International Journal of Mol. Ecol. and Conserv 2015, Vol.5, No.5, 1-6
2
imperative. Such data is needed for effective and
realistic conservation strategies. The required
ecological data include species composition,
abundance of each species, stem diameter distribution
and abundance of regeneration of each species. This
study was therefore carried out to assess the diversity
and population densities of plants species in the study
area. The data obtained may serve as a basis for
formulating strategies for sustainable management of
the forest and other similar forest tracts in the country.
1 Methodology
1.1 Study Area
The study area is located in the southern part of Nigeria
in the western axis of Akwa Ibom State between
latitudes 5°00`
-
5°25` N and longitudes 70°35`
-
8°
00" E. Ikono Local Government Area is bounded in
the North by Ini, in the South by Uyo Local
Government Area, East by Ibiono and in the West Ikot
Ekpene, Essien Udim and Abak Local Government
Areas (Figure 1). The forest fragment is an evergreen
forest fragment with an area of 3.2 ha managed by the
Ikot Efre Itak community as a sacred grove. The forest
is only access by the consent of the Village council who
gives such permission.
1.2 Sampling Method and Design
Three 300 m linear transect were laid into the core of
the forest 20 m away from the access routes. Each
transect was separated by a distance of 100 m. All
plant species producing valuable forest products
within 20 m on both sides of the transect lines were
identified and enumerated. Thus, the total sample area
assessed was 0.6ha. The data collection was
undertaken between November, 2011 and January, 2012.
1.3 Data Processing and Analysis
The identified and enumerated plant species were
classified into four life
-
forms, namely; trees, Shrubs,
herbs and climbers. The frequency of each plant
species was determined in order to estimate its
population per hectare by dividing its total population
by the sampled area. The Diversity Index of the plant
species was determined using Shannon Weiner index
(H1) as described in Magurran (1988)
Diversity Index (H1) = ∑Pi In Pi (1)
Where: Pi = Ni/N, Ni – Total number of individuals of
species i, N – Total number of individuals of all species
Species Richness was also calculated using Margalef
Index (d) as described by Aremu (2010)
Species Richness (d) = S
-
1/ln N (2)
Where: S – Total number of Species, N – Total number
of individuals of all species
The Species evenness was calculated using Pielon
Index (E) as described by Aremu (2010)
Pielon Index (E) = H1/ln S (3)
Where: H1–Diversity Index, S
-
Total number of Species
F
k
= ∑Y
i
/n ×100 (4)
Where: F
k
– frequency, Y
i
– incidence of species k in
site i, n – number of species sampled
*ln = Natural log (Figure 1).
2 Results
2.1 Plant species population density, diversity index,
richness and evenness
A total of 59 plant species were identified in the study
area. The distribution indicated 33 species of trees
(Table 1), 12 shrub (Table 2), 7 herbs (Table 3), 34
climbers (Table 4) and 3 palms species (Table 5). In
table 1, the result showed that
Mimusops heckelii
had
the highest population density of 16 individuals/0.6ha,
followed by
Canarium schweinfurthii, Dracaena
sp.
,
Combretodendron macrocarpum
and
Antrocaryon
klaineanum
with density of 12, 7, 6 and 6
individual/0.6 ha respectively. Other tree species
varied between 2 and 1 individual/0.6ha respectively.
The tree Species diversity index, Richness and
Evenness of tree species in the study area was
-
1.320
7, 16.295 0,
-
0.869 7 respectively.
2.2 Shrub species population density, diversity
index, richness and evenness
Table 2 indicates that
Bambusia vulgaris
had the
highest shrub population density of 31 individuals/ha
followed by
Glyphaea brevis, Harungana madasgarensis
,
Coelocaryon preussii, Maesobotrya dusenii
with 4/ ha
and
Garcinia mannii, Homalium letestui
with 3
individuals/0.6 ha respectively while the least shrub
species had a population density of 1 individual/0.6 ha.
The Species diversity index, Richness and Evenness
of shrub species in the study area was
-
0.7840, 6.4745,
-
0.7265 respectively.
