Project Database

Abstract:

The Bale Mountains of Ethiopia are a biodiversity hot spot in the south-eastern African highlands. Human pressure on the ecosystem strongly increases steadily because of a vast growing population of that region and the people's dependence on natural resources. The main impact of human land use is initial burning which shapes a whole vegetation zone: The Ericaceous belt. A plethora of research was and is conducted to analyze where fire has been and is set, to identify fire hot spots - areas which are very likely to be burnt - and ultimately to develop a fire management plan which might be applied in the future. Yet, the effect fire has on the vegetation of the Ericaceous belt of the Bale Mountains is unknown. In my study, I investigate the present post-fire floristic composition of the Ericaceous belt and identify the drivers of its dynamics. Especially altitude, climatic conditions and regeneration time as well as browsing by livestock were examined pertaining to their effect on vegetation's recovery. Data was first generated through vegetation assessment then subsequently through plant identification and analyzed by linear ordination methods. The vegetation's age was revealed applying different age methods of remote sensing, interviews and dendrochronology. In the whole Ericaceous belt not a single unburnt area was detected. The oldest recorded vegetation was determined to be 25 years old. Within these 25 years of regeneration no significant changes in floristic composition occurred. Little variation in floristic composition within the vegetation zone could be observed and was mainly associated with the slope of the mountains while elevation was of the second largest impact. Age, inclination, distance to settlements and browsing of the youngest vegetation additionally affected the species composition. Up to 70 % of variation of the floristic composition in the recently burnt areas and 50 % in older vegetation were associated with these variables. The name-giving Erica regenerated by resprouting from fire-surviving biomass. It's growth of height showed large variability in the researched areas and was directly and indirectly related to livestock browsing. With the baseline of information on post-fire vegetation recovery which I provide, I aim to contribute to prove that the current Ericaceous belt - contrary to previous considerations - does not consist of natural vegetation but was rather shaped by humans for a long time.

Abstract:

Based on a study of 2150 specimens of the genus Trechus Clairville, 1806 from the Bale Mts, Mount Chillalo, and Mount Enkuolo, southern Ethiopia, the current knowledge regarding systematics and distribution of the genus in the area is summarized. Twenty-six new species are described and figured in detail: Trechus abalkhasimi sp. nov. (southeastern slope of Bale Mts, below Mt Abalk-hasim); T. adaba sp. nov. (western Bale Mts, above Adaba); T. angavoensis sp. nov. (western Bale Mts, above Dodola); T. balesilvestris sp. nov. (western Bale Mts, above Adaba); T. bombi sp. nov. (southern escarpment of Bale Mts, Harenna Forest); T. colobus sp. nov. (western Bale Mts); T. depressipennis sp. nov. (northeastern margin of Sanetti Plateau, Bale Mts); T. dodola sp. nov. (western Bale Mts, above Dodola); T. fisehai sp. nov. (northern slope of Bale Mts, above Goba); T. grandipennis sp. nov. and T. hagenia sp. nov. (southern escarpment of Bale Mts, Harenna Forest); T. haggei sp. nov. (northeastern margin of Sanetti Plateau); T. harenna sp. nov. and T. harryi sp. nov. (southern escarpment of Bale Mts, Harenna Forest); T. iridescens sp. nov. (southeastern slope of Bale Mts, below Mt Abalk-hasim); T. mattisi sp. nov. (southern escarpment of Bale Mts, Harenna Forest); T. mekbibi sp. nov. (southern and western part of Bale Mts); T. minitrechus sp. nov. (northeastern slope of Mt Enkuolo); T. nanulus sp. nov. (southern escarpment of Bale Mts, Harenna Forest); T. nigrifemoralis sp. nov. and T. oppositus sp. nov. (western Bale Mts, above Dodola); T. rira sp. nov. (southern escarpment of Bale Mts, upper Rira Valley); T. sanettii sp. nov. (southeastern slope of Sanetti Plateau, Bale Mts); T. tragelaphus sp. nov. (western Bale Mts, above Dodola); T. transversicollis sp. nov. (southern escarpment of Bale Mts, Harenna Forest); T. wiersbowskyi sp. nov. (southern escarpment of Bale Mts, upper Rira Valley). New distributional data are provided for T. baleensis (Basilewsky, 1974), T. bastianinii Magrini & Sciaky, 2006, T. batuensis Magrini & Sciaky, 2006, T. chillalicus Jeannel, 1936, T. clarkeianus (Basilewsky, 1974), T. culminicola Jeannel, 1936, T. ericalis Magrini, Quéinnec & Vigna Taglianti, 2013, T. gallorites Jeannel, 1936, T. gypaeti Vigna Taglianti & Magrini, 2010, T. oromiensis Magrini, Quéinnec & Vigna Taglianti, 2012, T. relictus Magrini, Quéinnec & Vigna Taglianti, 2012 and T. rotundicollis (Basilewsky, 1974). Cothresia robini Basilewsky, 1974 is considered a junior synonym of T. chillalicus Jeannel, 1936. A key to all species known to occur in the Bale Mts and adjacent volcanos is presented.