Nora Schultz, New Scientist 20 Mar 09;
The modest plumage of the Sidamo lark may not catch the eye, but the bird could achieve the worst sort of fame – as the first contemporary African bird to go extinct, a new study warns.
The lark is adapted to Ethiopia's "rangeland" – the savannah of native grasses that traditionally covered large parts of east Africa, but is now rapidly disappearing. If the rangeland goes, so will the lark, says Claire Spottiswoode from the University of Cambridge.
"Rangeland degradation is often overlooked by conservationists, but it is not just the birds that suffer from the change in land use. The native people, the Borana pastoralists, also rely on intact rangeland to support their nomadic lifestyle," she says.
Inaccurate estimates
Spottiswoode and her team became interested in the Sidamo lark after a BirdLife International report estimated that only 1600 to 2000 individuals of this little known bird were left on Ethiopia's Liben plain, occupying an area of 760 km2.
However, once the team began to map the vegetation and count larks along transects, they quickly discovered that the population is actually much smaller.
Changes to traditional ways of life mean that much of the rangeland has disappeared. In areas where the Liben plain has been overgrown by bush, converted into farmland or destroyed by overgrazing, the team rarely found Sidamo larks. They conclude that the range of the bird is now down to only 35 km2 and that the remaining patch hosts 250 adult larks at best.
"If the situation does not improve rapidly, this species will be gone in four years or even sooner," says Spottiswoode, who is calling for the bird's status to be moved to critically endangered on the IUCN Red List
Local help
The Sidamo lark seems to be dependant on grassland 5 to 15 centimetres tall. Away from the Liben plain, there is no similar vegetation for over 200 km, meaning the lark has nowhere else to go. "It's effectively like living on an island, and that's where most extinctions happen," says Spottiswoode.
Africa may have been spared bird extinctions so far because there are still relatively few such severely fragmented habitats. Rangelands, however, are now being lost far beyond the Liben plain, and along with the Sidamo lark, other species are also threatened, including the Ethiopian bush-crow and the white-tailed swallow, Spottiswoode says.
This May, the researchers are planning to revisit the Liben plain to discuss conservation plans with the local communities. Spottiswoode is hopeful that support will be forthcoming, because many of the local pastoralists would prefer to revive their traditional lifestyle. This would include burning the shrubs that encroach on the rangeland and restricting agricultural expansion to make it a feasible option once again for the pastoralists to sustain their cattle herds by roaming larger areas of rangeland.
Journal reference: Animal Conservation (DOI: 10.1111/j.1469-1795.2009.00246.x)
