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The regional population of White-bellied Korhaan Eupodotis senegalensis satisfies the population size-reduction criterion for regionally Vulnerable (=30% decline over the past three generations where the reduction or its causes may not have ceased and may not be reversible, based on a decline in AoO, EoO and/or quality of habitat). It is believed that this trend will continue for the next three generations.
The White-bellied Korhaan is patchily distributed in the Afrotropics from West Africa to South Africa (Allan 2005i). Of the five subspecies, barrowii is geographically separated from other races further north in Africa, being restricted to eastern South Africa and adjacent south-western Swaziland (Allan 1997d, Barnes 2000k) with an AoO of 67 249 km2. Scattered records exist from extreme south-eastern Botswana at Kanye and Kaotwe Pan (grid cell 2525A) (Cyrus and Robson 1980, Penry and Jahns 1994) and it may occasionally wander into the lowlands of Lesotho (Bonde 1993). Densities vary greatly in different parts of the range, but overall it is most common in the Highveld regions east of Potchefstroom (Maclean and Robert 1985) to southern Mpumalanga (where it occurs mainly in the Wakkerstroom district; Moreira 2004), as well as in north-eastern Free State and the upper districts and midlands of KwaZulu-Natal. Isolated remnant populations occur on the Polokwane Plateau and Waterberg Plateau in Limpopo (Tarboton et al. 1987, Allan 1997d). Isolated populations also persist in the Eastern Cape: the species occurs in a fragmented band from west of Lesotho to Grahamstown, with a further remnant around Humansdorp. The White-bellied Korhaan is apparently absent from the former Transkei (Quickelberge 1989, Allan 1997d), although this may be due to inadequate surveys. The EoO has decreased by 15% between the SABAP1 and SABAP2 periods, while the AoO has decreased by 50% over the same period. The White-bellied Korhaan is well represented in the IBA network, being recorded at 14 different sites.
The global population has not been quantified (BirdLife International 2014bl) and evaluating the conservation status of such a low-density, widely distributed species is problematic (Senyatso et al. 2013). It is described as uncommon to locally common, with a measured density of about 2.0-2.5 birds/km2 in suitable habitat (Barnes 2000k, Tarboton 2011). Moreira (2004) recorded 151 birds in 68 groups in an area of 3 200 km2 or 0.047 birds/km2. On average, territories are recorded every 25 km during line transects, although they can be spaced as little as 2 km apart in optimal habitat (Allan 2005i). Barnes (2000k) estimated there to be less than5 000 mature individuals in the region in 2000. A comparison of the AoO estimates between SABAP1 and SABAP2 suggests that the species is now found in only 50% of its former habitat. If the relationship between the reported decrease in AoO and the regional population is linear, this would mean a reduction in population size of c. 2 000 mature individuals resulting in a current population of c. 3 000 birds. Likewise, if the densities proposed by Moreira (0.047 birds/km2) are extrapolated across the AoO measured in SABAP2 (67 249 km2), the regional population would be c. 3 160 individuals. This does assume that the species is distributed evenly across its entire AoO, which is unlikely. An estimate of 3 000 mature birds is provided. Confidence in this estimate is low.
The global population is suspected to be decreasing due to habitat destruction, but not at a rate sufficient to qualify the species as globally Vulnerable (BirdLife International 2014bl). Assuming the population estimates provided above are accurate, the decrease in the regional population over the past three generations (10.3 years) would be c. 73%, hence an assessment of regionally Vulnerable. Generation length was calculated based on extrapolated mean age at first breeding and extrapolated maximum longevity in the wild (BirdLife International 2014bl). Confidence in this is low.
The main threats is a familiar list of problems also facing other bustard species. The relative severity and potential impact of these threats have not been quantified or even assessed, but of particular concern are habitat loss and degradation due to agriculture, afforestation (invasive alien vegetation and timber plantations), overgrazing, urban development, unsuitable burning practices, and other habitat modifications as a result of growing human populations (Moreira 2004, Allan 2005i). Clancey (1972) mentioned fires as a threat to chicks, but this is unlikely to constitute a major threat during the breeding season in the summer rainfall area. The loss of habitat to bush encroachment poses a threat to White-bellied Korhaans, although the species appears to be adaptable to low levels of woody cover in grasslands. Apart from habitat loss, the threat of subsistence hunting and poaching, due to high human densities, also needs to be considered. Collisions with power-lines do not seem to pose as serious a threat as it does to larger bustard species (Shaw 2009), with only a single record of a male killed in this fashion on record (Allan 2005i).
Biodiversity stewardship programmes in the relevant biomes will reduce further habitat loss and unsustainable persecution. In 2010, BLSA formed the Bustard Working Group, which includes interested parties involved in the conservation of species belonging to this family. Research and conservation of White-bellied Korhaans is currently being undertaken, and forms part of a larger BirdLife South Africa initiative focused on grassland conservation. Funding for this research was partly generated through a sponsorship campaign run by a private birdwatcher (N Perrins); such initiatives can simultaneously help raise awareness of the plight of the White-bellied Korhaan and other species.
There is a danger that declines over long periods go unrecognised and hence unremedied; the White-bellied Korhaan is a prime candidate for this risk. Conservation of larger parts of the grassland biome on private and government level (formal protection currently less than3%) is strongly recommended. Proper management of fires and grazing pressure should be implemented in conservation areas and on private land, in order to create heterogeneity in the structural and floristic components of preferred habitats.
* An investigation into the life-history traits of the species should be conducted, including research on its breeding biology, foraging ecology, habitat requirements on a temporal and spatial scale, inter- and intra-specific behaviour, seasonal movements and density effects related to habitat use and availability.
* Clarification of the taxonomic status of E. s. barrowii and E. s. mackenziei is needed.
* An assessment of whether the existing IBA and protected areas network in the region are sufficient to ensure long-term survival of the White-bellied Korhaan in South Africa should be undertaken.