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Habitat degradation threatens the survival of the Ethiopian bush crow Zavattariornis stresemanni


Luca Borghesio a1c1 and Fabio Giannetti a2
a1 C. Re Umberto 42, I-10128, Torino, Italy
a2 IPLA, C. Casale 476, I-10132, Torino, Italy

Article author query
borghesio l   [PubMed][Google Scholar] 
giannetti f   [PubMed][Google Scholar] 

Abstract

The Ethiopian bush crow Zavattariornis stresemanni is one of the most remarkable ornithological discoveries of the 20th century. It is restricted to an area of c. 5,000 km2 in southern Ethiopia, and a large part of its range is protected inside Yabello Wildlife Sanctuary. We report on the results of roadside counts carried out in 1989, 1995 and 2003 showing that the population of the species has decreased by 80% during this time. By comparing two Landsat satellite images from 1986 and 2002, we highlight land cover trends within the range of the species. These include a general increase in bush density, probably related to increasing grazing pressure by domestic animals, fire suppression (only in the Sanctuary) and the disappearance of wild herbivores. Land cover trends differed between the Sanctuary and the area outside, where open areas expanded, apparently indicating an increase in agricultural exploitation. Satellite images also showed that, within its range, the bush crow selects areas having relatively open terrain. Our data suggest that the population decrease within the Sanctuary could be due to the encroachment of open savannah by dense bush and that, therefore, the Sanctuary has failed to protect the bush crow. More research is urgently needed to evaluate its conservation status outside the Sanctuary and the impact of human activities on the species.

(Received January 8 2004)
(Revised June 4 2004)
(Accepted August 12 2004)


Key Words: Conservation status; Ethiopian bush crow; habitat change; Landsat; remote sensing; Zavattariornis stresemanni.

Correspondence:
c1 Correspondence: C. Re Umberto 42, I-10128, Torino, Italy. E-mail borghesio@libero.it


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