Geology Reference
In-Depth Information
non-forest-dependent species, and of disinct
lowland and montane forest faunas in Africa (see
Stuart, 1983 for a review), there is less agreement
upon the exact alitudinal limits of the latter. The
dificulies of determining the posiion of a par-
icular
species with regard to forest dependence
as well as to type of forest are compounded by
lack of deinite data on precise collecing locality
and alitude, as noted earlier, and on the exact
vegetaion type in which a specimen was col-
lected. In some highland and mountain localiies
in subsaharan Africa the vegetaion above 1500 m
a.s.l. may be grassland, and above 3500 m may
give way to an Afroalpine type (Hughes, 1983).
However, in at least some of the Eastern Arc
mountains, forest is to be found well above 1500
m. Amphibians and repiles of the Aroalpine and
moorland zones have been specifically excluded
from this study; their origins are uncertain
(Hughes, 1983).
There also is a dearth of inormaion available
on the ecology, behaviour and physiology of forest
species. This conrasts with studies on non-orest
species. Drewes et al. (1977) discussed in some
detail the special adaptaions which help prevent
dehydraion and allow basking in ull sunlight in a
desert frog, Chiromantis petesi. Withers et al.
(1982) studied the physiology of Hy perolius
nasutus. Physiological studies on montane repiles
(Hebrard, Reilly
&
Guppy, 1982; Reilly, 1982)
have dealt with lizards which live in Afroalpine
rather than forest habitat. Westen (1974) studied
disribuion, density and biomass densiy of
lizards in semi-arid northen Kenya, and Kreulen
(1979) discussed factors afecing repile biomass
in African grasslands. Only Broadley
&
Blake
(1979) have conducted field studies on a forest
chameleon, Rhampholeon mashalli, in Zimbabwe,
and these were mainly concened with numbers
and movements of the animals rather than with
physiological adaptaions.
ted in Table 9 .1. These fall into several broad
pattens.
Spec.es ound in both the easten and Guineo-
Congo/ian oress
One of the striking features of the distribuions is
that vey few of the species found in the easten
forests of Africa are also found in those to the
west. Only a single species of frog,
Arthro/ptis
aoifririci,
falls into this categoy. Not a single
forest-dependent species of the anuran families
Ranidae, Hyperoliidae, Bufonidae or Micro-
hylidae is ound in both the westen and easten
forests, and no caecilian species in shared by the
two.
Among the repiles, the lizard Cnemaspis dicker-
soni, and the snakes Lycophidion melearis , Atrac-
taspis aterima and Naja melano/eua also are found
in westen orests. Subspeciic disincion has
been recognised for four of the repile species
found in the westen and easten forests: the
lizard Ho/aspis guenthei, the colubrid snakeNati-
iteres variegata and the vipers Bitis gabonica and
Atheris nitschei (see Table 9.2).
Spe.es ound in the Tanganyika-Nyasa oress
and southen Africa
These species are found in several forests in the
Tanganyika-Nyasa system (and in some cases,
other isolated forests) but also extend their range
into southen Africa. Included here are the frogs
Hy peolius mitchelli
and
Lptopelis lavomau/atus,
the lizards
Me/anoseps ater
and
Me/anosps
/oveidgei
and the snakes
Aparallactus guenthei
and
Dasype/tis medici. The taxonomy of some of the
species in this group is sill not without problems:
Hp ero/ius mitche//i and Hyperolius punaicu/atus
have only recently been shown to be separable in
the field (Schi0tz, 1975) and there may be some
confusion of past records. Poynton
&
Broadley
(1987) discuss the two species in southen Africa.
Previously many subspecies of Melanosps ater
were described; despite a recent revision of the
genus by Brygoo
&
Roux-Esteve (1981), the
status of some of these remains unclear. Several
of the species with this distribuion patten are
Pattens of disribuion of the
amphibians and reples of the easten
forests of Africa
The distribuions of the forest amphibians and
repiles of the easten forests of Africa are presen-
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