International Journal of Mol. Ecol. and Conserv. 2015, Vol.5, No. 1, 1-6
Figure 6: Species distribution of trees in Okuku fragment
Ikwat 1 fragment tree inventory
In Ikwat 1, the sample plot contained a total of 49
trees belonging to 18 species and 16 families. The
smallest tree height of dbh greater than 10 cm in the
Ikwat 1 fragment was 5.9 m with a diameter of 12.1
cm and the tallest tree had a 24.9 m with a dbh of 56.8
cm (Figure 7). The mean height and dbh of the
enumerated trees in the Ikwat 1 fragment was 25.5 cm
and 12.0 m with a standard deviation of 10.3 cm and
4.3 m respectively (Figure 5). The total basal area of
trees sampled in the plot was 242.5 cm
3
(3523.4/acre)
and the number of trees in the sample plot was
equivalent to 853 trees/acre (Figure 8). Moreover, the
dominant tree species in the sample plot was
Ficus
thoningii
with a frequency of 10 individual trees,
followed by
Spondias mombin
with a frequency of 8
individaual trees while the remaining 16 tree species
had a frequency that varied between 5 and 1
individual trees each (Figure 9).
Figure 7: Height and crown size distribution of trees in Ikwat 1
fragment
Figure 8: Diameter class distribution of trees in Ikwat 1
fragment
Figure 9: Species distribution of trees in Ikwat 1 fragment
Discussion
The mean tree height in the sample plots was 11.8m,
indicating a prevalence of relatively small trees inside
the study area. More than 90% of all the sampled trees
in the study area had a height between 0-20m
compared to other tropical rainforest areas in the
country such as Cross River National Park where the
average continuous canopy height is between 30 to
35m (WWF, 1990). Moreover, despite the sporadic
occurrence of trees with large diameter, trees with a
small diameter clearly dominate the area with a mean
diameter of 26.9 cm (Figure 4 and 8). The rather small
dbh and height of trees in the study area could also be
attributed the unsustainable exploitation of the forest
resources in the study area. Furthermore, the presence
of high tree density in the Ikwat 1 fragment than the
Okuku fragments can be attributed to the presence of
the sacred mound in the fragment and the marshy
forest floor due to the sacred stream that flows in the
fragment emptying itself in another fragment in the
form of a water fall. The Okuku fragment is located
on a upland and is less considered sacred as the Ikwat
1 fragment, hence, farm encroachment and logging
activities is more severe in the fragment than the
Ikwat 1 fragment (Jacob, 2012; Egwali et al., 2005).
Moreover, the forest fragments are located in
economically poor communities with a high
population growth rate in the area. The people depend
directly on the available resources such as land for
their subsistent agriculture (Baker, 2005). This does
not augur well for forest protection (Chapman et al.,
2006) which serves as the habitat for the endemic
primate species (
Cercopithecus sclateri
) in the area.
However, not all the habitat changes in the study area
are due to human activities. Other factors include
changes such as wind throws and tree dieback due to
cohort senescence. Consequently, all of these factors
affect the vegetation structure of the study area, thus
impacting on the primate populations negatively
(Ibong, 2002; Baker, 2005; Egwali et al., 2005; Jacob,
2012).
