Habitat and Altitude Preferences of Butterflies in Aralam Wildlife Sanctuary, Kerala
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SREEKUMAR AND BALAKRISHNAN 277 Tropical Ecology 42(2): 277-281, 2001 ISSN 0564-3295 © International Society for Tropical Ecology Habitat and altitude preferences of butterflies in Aralam Wildlife Sanctuary, Kerala P.G. SREEKUMAR & M. BALAKRISHNAN1 Department of Zoology, University of Kerala, Kariavattom 695 581, Thiruvananthapuram, Kerala, India; [email protected] Key words: Aralam Wildlife Sanctuary, butterflies, elevation gradient, habitat preference, mud puddling Butterflies are essential part of any natural Kannur District. The Brahmagiri Wildlife Sanc- ecosystem as their adults perform pollination tuary of Karnataka State, reserve forests of Wy- and larvae enact as primary herbivores thereby anad and Central State Farm, Aralam adjoin the transferring radiant energy trapped by plants to sanctuary on the northern, eastern and the west- the next trophic level; rendering dual roles as ern borders (Fig. 1). More than 90% of the sanctu- pollinators and as energy transferors. The ary is mountainous, with altitude varying from 50 holometabolus life history of butterflies exposes m at the foot hills to about 1145 m a.s.l. them to a wide range of environmental influ- Climatic conditions in Aralam are typical of ences. They are highly sensitive to changes in south Indian forest areas. Temperature varies temperature, humidity and light; parameters from 11o to 40oC. The hottest months are April that are easily influenced by habitat deteriora- and May. The period from December to February tion (Murphy et al. 1990). Therefore, butterflies is comparatively cool. The maximum rainfall are good indicator species to monitor ecological (south-west monsoon) is received during the changes in a habitat. months of June to August. Average annual rain- Among insects, butterflies are the most studied fall is around 3,000 mm as recorded at the mete- group. Larsen (1987a,b,c, 1988) made a detailed orological station of the Aralam State Farm. survey of butterflies of Nilgiri mountains and re- The natural vegetation comprises of west coast corded nearly 300 species including endemics. In tropical evergreen and semi-evergreen types. Ever- Kerala, butterflies of Silent Valley National Park green forests are seen at the higher reaches of the (Mathew & Rahamathulla 1993) and Parambiku- sanctuary. Palaquium ellipticum Engl., Mesua fer- lam Wildlife Sanctuary (Sudeendrakumar et al. rea L., Machilus macrantha Nees., Calophyllum 2000) have been carried out. The present paper elatum Bedd., Artocarpus hirsuta Lam. and Dip- deals with the occurrence and diversity of butterfly terocarpus indicus Bedd. are the major floral ele- populations in different altitude levels in a tropical ments in this type. Common trees of semi- rain forest ecosystem of Aralam Wildlife Sanctuary evergreen forest are Xylia xylocarpa Taub., Vitex in Kerala, South India. altissima L., Eugenia sp. and Terminalia spp., Aralam Wildlife Sanctuary (11o50′ - 11o52′ N though Hopea parviflora Bedd. and Dipterocarpus and 75o57′ - 75o59′ E), the northern most conserva- indicus Bedd. occur frequently. Monocultures of tion area in Kerala, has an area of 55 km2. This teak and Eucalyptus occur in 488.7 ha in this sanc- Sanctuary lies in Aralam and Kottiyoor villages of tuary. 1Corresponding Author 278 BUTTERFLIES IN ARALAM WILDLIFE SANCTUARY Fig. 1. Map of Aralam Wildlife Sanctuary showing transects of the present study. Six transects, each of 600 m long and 10 m number of sample units in which the species ob- width marked at varying altitudes (see Fig. 1), served) was computed for each elevation gradient viz. low elevation (<250 m), middle elevation to find out the most dominant species in each zone (251-700 m) and high elevation (>700 m). There and for the whole study area (Trivedy et al. 1987). were two transects in each altitude zone. Obser- Biodiversity index was computed using a statisti- vations were carried out in the morning between cal program SPDIVERSE. BAS. 08.00-11.00 h during August-December, 1995. Seventy one species of butterflies were re- Each transect was monitored 10 times. Butter- corded during the current investigation in Aralam flies observed in each habitat were individually Wildlife Sanctuary. Nearly 97% of them were rep- recorded. Unfamiliar species were collected for resentatives of the Oriental region while few spe- identification. To find out habitat preferences, cies such as Leptosia nina and Catopsilia sp. were the nearby agricultural area owned by the Cen- African forms. The family Nymphalidae had tral State Farm was also monitored. Species ob- maximum number of species (Fig. 2). served outside the transects and forest edges Eight species such as Papilio helenus, P. were noted separately. budha, Idea malabarica, Melanitis phedima, My- Butterflies observed along the transects alone calesis anaxias, Cyrestis thyodamas, Kallima, were considered for statistical analyses. Data philarchus and Matapa aria were habitat specific were analysed using a statistical package SYS- being restricted to evergreen forests and bamboo TAT. Variation in abundance of butterflies in thickets only, while 24 species were seen in ever- three altitude zones and differences in abundance green, semi-evergreen and in plantations. Nine among butterfly species irrespective of considering species were located in evergreen and semi- altitude were computed by ANOVA. For data evergreen forests, and the rest were in plantations analysis, number of transects selected in each alti- and in open forests. Species such as Idea mala- tude zone was considered as a replication. Species barica, Papilio budha, Cyrestis thyodamas, My- abundance (the ratio between total number of in- calesis anaxias and Kallima philarchus were fre- dividuals of a species in all study plots and total quent in undisturbed evergreen forests. Papilio SREEKUMAR AND BALAKRISHNAN 279 54, P<0.001). Similarly, the abundance of individ- ual butterfly species between transects of different altitudes were significant (F = 53.13, df = 2, P<0.001). Again, the interaction between parame- ters such as altitude and number of species was also highly significant (F = 2.42, df = 108, P<0.001). Shannon index also vary between tran- sects with maximum in the middle zone (H′ = 3.75), followed by low zone (H′ = 3.62) and mini- mum in high zone (H′ = 2.94). Among the identified butterflies, Eurema he- cabe was the most abundant species in all the three altitude gradients with a cumulative index value of 5.5. Abundant species recorded at differ- ent elevation gradients are shown in Fig. 3. Fig. 2. Dominant butterfly families observed during the Being one of the biodiversity hot spots, the present study. Western Ghats harbour nearly 331 species of but- terflies in its diverse habitats of varying climatic budha, and Papilio helenus were occasionally conditions. Larsen (1987a,b,c, 1988) reported 299 found in plantations and in open places. species of butterflies including several rare and Species such as Eurema hecabe, Catopsilia sp., endemics from the Nilgiri region. Mathew & Ra- Pachliopta aristolochiae, P. hector, Precis iphita, hamathulla (1993) recorded the presence of 100 Junonia atlites, J. orithyia, J. lemonias, Vanessa species of butterflies in Silent Valley National cardui, Polyura athamas, Euploea core, Acraea Park. Wynter-Blyth (1957) reported that March- terpsicore and Celaenorrhinus ambareesa were April and October were the two peak seasons for common either at the edges or in open plains Indian butterflies. Kunte (1997) reported that showing the light loving proclivity. butterflies in all habitats showed a highly seasonal Mud puddling was common during the sunny trend but, there was no evidence of peak in sum- hours in post-monsoon months. Both mixed and occasionally single species assemblages were formed at wet soil patches. Several species such as Graphium sarpedon, Eurema hecabe, Catopsilia sp., Polyura athamas, Pathysa antipathes, Euploea core, Caleta caleta and Graphium doson were pre- sent in mixed puddling group. But on most of the occasions, the yellows (pierids) dominated the as- semblages. Nine endemics, namely Troides minos, Pach- liopta hector, Idea malabarica, Mycalesis patnia, Cirrochroa thais, Celaenorrhinus ambareesa, Papilio polymnestor, P. budha and Acraea terpsi- core were recorded from Aralam Wildlife Sanctu- ary. Among the recorded butterflies, 21 species were common to all elevation gradients, 45 oc- curred only in low to medium altitude areas, three Fig. 3. Abundant butterflies in different elevation gradi- preferred medium and high elevations (Hypolim- ents. (a) Troides minos; (b) Eurema hecabe; (c) Caleta nas bolina, Papilio helenus and P. budha) and two caleta; (d) Jamides celeno; (e) Junonia orithyia; (f) Yp- (Kallima philarchus and Cyrestis thyodamas) pre- thima huebneri; (g) Euploea core; (h) Catopsilia sp.; (i) ferred only high elevation areas. Significant dif- Papilio demoleus; (j) Pachliopta hector; (k) Graphium ference was observed in abundance among butter- sarpedon; (l) Papilio polymnestor; (m) Leptosia nina; (n) fly species irrespective of transects (F = 7.29, df = Idea malabarica; (o) Kallima philarchus. 280 BUTTERFLIES IN ARALAM WILDLIFE SANCTUARY mer in his study site in Pune, northern Western them to fulfill their salt and protein deficiency Ghats. (Beck et al. 1999). Habitat specificity of butterflies can be directly Like amphibians, butterflies are also sensitive related to the availability of food plants (Thomas to changes in their environment and hence re- 1995). Each habitat has a specific set of micro