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).
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).
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.
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.
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.
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.
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.
* An updated population estimate is urgently required.
* An investigation into genetic variation and taxonomy of the wider Green Barbet complex should be performed.