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The regional population of Ludwig's Bustard Neotis ludwigii is projected to undergo a reduction of greater than 50% to be met within the next three generations (30 years) based on an index of abundance applied to the taxon, satisfying criterion A4.
Ludwig's Bustard is near-endemic to the region occurring in western Namibia and western South Africa, with scattered records from south-western Angola (Dean 2000), Botswana (Penry and Jahns 1994) and western Lesotho (Bonde 1993). This species also occurs marginally in south-western Botswana (Allan 2005b). Within the region, it occurs predominantly in the dry Karoo region of western South Africa (Herholdt 1988), extending eastwards into Free State, southwards into Eastern Cape and Western Cape provinces and northwards into Northern Cape. Brooke (1984) suggested that the historical distribution extended to the eastern and north-eastern portions of the Grassland Biome.
In the late 1980s the global population was estimated at 56 000-81 000 individuals (Allan 1994), with 50-75% of these thought to occur in the region (Anderson 2000). The 2000 Red Data Book assessment (Anderson 2000) provides a regional population estimate of 27 000-60 000 birds. The current regional population is unknown but certainly suspected to be greater than 10 000 mature individuals. Confidence in this regional estimate is low.
The global population is in decline. Anderson (2000) projected a 20% decrease in the population over the next thirty years. The power network in the region is extensive and increasing, and causes high levels of mortality with unsustainable rates of 0.63 fatal collisions/km/year being recorded on transmission lines in the Karoo, which result in an estimated annual toll of 8 600 birds (Jenkins et al. 2011). Worryingly, these current mortality estimates are conservative as they have not been adjusted for various survey biases as well as the impact of low voltage power-lines and telephone wires (Jenkins et al. 2011). Modelling indicates that a population reduction of greater than 50% is likely in the next 30 years (three generations). Confidence in this regional population trend is moderate.
Mortalities originating from collisions with distribution and telephone lines is the main threat to the regional Ludwig's Bustard population. Ludwig's Bustard is also impacted upon by hunting, poisoning and disturbance (Anderson 2000). Falconers from the Middle East have expressed an interest in hunting Ludwig's Bustard and other members of the Otididae. This form of hunting has proven to be unsustainable resulting in the near elimination of the Houbara Bustard Chlamydotis undulta (Anderson 2000) and poses a threat to regional bustard species including Ludwig's Bustard.
In 2010, BirdLife South Africa formed the Bustard Working Group, which connects interested parties involved in the conservation of species belonging to this family. The Percy FitzPatrick Institute of African of Ornithology is a) conducting a new census of the Ludwig's Bustard population in the region, to compare with the previous assessment in the 1980s; b) assessing the magnitude of power-line mortality through regular line surveys across the Karoo; c) investigating habitat use, and patterns of local and regional movement of bustards through satellite tracking and stable isotope analysis in relation to environmental conditions and the power grid; and d) exploring mitigation options through experimentation of line-marking devices and visual assessment of bustards.
A Population and Habitat Viability Assessment (PHVA) is recommended, as is a Biodiversity Management Plan, culminating in a National Species Recovery Plan. Continuing to raise awareness to stop hunting of this species, and for the public to report mortalities from power-lines would be beneficial. New infrastructure (power-lines, wind turbines) must be sited and managed appropriately, and dangerous sections of line should be fitted with mitigation measures.
* Further research into mitigation measures for power-line collisions, additional to those being tested at the De Aar site, should be instigated.
* Knowledge regarding key life history parameters for this long-lived bird is also crucial to facilitate an accurate assessment of increased mortalities on the population.
* Research currently underway in South Africa should be extended to Namibia, as this is a key part of the range.