Recreating pre historic environment based on the spread of land snails and fresh water snails

Abstract

Sri Lanka has been positioned as a small island in right direction in the Indian subcontinent. There are three major climatic and environmental zones in Sri Lanka including wet zone, dry zone and intermediate zone. Remains of snails found from the pre historic excavations and remains of presently living snails are supportive to identify the climatic differences occurred in more than thousands years ago. Research question of this study are to identify what were the eco system and climatic conditions appeared in ancient Sri Lanka (35000 years before present) and to examine the possibility of recreation of the ancient environment through the excavated remains of the snails. Objective of the study is to identify that how was the basic structure of the ancient environment prevailed in the island in ancient times.Major research method of the study is field observation and the data were collected from the primary sources including field observations carried out at the pre historic sites such as Pahiyangala, Batadombalena and Pothana. Previous researches were also referred as the secondary sources during the research. Remains of land snails were used as the main environmental factors to recreate the ancient environment consisted in ancient Sri Lanka. These snails had been adopted according to the various vegetation types of the Island. It is reported that 253 of land snails species and 94 of fresh water snail species have been found in Sri Lanka. Among them 05 of land snails are endemic to the island. Habitation of the land snails and fresh water snails can be found in the various vegetation types such as low land rain forest, sub Montana / Montana rain forest, dry monsoon forest and cultivated habitats.It has been identified that the snails have been survived at the pre historic cave sites (Fa-hian Cave, Batadomba Cave and Belilena Cave) and open areas 43,000 before present.Living patterns or habitats of these snails are different according to the climatic zones. It is possible to recreate the prehistoric environment through the usage of bio indicator species which are relative to the snail species found in currently. As most of the evidences of the snail remains are recorded from the wet micro habitats, it can be identified that the environmental and climatic condition of the country had not been changed severely. Some of the snail species examined during the research are cyclophorus (land snails), plandomus (fresh water snails) etc.