Geology Reference
In-Depth Information
Table 10.3.
Th e number and percentage of sp ecies shared between cetain Montane Forest Groups
Number of
Percentage of
Number of
Percentage of
species shared
species shared
species shared
species shared
Montane Forest Group
with ARa
with AR
with ECa
with EC
Cameroun
28
56
14
28
Ethiopia
13
57
9
39
Albertine Rift
East Coast Escarpment
27
31
27
47
64
Central East Africa
46
78
38
91
South Malawi
15
65
21
South of Zambezi
10
56
14
78
No te:
aAR, Alberine Rift; EC, East Coast Escarpment.
and Abyssinian Catbird Parophasma
ga/inieri.
3. Alberine Rift. This Group has by far the
largest number of endemics, a reflecion
of the species richness in this area. The
characterisic species are the Handsome
Francolin Francolinus nobilis, Red-faced
Woodland Warbler Phylloscopus laetus,
Masked Apalis, Blue-headed Sunbird
Nectarinia alinae and Dusky Crimson-wing
Cyptospiza jacksoni.
4. East Coast Escarpment. This is another
Group with a high level of endemism.
However, most of the endemics are very
rare, occurring in only a few forests, so
there are no completely characterisic
species, the nearest ones being Sharpe's
Akalat
Shppardia sharpei,
Spot-throat
Modulatix stictigula
and Chapin's Apalis
Apa/is chapini.
5. Cenral East Arica. Being a ransiion
zone between the previous two Groups,
this Group has only two endemics,
Jackson's Francolin
Francolinus jacksoni
and Abbott's Starling Cinnyriinclus
fe moralis, and no ruly characterisic
species.
6. Southen Malawi. There is only one
endemic and characterisic species, the
Thyolo Alethe Alethe choloensis.
7. South of the Zambezi. Of the three
endemic species, only one, Barratt's Scrub
Warbler Bradypterus baffatti, can be
considered characteric of this Group
(including the forests in South Africa).
Relationships between the montaneorest groups
The seven Montane Forest Groups that can be
idenified in Figure 10.1 are all valid in terms of
the species composiion of the orests. However,
this cluster analysis does not reveal much about
how these Groups originated. Table 10.2 reveals
that four of the Groups (Cameroun, Ehiopia,
Alberine Rift and the East Coast Escarpment)
have high endemism. It therefore seems that the
characterisic elements of these Groups are the
result of in situ evoluion. Insight into the origins
of the other three Groups can be obtained from
Table 10.3, which demonstrates that the
Albertine Rift and East Coast Escarpment have
acted as the colonising sources for the Groups
with low levels of endemism.
1. Central East Africa Group. With only two
endemics (see Table 10.2), and with 78%
of its species occurring in the Alberine
Rift and 64 % in the East Coast
Escarpment, the Cenral East Africa
Group is clearly a merging zone between
its two neighbours, as suggested above.
There is also a small Ethiopian influence
in the Cenral East African avifauna.
Fourteen species are shared between these
two Groups, and two species, Rueppell's
Robin-chat Cosspha semiua and the
Montane White-eye Zosterops abyssinica,
occur in no other Groups.
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