Aquatic macrophytes hold several niches within the ecosystem, including inter alia water purification, carbon sequestration and serve as microhabitats for aquatic insects. These dynamic roles make macrophytes good indicators of current environmental conditions. Hence assessing their abundance in line with wetland ecosystem dynamics and function is essential. Frequency of occurrence and density values were estimated, using twenty (20) 2 m x 2 m quadrats for each macrophyte encountered. The results of the study revealed twenty-one (21) macrophytes belonging to 16 families. These ponds varied markedly in terms of species composition and in numerical strength such that Polygonum lanigerum (1143+175st/ha), Setaria verticillata (337.5+ 32.8st/ha), Azolla pinnata (337.7+ 16.4 st/ha) recorded high density values while Lagenaria breviflora (18.7±2.19), Sida acuta (18.75±5.30), Ludwigia erecta (18.7±0.15) and Milletia aboensis (18.7±0.03) were the least abundant species. Pond A and D with 11 taxa each had the higher Shannon-Wiener (2.192, 2.214) and Simpson (0.8699, 0.8787) diversity indices respectively when compared to the other ponds. On the contrary, pond C with four taxa had the least Shannon-Wiener and Simpson diversity indices (1.253, 0.6782) respectively. Equitability and evenness ranged between 0.914 - 0. 952 and 0.814 - 0.900 respectively. Bray and Curtis cluster analysis showed that pond B was the most dissimilar compared to other ponds in terms of the taxa composition.

1. Trends in Macrophyte Diversity in Anthropogenic Perturbed Lentic Ecosystems within Uyo Metropolis
Trends in Macrophyte Diversity in Anthropogenic Perturbed
Lentic Ecosystems within Uyo Metropolis
1Anwana, E. D 2*Mbong E.O., and 3Etim, N.
1,3 Department of Botany and Ecological Studies, University of Uyo, Akwa Ibom State. Nigeria
2Department of Environmental Biology, Heritage Polytechnic, Ikot Udoata, Eket, Nigeria
Aquatic macrophytes hold several niches within the ecosystem, including inter alia water
purification, carbon sequestration and serve as microhabitats for aquatic insects. These dynamic
roles make macrophytes good indicators of current environmental conditions. Hence assessing
their abundance in line with wetland ecosystem dynamics and function is essential. Frequency of
occurrence and density values were estimated, using twenty (20) 2 m x 2 m quadrats for each
macrophyte encountered. The results of the study revealed twenty-one (21) macrophytes
belonging to 16 families. These ponds varied markedly in terms of species composition and in
numerical strength such that Polygonum lanigerum (1143+
175st/ha), Setaria verticillata (337.5+
32.8st/ha), Azolla pinnata (337.7+
16.4 st/ha) recorded high density values while Lagenaria
breviflora (18.7±2.19), Sida acuta (18.75±5.30), Ludwigia erecta (18.7±0.15) and Milletia aboensis
(18.7±0.03) were the least abundant species. Pond A and D with 11 taxa each had the higher
Shannon-Wiener (2.192, 2.214) and Simpson (0.8699, 0.8787) diversity indices respectively when
compared to the other ponds. On the contrary, pond C with four taxa had the least Shannon-
Wiener and Simpson diversity indices (1.253, 0.6782) respectively. Equitability and evenness
ranged between 0.914 - 0. 952 and 0.814 - 0.900 respectively. Bray and Curtis cluster analysis
showed that pond B was the most dissimilar compared to other ponds in terms of the taxa
composition.
Keywords: Macrophytes, Diversity, distribution, Evenness, Equitability and ponds
INTRODUCTION
Aquatic macrophytes play a vital role in a healthy
ecosystem. They serve as primary producers of oxygen
through photosynthesis, provide a substrate for algae and
shelter for many invertebrates. Additionally, they aid in
nutrient cycling from the sediment, and help stabilize river
and stream banks (Flint and Madsen, 1995, Madsen et. al.
2004 and Wetzel, 2001). Furthermore, they supply a wide
variety of wildlife with food and suitable nesting habitat.
Some even help to control pest population, for instance
duckweeds are known to reduce mosquito numbers, which
has the added advantage of decreasing the incidence of
air-borne diseases (Mitsch and Gosselink, 1993; Wetzel,
2001). They have served human well over the centuries,
providing food, medicine and building material. Aside from
these ecological roles, it has been reported in Nigeria that
the percentage cover and distribution of certain aquatic
plants correlates with fish diversity, fish production and
availability of fish stocks and gears and that giant reeds
growing up to a height of 3m viable option for construction
material (Murphy, 2002; Mohammed, Daddy and Adesina
2005).
In spite of this, most development involved reclamation of
large vast areas of wetlands, thereby endangering
dependent aquatic biodiversity and ecological functions of
wetlands. Additionally, research on wetlands lag behind
terrestrial ecosystems and in many climes such as the
study areas knowledge on extant wetland species and
ecology is in its nascent stages (Abell, 2002). Hence, this
research project was carried out to contribute to the
growing corpus of the different typologies of wetlands
within Akwa Ibom State in order to aid its management.
*Corresponding Author: Anwana, E. D., Department of
Botany and Ecological Studies, University of Uyo, Akwa
Ibom State, Nigeria. Email: ekomedem@yahoo.com
Research Article
Vol. 7(1), pp. 339-344, August, 2020. © www.premierpublishers.org, ISSN: 0274-6999
Journal of Environment and Waste Management

2. Trends in Macrophyte Diversity in Anthropogenic Perturbed Lentic Ecosystems within Uyo Metropolis
Anwana et al. 340
Figure 1: Map of Study Area showing pond location
MATERIALS AND METHODS
Description of Study Area
This research was carried out in four ponds designated as
ponds A, B, C (located at the Uyo City Cenotaph) and D
(located behind Shelter Afrique Housing Estate), all within
Uyo Capital City, Akwa Ibom State, Nigeria. Uyo lies
between latitude 5.02oN – 6.10 oN and Longitude 7.92oE –
9.48oE in the southern part of Nigeria (Figure 1). The area
has annual rainfall ranging between 2000 mm- 2500mm
which is bimodal in distribution. The rainy season begins
in the month of March and ends in the month of November
with a relatively short period of moisture stress generally
referred to as August break with relative humidity ranging
from 75 – 79 percent. The Annual temperatures are
uniformly high, with an average reaching 27 0C peak value
in the months of February through April (Ewenzor et. al.,
1990). The four ponds are strategically located within the
urban district and they experience a reasonable amount of
anthropogenic perturbations arising from recreational,
economic and social activities some of which include
swimming, bathing, laundering and waste dumps.
Vegetation Sampling
Systematic sampling was used in sampling the vegetation
and soil (Knight, 1978). Species were sampled in twenty
2m x 2m quadrats, spaced at regular intervals of 2m. In
each quadrat, plants were enumerated and species were
properly identified to the species level. Voucher specimens
of unknown species were collected for proper identification
at the herbarium of the department of Botany and
Ecological Studies, University of Uyo. Total number of
plant species encountered in each quadrat was recorded.
Frequency (in percentage) and density of species were
estimated according to the methods of Knight (Knight,
1978). Dominance diversity indices were computed with
the Paleontological software (PAST) version 2.17
(Hammer and Harper, 2005).

3. Trends in Macrophyte Diversity in Anthropogenic Perturbed Lentic Ecosystems within Uyo Metropolis
J. Environ. Waste Manag. 341
Table 1: The Geographical co-ordinates and Description of Studied Ponds.
Serial number Designation Site Coordinates Description
1 Pond A 5.0060N-5.0090N ;
7.9220N-7.9280E;
This is a large pond located at the periphery of the urban
cenotaph and is most proximate to a big urban drainage
channel. It is surrounded by commercial vegetable farms and
serves as reservoir for irrigation activities.
2 Pond B 5.00620N- 5.0140N;
7.9270N- 7.9300E;
A small pond but with diverse herbs and shrubs supporting
activities such as laundering and automobile washing and to
a lesser extent swimming. It surrounded by the turf vegetation.
3 Pond C 5.00650N- 5.0190N;
7.9310N- 7.9440E;
This pond is at the center of the cenotaph and is surrounded
by a thick shade cover of Bambusa vulgaris matrix which
provide a shade ambience for boating
4 Pond D 4.9760N-4.9620N;
7.9040N-7.9660E
This is located behind a residential estate (shelter afrique
housing estate) and receives large volumes of waste and
debris especially in the wet season. It is surrounded all over
by fragments of farmlands and an access road serving as the
exit route from the estate.
RESULTS AND DISCUSSION
The floristic composition of the ponds as shown in Table 2 indicates a total of 20 aquatic and terrestrial plants from 16
plant families. The plant with the highest mean density (1143st/ha) was Polygonum lanigerum while Milletia aboensis and
Sida acuta were the least common species found in the pond with a density value of 18.7±2.19st/ha.
Table 2. Mean density(± SE) and Frequency of Macrophytes in Selected ponds
Plant Family Density (st/ha) Frequency (%)
Ageratum conizoides L. Asteraceae 187±12.19 13
Aspillia Africana (Pers.) C. D. Adams Asteraceae 75±10.7 5
Azolla pinnata R.Br. Salviniaceae 337.7±16.4 22.3
Bambusa vulgaris Schrad. Ex J.C. Wendl. Var
vittata Riviere and C. Riviere
Poaceae 75±11.2 5
Calapogonum muconoides Desv. Fabaceae 225±19.1 15
Commelina bengalensis L. Commelinaceae 150±7.4 10.00
Acroceras zizaniodes (Kunth) Dandy Poaceae 75±6.01 5.00
Kyllinga diffusa Cyperaceae 112.5±10.2 7.50
Elaeis guineensis Jacq Arecaceae 112.5±19.4 7.50
Cyperus iria L. Fabaceae 93.75±18.4 6.25
Ipomoea carnae Jacq Convulvucaceae 225±12.4 15.00
Milletia aboensis (Hooke. f.). Bak. Leguminosae 18.7±0.03 1.30
Ludwigia erecta (L.) Hara Onagraceae 18.7±0.15 1.23
Mimosa pudica L. Mimosaceae 56.25±12.4 3.75
Nymphaea lotus L. Nymphaeceae 262.50±20.1 17.50
Panicum maximum Jacq. Panicoideae 300±52.8 20.00
Polygonum lanigerum R.Br. Polygonaceae 1143±175 76.25
Setaria verticillata ( L.) P. Beauv Panicoideae 337.5±32.8 22.50
Sida acuta Burm. F. Malvaceae 18.75±5.3 1.25
Lagenaria breviflora (Benth) Roberty Cucurbitaceae 18.7±2.19 2.64
Note: st/ha = stems per hectare; % = percentage.
Table 3 shows Numeric abundance of species across the four ponds. It records that Ageratum conyzoides recorded 5
individuals present in ponds C and D, Bambusa vulgaris (2 individuals), Aspillia africana (2 individuals), Mimosa pudica
(2 individuals) and Calopogonium muconoides (6 individual) were found solely in pond B. Azolla pinata (9 individuals) and
Ludwigia erecta (2 individuals) were exclusively present in ponds A and D. Commelina bengalensis (6), Cyperus iria (7
individuals) and Panicum maximum (8 individuals) were common to ponds A and B. Acroceras zizaniodes recorded 3
individuals common to ponds A and C. Khyllinga diffusa (3 individuals), Elaeis guineensis (3 individuals) and Lagenaria
breviflora (1) were solely present in pond A, Ipomoea carnea (6 individuals), Milletia aboensis (5 indivduals) and Sida
acuta (5 individuals) were solely present in pond D, Setaria verticillata (9 individuals) were found in Pond B and D.
Nymphea lotus (8 individuals) were found in Ponds A, C and D while Polygonum lanigerum (31 individuals) were found
present in ponds A,B, C and D.

4. Trends in Macrophyte Diversity in Anthropogenic Perturbed Lentic Ecosystems within Uyo Metropolis
Anwana et al. 342
Table 3: Macrophyte species (MS) and Associate (AS)
species abundance (by quadrats) in each pond
Species Plant
group-
ing
POND
A
POND
B
POND
C
POND
D
Total
Ageratum
conizoides
AS 0 0 3 2 5
Aspillia
Africana
AS 0 2 0 0 2
Azolla pinnata MS 5 0 0 4 9
Bambusa
vulgaris
AS 0 2 0 0 2
Calapogonum
muconoides
AS 0 6 0 0 6
Commelina
bengalensis
MS 2 4 0 0 6
Acroceras
zizaniodes
MS 1 0 2 0 3
Khyllinga
diffusa
MS 3 0 0 0 3
Elaies
guineensis
AS 3 0 0 0 3
Cyperus iria MS 1 5 0 1 7
Ipomoea
carnae
MS 0 0 0 6 6
Milletia
aboensis
AS 0 0 0 5 5
Ludwigia
erecta
MS 1 0 0 1 2
Mimosa
pudica
AS 0 2 0 0 2
Nymphaea
lotus
MS 3 0 4 1 8
Panicum
maximum
AS 4 4 0 0 4
Polygonum
lanigerum
MS 7 8 8 8 31
Setaria
verticillata
MS 0 5 0 4 9
Sida acuta AS 0 0 0 5 5
Lagenaria
breviflora
AS 1 0 0 0 1
31 38 17 42
Table 4 shows the biodiversity status of the pond using
accepted diversity indices (Mbong et. al. 2020). Ponds A
and D are characterized by 11 taxa each, and so are the
most diverse, while B and C record 9 and 4 taxa
respectively. Pond C record the highest dominance value
(0.3218) followed by ponds B, A, and D with values 0.1343,
0.1301 and 0.1213 respectively. Shannon diversity index
values were 2.214 in pond D, 2.192 in pond A and 2.092
in pond B while pond C recorded 1.253. Simpson index
revealed 0.8787, 0.8699, 0.8657 and 0.6783 for ponds D,
A, B and C respectively. Evenness was highest for pond B
with value 0.9002, while ponds C, D and A have values
0.8752, 0.8318 and 0.8143 respectively. Bray and Curtis
analysis showed that pond B was most dissimilar (40%) to
the other three ponds (Fig. 2).
Table 4: Diversity trend of the four Metropolitan ponds
Pond A Pond B Pond C Pond D
Taxa 11 9 4 11
Dominance 0.1301 0.1343 0.3218 0.1213
Shannon (H) 2.192 2.092 1.253 2.214
Simpson Index 0.8699 0.8657 0.6782 0.8787
Evenness 0.8143 0.9002 0.8752 0.8318
Equitability 0.9143 0.9521 0.9039 0.9232
Figure 2: Dendrogram (Bray and Curtis method)
showing disimilarites based on species abundance
DISCUSSION
The presence of species such as Azolla pinnata,
Polygonum lanigerum, Nymphaea lotus, Setaria verticillata
and Ageratum conyzoides is characteristic for wetlands
(Mbong et al., 2020). The vegetation attributes of the
selected ponds reflect a rich diversity of annuals, biennial
and perennial plants. A total of twenty plants belonging to
sixteen families were recorded in this study. Particularly,
the presence of floating and rooted macrophytes is well
noted within the ponds. A similar observation had been
made by some previous researchers including Anwana, et
al., (2018a); Ubom et al., (2012) and Ogbemudia et al.,
(2014) in other lentic systems. In this study there is a
complete absence of submerged macrophyte which is
contrary to the results of Rasal et al., (2014). Worthy of
concern is the fact that the diversity or number of taxa
reported in this research is higher than that reported by
Anwana, et al., (2015) in a recreational pond. Contrarily, it
is lower than that reported by Rasal et al., (2014) in a Lake
in Mumbai. These numerical gaps might be justified in
terms of the variation existing in the sizes of the ponds
studied and individual plant species adaptation to varied
pedological and hydrological regimes as well as nature
and intensity of anthropogenic influence in the different
locations.
Going by the views of Kumara, Raghavendra and Pramod,
(2011), the quantification of biological diversity and (or) its
elements in numerical sense assists in a great way for
objective evaluation to be made. This aid valid comparison
1 2 3 4 5
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Similarity
PONDC
PONDA
PONDD
PONDB

5. Trends in Macrophyte Diversity in Anthropogenic Perturbed Lentic Ecosystems within Uyo Metropolis
J. Environ. Waste Manag. 343
of biodiversity status of different or similar habitats
(Kumara et al., 2011). This concept validates the
application of standard diversity indices in evaluation of the
different ecosystems for ease of comparison. In line with
this, the current result reflects that both species diversity
and dominance values computed for each pond varied
with the ponds. This work corroborates wholly with the
diversity trends which had earlier been proposed by other
researchers (Clarke and Warwick, 2001; Ogbemudia et al.,
2014). They proposed that species diversity and
dominance value varied together but inversely in different
ecosystems. This is evident in this work in that Pond A and
Pond D which is the most diverse and has the highest
number of taxa records the least dominance value
whereas pond C which had the least Shannon-diversity
index records the highest dominance value across the four
ponds. The endemic low Shannon-weinner value recorded
in pond C is essentially associated with the periodic
dredging and clipping of embankment plants to aid
boating. These activities favour reduced diversity. Also,
the area surrounding this particular pond possesses a
relatively flat land mass as opposed to the undulating
surroundings of other ponds. This topographic peculiarity
in pond C prevents massive inflow of seeds from
surrounding vegetation via rain water while the undulating
surroundings enjoy such depositions during the wet
season.
Clarke and Warwick, (2001) also portrayed the notion that
different plant species growing in the same habitat or
growing under similar environmental conditions show
corresponding differential response to environmental
gradient or nutrient limits within such ecosystems. This
emphasizes the density gaps amongst species imminent
in the study area. In line with this, the profuse presence of
Polygonum lanigerum and Setaria verticillata in all the
ponds is precedented and indicates its tolerability to the
prevailing moisture and salinity regimes in the different
ponds. This bears much similarity with another related
study (Rasal et al., 2014). It could also be that these
species have a high regeneration potential which can
withstand the prevailing environmental conditions and
perturbations. The low values of frequency and density
recorded for other species may be linked with their inability
to fully adapt to environmental stress factors such as
inundations and habitat degradation in the pond. It could
also be as a result of the slow rate of regeneration of these
species which cannot compensate for mortality, herbivory,
and other exploitation sources. The equitability and
evenness indices as computed in this work confirmed the
views of Clarke and Warwick, who opined that both
equitability and evenness indices increase with a decrease
in species richness (Kumara et al., 2011). The results from
the Bray and Curtis analysis as deduced from the
dendrogram further strengthen its application in
interpretation of site similarities based on the common
continuous or discrete variables (Anwana, et. al. 2018). In
this research, among the four pond, pond B exhibits almost
about 40% dissimilarity (Fig. 2). This evidence is
buttressed by the fact that this pond supports four out of
nine taxa which are not found in the other ponds.
CONCLUSION
The result of this research makes it clear that these ponds
supports a number of floating and rooted macrophytes and
this flora thus confirm typified aquatic vegetation (Rasal et
al., 2014). Individual species responses to prevailing
conditions in their environment differ markedly and this is
reflected in the frequency of occurrence and density
values of species. Also, macrophyte dominance and
diversity indices differed within and between the ponds.
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Accepted 11 August 2020
Citation: Anwana ED, Mbong EO, and Etim N (2020).
Trends in Macrophyte Diversity in Anthropogenic
Perturbed Lentic Ecosystems within Uyo Metropolis.
Journal of Environment and Waste Management, 7(1):
339-344.
Copyright: © 2020: Anwana et al. This is an open-access
article distributed under the terms of the Creative
Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium,
provided the original author and source are cited.