Geology Reference
In-Depth Information
specific assoc1abons among forest primates.
These associaions can, in turn, affect behavior
and niche breadth of sympatric species, facilitate
hybridisaion, and perhaps even enhance rates of
speciaion (Gauier-Hion, 1988).
obus (. angolensis palliatus) and the Sykes
monkey (Cercopithecus mitts molonyt) .
*
As
elsewhere, the red colobus and the mangabey
typically occur in muli-male and emale groups
in the Uzungwas, whereas the black-and-white
colobus and the Sykes monkey typically occur in
single-male, muli-female groups (personal
observation).
The plant and primate communities of the
Uzungwa Mounain Forest
The Uzungwa Mountains contain some of the
richest forest in the Easten Arc chain (Rodgers &
Homewood, 1982; Rodgers, Chapter 14). They
are the only mountains in East Africa that have
forest on the escarpment ranging from 300 to
2600 m a.s.l., receiving up to 2500 mm in annual
rainfall (Lovett et al., 1988). Plant species in the
Uzungwa orests show marked alitudinal vari-
aion; however, a number of important plant food
species in the Guine-Congolian forests either
are absent or are present at very low densities in
the Easten Arc (Lovett, Chapter 4). Unlike the
other montane orests in the Easten Arc, these
southenmost orests also have a disinct dry
season June-September) and a single rainy
season (November-May), which also may have
contributed to the forest plant biogeography of
these communiies (Lovett, Chapter 4). The com-
posiion and interacions of the primate com-
munity are likely to have been affected by these
latter condiions as well.
The Uzungwa Mountains contain the only for-
est in the Easten Arc that has representaives of
Cercopithecus, Cercocebus and Colobus monkeys (the
three major genera of Old World monkeys found
in forests throughout Central Africa). Moreover,
two of the three endemic subspecies of primates
found in Tanzania are found only in the Uzungwa
Mountains: the recently discovered Sanje crested
mangabey (Cercocebus galeritus sanjei: Homewood
& Rodgers, 1981) and the Uhehe red colobus
(Colobus badius goronoum). [Tanzania's third
endemic subspecies is the Zanzibar red colobus
(. b. kirkit) of Zanzibar Island: Mturi, Chapter
12.] The other two forest primates found in the
Uzungwas are the black-and-white or pied col-
Forest monky biogeography
The red colobus and the mangabey are narrowly
adapted to rain forest or large stretches of riverine
forest in Central Africa, such as in the Tana River
in Kenya. The Sykes monkey and the black-and-
white colobus also prefer forest but have a much
higher tolerance for drier woodland habitat.
These pattens are reflected by a more patchy
disribuion of the former two species compared
with the latter two throughout Tanzania. For
example, the more common Central African red
colobus, . b. tephroseles, is ound at several loca-
ions along the heavily forested western border of
Tanzania, including Gombe Stream, Mahale
Mountains, Mbizi and Biharamulo. However, the
only red colobus populaions found in Tanzania
east of the arid corridor are
. b. gordonorum
in the
Uzungwa Mountains/Magombera Forest, and .
b. kirkii
in a few patches of forest on Zanzibar
Island (Rodgers, 1981; see also Mturi, this
volume). . b. kirkii appears to be the most evolu-
ionarily conservative of these three subspecies
(Kingdon, 1981). However, . b. goronorum most
closely resembles . b. kirkii (Kingdon, 1981;
Rodgers, 1981; Sruhsaker, 198lb), showing con-
siderable evoluionary conservaism as well. Thus
far, the only mangabeys reported in Tanzania
(Cercocebus galeritus sanjet) occur in the Uzungwa
Forest (Homewood & Rodgers, 1981). As a
genus, mangabeys also tend to show considerable
evoluionary conservaism (Waser, 1984). In con-
trast to red colobus and mangabeys, black-and-
white colobus (. guereza) are found in dry and
wet montane orests in northen Tanzania,
including Mount Kilimanjaro, Mount Meru, and
Judging from coat colour, the Sykes monkey is probably a hybrid between .
m. molonyi
and .
m. monoies
I. Kingdon, personal communicaion).
Search WWH ::
Custom Search