Lesson 01: The Ecological Setting of the Country PDF

LESSON 01 THE ECOLOGICAL SETTING OF THE COUNTRY Topics 1.1 Location of the Country 1.2 Geology 1.3 Climate 1.4 Soil Learning Objectives After reading this lesson you should be able to:  Understand the location of the country and it...

LESSON 01 THE ECOLOGICAL SETTING OF THE COUNTRY Topics 1.1 Location of the Country 1.2 Geology 1.3 Climate 1.4 Soil Learning Objectives After reading this lesson you should be able to:  Understand the location of the country and its significance as a focal point of sea routes,  Its diversity in terms of geology and climate and influence of these conditions on its economic structure and culture. Introduction This lesson examines the influence of the location of the country, its climate and geology on the Sri Lankan society and culture. The strategic location of the country, diversity in terms of geology and climatic conditions have been contributory factors to the extent of foreign influence as well as the demographic, economic and social changes in the country. The country has been historically closely linked to India and three Western Countries while also evolving its own complex hydraulic technology and a great civilisation based on irrigated agriculture. 1 1.1 Location of the country Sri Lanka, formerly known as Ceylon is situated off the very southern tip of India. It has an area of 65525 square Km and lies between latitudes 50 55’ – 9’N and longitudes 790 41 – 810. Sri Lanka separates from India by a very narrow strip of sea, Palk Strait. The country is 224 Km wide from east to west and 432 Km in length from south to north. Culturally and geographically, Sri Lanka belongs to the South Asia region. Throughout its history, Sri Lanka has had close links with South and Southeast Asian countries, but it has developed its own indigenous distinctive culture while maintaining common cross cultural connections with neighbouring countries. The location of the country in the middle of the Indian Ocean has made it a focal sea route for many travellers. Therefore, Sri Lanka has been a major commercial centre in South Asia from the very dawn of its civilisation. Historically it has had links with the ancient Mediterranean civilisations and, during the Mediterranean civilisations and, during the medieval period, Chinese and Arab traders and sailors had frequently visited the country. In brief, even before the discovery of sea routes by western countries, Sri Lanka was a meeting place for eastern and western traders and sailors. With the arrival of the Western colonial rulers in Sri, Sri Lanka became a major trading centre and a more strategic place for colonial expansion. After the opening of the Suez Canal in 1969, Sri Lanka was regarded as a very important location in the middle o the Indian Ocean, mainly because the main sea routes, linking Europe with Australia and the Far East lie across Sri Lanka. The names that prople have used in different times to identify the country reflect the multiplicity of its intercultural relationships with other nationalities and ethnic groups in the world. The Chinese named the island the ‘Land of no Sorrow’; the tamils of South India knew it as the ‘Isle of Gems’; the Arabs gae the name ‘Seren-dib’; the Greeks and the Romans called the island ‘Taprobane’, derived from pali the term ‘Tambapanni’. Until Sri Lanka gained its independence in 1948, the three colonial regimes, the Portuguese, the Dutch, and the British named the island ‘Ceylon’ deriving from the Portuguese ‘Zey-Lan’. The present name ‘Sri Lanka’ means the 2 resplendent island’ in Sinhala. The name Sri Lanka goes back to the country’s more than 2500 years old history, linking it to the days of the legendary demon king Ravana. According to the Mahavansa, the main historical chronicle of the Sinhalese and the Mahabharatha, the main epic of the Hindus, the pre-Vijayan Sri Lanka is said to have been ruled by King Ravana. 1.2 Geology Geologists state that Sri Lanka and India constituted one land mass until recently and that Sri Lanka was separated as an island from the sub-continent during the tertiary period (about 70 million years ago). Some geologists have stated that Sri Lanka was a part of the sub-continent before the tertiary period. The bases for their statement are: location of both India and Sri Lanka in the same continent basin, similarity in the structure of rocks in both countries, similarity in the orientation of mountain ranges and similarity in the kinds of inland fish and the chain of shoals (Adam’s Bridge) between Rameswaram of South India and the island of Mannar. Geologists believe that the island is the southern continuation of the Indian Decan Massif. According to lithographical morphology, Sri Lanka is a great antique place for geological observations. On the basis of the physiography of in country, geologists divide it into four different ages according to the different types of rocks found: (a) Recent and Pleistocene deposits, (b) Miocene rocks, (c) Jurassic rocks, (d) Pre-Cambrian rocks. The Pre-Cambrian age is further divided into two categories: the Vijayan series and the Khonadalite series. The physiological morphology of Sri Lanka provides a fascinating geological diversity. The lowlands are 300 feet in elevation from the sea level. The lowlands as one plane is relatively narrow and it consists of natural harbours, like Trincomalee and Galle, parks, forest reserves and rivers which originate from the central highlands. The central highlands are from 6000-6500 feet in average elevation from the sea level. The highlands are full of valleys, basins, escarpments and peaks, such as Pidurutalagala and Adams Peak. 3 1.3 Climate The Principal climatic factors that affect Sri Lanka because of its centricity in the Indian Ocean are the monsoons. Monsoon means periodic winds. Sri Lanka receives rain mostly from the South-West Monsoon. From the southern high pressure zone winds flow across Sri Lanka to the low pressure Zone of Jammu Kashmir of India bringing in its rain to Sri Lanka from May to September. Although the Western and Southern regions of the island and the Western slope of the central hills receive a great quantity of this rainfall, the Northern and Eastern regions and the Eastern slope of the central hills do not receive much rain and are, therefore, dry. Generally, the climate is luxuriant throughout the country. The heat of the lowlands is kept low by cool sea breezes. Therefore, the mean temperature in the lowlands ranges from 78 f to 85 F with seasonal variations. The central hilly region has a cooler climate than the other region of the country. The minimum temperature in Nuwara eliya from January to April is around 35 F and is the coolest temperature in country. The highest temperature is reported from the North and the northeast during the north of March to June. The relative humidity throughout the island varies on the basis of changing weather patterns. Rainfall becomes the principle criterion in determining the climate of Sri Lanka and it consists of three types – monsoonal, convectional and depressional. The climate year of Sri Lanka can be divided in to the following categories: (a) Convectional convergence period (March to mid April) (b) Pre0Monsoonal period (mid April to late May) (c) Southwest monsoon period (late May to late September) (d) Convectional cyclonic period (late September to late November) (e) Northeast monsoon period (December to February) The Dry Zone receives much of its rainfall from the North-Eastern Monsoon. The wind that blows towards the low pressure southern oceanic region across Sri Lanka 4 brings with it this rain. Rainfall received from November to January during this monsoon is not enough for paddy cultivation. This has resulted in the construction of irrigation systems including tanks or reservoirs, for storing and distribution of water. The foundation of the culture and civilisation of the dry zone comprises these artificial water supply systems. 1.4 Soil The basis for the Sinhala civilisation was formed around areas having fertile soil for paddy cultivation. Since alluvial soil was more suitable for paddy cultivation river valleys were used more for that purpose. Except for the Jaffna Peninsula, the soil in all other parts of the island was good for paddy cultivation and thus emerged the main livelihood of the people and the socio-cultural pattern founded on it. The cultivation system of the Jaffna Peninsula differed from that of other parts of the country mainly because of this soil. It was difficult to cultivate in the limestone soil there without water supply and without using much labour. Until the advent of the war in the North and East, farmers in the Jaffna Peninsular very successfully cultivated onions, chilies, tobacco through evolving a system of drawing on underground water reserves. This particular pattern of economic activity has seen the development of a socio-cultural identity inherent to that area. The social and cultural patterns originating from the two main physical features of Sri Lanka, the central hills and the surrounding plains show marked differences. The settlements of the first settlers or the Aryans originated in the North-Western plains of the island. While they gradually spread to the rest of the country along river valleys they had to construct reservoirs or tanks to store water because the rainfall necessary for their main source of livelihood, paddy cultivation, was insufficient. Irrigation systems and small tanks were constructed to carry water from the large reservoirs to their fields. The existence of these irrigation works makes it clear that at that time there were people not only with the technical knowledge about the construction of reservoirs and canals but also with extensive experience in water management. Engaging in 5 irrigation activities emerged as an important clement in the tasks and duties of the different reigns of kings. The groups of dwellings associated with the paddy fields metamorphosed into villages which became the chief economic and social units of the country. After the arrival of Arahath Mahinda and the introduction of Buddhism to the country the livelihood and religion of the people were entwined with the attendant development of the civilisation. Accordingly, the concept of tank-dagaba-village became an important factor in the formation of a Sinhala ethnic identity. The dry zone which for various reasons was depopulated over hundreds of years, was repopulated only after Sri Lanka gained independence. This was achieved through the farmer-colony schemes implemented by post-independence governments along with the building of artificial water supply schemes and the renovation of irrigation works. Multi-purpose schemes such as the Gal Oya, Uda Walawe and Mahaweli schemes have directly influenced the adaptation of the modern socio-cultural patterns in human settlements. Due to the fertile soil, year-around rain fall, rivers and reservoirs, cultivation has been the principle livelihood of the people of central and Southern Sri Lanka. The main cultivation seasons are known as Yala (from April to August) and Maha (from September to March). Rice is the main crop of Sri Lanka. European vegetables are grown in the highlands while traditional tropical vegetables are grown mainly in the low land and the dry zone. Summary Sri Lanka has been a major trade centre in Sough Asia from the beginning of its civilisation due its strategic location. The geological diversity in terms of low lands, coastal areas, highlands, natural harbours etc. has largely influence the structure of its economy and culture. The tropical climate and variations of rainfall have produced two ecological zones, dry zone and wet zone with distinct economic structures and social organisations. 6