Fisheries in the Southern Border Zone of Takamanda - Impact ...

Surveys of the Cross River Gorilla and Chimpanzee Populations in
Takamanda Forest Reserve, Cameroon
Jacqueline L. Sunderland-Groves, Fiona Maisels and Albert Ekinde
1 Introduction
Takamanda and Mone rorest reserves and the Mbulu
forest are located on the Cameroon side of the Nigerian-
Cameroon border. Together with the adjoining area in
Nigeria—the Okwangwo division of the Cross River
National Park—they form part of the last stronghold of
the Cross River gorillas Gorilla gorilla diehli. These
gorillas are classified as Critically Endangered (IUCN
2000) and now occur only in four isolated subpopulations
(Afi, Mbe, Obudu, and Okwangwo/
Takamanda/Mone/Mbulu) within an area of about 5,000
km 2 .
Cross River gorillas were originally described as a
new species (Gorilla diehli) by the German taxonomist
Paul Matschie in 1904. Later taxonomic research
reduced this species rank to that of a sub-species, leading
to their eventual amalgamation with other lowland
gorillas (Gorilla gorilla gorilla; Rothschild 1904, 1906,
Elliot 1912, Coolidge 1929, Groves 1970). However,
craniometric research by Stumpf et al. (1998) reopened
the question as to whether the Cross River gorilla is a
sub-species. Additional study by Sarmiento and Oates
(2000), including the re-measurement of Nigerian and
Cameroonian gorilla skulls, concluded that these gorillas
are indeed more taxonomically distinct than previously
described, and they are now recognized as the fourth subspecies
of gorilla.
Information on gorilla abundance and distribution
within this region has been documented for more than 70
years (Allen 1930, Sanderson 1940, March 1957,
Struhsaker 1967, Critchley 1968, Harris et al. 1987,
Thomas 1988, Harcourt et al. 1988, 1989, Oates et al.
1990, Groves 1996, Obot et al. 1997, Oates 1998). A call
for surveys of the Mamfe-Obudu region (Oates 1996)
mentioned that hunting was a major environmental
problem and recommended that biological surveys of
Takamanda should be undertaken, then followed by
conservation management. Field surveys were
subsequently conducted by Sunderland-Groves in 1998
and 1999 in Cameroon, which led to additional research
in 2000 and 2001 that continues today.
The objectives of the initial 1998-1999 surveys were
to collect baseline data on the large mammals of the
reserves, focusing on the gorilla population, and assess
conservation threats and potential. In relation to the
gorilla population, the aim was to obtain an estimate of
size and of habitat types most used by the animals.
Results on apes from the 1998-1999 surveys are reported
in detail in Sunderland-Groves and Maisels (in prep). To
compare the results obtained in 2000 and 2001, the 1998-
1999 data are summarized in this paper.
Although there is still much to learn about this subspecies
of gorilla, considerable progress has been made
over a relatively short period of time, elicting a more
comprehensive overview of their range, distribution, and
abundance within Cameroon.
2 Ape Conservation Status
Chapter 9
According to local tradition in this region, the meat of
great apes may not be sold, but gorilla hunting occurred
before this survey started and still occasionally takes
place in areas outside of Takamanda. Ape populations are
more vulnerable to hunting than smaller primates; they
recover very slowly from population reduction because
of their inter-birth interval of about four years, late date
of maturity, and complex social system (see Walsh et al.
2003 for an overview of present gorilla status in the
region as a whole).
SI/MAB Series #8, 2003, Pages 129 to 140