculture, if not already lost.  The status of the Basile and Adamawa sites is not known.

Conservation Actions [top]

Conservation Actions: The species occurs in a national park on Bioko (Equatorial Guinea) and some of the sites are in Mount Cameron National Park (Cameroon). Monitoring at the secure sites and a recensus at the remaining locations is recommended.

Citation: Cheek, M. 2014. Isoglossa nervosa. The IUCN Red List of Threatened Species 2014: e.T39469A2926941. . Downloaded on 27 May 2018.
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