Donald P.F.,Royal Society for the Protection of Birds |
Buchanan G.M.,Royal Society for the Protection of Birds |
Collar N.J.,BirdLife International |
Gabremichael M.N.,C o Atsede W Mariam |
And 4 more authors.
Bird Conservation International | Year: 2010
The Critically Endangered Liben Lark (formerly Sidamo Lark) is known only from the Liben Plain of southern Ethiopia, where rapid grassland deterioration is driving the species towards extinction. Fieldwork on the Liben Plain in May 2009 to assess changes in habitat and population since June 2007 recorded a significant deterioration in habitat and decline in numbers. In both 2007 and 2009, birds were associated with areas with greater than average grass cover, and in 2007 with areas of higher grass. However, between 2007 and 2009 there was a significant decline in grass cover and height, a 40% decline in number of birds recorded along repeated transects, and a contraction of 38% in the occupied area of the Liben Plain. Moreover, the cover of bare ground increased more in areas where the species was recorded in 2007 than at random points, suggesting a more rapid degradation of the best sites. There was also a loss to arable agriculture of 8% of the grassland present in 2007. Invading fennel plants increased in number and area on the plain but did not appear to influence the distribution of the lark. An analysis of NDVI showed that grassland deterioration could not be explained by drought, and the most likely explanation is that grassland quality is suffering from overgrazing. Predictive modelling suggests that, apart from a smaller and politically insecure area some 500 km to the north-east near Somalia, there is no suitable habitat for this species elsewhere in the Horn of Africa. As a matter of extreme urgency, cattle exclosures need to be established on the Liben Plain to allow grassland regeneration. This may require the ploughing of land to reduce soil compaction and re-sowing with local grass species. In the longer term, further degradation of the plain should be prevented by, for example, clearing encroaching scrub to increase grassland area and reduce grazing pressure, and by developing sustainable rangeland management practices. These actions have the full and active support of local pastoralists. Copyright © 2010 BirdLife International. Source
Serra G.,Secretariat Pacific Regional Environmental Programme |
Lindsell J.A.,Royal Society for the Protection of Birds |
Peske L.,Slezska 43 |
Fritz J.,Waldrappteam |
And 5 more authors.
ORYX | Year: 2015
The poor survival rate of immature northern bald ibises Geronticus eremita during their first years spent outside the natal site is driving the last known wild colony of the migratory eastern population to extinction. To inform emergency conservation action for this Critically Endangered species we investigated the distribution range and behaviour of immature birds in passage and wintering areas, and the threats to which they are subject. We integrated recent satellite telemetry data with visual observations spanning 130 years. We assessed threats across the range, using satellite tracking and field surveys. Our results show that during the years before they return to the natal site in Syria, immature northern bald ibises reside away from the recently identified adult wintering site in the central Ethiopian highlands. They occur mainly across the northernmost 70-80% of the adult migratory range. Historical records suggest that immature birds spend more time along the western Arabian Peninsula now than in the past. This range shift exposes them for longer periods to threats, such as hunting and electrocution on power lines, which are absent from the wintering site used by adult birds. We suggest that other threatened and declining bird species sharing the same flyway probably face the same threats during migration. Copyright © Fauna & Flora International 2014. Source
Donald P.F.,RSPB |
Gedeon K.,Saxon Ornithologists Society |
Collar N.J.,BirdLife International |
Spottiswoode C.N.,University of Cambridge |
And 2 more authors.
Journal of Ornithology | Year: 2012
We attempt to describe and explain the peculiarly restricted distribution of the globally threatened Ethiopian Bush-crow Zavattariornis stresemanni. At a regional scale, models containing only correlates of land cover suggested a far wider distribution of suitable habitat in north-east Africa than the area actually occupied. However, models including only climate variables predicted the known distribution almost perfectly, and suggested that the species' area of occupancy is delimited by a pocket of climate that is cooler, dryer and more seasonal than surrounding areas. The predicted probability of occurrence was low outside a narrow range of mean annual temperatures of 17. 5-20°C. Within the area predicted to be climatically most suitable, records of Bush-crows were concentrated in 1-km cells of marginally but significantly lower normalised difference vegetation index (NDVI), indicating a preference for areas of lower photosynthetic activity. At a finer spatial scale within a 10-km 2 intensive study site in the core of the species' range, nests were located in 30-m cells of higher NDVI but always close to areas of lower NDVI. These areas of lower NDVI comprise open grassland, which standardised observations of individual birds showed to be the main foraging habitat. However, taller vegetation is also necessary for nesting and roosting; the average height of nests from the ground was nearly 5 m. Therefore, the species' range appears to be defined primarily by a unique climate pocket within which it shows a preference for park-like habitats of grassland interspersed with taller vegetation, largely the result of clearance of vegetation by people and their associated grazers. The diet appeared unspecialised and a wide range of feeding methods was observed. Models estimate the species' optimal climatic range to cover around 6,000 km 2, of which perhaps 4,500 km 2 has suitable land cover. We tentatively estimate the global population to be at least 9,000 breeding pairs, with a potentially larger additional population of non-breeding birds, particularly nest-helpers. Several climate models predict increases in both temperature and precipitation in the southern highlands of Ethiopia. The species' narrow climatic range suggests that global climate change may therefore pose a serious threat to its long-term survival. © 2012 Dt. Ornithologen-Gesellschaft e.V. Source
Serra G.,Secretariat of the Pacific Regional Environment Programme |
Bruschini C.,University of Florence |
Peske L.,Slezska 43 |
Kubsa A.,Ethiopian Wildlife and Natural History Society |
And 2 more authors.
Bird Conservation International | Year: 2013
The long-range, migratory eastern relict population of Northern Bald Ibis Geronticus eremita has been steadily declining since the time of discovery in 2002, despite the protection programme in place at the breeding grounds in Syria. Assessing the ecological conditions and threats along the migration route and at the wintering site, both discovered in 2006, has become a priority for this Critically Endangered species. Adult ibises spent the winter at the same site on the central Ethiopian highland plateau, from August until mid-February during five consecutive winters (2006-2011). The wintering site was surveyed during four field visits and assessed through a spatial analysis of 1,067 satellite locations. The site is in an agro-pastoral landscape, inhabited by a settled community of people living in relatively poor and isolated conditions. Home range analysis based on kernel distributions showed that the bald ibises used a core range area of 9.1-19.0 km2 (confirmed by direct visual observations in the field) and an extended range area of 61.0-126.1 km 2. These figures are c.20 and 60 times smaller, respectively, than those calculated for the breeding site in Syria. Eighty-one percent of the core area in Ethiopia was used in all five years confirming the birds' fidelity to this wintering site. Ibises preferred to forage in wet or dry pastures and in recently cut hayfields, and avoided tall grass, uncut hayfields and cultivation. Despite dependence on human-created habitats, human disturbance observed in the field was minimal. The main short-term threat for the ibises was judged to be the potential raising of attention on the part of the local community specifically towards these few individual ibises. In the medium term, the main threat comes from the conversion of pastures into crops and the potential use of fertilisers and pesticides. © BirdLife International 2013. Source