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The regional population of Chestnut-banded Plover Charadrius pallidus is believed to be approaching the threshold for regionally Vulnerable under criterion C1 (area of occupancy is estimated to be less than 2 000 km2, with a severely fragmented population, and there has been a continuing inferred decline in the range and numbers. The Chestnut-banded Plover is listed as both globally and regionally Near Threatened.
The Chestnut-banded Plover occurs in two disjunct populations: a smaller East African population of the subspecies C. p. venustus and a larger southern African population of the nominate C. p. pallidus. The latter subspecies is endemic to southern Africa, is represented by an estimated 11 500 birds. This population has a patchy distribution along the coast from south-western Angola to central Mozambique, and inland in Namibia (mainly Etosha Pan), Botswana (mainly Makgadikgadi Pans) and South Africa (Turpie 2005). In Namibia, three sites regularly support 1% or more of the world population: Walvis Bay (on average 7 063 birds or 40% of the world population, in 50 km2), Sandwich Harbour (8 338 birds or 47%, in 20 km2) and Mile 4 Saltworks near Swakopmund (174 birds or 1%, in 8 km2). In Botswana, the Nata River Delta supports on average 188 birds (1.6%, in 150 km2) (Simmons et al. 2007). Migration is suspected between central coastal Namibia and Etosha and Makgadikgadi Pans (Tree 1997a).
Within the region, the Chestnut-banded Plover occurs sparsely along the Northern, Western and Eastern Cape coastlines, and at scattered locations at inland waterbodies, mostly in Northern Cape, western Free State and North West provinces but occasionally elsewhere (for a summary of recent inland records see Peacock et al. 2014). The Berg River Estuary system on the West Coast, and its associated commercial salt pans, is the single most important site for this species, and is the only South African site to regularly support more than 1% of the world population (181 birds or 1.1%, in 3 km2) (Simmons et al. 2007). Other important sites include the Orange River Mouth (Northern Cape), Langebaan Lagoon and the nearby Yzerfontein Salt Pans (Western Cape), Swartkops River Estuary (Eastern Cape), Barberspan (North West) and various ephemeral pans in the north-eastern Northern Cape and central and western Free State.
However, the availability of suitable habitat depends on rainfall (except under controlled conditions such as at commercial salt pans), and the movements of this species are complex and difficult to predict. In some areas the birds generally occupy inland sites during the dry season when water levels fall and salinity rises (Hockey and Douie 1995). Some birds reportedly move east from the Namibian coast to breed inland when pans are drying out in autumn and winter, but remain at coastal sites year-round during droughts. Coastal populations in South Africa appear to be fairly sedentary (Tree 1997).
SABAP2 atlas data suggest that the distribution has contracted in many areas, particularly in Northern Cape; however, this might in part be due to incomplete atlas coverage, and natural temporal and spatial fluctuations in distribution. The species is mostly an erratic visitor to the Eastern Cape coast, possibly in winters following years with high breeding success (Martin 2001) and is a vagrant to KwaZulu-Natal. It is also partly nomadic and singletons or pairs are occasionally encountered in isolated and unexpected localities (Tree 1997). It can be locally common in optimal habitat, especially at coastal sites, e.g. a 100 ha area at Yzerfontein Pan was estimated to support 0.06-0.71 birds/ha (average 0.23/ha).
Based on instantaneous counts during the period 1991-2005, the total world population was estimated at 17 830 birds, of which 6 338 occur in East Africa and 11 486 in southern Africa (Simmons et al. 2007). The bulk of the southern African population occurs in coastal Namibia; Walvis Bay can at times hold c. 40% of the world population, and Sandwich Harbour c. 47%. Together with Lake Natron in Tanzania (c. 13.3%), these three sites can, in theory, hold between them almost the entire global population of this species (Simmons et al. 2007). Waterbird counts suggest that the regional (South African) population is likely 416-608 (Simmons et al. 2007) or at times possibly up to 1 000 birds. The only South African site believed to regularly hold more than 1% of the global population is the lower Berg River wetlands and associated salt pans, where an average of 181 birds (1.1%) occur, making it one of the eight most important global sites for this species. Confidence in this regional population estimate is medium.
The regional population is considered stable, and it is unlikely that the historical and current distributions differ greatly (BirdLife International 2014). Overall numbers, especially in coastal populations, may have increased thanks to the construction of commercial salt pans over the last 4-5 decades (Tree 1997, Turpie 2005). Nevertheless, SABAP2 atlas data suggest that this species has undergone a marked decrease in range (25% decrease in EoO; 58% decrease in AoO), especially at inland pans in the interior of Northern Cape. This pattern may be in part attributable to a lack of field surveys in that sparsely populated region, but may also be the result of changes in habitat suitability due to climate change (salt pans remaining drier for longer). Given the scattered and ephemeral nature of this species' habitats, its poorly understood movements, and the inherently small population, ongoing population monitoring is recommended (Underhill 2000). The global population is believed to be stable (Simmons et al. 2007). Nevertheless, the considerable apparent range reduction suggests that this species may have undergone a population reduction of 30%, the causes of which are not understood, approaching the thresholds for the regionally Vulnerable criterion. Confidence in this estimate is low.
The Chestnut-banded Plover's breeding and non-breeding habitats are subject to increasing human-induced disturbance and degradation (Underhill 2000e). The construction of commercial salt pans has benefited this species, with these artificial habitats have increased the saline habitat available, and consequently population numbers of the Chestnut-banded Plover (Simmons et al. 2007), a rare example of a specialised species benefiting from commercial activity (Hockey and Douie 1995). It is fairly tolerant of human disturbance but may be locally influenced by salt extraction activities (Hockey and Douie 1995). In addition, the quality and extent of its habitat is in the hands of private and commercial land-owners, and dependent on land-use and management of properties that are not formally protected. Its tendency to nest beside access roads around pans make nests vulnerable, and the increasing popularity of recreational offroad driving on salt pans may also be of concern. Extensive foraging on intertidal mudflats and salt marshes occurs during winter in some areas (Hockey and Douie 1995), and these birds are faced with a different suite of threats, including a reduction in mean annual runoff due to direct abstraction and impoundments, dredging, erosion, eutrophication, pollution and alien vegetation (Barnes 1998). At Walvis Bay, Namibia, pollution in the form of fish oils from local factories and other detritus flushed from anchored ships, as well as siltation are real risks (Simmons et al. 2007). Its specific habitat requirements, small population, and reliance on a few key sites, make ongoing monitoring of the Chestnut-banded Plover essential, and its conservation status should be regularly re-assessed (Underhill 2000).
No species-specific conservation actions are currently in place, but several key sites have been designated as IBAs.
Important breeding and non-breeding sites for the species should be identified and protected, either through formal legislation or collaboration with private or commercial land-owners. With sensitivity towards the Chestnut-banded Plover's specific breeding and foraging requirements, commercial salt production properties may play an increasingly critical role in the regional conservation of the species. Owners, site managers and workers of such properties should be fully briefed on the plover and its conservation. Even an act as simple as temporarily cordoning off an active nest will be beneficial. Disturbance, habitat degradation or detrimental habitat modification at key sites should be prevented. Ongoing population monitoring, preferably through synchronised international waterbird counts, should be undertaken. Investigations into the movements of this species should also be conducted.
* Fine scale population surveys will help in identifying key sites of conservation important to the species.
* The suitability of such sites in terms of the specialised ecological requirements of the Chestnut-banded Plover should be investigated.
* Actual or potential threats facing the species and its habitats should be evaluated.