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University of the Witwatersrand (2020)

African wild ass (Equus africanus) key resources overlap with livestock and population viability in the Danakil Ecosystem (Eritrea)

Tesfai, Redae Teclai

Titre : African wild ass (Equus africanus) key resources overlap with livestock and population viability in the Danakil Ecosystem (Eritrea)

Auteur : Tesfai, Redae Teclai

Université de soutenance : University of the Witwatersrand

Grade : Doctor of Philosophy in Animal Ecology 2020

Résumé partiel
The African wild ass (Equus africanus) is the world’s most endangered equid and is classified as ‘Critically Endangered’ by the IUCN Red List. This species faces a high risk of extinction in the wild. They persist in the Danakil desert which is one of the harshest climates and terrains in the world, where they share and potentially compete with livestock and local people for water and forage. An important population exists on the Messir Plateau in the Danakil desert of Eritrea. Long-term data on reproduction and survival rate of the African wild ass are limited. The population’s potential viability was estimated given assumptions on fecundity, survival rates and carrying capacity. The probability of persistence at the current capacity of 18 adult females was less than 50% in the worst-case scenario. A population with a potential carrying capacity of 37 females was projected to be almost 100% persistent under all scenarios. The model results indicated that the greatest threat to population viability may be livestock impacts on the vegetation resources that limit the African wild ass population size under anticipated climate change scenarios. During the rainfall months high numbers of livestock, particularly cattle, come from the highlands and utilize the Messir Plateau daily for three to four months, depending on green forage and seasonal water availability. This may limit forage availability for African wild ass. Density, location and faecal samples of African wild ass and livestock were collected to compare the spatial and diet overlaps between the sampled herbivore species in dry vs. rainfall months. During dry months, African wild ass spatially overlapped with resident camels, domestic donkeys, goats, and sheep. During the rainfall months, African wild ass were dispersed throughout the study area, while a high number of livestock, particularly cattle, were concentrated in the northern section nearer to temporary water sources and better vegetation

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