Ecology, Diversity and Conservation Priorities of Cave Dwelling Fauna in Mandaramnuwara Cave, Nuwara Eliya District

Abstract

Cave biodiversity studies are scarce in Sri Lanka though caves support large number ofspecies. Formation of a cave takes thousands or millions of years. Mandaramnuwara cavewhich is a crystalline limestone cave comprised of beautiful formations of Stalactites. Thecave is located in the wet zone of Sri Lanka where the annual rainfall is between 2000-2500mm. Field studies were carried outfrom September 2012 to September 2013 to assess thediversity of bats, birds, herpatofauna and macroinvertebrates. Acave biodiversity databaseincluding species richness and description on cave fauna was developed to carry out anecological survey that will lead to identify the factors which contribute to cave fauna and toimprove cave fauna conservation.

Throughout the study period transect walks were carried out inside the cave chambers andfauna were recorded in relation to their habitat occupation by direct observation. Randomsamples were taken for identification purposes. Cave environmental conditions such as lightintensity, temperature, humidity and pH of dripping waterwere recorded. The inner space ofthe cave has been separated into three large chambers. The entrance zone was mainlyoccupied by Pseudophilautus macropus. Breeding colony consisting of 34 nests ofAerodramus unicolor was observed in the twilight zone. Endemic snail Ravana politissimacolony was observed inside the dark zone. Cave crickets were the most abundant arthropod.Most abundant vertebrate species were Rhinolopus rouxii and Miniopterus schreibersii.

Microchiropterans and the Indian swiftlet species prey upon insects contributing to the forestinsect population control. The recorded pH of the water inside the cave was 4.6. Humiditywas 84.3%. The average temperature was 19.6 °C. The information provided by the cavebiodiversity data base can be used as baseline information for cave fauna conservation andmanagement, cave eco-tourism and further investigations of cave habitats.