Species diversity and habitat association of butterflies around 30 km radius of Kudankulam Nuclear Power Plant area of Tamil Nadu , India

A detailed study on the butterfly species diversity was carried around 30 km radius of Kudankulam Nuclear Power Plant area, Tirunelveli, India during 2011-2013. The survey yielded 6347 individuals of 64 species, belonging to the families Nymphalidae, Pieridae, Lycaenidae, Papilionidae and Hesperiidae. A total of 64 species of butterflies belonging to 47 genera were recorded. The relative abundance was high for Nymphalidae (27 species) (41.93%) followed by Pieridae 15 (24.19%), Lycaenidae 11 (16.12%), Papilionidae 7 (11.29%) and Hesperiidae 4 (6.45%). The Nymphalidae were found to be the dominant family in terms species, general and individual relative abundance. Eight species of butterflies are listed as endangered in Wildlife (Protection) Act, 1972. Such studies on monitoring the species diversity and abundance of butterflies offer valuable information on their population dynamics. A detailed study on ecologically important local butterfly fauna in various habitats is in progress to construct a various habitat survey around 30 km radius of Kudankulam Nuclear Power Plant area.


INTRODUCTION
Butterflies are taxonomically well studied group of insects, which have received a reasonable amount of attention throughout the world (Ghazoul, 2002;Robbins and Opler, 1997).The impact of human society on the global environment has triggered mass extinction of significant species and is causing widespread changes in the global distribution of existing species (Chapin et al., 2000;Thomas et al., 2004).Insects are the earth's most diverse organisms, accounting for half of described species of living things and three-quarters of all known animals and it is estimated that more species of insects than known at present remain to be discovered (Wijesekara and Wijesinghe, 2003) among insects, butterflies occupy a vital position in ecosystems and their occurrence and diversity are considered as good indicators of the health of terrestrial biota (Kunte, 2000b).Butterflies are one of the best insect studied groups and are highly sensitive to habitat disturbances; they are commonly used as an indicator of environmental quality (Varshney, 1993;Kremen, 1994;Kocher and Williams, 2000;Koh and Sodhi, 2004).Since the 18 th century, about 19,238 species of butterflies have been studied worldwide systematically (Heppner, 1998).In Indian subcontinent, 1504 species of butterflies are recorded (Tiple, 2011) and 285 species found in southern India (Thomas, 1966) of which peninsular India and Western Ghats have 351 and 334 species, respectively.Southern parts of the Indian Peninsular are rich and diverse in butterflies as compared to other parts of Peninsular due to diverse habitats, microclimatic conditions and altitudinal ranges (Chakravarthy et al., 1997).One fifth of the world's total butterflies are available in India (Haribal, 1992).Many researchers have significantly contributed to our understanding of butterfly and abundance in Tamilnadu (Asaithambi, 1994;Baskaran and Eswaran, 2003;Ambrose and Raj, 2005;Eswaran and Promod, 2005;Rajagopal et al., 2011).Human dominated landscape form a substantial and ever increasing amount of the earth's land surface.These modified habitats often negatively influence butterfly species and their dynamics (Gascon et al., 1999) made a detailed study of butterflies of atomic energy campus and recorded a total of 1908 individuals representing 55 species (Ramesh et al., 2010) and seasonal dynamic of butterfly survey yielded 2177 individuals of 56 species (Jahir Hussain et al., 2011).However, comprehensive long-term ecological study to monitor the butterfly diversity of the nuclear power plant area remains serious lacuna.Such studies are imperative to improve the ecological utility of butterflies as indicator taxa.There is a unique relationship between butterflies and plants (Feltwell, 1986).Jha et al (2000) reported that butterflies diversity indirectly reflects overall plant diversity, especially herbs and shrubs in the area.Butterfly species varies in different habitats (Kunte, 1997).Natural vegetation is important for the survival of species and relatively minor perturbation in the habitat that are highly sensitive to change the environment (David et al., 1986).Biotic and abiotic factors influence the butterfly population (Pollard, 1988).
According to WPA, the taxa listed under schedule I have the highest legal protection, Schedule II and IV, second and third highest level of protection (Kunte, 2000b).Eight species of endemic butterflies were listed under the Wildlife (Protection) Act 1972 scheduled under I, II, I and II and IV (Rufus and Sabarinathan, 2007).Studies on butterflies would help to explore their biodiversity and to understand the status of ecosystem and human pressure on natural resource which requires a reliable account of biodiversity (Kremen, 1992).The most important objec-tive of such applied biology is preserving biological diversity for future generation.The aim is to ensure long term conservation of entire flora and fauna of a region (Kerr, 1997;Araujo et al, 2004).The importance of biological diversity is now increasing and is recognized as a vital parameter to assess the global local environmental changes and sustainability.It is impractical to monitor each and every species; some of the key indicator taxa play a vital role in biodiversity monitoring studies.Butterflies are an excellent choice for monitoring the habitat quality (Kunte et al., 1999).Several studies have analysed how radiative substances affect uptake of food chains and ecosystems (Beresford et al., 2012), but ecological impact assessment studies are limited (Moller and Mousseau, 2006).Therefore, the present study, which aimed to contribute to our understanding of the species diversity in different habitats and explore the knowledge of conservation efforts in existing environment, is to be collect and characterized baseline surveys of butterfly fauna in relation to flora in 30 Km radius of Kudankulam Nuclear Power Plant area.

Study area
Field survey of butterflies was conducted from June 2011 to June 2013, following modified Pollard walking methods (Pollard, 1975) in six distinct habitats: pond area, scrub jungle area, cultivated area, plain area or barren land, sandy area and monoculture or cashew nut plantation around 30 km radius of Kudankulam Nuclear Power Plant area which is approximately 1350 km 2 , which lies between latitudes 8° 5 and 8° 28 of north and longitudes 77° 28and 77° 57 of east (Image 1).
Butterfly species density and relative abundance were assessed quantitatively across the different habitats based on the vegetation.The entire study area was divided on the basis of habitats.In this method, permanent approximately 900 m long and 5 m wide line transect was set up in each habitat and marked in the field along with GPS data and landmark for repeated observations.
The transect in each habitat was slowly traversed at a uniform pace for 40 min at each habitat from 7.30 to 16.30 h during the good weather period without heavy rain.Butterfly species were recorded around the radius of five meters from the observer covering his either side, above and front.This was repeated in each season, maintaining the same spatial scale in each of the five habitats.
Collected butterfly individuals were identified either in the field and/or after reaching the laboratory also following the standard field guides (Gunathilagaraj et al., 1998;Kunte, 2000a).All the scientific names followed Varshney (1983) and family classification (Ackery, 1984).The vouchers of collected specimens were photographed and maintained at Manonmaniam Sundaranar University, Sri Paramakalyani Centre of Excellence in Environmental Science, Alwarkurichi.
The main vegetation types of 30 km radius include dry evergreen, scrub jungle, plain area, sandy area and pond area.The

RESULTS AND DISCUSSION
The study revealed the occurrence of 64 species of butterflies around 30 Km radius of Kudankulam Nuclear Power Project area (Table 1).Occurrence of maximum number of species in the family Nymphalidae, Pieridae and Lycaenidae could be due to high availability of food plants in the study area.
A similar pattern of predominance of Nymphalidae was also reported by different researchers.These results are similar to that found by Tiple (2012) and Murugesan et al. (2013) at the biosphere reserve of Seshachelam hills which were a total 50 species of butterflies in five families (Guptha et al., 2012).Ramesh et al. (2010) reported 55 species of butterflies inhabiting the Department of Atomic Energy, at Kalpakkam campus.The family Nymphalidae was the dominant one, followed by Lycaenidae, Pieridae, Papilionidae and Hesperiidae (Guptha et al., 2012).A total of 66 species of butterflies belonging to 47 genera and five families were recorded in Tropical Forest Research Institute, Madhya Pradesh (Tiple, 2012).Murugesan et al. (2013) observed total of 63 butterfly species belonging to 47 genera under the five families in Oussudu bird sanctuary, Puducherry.Shamsudeen and Mathew (2010) found 73 butterfly species in Shenduruny Wildlife Sanctuary.Chandra et al. (2007) observed 174 species, subspecies of 100 genera under 8 families in Madhya Pradesh and Chhattisgarh state.Wijesekara and Wijesinghe (2003) revealed 2158 species of lepidopterans, 234 species of butterflies in ten families recorded in Sri Lanka.Gunathilagaraj et al. (1998) observed that high percentage of Nymphalids may be due to the presence of flowers belonging to families Euphorbiaceae, Compositae, Rubiaceae and Verbinaceae.The great variety of butterflies, moths and skippers are recorded and supported by their food and host plants (Borkar and Komarpant, 2004).Availability of larval and adult food plants, habitat quality appeared to be one of the most important parameters to determine butterfly community (Barlow et al., 2007).Abundance of Kumar and Murugesan 611 butterfly species is due to favourable tropical climate conditions, availability of host plants, food and vegetation (Ravindra et al., 1996); topographic features (Amala et al., 2011); predators, parasitoids and prevalence of disease (Mathew and Rahamathulla, 1993).Chandra et al. (2002) observed 38 species in 8 families in Pench Tiger Reserve, Madhya Pradesh.Around Nagpur, 145 species of butterflies, of which 62 species are new records seen.Nymphalidae showed the highest number of butterflies (Tiple and Khurad, 2009).Nymphalids butterfly feed on fourteen species of angiosperms whereas papilionids feed on eight species.Pieridae have six species of plants as feed, Lycaenidae feed on two species of plants but Hesperiidae prefer only one plant species (Raut and Pendharkar, 2010).The higher species richness of butterflies associated with gardens indicates availability and access to food plants.The exotic species, L. camera is an important nectar source for several species of butterflies in degraded and urbanized habitat (Raju and Reddy, 1995).Nymphalidae was the dominant species and the relative abundance recorded was 36.3% (Ramesh et al., 2010).The least number of butterfly species were recorded in the family Papilionidae (14%) and Hesperiidae (14%) with nine species each (Murugesan et al., 2013) 27) were common, 23% (15) were uncommon and 16% were rare (10) as shown in Figure 1.Guptha et al. (2012) reported that butterflies of Eastern Ghats of Seshachalam biosphere reserves were categorized as very common (VC) 40% (20 species), common (C) 36% (18 species), uncommon (UC) 10% (5 species), occasional (O) 8% (4 species) and rare (R) 6% (3 species).Five species of protected and seven rare species are distributed in Shendurny Wildlife Sanctuary, Kerala (Shamsudeen and Mathew, 2010).Among the 64 species 15 were found very common, 27 species common, 17 species not rare and five species were found rare.None of the species were observed in very rare category from the study area.Six species are under protection of the Indian Wildlife (Protection) Act 1972 (Nimbalkar et al., 2011).Five endemic species were listed from encountered butterflies in the study area in different habitats.The   subcontinent.In the study area, significant number of protected and endemic butterflies species need conservation.Minimizing the anthropogenic disturbances can help to improve the status of habitat specialized butterflies of 30 km radius of KKNPP area as given in Table 3. Conservation of biodiversity covered 99 national parks 513 wildlife sanctuaries, 44 conservation reserves and 4 community reserves (Anonymous, 2008).Borkar and Komarpant (2004) reported that Wildlife Sanctuary of Goa 13 species are scheduled category and 8 are endemic species.
The Southern bird wings are endemic to Indian Subcontinent and Western Ghats and Grass jewel are endemic to Peninsular India.The study is dry evergreen and supports a variety of rare and endemic species, these areas are facing severe anthropogenic disturbances.Kunte (2008) reported that 33 out of 333 butterflies are endemic to Western Ghats; eight species shared the WG and Sri Lanka biodiversity hot spots.Six species of butterflies are under schedule act and there is an urgent need to adapt conservation polices (Guptha et al., 2012).

Conclusion
The surrounding area of KKNPP site is rich in butterfly species, representing many families.The butterfly fauna of the microhabitats are to be protected as per the Wildlife (Protection) Act, 1972.The situation reflects on the availability of diverse habitats as well as microclimatic zones around the project sites.
Any change in the landscape, land use pattern, loss of vegetation in the habitats that are harmful to the butterfly diversity in terms of species richness leads to a potential loss of endemism and endangerment.Butterfly diversity depends upon the floral diversity (among other factors), so conservation of butterflies may possibly be by enhancement of vegetation composition of habitats around the project area.

Image 1 .
Map of 30 km radius of Kudankulam Nuclear Power Project area.dominant species of scrub jungle are Acacia nilotica (Fabaceae), Prosobis juliflora (Fabaceae), Cassia auriculata (Fabaceae) and Lantana camera (Verbenaceae).The plain area has mostly grasses and Euphorbia antiquorum (Euphorbiaceae).The sandy area has Prosobis juliflora and Acacia nilotica.The pond area has Azima tetracantha (Salvadoraceae).The trees, shrubs and herbs comprising members of predominant family belong to Anacardiaceae

Figure 1 .
Figure 1.Status of butterflies recorded in the study area.

Table 1 .
List of butterflies present around 25 km radius of KKNPP Project area.

Table 2 .
Species, general relative abundance (%) of butterflies in the study area.

Table 3 .
List of butterflies with status of endemism.