Red List of South African Species

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Endangered (EN)
B1ab(iii)+2ab(iii)
Assessors: Moira Brown
Reviewers: Martin R Taylor Brent M Coverdale

Rationale (Changed due to Criteria revision)

The regional population of Green Barbet Stactolaema olivacea satisfies the range criterion of B1 for regionally Endangered (extent of occurrence less than 5 000 km2, occurring at a single location and a predicted decline in extent and quality of habitat) as well as B2 (area of occupancy less than 500 km2, occurring at a single location and a predicted decline in extent and quality of habitat).

Distribution

The Green Barbet group is distributed in a disrupted chain of isolated populations from coastal Kenya and north-eastern Kenya, Malawi and Mozambique to South Africa (Clancey 1989). Within the region, it occurs at a single locality, Ngoye Forest in KwaZulu-Natal (Berruti 2000, Chittenden 2005), a patch of relict Afromontane and coastal forest (Berruti 1997). Birds are more common in the higher-lying parts of the western side of the forest and scarcer in the eastern sector (Johnson et al. 1998). The EoO is 110 km2 while the AoO is just 39 km2. The Green Barbet is not known to undertake any movements outside of the forest (Cyrus and Robson 1980).

Population

The global population has not been quantified (BirdLife International 2014). The most recent estimate of the regional population is that of Chittenden et al. (1999) who provided a figure of 400-600 mature individuals. The population is thought to be stable, so this figure is taken as the current population size. Confidence in this regional population estimate is medium.

Population trend

In the most recent revision of the species, Chittenden (2005) chose not to adjust the population estimate from the 1999 estimate, indicating that the population trend over three generations had been stable. Confidence in this estimate is moderate.

Threats

Ongoing human exploitation of the forest is a concern that has been raised repeatedly (Johnson et al. 1998, Chittenden 2005), but appears to be unchanged. Damage and death to some fruiting trees (e.g. Onionwood Cassipourea malosana) as well as other favoured medicinal trees within the forest, pose a problem. The edge of the forest is subjected to burning, which may gradually reduce the forest area.

Conservation

Underway

The Ngoye Forest is listed as a Provincial Nature Reserve under the administration of Ezemvelo KwaZulu-Natal Wildlife. Although the Green Barbet's entire regional population thus falls within a protected area, inadequate resources are currently available for the reserve's management. There are no current conservation actions for the species.

Proposed

A Population and Habitat Viability Assessment (PHVA) is recommended, as is a Biodiversity Management Plan, culminating in a National Species Recovery Plan. Adequate protection of Ngoye Forest is critical to ensure the longevity of this population. Improved forest management is also essential, including an immediate reduction in illegal forest utilisation. A research programme directed at estimating population size and monitoring breeding success of the Green Barbet at Ngoye Forest should be initiated. The species is sought-after by birdwatchers and a responsible ecotourism programme could encourage involvement of local communities and safeguarding of the forest.

Research

* An updated population estimate is urgently required.

* An investigation into genetic variation and taxonomy of the wider Green Barbet complex should be performed.

References 

[@inbook{RN502,
 address = {Johannesburg, South Africa},
 author = {Johnson, D N and Barnes, K N and Taylor, B},
 booktitle = {The Important Bird Areas of Southern Africa},
 editor = {Barnes, K N},
 pages = {141-196},
 publisher = {BirdLife South Africa},
 title = {The Important Bird Areas of KwaZulu-Natal},
 year = {1998}
}
,@book{RN622,
 address = {Pietermaritzburg, South Africa},
 author = {Cyrus, D P and Robson, N and Clarkson, T},
 isbn = {0869802151},
 publisher = {University of Natal Press},
 title = {Bird Atlas of Natal},
 year = {1980}
}
,@book{RN1401,
 address = {Edinburgh, Scotland},
 author = {Clancey, P A},
 publisher = {Oliver and Boyd},
 title = {The birds of Natal and Zululand},
 year = {1964}
}
,@inbook{RN2352,
 address = {Johannesburg, South Africa},
 author = {Berruti, A},
 booktitle = {The atlas of southern African birds Vol II: Non-passerines},
 editor = {Harrison, J A and Allan, D G and Underhill, L G and Herremans, M and Tree, A J and Parker, V and Brown, C J},
 pages = {716},
 publisher = {BirdLife South Africa},
 title = {Green Barbet Cryptolybia woodwardii},
 year = {1997}
}
,@article{RN670,
 author = {Dowsett-Lemaire, F and Dowsett, R J},
 issn = {0030-6525},
 journal = {Ostrich},
 number = {4},
 pages = {160-163},
 title = {Vocal responses of Green Barbet populations, and the taxonomic implications},
 volume = {58},
 year = {1987}
}
,@article{RN671,
 author = {Holliday, C S and Tait, I C},
 issn = {0030-6525},
 journal = {Ostrich},
 number = {2},
 pages = {115-117},
 title = {Note on the identification of: Buccanodon olivacea woodwardi (Shelley)},
 volume = {24},
 year = {1953}
}
,@inbook{RN672,
 address = {Cape Town, South Africa},
 author = {Chittenden, H N},
 booktitle = {Roberts - Birds of Southern Africa, ViIIth ed},
 editor = {Hockey, P A R and Dean, W R J and Ryan, P G},
 pages = {140},
 publisher = {The Trustees of the John Voelcker Bird Book Fund},
 title = {Green Barbet Stactolaema olivacea},
 year = {2005}
}
,@article{RN2353,
 author = {Chittenden, H N and Coley, D and Coley, V},
 journal = {African Wildlife},
 pages = {18-21},
 title = {Woodward's Barbet: a unique forest specialist},
 volume = {52},
 year = {1999}
}
,@inbook{RN2346,
 address = {Johannesburg, South Africa},
 author = {Berruti, A},
 booktitle = {The Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland},
 editor = {Barnes, K N},
 pages = {119-120},
 publisher = {BirdLife South Africa},
 title = {Woodward's Barbet Cryptolybia woodwardi},
 year = {2000}
}
,@article{RN616,
 author = {Clancey, P A},
 journal = {Bonner Zoologische Beiträge},
 pages = {11-18},
 title = {The taxonomy of the Green Barbets (Aves: Lybiidae) of the eastern Afrotropics},
 volume = {40},
 year = {1989}
}
,]
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