Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 July 2021 | 13(8): 19053–19059
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.7328.13.8.19053-19059
#7328 | Received 10 April 2021 | Final
received 14 June 2021 | Finally accepted 04 July 2021
On the diversity and abundance of
riparian odonate fauna (Insecta)
of the midstream Chalakkudy River, Kerala, India
C. Nitha
Bose 1 , C.F. Binoy 2 & Francy K. Kakkassery 3
1 Research and Postgraduate
Department of Zoology,, St. Thomas’ College (Autonomous), Thrissur, Kerala
680001, India.
1 nithabose123@gmail.com, 2 drcfbinoy@gmail.com,
3 fkakkassery@gmail.com (corresponding author)
Editor: Ashish D. Tiple,
Vidyabharati college, Seloo,
Wardha, India. Date of publication: 26 July 2021
(online & print)
Citation: Bose, C.N., C.F. Binoy & F. Kakkassery (2021). On the diversity and abundance of
riparian odonate fauna (Insecta)
of the midstream Chalakkudy River, Kerala, India. Journal of Threatened Taxa 13(8): 19053–19059. https://doi.org/10.11609/jott.7328.13.8.19053-19059
Copyright: © Bose et al. 2021. Creative Commons Attribution
4.0 International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: Human Resource Development Group -
Council of Scientific and
Industrial Research(CSIR).
Competing interests: The authors
declare no competing interests.
Author details: Nitha Bose C, is a
research scholar under the guidance of Dr. Francy K. Kakkassery and the co guidance of Dr. C.F. Binoy at the Department of Zoology, St.Thomas’
College (Autonomous). Her research work is based on taxonomy and molecular
phylogeny of odonates of Kerala. Dr. C.F. Binoy,
has been working as Assistant Professor (Selection Grade) in the Research and
Post Graduate Department of Zoology, St.Thomas’
College (Autonomous). He is a research guide under the University of Calicut,
guiding four doctoral students and as co-guide of three. Entomology, especially biodiversity
conservation related to insects, insect ecology, pollination biology of
mangrove ecosystem are the fields of interest. Dr.
Francy K. Kakkassery
has been working as Associate Professor and Head in the Research and Post Graduate Department of
Zoology, St.Thomas’ College (Autonomous). He retired
from service last year after a long 30 years. He has been doing research in
field Entomology, specializing in dragonflies and damselfiles,
and also in aquatic biology. Six
students are doing doctoral research work under his guidance.
Author contributions: NBC— data collection, data
analysis and interpretation, drafting the article, editing; CFB—final approval
of the version; FKK—conception or design of the work, critical revision of
article, editing, final approval of the version.
Acknowledgements: The authors are grateful to the
Council of Scientific and Industrial Research (CSIR) for financial support. The
authors express indebtedness to Dr. K.H. Amitha Bachan, assistant
professor & research guide, Research Department of Botany, MES Asmabi College, Kodungallur. The
authors are thankful to the principal, St. Thomas’ College (Autonomous),
Thrissur for facilities provided.
Abstract: The riparian Odonate
insect diversity of the midstream Chalakudy River at
six locations assessed from February 2018 to January 2019 has revealed the
occurrence of 25 species of odonates. Among them,10
species are dragonflies belonging to seven genera of the family Libellulidae and the remaining 15 species are damselflies
belonging to six families and 11 genera. Five endemic damselfly species have
been recorded. Pseudagrion indicum
is endemic to the Western Ghats, while the remaining four species, Vestalis apicalis, Libellago indica, Dysphaea ethela, and Heliocypha bisignata,
are endemic to India. Diversity indices of the odonates
in all the six locations were analyzed and it showed
less abundance at sites where tourist activities are more and with thin native
riparian vegetation. Further, the study has unequivocally revealed that thick
native riparian vegetation is essential for their perching and existence. By
and large, the uncontrolled tourism activities and habitat alteration interfere
with the density and diversity of these endemic species.
Keywords: Damselflies, dragonflies,
endemism, odonates, tourism, Western Ghats.
INTRODUCTION
Kerala has a comprehensively
documented odonate fauna. The relevant works among
them include that of Rao & Lahiri (1982), Mathavan &
Miller (1989), Radhakrishnan (1997), Emiliyamma &
Radhakrishnan (2002), Emiliyamma (2005), Palot et al. (2005), Adarsh et al. (2014), Varghese et al.
(2014), Nair (2017), and Susanth & Anooj (2020). Recent works further added up the rich odonate diversity of Kerala to 174 species (Emiliyamma et al. 2020; Joshi et al. 2020). The seasonal
and habitat distribution of Odonata diversity of riparian habitats such as Mula and Mutha river basins in
Maharashtra was studied by Kulkarni & Subramanian (2013). Species turn over
and abundance of the odonates of riparian zones
depends on season and land use types. Endemics and habitat specialists are
restricted to undisturbed riverine ecosystems as they possess a narrow range of
habitat tolerance. Conservation of riparian zone results in the conservation of
endemics of odonates (Subramanian 2007; Subramanian
et al. 2008). The present study investigated the odonate
diversity and abundance of midstream Chalakkudy river
giving special reference to endemics.
METHODS
The survey was conducted once a
month from February 2018 to January 2019 by conventional random sampling. Six
locations of midstream Chalakkudy River were randomly
selected for the observation of odonates. The river
is 13.5 km (approximately) long from the first location to last one (Bachan 2003). The details of the study localities are given
in Table 1. All the six locations are with rocky river bed and evergreen and
semi evergreen forest vegetation. Madhuca neriifolia, Syzigium occidentale, Humboldtia vahliana, Elaeocarpus, and Homonoia riparia
are the dominant species of flowering plants in these locations (Bachan 2010). The selected locations have been confronted
with anthropogenic disturbances such as habitat alteration due to tourism
activities including resorts & commercial establishments, oil palm
plantations, and activities of local people. The odonates
were documented and identified with the help of photographs, keys, and
descriptions given in the literature (Fraser 1933, 1934, 1936; Kiran & Raju
2013). The species richness and abundance were recorded and Simpson &
Shannon diversity indices and eveness values were
calculated using PAST software. The observed species of odonates
were categorized as VC—Very common (180–240 sightings), CO—Common (120–180
sightings), OC—Occasional (60–120 sightings), and RA—Rare (1–60 sightings))
depending upon their occurrence during the survey (Palot
et al. 2005; Tiple et al. 2012).
RESULTS
During the study period, 2,186
individuals of 25 species were observed. Out of these, 10 species were
dragonflies of the suborder Anisoptera, belonging to
seven genera and the family Libellulidae. The remaining
15 species were damselflies under the suborder Zygoptera
and they come under 11 genera in six families (Tables 1, 2). Libellulidae is the
only anisopteran family, which has been observed
among the odonates in the present survey. Orthetrum sabina a
well-known cannibalistic dragonfly, has been found to be very common. On the
other hand, Onychothemis testacea was
encountered very rarely during the present survey. Members of the family
Coenagrionidae (6 species) were dominating in the
order Zygoptera succeeded by Calopterigidae
(3 species) and Platycnemididae (3 species). Vestalis apicalis
and Prodasineura verticalis
were common but Aciagrion occidentale was observed only sporadically in this
region. Out of the 25 species recorded, five species are endemics and they
belong to the suborder Zygoptera. But Pseudagrion indicum is
endemic to Western Ghats, while Vestalis apicalis is endemic to southern and central India, Libellago indica is
endemic to peninsular India, whereas Dysphaea
ethela and Heliocypha
bisignata are endemic to India (Kalkman et al. 2020). The most dominant endemic species
observed in the present survey was Dysphaea
ethela and Heliocypha
bisignata, which exhibited a minimum level
of occurrence. The percentage distribution of each endemic species is as
follows: Pseudagrion indicum
9%, Vestalis apicalis
26%, Libellago indica
28%, Dysphaea ethela
34%, and Heliocypha bisignata
3%. The first location Ezhattumugham (L1) harboured
as many as 536 individuals in 21 species. Vestalis
apicalis was the most abundant, and endemic
species. Onychothemis testacea
and Zygonyx iris were recorded only
from this location. The highest number of endemics were also recorded from
here. Inspite of the disturbances from tourists, this
location showed a good quantity of native vegetation including emergent
vegetation and shade cover and that perhaps resulted in the collection of a
maximum number of individuals. The second location, Chiklayi
(L2) yielded a maximum observation of 363 individuals of 17 species. Orthetrum sabina was
the common species but Libellago indica was the prevalent endemic of this location. The
habitat is rocky in nature with moderate shade cover and prominent emergent
vegetation. Tourists’ activities are appreciably low and the native vegetation
is limited by oil palm plantation. Maximum value of diversity indices was shown
by location. The third location, Ayyampuzha (L3) was
polluted by the activities of local people and tourists to some extent. But the
oil palm plantation ousted the native vegetation. From this location having
traces of shoreline plants, limited shade cover, boulders and rocks, 284
individuals of 15 species were recorded of which, Trithemis
aurora was dominant with the endemic species Libellago
indica. Vettilappara
(L4) is yet another location having least human interference with appreciable
shade cover and riparian vegetation. But the native riparian vegetation is
narrowed into a thin belt by the plantation crops. Libellago
indica (endemic) and Pseudagrion
rubriceps were the commonly found species during
the study period. A total of 501 individuals belonging to 17 species were
encountered in Vettilappara. Athirappilly
(L5) is slightly polluted by human activities (tourism and nearby construction
works) with minimum shade cover and moderate emergent vegetation. Eighteen
species were recorded during the survey. Orthetrum
sabina and Prodasineura
verticalis were the common species found along
with the frequently encountered endemic damselfly, Libellago
indica. Athirappilly
waterfalls (L6) is another beautiful
location where the tourists activities are significantly high and endowed with
rocky habitat and riparian vegetation. But the presence of macrophytes and
overhanging vegetation is scanty due to tourists disturbances. As a result, the
numerical abundance of species recorded from this location was very less.
However, the endemic dragonflies, Dysphaea ethela and Vestalis
apicalis were the dominating species of this
location.
Effect of flood
During the month of August of the
study period, heavy down pour at Kerala led to a deluge and it badly affected
the study areas. Riparian vegetation was totally destroyed. Natural soil
texture was lost, soil accumulation could be found in river and river banks. As
a consequence, a sudden drop in damselfly diversity was noticed just after the
flood. Only two species of damselflies were recorded in the first two months
after the flood, i.e., September and October 2018. But dragonfly diversity was
not much affected. In the succeeding months the species richness and abundance
were observed to have rebounded.
Simpson & Shannon diversity
indices and evenness values of the six locations were calculated (Table 4).
Maximum species richness and abundance were found at Location 1. Simpson and Shannon diversity indices (0.9197
and 2.628, respectively) were found to be equally high for location 2, while
the least values were shown by Location 6 (0.8694 and 2.191, respectively).
Maximum value of evenness (0.8257) was recorded at Location 3 and a minimum at
Location 1.
DISCUSSION
The current study points out the
role of native riparian vegetation and the impact of human interference such as
habitat alteration by tourism, construction works and plantations on the
density and diversity of odonate fauna. Studies
revealed that riparian vegetation promotes the occurrence of invertebrates
including insects and facilitates suitable habitat for insects by providing
food, resting and hiding places for emergent adults and substratum for egg
laying. Also the shade cover regulates water temperature and overall quality of
the stream (Knight & Bottorff 1981; Ober & Hayes 2008). Moreover, the
prey insects are attracted by flowering plants, which in turn form ideal food
for odonates. Therefore, these conditions become more
pertinent for the carnivorous odonates. The hanging
plants and emergent macrophytes furnish perching sites and structures for egg
laying and emergence of adults. Literature delineates the role of macrophytes
and shoreline structures in oviposition, formation of larval microhabitat,
emergence support and adult perching site (Samways & Steytler
1996; Schindler et al. 2003).
In the present study 15 species
of damselflies and 10 dragonflies were recorded. As the damselflies are weak
fliers, they may depend on their own microhabitat for food and reproduction.
But the agile fliers, dragonflies are free to move to more extensive habitats
according to their preferences. This is a factor of variation in species
richness between the two suborders. The most commonly encountered dragonfly was
Orthetrum sabina,
which predate on other insects and
exhibits cannibalistic behavior too (Iswandaru 2018). Further, adequate quantities of reeds
support the occurrence of damselflies than dragonflies (Fulan
et al. 2008). In the present study, L1, L2, L4 and L5 locations showed the
maximum species richness, abundance and diversity. Despite the human
disturbances, L1 showed the highest value of species richness and abundance.
Presence of comparatively abundant native vegetation including emergent
macrophytes supported the diversity in L1. Moreover, in L2, L3 and L4 sites, the native riparian
vegetation is narrowed by the plantation crops. Vegetation in location L5 was destroyed as a result of
resort construction. Pristine habitat loss results in the loss of odonate diversity (Rodrigues et al. 2016). But the presence
of a modest percentage of riparian vegetation could hold up the diversity in
these locations to some extent. Although L6 is devoid of plantation crops, the
prominent disturbances from tourists have destroyed the emergent macrophytes
and overhanging vegetation. This has led to the least diversity indices on
species richness and abundance in L6. Another observation noticed in the
present study was on the high abundance of endemic species in L1 and minimum
distribution at L6. Dysphaea ethela and Heliocypha
bisignata were reported to be respectively the
common and rarely occurring endemic species.
As per the literature,
undisturbed riparian forests are typically rich with the presence of endemics
(Subramanian et al. 2008). Destruction of riparian flora and fauna could be
attributed to damming, tourists activities, construction works and expanding
the area for agricultural plantations leading to the declined number of
species. For instance, it is evident that the fish fauna of Chalakkudy
river is highly threatened by damming, deforestation and pesticide pollution
(Raghavan et al. 2008). Habitat alteration interferes with the abundance of
endemic odonates and supports the occurrence of
generalist species like libellulids (Kalkman et al. 2008; Subramanian et al. 2008), and that is
evident in the present study. Research work delineates the resilience capacity
of organisms to flood (Death 2008; Golab & Sniegula 2012; Raghavan 2019). Inspite
of the destructive flood during the current study, odonates
showed a tendency to bounce back to pre-flood conditions within a very short
time. Further studies are required to authenticate the same.
Table 1. Odonate
collection localities.
|
|
Sample collection sites |
Latitude |
Longitude |
Altitude (m) |
|
L1 |
Ezhattumugham |
10.295 |
76.451 |
39 |
|
L2 |
Chiklayi |
10.294 |
76.470 |
46 |
|
L3 |
Ayyampuzha |
10.292 |
76.478 |
47 |
|
L4 |
Vettilappara |
10.289 |
76.512 |
64 |
|
L5 |
Athirappilly |
10.285 |
76.558 |
86 |
|
L6 |
Athirappilly waterfalls |
10.284 |
76.569 |
116 |
Table 2. List of dragonflies
recorded from Chalakudy River.
|
|
Scientific name (Family: Libellulidae) |
Abundance |
IUCN status |
|
1 |
Diplacodes trivialis (Rambur, 1842) |
O |
LC |
|
2 |
Neurothemis tullia (Drury, 1773) |
O |
LC |
|
3 |
Onychothemis testacea (Laidlaw, 1902) |
R |
LC |
|
4 |
Orthetrum chrysis (Selys, 1891) |
R |
LC |
|
5 |
Orthetrum pruinosum (Burmeister, 1839) |
R |
LC |
|
6 |
Orthetrum sabina (Drury, 1770) |
VC |
LC |
|
7 |
Pantala flavescens (Fabricius, 1798) |
O |
LC |
|
8 |
Trithemis aurora (Burmeister, 1839) |
VC |
LC |
|
9 |
Trithemis festiva (Rambur, 1842) |
C |
LC |
|
10 |
Zygonyx iris (Selys, 1869) |
R |
LC |
VC—Very common | CO—Common |
OC—Occasional | RA—Rare | EN—Endemic.
Table 3. List of damselflies
recorded from Chalakudy River.
|
|
Scientific name (Suborder: Zygoptera) |
Abundance |
IUCN Red List status |
|
|
Family: Calopterygidae |
|
|
|
1 |
Neurobasis chinensis (Linnaeus, 1758) |
R |
LC |
|
2 |
Vestalis apicalis (Selys, 1873) |
VC & EN |
LC |
|
3 |
Vestalis gracilis (Rambur, 1842) |
C |
LC |
|
|
Family: Chlorocyphidae |
|
|
|
4 |
Libellago indica (Fraser, 1928) |
C & EN |
LC |
|
5 |
Heliocypha bisignata (Hagen in Selys, 1853) |
R & EN |
LC |
|
|
Family: Coenagrionidae |
|
|
|
6 |
Aciagrion occidentale (Laidlaw, 1919) |
R |
LC |
|
7 |
Agriocnemis pieris (Laidlaw, 1919) |
R |
LC |
|
8 |
Agriocnemis pygmaea (Rambur, 1842) |
R |
LC |
|
9 |
Ischnura rubilio (Brauer, 1865) |
R |
LC |
|
10 |
Pseudagrion indicum (Fraser, 1924) |
O & EN |
DD |
|
11 |
Pseudagrion rubriceps (Selys, 1876) |
C |
LC |
|
|
Family: Euphaeidae |
|
|
|
12 |
Dysphaea ethela (Fraser, 1924) |
VC & EN |
LC |
|
|
Family: Platycnemididae |
|
|
|
13 |
Copera marginipes ((Rambur, 1842) |
R |
LC |
|
14 |
Copera vittatta (Selys, 1863) |
R |
LC |
|
15 |
Prodasineura verticalis (Selys, 1860) |
VC |
LC |
Table 4. Community structure of odonates.
|
Parameters/ Indices |
L1 Ezhattumugham |
L2 Chiklayi |
L3 Ayyampuzha |
L4 Vettilappara |
L5 Athirappilly |
L6 Athirappilly waterfall |
|
Species richness |
21 |
17 |
15 |
17 |
18 |
12 |
|
No. of individuals (per 200m unit sample) |
536 |
363 |
284 |
501 |
377 |
125 |
|
Simpson 1-D |
0.8983 |
0.9197 |
0.9091 |
0.9121 |
0.9064 |
0.8694 |
|
Shannon H |
2.518 |
2.628 |
2.517 |
2.561 |
2.545 |
2.191 |
|
Evenness |
0.5907 |
0.8142 |
0.8257 |
0.7617 |
0.7079 |
0.7456 |
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