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

112 Sunderland-Groves and Maisels
hunting. Three highland sites were also selected for
survey: Matene in the northern section of the Reserve,
Obonyi I in the eastern part of the Reserve along the
border with the Okwangwo division of Cross River
National Park in Nigeria, and Basho on the western edge
of the Reserve (Figure 2 in Chapter 1).
The survey used standard line transect methods that
are practiced widely in animal density censusing
(Burnham et al. 1980, Buckland et al. 1993). General
transect protocols followed White and Edwards (2000).
Forest in the transects was cut just enough to allow one
person to pass. All transects were marked at 25-m
intervals with flagging tape and allowed to settle for a
minimum of three days before they were walked and data
collected. The reason was to ensure that the disturbance
and noise caused by cutting the transects did not bias
direct observations of mammals such as monkeys.
In the lowland forest, 40 transects—all 2 km in
length, except for one that measured 3 km (81 km in
total) were laid out perpendicular to the main rivers, the
Makone and the Oyi (20 along each river, each transect 1
km apart from and parallel to the next). In this manner,
the rivers were sampled along much of their lengths
within the Reserve, and vegetation on each side of the
rivers was sampled in the same proportion as it occurs in
the environment (Buckland et al. 1993). Four sampling
sections, Makone River East, Makone River West, Oyi
East, and Oyi West, contained 10 transects each and were
surveyed during both the dry and wet seasons. The other
two lowland sites were sampled only in the wet season.
Sixteen transects were cut in submontane/ridge
forest (8 km in total), five in the Matene and Obonyi 1
hills, and six in the Basho hills. An additional 6 km of
baseline was used to calculate encounter rates in the
submontane forest. Transect starting points were selected
randomly from a map and located using GPS. The
baseline was located parallel to the contour of the hill,
and transects were cut perpendicular to it. Each transect
was 500 m in length; longer transects would not have
sampled the desired topographical areas. The three
highland forest areas were surveyed only during the dry
season as time constraints made it impossible to repeat
Takamanda: the Biodiversity of an African Rainforest
sampling of the highland strata during the wet season.
Using portions of the baseline as separate transects is
statistically invalid because they are not independent.
The data collected included indirect mammal sign
such as dung and tracks and direct observations (animals
seen or heard). All evidence of human presence such as
traps, snares, hunter paths, bush houses, spent cartridges,
and gunshots was recorded to evaluate hunting pressures.
Changes in topography and vegetation were also
recorded along each transect.
To standardize the sampling effort, the number of
observers, speed of travel, and time of day were kept
constant for each transect. Transects were not walked
during heavy or medium rainfall because such conditions
affect mammal movements and observer reliability.
Additional reconnaissance surveys in the other
vegetation types of the Reserve were carried out,
especially in the higher altitude areas, and all signs of
large mammals were recorded.
2.2 Data analysis
Although the survey was designed to estimate densities
of animals, there were too few observations to use the
DISTANCE program (Thomas et al. 2002), which
requires at least 60 observations per species per stratum.
Thus, we used encounter rate (number of animals or their
sign encountered per kilometer) as the standard unit to
assess the relative abundance of animal (and human)
sign. Analysis of differences between datasets were made
using the Mann-Whitney U test; unless data was paired,
where we used the Wilcoxon Paired Rank test (Siegel
and Castellan 1988).
3 Results
3.1 Species presence
Fifteen species of large mammal were recorded within
the TFR, including forest elephant Loxodonta africana
cyclotis in both lowland strata (Table 1). Of the eight
primate species recorded, several are endemic, and some
are internationally endangered. The gorilla Gorilla
gorilla diehli is classified by IUCN (2002) as Critically