Walia Special Edition on the Bale Mountains (2011) - Zoologische ...

August, when livestock were moved from lower pastures where agricultural crops were being grown
(OARDB 2007). In the Harenna Forest, influxes of pastoralists from the surrounding lowland areas
were reported for 3-4 months in the dry season (December-March) (OARDB 2007). Livestock also
entered the BMNP to access the natural mineral springs, or horas, that are found in various areas of
the park and have high levels of sodium, potassium, calcium, manganese and zinc (Hillman 1986,
Chiodi and Pinard this edition).
Human settlements inside BMNP have been increasing since the park was established in the
1970s. In 1986 the estimated human population was just 2500 and 10,500 head of livestock (Hillman
1986) with three main areas inhabited: the Upper Web Valley, the western boundary, and the Harenna
escarpment. Current estimates however place the number of people living in the park permanently
and seasonally at approximately 20,000 and 40,000 respectively, bringing with them an estimated
168,300 head of livestock (OARDB 2007). The population expansion has brought a change to the
pattern and seasonality of land use in BMNP. Today, fewer pastoralists still practice the Godantu
system and the majority have settled down with their livestock. The number of permanent pastoralist
settlements in the park now represents over 50% of the number of households both in the Afroalpine
and the Harenna Forest (FZS unpublished data). The explosion in livestock numbers is both a result
of population expansion within the park and of the immigration of pastoralist communities from
the lowlands. This influx of livestock into the park is a direct result of poor land planning outside
the park, where grazing land has been ploughed up, forcing livestock higher into the mountains and
into the park to graze all year round. Such radical changes in land use patterns have been facilitated
by the open access “property” regime (no user holds rights to the resource and nobody is excluded
from it) the grazing land in BMNP falls under (see Tadesse et al. this edition). The rule that governs
resource utilisation under open access is the rule of “first capture” (or first come first served rule)
(Bromley 1997).
A crucial question in Bale therefore is how to conserve the natural resources and the biotic
elements of the environment in the face of intensified human use, given that the livelihoods of
thousands of people depends upon them. Sustainable management of the natural resources needs
to be achieved. This paper and ongoing research specifically deals with the environmental impacts
of grazing on the BMNP ecosystem and aims to quantify this impact on the resources (namely
grassland pastures; Artemisia/Helychrisum shrublands and rodents) that may require protecting.
Environmental Impacts of Grazing on Rangelands
There has been much controversy concerning the effects of livestock grazing on biodiversity and
functioning of native ecosystems (McNaughton 1979; Milchunas and Lauenroth 1993; Hiernaux
1998). The impact of grazing animals can vary greatly across different ecosystems and can depend
upon the response variable used to assess the impact (Milchunas and Lauenroth 1993). Great attention
has been focused on the many effects that herbivores have on plant communities (Huntly 1991).
Domestic livestock and wild grazers have been cohabiting in the highlands for centuries and there is
<strong>Walia</strong>-<strong>Special</strong> <strong>Edition</strong> on the Bale Mountains 198