Published online by Cambridge University Press: 24 September 2007
Species that show obvious population declines are relatively easy to categorize as globally threatened under IUCN Red List criteria. However, species whose populations are highly concentrated at a few inaccessible sites that are unprotected or habitat-threatened and then disperse are more difficult to pigeon-hole. Here we re-assess the conservation status of one such species – the Chestnut-banded Plover Charadrius pallidus – that occurs across Africa in specialized, inaccessible and arid habitat. Wetland bird counts from 1991 to the present allow us to determine a new world population estimate of about 17,830 birds. This allows us to determine a new 1% level and we identified only eight sites in southern and East Africa where these plovers congregate in numbers >1% when non-breeding. There are only five other sites that hold more than 100 birds, indicating that the species is not simply widely dispersed across suitable habitats. Simultaneous counts across southern and East Africa indicate that just three sites – Walvis Bay and Sandwich Harbour in Namibia and Lake Natron in Tanzania – can hold 87% of the world population during non-breeding periods. Since two of these sites are under threat from pollution, siltation and water abstraction, and the eight sites in total comprise just 30% of the area criteria set by IUCN, the bird meets one of the two qualifiers for globally Vulnerable status. Despite this, we cannot detect any long-term declines in population size, partly because of wide variations in population numbers over decadal time periods (itself an IUCN qualifier). It is clear that this bird should move from its present Least Concern status to Near Threatened and conservation measures be enacted at two of the top three sites – Walvis Bay and Lake Natron.