Question: Evergreen bushlands in Ethiopia have been inadequately studied and mapped. We address the question whether there is a transitional semi-evergreen bushland on the eastern escarpment of the Ethiopian Highlands, with unique floristic characteristics that distinguish it from the evergreen bushlands in other parts of Ethiopia and eastern Africa. Methods: Based on a review of the recent descriptions of evergreen bushlands in Ethiopia, we hypothesize that there is a distinct zone of natural semi-evergreen bushland, which is restricted to the eastern and southeastern escarpment of the Ethiopian Highlands. In contrast, evergreen bushlands in other parts of Ethiopia are considered to be of a secondary nature. To test this hypothesis, we carried out qualitative vegetation surveys in 354 locations across Ethiopia and classified the vegetation in these locations based on the occurrences of indicator species. Based on this data, we created predictive distribution models of the semi-evergreen bushland in Ethiopia using various environmental distribution models. We furthermore compared the occurrences of characteristic evergreen bushland species in Ethiopia with the occurrence of these species within the evergreen bushlands in Kenya and Uganda. Results: The vegetation surveys confirmed the existence of a distinct type of evergreen bushland vegetation. The transitional semi-evergreen bushland forms a transitional zone between the Acacia-Commiphora woodland and bushland and the Afromontane forest on the eastern and southeastern escarpments of Ethiopia, but is also characterized by a number of species that, within Ethiopia, are unique to this zone. Most of the characteristic species of the transitional semi-evergreen bushland are not found or only in lower densities in western Ethiopia. There is, furthermore, a limited overlap in characteristic species of the evergreen bushlands of Kenya and Uganda. Conclusions: Our results provide important information on the hitherto inadequately studied semi-evergreen bushland of Ethiopia. It highlights the unique character of this part of the evergreen bushlands in Ethiopia, which we argue should be taken into account for future conservation planning. © 2016 International Association for Vegetation Science.
DOI:
https://doi.org/10.1111/avsc.12220Dimensiones Recuento de citas:
Año de publicación
2016
Autores
van Breugel, P.; Friis, I.; Demissew, S.
Idioma
English
Palabras clave
bushlands, evergreen, species, biogeography, conservation
Geográfico
Ethiopia
