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

the woody species, the DBH (diameter at breast height) and DSH (diameter at stump height =
basal diameter) were used; measurements were classified into ten classes that range from seedling/
saplings, which have DBH/DSH of less than 2.6 cm, to adults that have DBH/DSH of 42.5 cm and
more (Lamperchet 1980).
Results and Discussions
Plant communities
A total of 84 species of vascular plants were encountered, including eight trees and shrubs. The
Ericaceous vegetation was grouped into three altitudinal subzones following previous works: Lower
subzone (3000-3400 m), Central subzone (3400-3600 m), and the Upper subzone (3600-4200 m,
see also Hedberg 1951, Miehe and Miehe 1994). Thirteen community types were identified from
the cluster analysis; cut levels were set at dissimilarity values between 0.3 and 0.7. Dissimilarity
was calculated using the cover-abundance values of the 84 species. The communities were named
according to the species with the highest cover-abundance. The distribution of the communities
varied in the lower (3000-3400 m), central (3400-3600 m), and upper (3600-4200 m) subzones of
the Ericaceous belt. Some communities occurred over the entire altitudinal range (3000-4200 m),
while others were restricted to certain subzones. Overall plant diversity showed an inverse bell
shaped pattern with altitude. The upper (Community type 10 in Table 1) and the lower (Community
type 1 in Table 1) subzone has shown the highest richness than the central one. The complete list of
communities and their respective distribution, species richness, diversity and evenness in the three
subzones is given in Table 1.
<strong>Walia</strong>-<strong>Special</strong> <strong>Edition</strong> on the Bale Mountains 162