Lake 2010: Wetlands, Biodiversity and Climate Change

ANALYSIS OF BUTTERFY COMMUNITIES IN RELATION TO THE TREE DENSITY AND CANOPY COVER IN BIO-PARK OF BANGALORE UNIVERSITY, BANGALORE, KARNATAKA,

L. Shashikumar and M.G. Venkatesha* Department of Zoology, Bangalore University, Jnana Bharathi Bangalore – 560056 *Correspondence: [email protected]

ABSTRACT

A study was conducted on the occurrence of various species of in relation to the tree density and canopy cover in Bio-Park, Jnana Bharathi Campus, Bangalore University during 2008-09. The various species of trees in the park attract wide varieties of especially butterflies. Regular surveys were conducted once a fortnight in the park to record various species. Line transect method was used in surveying butterflies as well as for tree density. Canopy closure estimates were obtained from photographic images. The relationship between vegetation structure and butterfly species diversity was analyzed. The total number of 64 species of butterflies belong to eight families were recorded. Seasonal variations in adult populations of butterfly species showed that 43 species in winter were decreased to 38 in summer and further raised to 50 in monsoon. Variations in density of tree species at different plots were found and it was significantly different (P<0.05) from one plot to another. Canopy height ranges from approximately 30 to 40 feet with occasional emergent reaching 45 feet. Among recorded butterfly species, a few butterfly species of Nymphalidae, Lycaenidae, Pieridae, Papilionidae, Danaidae, Satyridae and Hesperiidae were showed high preference to shade and were flying under tree canopy. Results indicate that the butterflies species sampled in closed canopy had more restricted geographical distribution than those found in open area. The species with greater shade preferences has narrower geographical distribution.

INTRODUCTION

Cities constitute a habitat and home for an increasingly large proportion of the world’s population, playing a critical role in maintaining ecological, economic and social well being. Unlike protected forests in distant areas, city parks constitute green spaces managed largely for recreational purposes, and form the largest proportion of publicly available green space for urban dwellers (Oleyar et. al., 2008). Urban parks provide critical habitat for urban flora and fauna (Freestone and Nichols, 2004). Though often very small in area, they tend to be characterized by high levels of diversity with large proportion of exotic species (Khera et. al., 2009) and constitute critical biodiversity hotspots (Goddard et. al., 2010). Despite the importance of these green spaces, they remain little researched in most

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Lake 2010: Wetlands, Biodiversity and Climate Change parts of the world (Clarke et. al., 2008). Bangalore city is the fifth largest city in India and is also known as the garden city because of its many beautiful parks, lakes, gardens and natural vegetations.

The Bio-Park of Bangalore University is the verdant area for various species of insects, especially for butterflies. The various species of trees in the park attract wide varieties of butterflies. The activities of flagship species of butterflies of the Bio-Park of Bangalore University have to be studied in the interest of conservation of biodiversity and environment. Butterflies play a major role in pollination of various flowering plants in the city besides a major component of food chain. The occurrence and diversity of butterflies are considered to be good indicator of the status of any given terrestrial habitat (Kunte, 2000; Raju and Rao, 2002). Like any other species their extinction could narrow the species gene pool considerably (Khatri, 1998). The successful design and implementation of conservation strategies requires information about canopy cover. Canopy cover is an important component of habitat, which is quantified for management and monitoring purposes. No studies are made on butterflies of the Bio- park and thus there was an urgent need to study them in situ. Hence, a study was conducted to analyse the butterfly community in relation to the tree density and canopy cover in Bio-Park of Bangalore University, Bangalore.

MATERIALS AND METHODS Study area Bangalore city, a capital of Karnataka is located in the heart of South Deccan of Peninsular India. The Bangalore region lies between latitudinal parallels 12º 39' -13º 18' N and longitudinal parallels 77º 22' -77º 52' E at an elevation range 839-962m MSL. The city is blessed with pleasant climate with maximum temperature of 33ºC, minimum temperature of 14ºC and humidity ranging from 40 to 95%RH. The climate in Bangalore from March to May is dry and hot, and December to February is cold. It rains intermittently from June to December and the city receives both southwest and northeast monsoon rains. Over 6.52 million people inhabit in about 2191sq.km of the metropolitan area. Jnana Bharathi Campus of Bangalore University located in South West of Bangalore is about 15km from city railway station (Fig.1). It is an isolated serene place with an area of 486 ha. and has a diverse habitats consisting of mixed deciduous and non-deciduous trees, shrubs, scrubs, clumps of bamboos, marshes, checkdams and miniparks. Bangalore University has developed a Bio-Park in the campus in the year 2000 and about two lakhs saplings of different plant species were planted. The flora of the campus has created a successful local interwoven symbiotic relationship with . Mammals, birds and several species of insects are the common agents of kingdom which are found in the Bio-Park. The Bangalore University Bio-Park mainly aims at the conservation of native flora. The Bio-Park would go a long way in further the growth and conservation of the biodiversity.

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Lake 2010: Wetlands, Biodiversity and Climate Change

a b JB campus

N ↑ Scale = 150.000

Figure 1. a. Map of Bangalore showing location of the study site (Courtesy: www.GoogleEarth.com). b. General view of Bio-Park, Jnana Bharathi, Bangalore

Sampling methods Regular surveys were conducted to investigate on butterfly fauna in the study site once a fortnight from January 2008 to December 2009. Observations on the occurrence and seasonal activities of various butterfly species were made using presence – absence scoring method (Bholodia et. al., 2002). The sampling of butterfly fauna and tree density was made using linear transect method (Pollard, 1977; 1982). This method has proved to be reliable in collecting a large set of data for common and widespread species. Moreover, this procedure is quick and easy to use. Intermittent stops were made to resolve identification of butterfly species (Jimenez-valverde et. al., 2006). Wherever butterfly species which could not be identified in the field one or two individuals of such species were collected and preserved, and subsequently identified with the help of reference books (Moore and Swinhoe, 1890 -1907; Wynter-Blyth, 1957; Kunte, 2000; Kehimkar, 2008). Transect counts in the morning between 0700 to 1200hr and afternoon between 1400 and 1700hr were made along the fixed routes in the identified locations. The observations were not made when it rained or when the wind exceeded a gentle breeze.

Butterfly populations in relation to tree density and canopy cover The study was conducted using data collected from six different plots in Bio-Park of Bangalore University. Data on tree density and canopy closure were collected. The relationship between vegetation structure and butterfly species diversity was analyzed. Canopy estimates were obtained from photographic images. Photographs were taken only on overcast days in order to maximize the contrast between sky and leaves. We collected mean canopy closure of six different plots using Digital Canopy Photography (DCP). The DCP measurements of canopy closure estimate relative understorey light conditions (Engelbrecht and Herz, 2001), which is related to forest structure, leaf area index (Cournac et. al., 2002), and possibly primary productivity (Gholz, 1982). We calculated the canopy closure of each plot by transforming all digital images so that they consisted of only pure black (leaves) and pure white (sky) pixels and using the “histogram option” on the

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Lake 2010: Wetlands, Biodiversity and Climate Change software Adobe Photoshop (Adobe Systems Inc.,) to determine the percentage of black pixels (canopy closure) per image (Engelbrecht and Herz, 2001).

RESULT AND DISCUSSION Butterfly fauna During the study period, 64 species of butterflies from eight families were recorded in the Bio-Park. Of which, 18 species belonged to Lycaenidae, 17 species to Nymphalidae, 14 species to Pieridae, Seven species to Papilionidae, four species to Danaidae, two species to Satyridae and one species each to Acraeidae and Hesperiidae. However, 84 species of butterflies are recorded in the Bangalore region (Shashikumar and Venkatesha, 2010).

Relationship between vegetation structure and butterfly species diversity Association between tree species population and butterfly species studied in the Bio-Park is given in Table 1. Variations in diversity of tree species at different plots were found and it was significantly different (P<0.05) from one plot to another. The greatest diversity of canopy trees was found in plot 5 (31.978%) and the least diverse community was found in plot 1 (7.773%) (Table 2). Habitat heterogeneity is often associated with species diversity (Ricklefs, 1977). Canopy closure ranged from 87 to 94%. Canopy height ranges from approximately 30 to 40 feet with occasional emergent reaching 45 feet. Tree height and length of the live crown do not affect the estimates of canopy cover, whereas canopy closure increases as the trees become taller, and as the height to the live base of the crown decreases (Jennings et. al., 1999). Canopy cover has been shown to be a multipurpose ecological indicator, which is useful for distinguishing different plant and animal habitats (Korhonen et. al., 2006).

A total of 471 trees belong to 28 different species were identified in contiguous plots located in Bio-Park of Bangalore University (Table 1). A positive relationship between butterfly species and tree species were found. Out of 64 recorded butterfly species, 31 species (48%) were shade loving butterflies and they preferred canopy. They were positively correlated with canopy closure. Other butterfly species were found flying in open places and at road corners. It is reported that open fields are the suitable habitats for sun loving butterflies (Ruszczyk et. al., 2004). Delias eucharis (Pieridae) and Euploea core (Danaidae) were found flying under the canopy of Ficus bengalensis trees, whereas Elymnias hypermenstra preferred Cocos nucifera for shade (Table 1). The fast fliers especially pierids generally preferred the canopy, whereas slow fliers preferred low stratum. Preference of pierids to fly in high canopy area and that lycaenids in lower strata is attributed to their size and it is reported that in butterflies sustained and vigorous flight is necessary for male mating success (Viswanathan et. al., 2000). Moreover, it is reported that large trees constitute a better habitat for urban species by providing greater shade and more effective cooling (McPherson and Rowntree, 1989; Pauleit, 2003).

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Lake 2010: Wetlands, Biodiversity and Climate Change

Table 1. Association between tree canopy and butterfly species in Bio-Park of Bangalore University

Sl. No. Tree Species No.of Trees Attracted butterfly species 1 Ficus bengalensis 03 Delias eucharis*, Euploea core* 2 Cocos nucifera 09 Elymnias hypermenstra* 3 Mangifera indica 06 Euthalia aconthea* 4 Tamarindus indica 08 Charaxes fabius* 5 Cassia sp. 08 Catopsilia pyranthe*, Catopsilia pomona* 6 Pongamia pinnata 32 Catopsilia pyranthe 7 Santalum album 42 Danaus chrysippus 8 Acacia leucophloe 11 Euploea core, Tirumala septentrionis, Danaus genutia 9 Syzygium sp. 21 Catopsilia pyranthe, Tirumala septentrionis, Kibreeta libythea 10 Grewilia robusta 50 Neptis hylas, Danaus chrysippus, Hypolimnas misippus, Iliades polymnestor 11 Artocarpus sp. 37 Hypolimnas bolina, Mycalesis perseus, Melanitis leda 12 Persia americana 27 Actolepis liliacea, Junonia lemonias 13 Phyllanthus emblica 05 Lycaena omphisa, Chilades laius, Papilio polytes, Pachliopta aristolochiae 14 Aegel marmulosa 17 doson, Pachliopta hector 15 Anacardium occidentale 06 Mycalesis perseus, Melanitis leda 16 Bambusa 12 Elymnias hypermenstra, Neptis hylas 17 Psidium gujava 03 Mycalesis perseus, Melanitis leda 18 Areca catechu 50 Mycalesis perseus, Terias davidsonii 19 calibura 06 Neptis hylas, Jamides boeticus 20 Carica papaya 07 Junonia iphita, Euthalia nais 21 Araucaria sp. 06 Neptis hylas, Leptosia xiphia 22 Spathodea companulata 01 , Catopsilia pyranthe 23 Bauhinia variegata 10 Hypolimnas misippus 24 Polyalthia longifolia 27 Graphium agamemnon, Graphium doson 25 Millingtonia hortensis 13 Pachliopta hector, Acraea violae 26 Samanea saman 31 Hipolimnas misippus, Catopsilia pyranthe 27 Melia azadirachta 19 Euploea core, Tirumala septentrionis 28 Michelia chempaka 04 Elymnias hypermenstra, Graphium agamemnon, Graphium doson * Species prefer trees for shade as well as for food; Rest of the species attracted only to shade

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Lake 2010: Wetlands, Biodiversity and Climate Change

Table 2. Percent of the tree species and canopy closure of the study plots in Bio-Park

Plot No. Tree density (%) Canopy closure (%)

1 7.773 94.500

2 10.777 89.910

3 18.727 89.530 4 19.434 90.760 5 31.978 87.970 6 11.307 93.500

Seasonal occurrence In Bio-Park, during different seasons varying number of butterfly families, genus and species was observed (Figure 2). The number of butterfly species observed in winter was 43 (67.18% of total species) which decreased to 38 (58.37%) in summer, but increased up to 50 (78.12%) species in monsoon. However, 25 species (39.06%) were common throughout the year. Seasonal variations in occurrence of butterfly is obvious due to availability of host plants and suitable temperature and humidity during premonsoon to late winter (Ahir and Parikh, 2006). Weather plays an important role in determining changes in butterfly abundance (Pollard, 1988) and also large variations in abundance between sites have been noted for 31 butterfly species in Neyyar Wildlife Sanctuary, South India (Sreekumar and Balakrishnan, 2001).

50 90

45 80

40 70 35 60 30 50 25 40 20 No./% species 30

no. of Family/Genus 15 20 10

5 10

0 0 Winter Summer Monsoon Common throughout the year

No. of family No. of genus No. of species % species

Figure 2. Seasonal variations of butterfly fauna in Bio-Park during 2008-09 The five butterfly species viz., Danaid Eggfly (Hypominas misippus), Common Pierrot (Castalius rosimon), Common Nawab (Polyura athamas) and Crimson Rose (Pachliopta hector) (Fig. 3) in the park are endangered species and treated under Schedule-I of Wildlife Protection Act, 1972 (Anonymous, 2002).

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Lake 2010: Wetlands, Biodiversity and Climate Change

Hypolimnas misippus Castalius rosiman

Polyura athamas Pachliopta hector

Figure 3. Endangered butterfly species recorded in the Bio-Park CONCLUSIONS The studies indicated that the butterflies species sampled in closed canopy had more restricted geographical distribution than those found in open area. Bio-Park of Bangalore University harbours a modest number of butterfly species. The butterflies are particularly sensitive to climate (Dennis, 1993). Large number of butterfly species observed during monsoon period may be due to suitable temperature, humidity and availability of larval host plants and adult nectar plants. The nature of vegetation, humidity, sunshine, availability of water source etc. are factors that determine the survival of a given species in a particular habitat (Mathew and Rahamathulla, 1993). Hence, by maintaining more trees, nectar and host plants, it is possible to conserve various butterfly species in the Bio-Park of Bangalore University.

RECOMMENDATIONS The present investigation forms part of a larger project on urban biodiversity in Bangalore, encompassing research on biodiversity on city streets and in home gardens as well as in parks, and studies of patterns in urbanization and its impact on ecological networks and ecosystem services in the city. The results of this analysis eventually be disseminated through a freely accessible, spatially explicit database which will be useful for city planners, researchers, educators, students, urban activists and the interested public. Greater attention to be paid to select appropriate trees that supports biodiversity and provides environmental and ecological services. The proper design and conservation practices helps to save the large number of urban butterfly species.

REFERENCES

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Ahir K and Parikh P 2006 Diversity of Butterflies in Gir Protected Area, Gujarat; in Biodiversity and pest management (eds) S J Ignacimuthu and S Jayaraj (Narosa Publishing House: New Delhi) pp 333-339 Anonymous 2002 The Wildlife Protection Act, 1972 (as amended up to 1993) with rules until 1995, Wildlife (Protection) Amendment Act, Government of India (Natraj Publishers: Dehra Dun, 1997) 4th edition available at http://envfor.nic.in Bholodia V J Bhuva and Soni V C 2002 Butterflies of Barda Wildlife Sanctuary. Entomon 27 403-409 Clarke K M Fisher B L LeBuhn G 2008 The influence of urban park characteristics on ant (Hymenoptera, Formicidae) communities. Urban Ecosyst. 11 317-334 Cournac L M A Duboise J Chave and Riera B 2002 Fast determination of light availability and leaf area index in tropical forests. J. Trop. Ecol. 18 295-302 Dennis R L H 1993 Butterflies and Climate change (Manchester University Press:New York) Engelbrecht M J and Herz H M 2001 Evaluation of different methods to estimate understorey light conditions in tropical forests. J. Trop. Ecol. 17 201-224 Freestone R Nichols D 2004 Realising new leisure opportunities for old urban parks: the internal reserve in Australia. Landsc. Urban Plan. 68 109-120 Gholz H L 1982 Environmental limits on aboveground net primary production, leaf area and biomass in vegetation zones of the Pacific Northwest. Ecology 52 651-659 Goddard M A Dougill A J Benton T G 2010 Scaling up from gardens: biodiversity conservation in urban environments. Trends Ecol. Evol. 25 90-98 Jennings S B Brown N D and Sheil D 1999 Assessing forest canopies and understorey illumination: Canopy closures, Canopy cover and other measures. Forestry 72 59-74 Jimenez-Valverde A Mendoza S J Cano J M and Munguira M L 2006 Comparing relative model fit of several species-accumulation functions to local Papilionidae and Hesperiidae butterfly inventories of Mediterranean habitats. Biodiversity Conserv. 15 177-190 Kehimkar I 2008 The book of Indian Butterflies (Bombay Natural History: Mumbai) Khatri T C 1998 On some Butterflies of Little Andaman; Indian J. For. 21 298-303 Khera N Mehta V Sabata B C 2009 Interrelationships of birds and habitat features in urban greenspaces in Delhi, India. Urban for Urban Green 8 187-196 Korhonen L Korhonen K T Rautiainen M and Stenberg P 2006 Estimation of forest canopy cover: a comparison of field measurement techniques. Silva Fenn. 40 577-588 Kunte K 2000 India –A Lifescape: Butterflies of Peninsular India (University Press: Hyderabad) Mathew G and Rahamathulla V K 1993 Studies on the butterflies of the Silent Valley National Park, Kerala, India; Entomon 18 185-192

McPherson E G Rowntree R A 1989 Using structural measures to compare twenty-two U.S. Street tree populations. Lands J. 8 13-23 Moore F and Swinhoe C 1890-1907 Indica (Calcutta) vol. 1 to 10

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Oleyar M D Greve A I Withey J C Bjorn A M 2008 An integrated approach to evaluating urban forest functionality. Urban Ecosyst. 11 289-308 Pauleit S 2003 Urban street tree plantings: identifying the key requirements. Proc. Ins. Civ Eng-Munic Eng. 156 43- 50 Pollard E 1977 A method for assessing changes in the abundance of butterflies. Biol. Conser. 12 115-134 Pollard E 1982 Monitoring butterfly abundance in relation to the management of a nature reserve; Biol. Conser. 24 317-328 Pollard E 1988 Temperature, rainfall and butterfly numbers. J. Appl. Ecol. 25 819-828 Raju A J S and Rao S P 2002 A case study on the decline of butterfly colonies in degraded habitats of Visakhapatnam. Bull. Andh. Uni. Res. Forum 7 57-59 Ricklefs R E 1977 Environmental heterogeneity and plant species diversity: A hypothesis. Am. Nat. 111 376-381 Ruszczyk A, Motta P C, Barros R L and Araujo A M 2004 Ecological correlates of Polyphenism and Gregarious roosting in the Grass Yellow Butterfly Eurema elathea (Pieridae); Braz. J. Biol., 64 151-164 Shashikumar L and Venkatesha M G 2010 Biodiversity of Butterflies of the Bangalore Region, India. Proceedings of international symposium on Biodiversity-Biotechnology: Gateway to discoveries, Sustainable utilization and Wealth creation. Manurung R Zaliha C A Fasihuddin B A and Kuek C (eds), Kuching, Sarawak, Malaysia. Sarawak Biodiversity Centre, Kuching. pp 76-83 Sreekumar P G and Balakrishnan M 2001 Diversity and Habitat Preference of Butterflies in Neyyar Wildlife Sanctuary, South India. Entomon 26 11-22 Viswanathan G Ramanujam P and Singh H 2000 Comparative study of biodiversity of butterflies between Bangalore and Jammu region. Indian J. of Environ. & Ecoplan. 3 599-602 Wynter–Blyth M A 1957 Butterflies of the Indian Region (Bombay Natural History Society: Bombay)

BIO-DATA OF AUTHORS: Dr. M. G. Venkatesha is working as Assoc. Professor in the Department of Zoology. Bangalore University, Bangalore. He is actively involved in teaching as well as research in the field of entomology and biodiversity. His areas of interest are Biodiversity, ecobiology and Insect Pest Management. He is also a Fellow of Royal Entomological Society of London, UK.

Dr. L. Shashikumar is working as Guest Faculty in the Department of Zoology, Bangalore University, Bangalore. He is doing research on Biodiversity and Ecology of Butterfly fauna. He has actively participated in many workshops related to biodiversity aspects. His areas of research interest are biodiversity, ecology and ethology of butterfly fauna.

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