Butterfly diversity of Western Ghats, India

BUTTERFLY DIVERSITY OF WESTERN GHATS GRASSLANDS OF KERALA – A CASE STUDY IN VAGAMON 01 13 Brilliant Rajan, Vincy Mary Varghese, Toms Augustine Babu Padmakumar and PradeepKumarA. P. First Indian Biodiversity Congress 2010 : Book of Abstracts School of Environmental Sciences, Mahatma Gandhi University, Kottayam The Western Ghats, also known as the Sahyadri Mountains is one of the world’s ten “hottest biodiversity hotspots”. The Western Ghats boasts exceptional endemism for many taxonomic groups, including plants (35%), fishes (42%), reptiles (48%) and amphibians (75%). The habitat types of the southern Western Ghats include the wet montane evergreen forests and shola-grassland complexes at elevations over 1000 meters. The South Western Ghats montane rain forests are the most species-rich ecoregion in peninsular India; eighty percent of the flowering plant species of the entire Western Ghats range are found in this ecoregion. It also holds a very rich butterfly fauna with a number of endemics (Gaonkar, 1996). Butterflies are widely considered as good ecological indicators in terms of anthropogenic disturbance and habitat quality and important ‘flagship taxa’ in biodiversity inventories. Vagamon (9 0 34’ N and 760 58’ E) is a hill station in Kerala, located on the western fringes of Idukki district, bordering with Kottayam district. It falls within the Western Ghats, lies 1100 metres above MSL and is rich in endemic flora and fauna. This area, unique for grasslands and shola forests with laterite soil type has an extent of 27.19 sq. km. However the threats to this ecoregion’s natural habitats and biodiversity are manifold. Recent introduction of tourism development activities has resulted in deterioration of the environmental quality of these hills. The wetlands and sholas are being drained, cleared and filled at an alarming pace. Extensive developmental activities like road construction in the grass lands undermined the stability of hill slopes and cause hazards like landslides. The present study is intended to reveal the current status of butterfly fauna in the hill areas of Vagamon. The methodology consists of observation of butterflies in selected transects along different types of habitats such as sholas, grass lands, croplands and streams. Butterfly species were identified directly in the field or, in difficult cases, following capture or photography. Collection was restricted to those specimens that could not be identified directly and released them after identification. Nomenclature and systematics followed are after Gaonkar (1996). A total of 112 species of butterflies belonging to five families were recorded during the study period. The family Nymphalidae dominated with 44 species followed by Lycaenidae (24), Hesperiidae (19),Papilionidae (13) and Pieridae (12). This included four species endemic to the Western Ghats. They are Troides minos Cramer (Southern Birdwing), Pachliopta pandiyana Moore (Malabar Rose), Parantica nilgiriensis Moore (Nilgiri Tiger) and Aeromachus pygmaeus Fabricius (Pygmy Grass Hopper). The butterflies observed were segregated into categories such as Common (C), Uncommon (UC) and Rare (R) based on their occurrence during the survey. Catopsilia Pomona (Common Emigrant), Ypthima huebneri (Common Four-ring) and Tirumala limniace (Blue Tiger) were the common species found in the study area. 22