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

Such a map is necessary to investigate fine-scale patterns of habitat selection and dependency of
the endangered and endemic alpine species. It provides a baseline from which to monitor the effect
of anthropogenic activities on the alpine plant communities and informs decision-making by the
national park authorities about how to minimise potentially adverse impacts on ecosystem services
provided by the park.
The Bale Mountains are in the southern highlands of Ethiopia (06°41’N, 39°03’E and
07°18’N, 40°00’E), and represent the largest area in Africa of Afroalpine vegetation over 3000m
(Yalden, 1983). The contiguous massif is 2067 km2 , or 17.5% of African land above 3000m, and is
the most intact remnant of original highland vegetation (Brooks et al. 2004). The massif comprises
one of Conservation International’s Key Biodiversity Areas, included in their Eastern Afromontane
hotspot (Brooks et al. 2004), and is listed as an Important Bird Area (IBA) by Birdlife International
(Fishpool and Evans 2001). Many of the species endemic to Ethiopia are associated with the highaltitude
moorland and grassland abundant in Bale (Yalden 1983). These national endemics include
19 species of mammal, three of which are found only in the Bale mountains (Asefa this edition): the
giant molerat Tachyoryctes macrocephalus, unstriped grass rat Arvicanthis blicki and harsh-furred
mouse Lophuromys melanonyx (Yalden and Largen 1992). The area is also a hotspot of endemicity
for amphibians (Largen and Spawls this edition) and birds (Shimelis et al this edition), and supports
a diverse raptor guild which exploits the abundant rodent fauna (Birdlife International 2005). The
flora of the alpine zone is equally notable, with no less than 163 highland endemics, 27 of which are
restricted to Bale itself, including Alchemilla haumannii (Birdlife International 2006) and Euryops
prostratus (Williams et al. 2004).
The BMNP was created in 1969 with the purpose of protecting the endemic mountain nyala
Tragelaphus buxtoni and Ethiopian wolf Canis simensis, and the alpine zone and the tropical forest
on the southern slopes (Hillman 1986a). The park boundaries encompass 52% of the land above
3000 m a.s.l., with most of the remainder in Somkero-Korduro, a spur to the west, and in Gaysay to
the north. The area is characterised by high-altitude plateaux and wide valleys bounded by volcanic
plugs, lava flows and the precipitous Harenna escarpment to the south (Miehe and Miehe 1994).
The first map of vegetation within and around the BMNP was published by Waltermire (1975,
cited in Hillman 1986a), and most work has focussed on the montane forest and ericaceous belt (e.g.
Miehe and Miehe 1993, 1994; Bussmann 1997, Hillman 1986a). These brief descriptions of the
vegetation are restricted to small areas at the top of altitudinal transects, and the initial maps were
hand-drawn from field surveys and aerial photography on 1:50,000 base-maps (Ethiopian Mapping
Agency). More detail is presented in the management plans of the BMNP (Hillman 1986a, Nelson
this edition), which includes a map of five subdivisions of the park, based on altitude and dominant
flora. This map was derived from ground-surveys, 1:50,000 base maps, Landsat imagery and EMA
aerial photography from the late 1960s and early 1970s. Nine of the 16 vegetation types described
fall within the alpine grassland and moorland (subalpine) zones. Although useful for broadscale
management, these few categories do not adequately represent the complexity of vegetation
communities, or the diversity of the animal communities that inhabit them. Other published studies
<strong>Walia</strong>-<strong>Special</strong> <strong>Edition</strong> on the Bale Mountains 98