Geology Reference
In-Depth Information
the Serengeti and Arusha Naional Parks. .
angolensis has been reported in at least 42 dif-
ferent localities in Tanzania, including virtually all
southen montane forests in the Easten Arc, and
a variety of riverine forest and woodland habitats
in southen and easten Tanzania (Rodgers,
1981). The Sykes monkey, Cercop itheus mitis,
shows a somewhat similar distribuion to that of
the black-and-white colobus in Tanzania
(Gauier-Hion et al., 1988).
Mammals show evidence of both southen and
northen routes of migraion into the Easten Arc,
although some species in the arc undoubtedly
originated there (Kingdon, 1981, 1989; Rodgers
et al., 1982;
Kingdon
&
Howell, Chapter
11
).
Both Kingdon (1981, 1989) and Rodgers et al.
(1982)
argue convincingly for a predominantly
southen migraion route for mammals in the
Uzungwas. Based in part on he conservaism and
patchy distribution of the red colobus and
mangabey subspecies in the Easten Arc, King-
don (1981, 1989; see also Kingdon
&
Howell,
Chapter
11)
further argues that the southen con-
necions between the Tanzania coast and the
Guineo-Congolian forest block are 'particularly
ancient'. . b. gownorum and . g. sanjei accord-
ingly appear to have experienced long-term bio-
geographical isolation in the Uzungwas over
evoluionary ime (see also Kingdon
&
Howell,
Chapter 11). The assumpion of long-term isola-
tion among these primate species is an important
component of the hypothesis generated in this
chapter for the origin of their interspecific associ-
aions in the Uzungwas.
in mixed species groups with one another in over
half oftheir sighings. This chapter examines how
rates of interspecific associaions among these
primates may have been affected by the biogeo-
graphic isolaion of the Uzungwa forest
community.
Mehods
Study area
The Mwanihana Forest is located in the north-
eastern part of the Uzungwa Mountains, due west
of Sanje Village (lat. 8° 10' S, long. 35° 50' E).
The study area consisted of a series of circuits.
Two routes were formed by parallel trails running
east-west along each side of the Sanje River.
Each of these trails accessed a narrow srip
approimately 0.15
m
wide and 2.25
m
long,
from 450 to 1050 m alitude. Two addiional loop
rails were cut: one to the north of Sanje River for
approimately 2 km, and the other to the south for
approimately 1 km. A small number of censuses
also were conducted at higher alitudes, up to
1700 m, using 'pit sawyer's trails' that connected
to the northen ransect route.
Census data
Data were collected from August to November
1984,
and February, June-October and Decem-
ber 1986. Individual trails were walked on a rotat-
ing basis, five monings per week beginning at
0700 h (an addiional aftenoon ransect begin-
ning at 1530 h was occasionally walked as well). A
minimum of 20 censuses per month were con-
ducted during each of these months, with the
excepion of September 1984. During each cen-
sus, data were collected on the size, composiion,
map locaion and alitude of all monkey groups
sighted, as well as on monkey diets, behaviour and
predaion. Individual monkey groups were not
habituated as we chose instead to concentrate on
as many different groups as possible over the
study period.
Observers tried to maimise obsevaion of
feeding and other behaviour whenever a group
lntespedic assodations in a biogeographic
context
Struhsaker (l98la) reviewed the interspecific
assoc1a0n data in five different forests
throughout Cenral Africa. Interspecific associa-
tions were common between the guenons,
mangabeys and red colobus, albeit relaively
uncommon among the black-and-white colobus.
Associations between black-and-white colobus
and red colobus were paricularly rare, with one
excepion: the black-and-white and the red col-
obines in the Magombera/Uzungwa region were
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