Species composition, habitat preference and relative occurrence of Chiroptera populations in South Gujarat with comparison of two major biomes
Species composition, habitat preference and relative occurrence of Chiroptera populations in South Gujarat with comparison of two major biomes. Ecological investigations were carried out on species composition, habitat preference, relative percent occurrence and interrelationship of bat populations with insects and fruit crops in South Gujarat. 286 bats were collected from several localities in eight districts and later grouped under three mam habitats of their occurrence: rocky, forest and human settlement habitat. The insect fauna in a particular habitat was evaluated by trapping and examination of stomach contents of captured bats. 13 species of bats (3 fruit eating, 10 insectivorous) belonging to two suborders and six families were collected in varied relative percentage. Vespertiliomdae among families and Rhinopoma microphyllum kinnean and Pipistrellus dormeri among species were predominant groups in South Gujarat. Cynopterus sphinx and Taphozous melanopogon roosted exclusively in the forest habitat, while Rhinopo- ma. hardwickei and Hipposideros speons were found only in rocky habitat. Four species, Ronsettus leschenaulti (a fruit eating bat), Taphozous kachhensis, T. longimanus and Pipistrel- lus dormeri were found in all three main habitats. The remaining five species occurred in various combinations of two habitats in varying relative densities. There was a direct relationship between diversification and composition of insect fauna and bat species composi- tion in all three main habitats. Distribution of fruit tree plants determined distribution of three fruit bat species. A comparison was made between northern districts' biome (low rainfall, greater temperature fluctuations, lesser wind speed and dry deciduous forest) and southern districts' biome (high rainfall, deciduous forest) both separated by two rivers. Both biomes shared ten species. However, R. hardwickei, P. mimus and H. speoris occurred exclusively in the northern while C. sphinx, Megaderma lyra and T. melanopogon were found only in the southern biome of South Gujarat. Relative percent occurrence of Pteropus giganteus, R. leschenaulti, R. m. kinnean, T, kachhensis and Scotophilus heathi reduced, whereas that of 7". longimanus and P. dormeri increased from north to south. This distribution pattern of bats has been discussed in the light of morphological, ecological and behavioural adaptations.