Rationale
(Changed due to Not applicable)
The global population may approach the threshold for 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). Although it is not of immediate conservation concern, the Agulhas Long-billed Lark has a naturally small range and population that make it vulnerable to natural or anthropogenic changes to its habitat. Widespread conversion of scrub habitat into agriculture fields and pasture has more than likely benefited this species, but future changes in land-use may prove detrimental. For these reasons, the species was assessed as regionally Near Threatened.
Distribution
As its name implies, the Agulhas Long-billed Lark is endemic to South Africa's Western Cape Province and largely restricted to the Agulhas Plain and Overberg wheatbelt, east of the Hottentots Holland Mountains. The species is mostly limited to a c. 15 000 km2 area between the Bot River and Caledon (approximately 19°E) and Mossel Bay (22°E), and mostly south of 34°S (Ryan and Bloomer 1999). It reportedly occurs northward along the Breede River Valley to at least Worcester, and possibly as far north-west as Tulbagh (Dean 1997), but this has not been confirmed by most recent bird atlas data. While the species can be common in its small range, its distribution is patchy and fragmented for unknown reasons (Barnes 2000).
Population
The Agulhas Long-billed Lark is fairly common within its fragmented, patchily distributed habitat (Ryan and Dean 2005). The total population has not been accurately quantified. Crude preliminary findings suggest that, in optimal habitats, local densities range from c. 0.075-0.2 calling males/ha, while overall densities range from c. 0.02-0.11 calling males/ha in good habitat to c. 0.003-0.009 in poor habitat (Louw 2000). Not correcting for sampling bias and variations in detectability, assuming a sex ratio of 1:1, and regarding only 25% of the above mentioned area as suitable habitat, a rough total population estimate is between 1 600-60 000 adults. The true population is possibly c. 9 000 individuals. Confidence in this population estimate is low.
Population trend
This taxon was only recently recognised as a full species and, as such, demographic trends are not yet well documented.
Threats
Vegetation management practices in formal conservation areas, such as De Hoop Nature Reserve and Bontebok National Park, are not beneficial to the Agulhas Long-billed Lark, and it is poorly represented in protected areas (Louw 2000). It is unclear to what extent this species has been influenced by the large-scale conversion of its natural habitat, but it has been suggested that certain forms of agriculture are beneficial to it (Dean 1997). Nevertheless, its naturally limited range and small population, as well as its dependence on transformed and privately-owned land, makes ongoing monitoring essential (Louw 2000). The potential effects of climate change on this species have not been fully investigated. The farming practices on which this species depends are unlikely to change over a broad geographical area in the near future, but economic pressures are causing farmers to abandon agriculture in drier areas. This may lead to local extinctions or further range fragmentation in the Agulhas Long-billed Lark (Louw 2000).
Conservation
Underway
No species-specific conservation actions are currently underway. Basic research into the habitat requirements and ecology of this species has been conducted (Louw 2000).
Proposed
The long-term survival of the Agulhas Long-billed Lark rests in the hands of private land-owners. Education and, where possible, guidance on land-use practices that are beneficial to this species are recommended. Concurrently, attempts should be made to improve the status of this species within conserved areas. To this end, a burning regime aimed at preventing bush encroachment is recommended, and a system of occasional autumn fires with three years of follow-up burns will benefit the Agulhas Long-billed Lark, while simultaneously improving grazing conditions for larger species of game (Louw 2000). Monitoring in the form of bird atlasing and species-specific surveys should be conducted to elucidate demographic trends. Finally, a thorough investigation of the taxonomic status of this taxon within the long-billed lark complex is essential, as it may have important implications for biodiversity conservation (Ryan and Bloomer 1999).
Research
* Direct monitoring of breeding success in different habitats throughout its range will highlight the requirements of this species.
* Further research on agricultural practices most beneficial to this species should be conducted.
* Effectiveness of formal protected areas in conserving the Agulhas Long-billed Lark should be investigated.
* Impacts of terrestrial predators on breeding success in artificial pastures should be quantified.
