Rationale
(Changed due to Not applicable)
The regional population of Barlow's Lark Calendulauda barlowi has a restricted range, and an AoO less than 2 000 km2, which would qualify it as Vulnerable under the range-size criterion. However, the species is not limited to a small number of locations and is not believed to be subject to severe range fragmentation or extreme fluctuations in range or population. Although the population is apparently decreasing, the decline is not believed to be sufficiently rapid to meet the threshold for Vulnerable (greater than 30% decline over ten years or three generations). The population size has not been quantified, but may qualify the species as regionally Vulnerable under the population-size criterion (less than 10 000 mature individuals with a continuing decline estimated to be greater than 10% in ten years or three generations). However, further research is required before such conclusions can be drawn. For these reasons Barlow's Lark is provisionally evaluated as regionally Near Threatened.
Distribution
Barlow's Lark is endemic to the coastal plain of Namaqualand in north-eastern Northern Cape, South Africa, and adjacent south-western Namibia. Its range extends from Port Nolloth and Sendelingsdrift in Northern Cape to about 10-15 km south of the Koichab River, east of Lüderitz in Namibia. It has a maximum EoO of 18 000 km2, making it one of the most restricted southern African endemics (Ryan et al. 1998). Although locally common, it is marginal in South Africa and the regional population is small (Barnes 2000). More than 80% of its global range falls within Namibia, particularly in that country's inaccessible Sperrgebiet diamond-mining region (Dean and Ryan 1997, Ryan et al. 1998).
Population
The global population has not been quantified (BirdLife International 2014). The species is described as locally common in suitable habitat (Barnes 2000). It appears to now be absent from commercial farms around Aus in Namibia, where it was first collected (Ryan et al. 1998). However, detailed quantitative and demographic data are unavailable.
Population trend
The population trend is suspected to be in decline (BirdLife International 2014), possibly as a result of grazing pressure which leads to a lack of suitable vegetation. Populations in restricted-access diamond-mining zones may be relatively stable, and population declines are not currently believed to be sufficiently rapid to qualify Barlow's Lark as regionally Vulnerable. Confidence in this population trend estimate is low.
Threats
Barlow's Lark, and other species in the Karoo Lark complex, are restricted to natural habitats and are generally absent from transformed areas, being sensitive to overgrazing (Dean and Ryan 1997a). The related Red Lark C. burra has disappeared from some areas because of grazing and trampling by livestock, and associated changes in vegetation structure and composition (Dean et al. 1991). Fortunately, almost all of the Barlow's Lark's range falls within diamond-mining areas, where domestic livestock are excluded. However, if diamond mining becomes less profitable, alternative land-uses may be implemented in such areas in future (Dean and Ryan 1997). The effects of climate change on this species have not been fully investigated; however, its restricted range and westerly, coast-bound distribution potentially put it at risk (Simmons et al. 2004).
Conservation
Underway
No species-specific conservation efforts are underway.
Proposed
Barlow's Lark is an excellent candidate as an indicator species to monitor the effects of climate change, and a flagship species for conservation of a range of other threatened endemic taxa (Ryan et al. 1998). The long-term protection of the species is relatively secure, especially in view of the declaration of the Sperrgebiet in southern Namibia as a national park in 2004 (Dean and Ryan 1997). Within South Africa, the Orange River Mouth Wetlands IBA (SA030) and Ramsar site may support small numbers of this species. However, a large proportion of its regional range falls within diamond-mining zones, where restricted access, low human population and exclusion of livestock have ensured relatively pristine vegetation (Barnes 2000). Monitoring of population trends, and concurrent distribution mapping, should be priorities. Research on habitat requirements and land-management practices advantageous to this species should be conducted.
Research
* An accurate estimate of the regional and global population is required; ideally this should include a full survey of the inaccessible Sperrgebiet zone in Namibia as well.
* An investigation into Barlow's Lark's ecology, life history and ecological requirements should be undertaken.
* The impact of different land-use classes on this species should be thoroughly investigated.
* A re-assessment of the taxonomic status of the Calendulauda species-complex is recommended.
