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

J. mima mounds and grazed mineral springs (horas)
Characteristic of mima mounds occupied by high densities of giant molerats Tachyoryctes
macrocephalus, this class has a very high proportion of bare earth, with the lowest percentage cover
and shortest vegetation. It is found on the flattest ground (
Table 2) and also has the narrowest range of slope values of all the classes. Trifolium sp. occur at
high densities beneath the sparse grasses and A. abyssinica.
K. Short heather and mixed shrubs
Dense, short Erica bushes interspersed with A. haumannii and H. splendidum.
L. Boulders and grazed heather
Similar in plant species composition to class K, this class has the highest proportion of rock substrate,
in the form of boulders. It has the highest cover of Thymus sp., and scattered Artemisia afra bushes.
M. Dense Erica on steep, sun-facing slopes
This class is found on the steepest sun-facing slopes, and has the densest Erica of all classes except
class A, for which too few representative samples are available for comparison. There are too few
vegetation samples to give an accurate description of its floral composition.
N. Helichrysum splendidum grassland
H. splendidum dominates the shrub layer, with interstitial and underlying short grass pasture, E.
prostratus and H. gofense. H. splendidum is present at lower densities than class H, and at a density
comparable to class G. Along with class O, this class has the highest vegetation cover. This is the
most prevalent land cover class in the southwest and south centre of the massif in the rain shadow of
Tullu Deemtu mountain. In its southernmost reaches, close to the Harenna escarpment, short Erica
bushes become more common.
O. Rocky Helichrysum splendidum grassland with scattered heather
With a similar plant species composition to class N, this class is found on sunnier slopes and
contains more Erica intermingled with the H. splendidum. Its discrete distribution and high thermal
reflectance probably result from a higher occurrence of boulders than found in class N.
P. Sedge swamp
Deep sedge swamps, springs and waterlogged soils with the second greatest extent of open water.
This class has the highest prevalence of Carex monostachya, and high occurrence of wetland species
such as Haplocarpha rueppellii and Ranunculus sp.
Q. Kniphofia wetlands, riverbanks and vegetated mesa edges
This mixed class represents wet soils with dense shrubby vegetation, including Kniphofia foliosa
wet pastures, mesa edges covered by dense A. afra, L rhynchopetalum and few boulders, and mixed
pasture/open water pixels along river banks. It has the greatest mean height, with high A. afra, K.
foliosa and A. pedata cover.
r. Artemisia/Kniphofia/Alchemilla haumannii grassland
Dry bushy grasslands dominated by A. afra and K. foliosa, with a ground cover of A. abyssinica
and grasses. Less rocky than classes S and T, with a higher level of illumination and the highest
coverage of Hebenstretia dentata, which favours rocky and dry ground (Hedberg 1957).
<strong>Walia</strong>-<strong>Special</strong> <strong>Edition</strong> on the Bale Mountains 107