The zoogeography of the montane forest avifauna of eastern Tanzania - Biogeography and Ecology of the Rain Forests of Eastern Africa - page 221

Table 10.7. Th efrequeny of subspeiic boundaries
at various locations within the East Coast
Escarpment

There is also a considerable degree of subspe-
ciic disconinuity between the Ulugurus and the
nearest part of the East Coast Escarpment. Table
10.8 gives details of the single forest endemic
montane subspecies in the East Coast
Escarpment.

Frequency of
subspecific
distribution
boundaries
4
3
1 6 4

Location (i.e. between these
mountain blocks)

From this table the relaive isolaion of the Ulu-
gurus, with five endemic subspecies, in addiion
to the two endemic species menioned earlier, is
apparent. From a biogeographic point ofview, the
study of subspeciaion is valuable in that it pro-
vides circumstanial evidence of small-scale
movements of birds between certain mountain
blocks but not others (perhaps during a period
when the forest cover in the lowlands between the
mountains was more extensive than it is now).
Such small-scale occasional movements between
mountains would be very difficult to detect by
direct observaion because there are so ew oni-
thologists in Tanzania. It is possible that move-
ments between mountains could be related to the
seasonal alitudinal movements undertaken by
certain species, discussed in the following secion.

Usambara-Nguaguru
Nguru/Ukaguru-East Uzungwa
East Uzungwa-Mufindi
Mufindi-Mount Rungwe
Mount Rungwe-Nyika Plateau

2. between Nguru/Ukaguru and the
Uzungwas;
3. between south Uzungwa (Mufindi) and
the Southen Highlands (Mount Rungwe);

4. between the Southern Highlands and
North Malawi (Nyika Plateau).

It seems likely, therefore, that geographical and
vegetaional factors have resricted movements of
at least certain species of birds at these points. It
can also be seen from Table 10.5 that several
species have disjunct disribuions, or reach their
distribuional limits at these same locaions.

Seasonal altitudinal movemens

Most montane forest birds in Africa have usually
been considered to be sedentary. However, in the

Table 10.8. he single orest endemic montane subspecies of the East Coast Escapment mountains

Forest Subspecies

Usambara Modulatrix orostruthus amani

Apa/is moreaui moreaui
Ploceus nicolli nicolli
Shppardia lowei subsp. nov.
Andrpadus tphrolaemus neumanni
Shppardia shapei bangsi
Phylloscopus umbrovirens fu glescouchmani
Apa/is thoracica uluguru
Orthotomus metpias altus
Swynnertonia swynnertoni rodgersi
Modulatrix orostruthus sanjei
Apalis thoracica injectivora
Tr ichastoma pyrrhop terum nyasae
Neaarinia luuvicensis whytei

Ukaguru
Uluguru

Uzungwas (including Mufindi)

Nyika Plateau