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.
