International Journal of Mol. Ecol. and Conserv. 2015, Vol.5, No. 2, 1-6
4
Table 2: Estimates of density, abundance and biomass of Sclater’s guenon in Ikot Uso Akpan
Parameters
Jacob (2012)
Egwali et al. (2005) Okon (2004)
Udoedu (2004)
Ibong (2002)
Survey method
Line transect
Point survey
Point survey
Point survey
Point survey
Mean encounter rate (n/L)
1.18
-
-
-
-
Cluster/group density (km
-1
)
16.86±0.99
14.29±2.86
-
-
-
Individual density (km
-1
)
82±2.64
85±3.57
82.06
70.32
80
Population density (D)
57.40±1.85
59.5±2.5
58
50
56
Mean weight (kg)
3.25
3.25
3.25
3.25
3.25
Biomass density (kg/km
2
)
266.5±8.58
276.25±11.6
266.70
228.54
260
Population biomass (kg)
190.35±9.81
193.38±8.13
188.50
162.50
182
Discussion
Primate socio-ecological models indicate that the time
spent on resting by Sclater’s guenon and other tropical
primates is a function of seasonality, the percentage of
leaves in the diet, and the annual mean temperature
(Korstjens et al., 2006; 2010). In concurrence with this
hypothesis, it was observed that the time spent by
Sclater’s guenon resting was higher during the dry
season, when consumption of leaves was low, and
ambient temperature was high, hence there was low
detection than in the rainy season.
Also, independent of habitat type, time spent feeding
by some primate species are usually higher during the
rainy than the dry season. Studies suggests that
seasonal increases in ambient temperature, such as
that occurring during the dry season, may stimulate
primates to reduce heat-generating activities such as
feeding to avoid thermal overload and its associated
energetic costs (Dunbar, 1992; Korstjens et al., 2010).
This explanation is consistent with studies on spider
monkeys (Chapman and Peres, 2001; Korstjens et al.,
2006). Greater feeding in the rainy season is
interpreted as strategy for some tropical monkeys to
take advantage of peak seasonal foods, allowing them
to ingest surplus energy and store it as fat in
preparation for the impending period of food scarcity.
This study’s observation partially supports this
possibility because it was observed that as a result of
Sclater’s guenon spending more time feeding,
detection was slightly higher in the rainy season than
in the dry season which therefore corresponded in
higher population data in the rainy season and a
subsequent less detection distance.
The quality of habitat in Ikot Uso Akpan is believed to
have a great influence on the birth, death, immigration,
and emigration rates of the species population living
there. It supports the hypothesis that the female
reproductive success is dependent on habitat quality
and group size, implying that increased competition in
larger groups is usually offset the amounts of food
available in the habitat. However, some other studies
of primarily folivorous primates have shown that
group size has no effect on their reproductive success
(Stokes et al., 2003; Robbins et al., 2007; Steenbeek
and van Schaik, 2001) although such results are not
universal (Borries et al., 2008; Snaith and Chapman,
2008; Marshall, 2010). Illegal logging activities (Plate
1 and 2), rubber plantation establishment (Plate 3),
and clearance for farming activities in the study area
could also be said to have impacted negatively on the
population of Sclater’s guenon. Consequently, there
was a decrease (3.53%) in the species population
between 2005 and 2012 as there has been increased
rate of deforestation over the period under survey.
Plate 1: Logging activities in the study area
Plate 2 Logging activities in a different section
