Geology Reference
In-Depth Information
Table 11.2. Comparison of major txa of orest and non-orest mammals
West Uganda
forests
East and southwest
East and southwest
Tanzania forests
Tanzania non-forest
Primates
13
8
2
Pangolin
2
0
1
Hyraxes
2
2
2
Orycteropus
0
0
1
Insecivores
11
11
12
Fruit bats
8
7
4
Insect bats
20
7
43
Squirrels
7
4
4
Other rodents
21
9
37
Hares
0
0
4
Carnivores
8
4
24
Large herbivores
2
0
24
Duikers and pygmy antelope
6
5
3
Totals
100
57
161
adapive backgrounds lends every easten
endemic a peculiar interest. There must have
been interchanges between the major biotopes of
forest and various grades of wooded grasslands
and the climaic oscillaions of the Pli-Pleisto-
cene (see Chapters 2-5, his volume) would have
created opportuniies or animals to adapt towards
moister or drier regimes even if the core areas of
orest were relaively stable.
The easten orest mammal auna is not only
less numerous in species but the counterparts
from the two regions differ both at specific level
and at the more subtle level of ecological niche.
Those species that are common to east and west
are likely to occupy different niches because the
easten communiy has a diferent, often simpler
composiion. Fewer or diferent food plants may
imply greater specialisaion, while fewer or dif-
ferent compeitors might broaden the niche.
The interest of mammals
There are indisputably far fewer species in the
East African forests than in Cenral and West
Africa. Furthermore, the shared occurrence of
various rodent, insecivore and primate species,
blue duiker Cphalophus monticola, palm civet
Nandinia binotata, and the anomalure Anomalorus
erbianus, has encouraged the view that these for-
ests are merely impoverished outliers of the
Guineo-Congolian block. The small number of
species in common (see Table 11.2) implies that
tenuous bridges between these regions have been
traversed by only a limited number of versaile or
mobile species or that excepional geneic stability
has been maintained in disjunct populaions over
very long periods.
The disincness of each endemic species can
be examined for clues to its origins. Do its affi-
niies with westen species suggest a modified
descendant from an earlier specifically forest con-
necion? Are there indicaions of derivaion from a
non-forest lineage? Could they be relicts of
former dominant or widespread populaions that
once embraced a wider spectrum of habitats? Are
its origins opaque? Every endemic can, to a
greater or lesser extent, be described as a
localised specialist but the likelihood of varied
Prvious studies
Matschie (1895) compiled the first checklist for
what was then Deutsch Ost Afrika. Loveridge
(1923, 1928) and Allen & Loveridge (1927, 1933)
reported on mammals collected for the Harvard
Museum of Comparaive Zoology and the Smith-
sonian Insituion. Moreau & Pakenham (1941)
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