Thursday, November 29, 2007
Butterflies of Sri Lanka
244 species of butterflies occur in Sri Lanka, of which about 20 are endemics. Their habitats range from the hottest areas in the arid zones to the coolest areas in the forested hills. Some butterflies can be seen all year round while others are seasonal. In size, they range from the large, aptly named Bird-wing butterfly to the tiny, just as aptly named, Grass Jewel.
The highest number of species of butterflies occur in the foothills up to 3000 feet elevation. About half a dozen species occur above 4000 feet. Twenty species are strictly confined to the dry zone below 500 feet. There are two major seasons in which the butterfly numbers peak. These correspond to the onset of the south-west monsoon in March-April and the north-east monsoon in September-October.
The eleven families found in Sri Lanka are Danaidae, Satyridae, Amathusiidae, Nymphalidae, Acraeidea, Libytheidae, Riodinidae, Lycaenidae, Pieridae, Papilionidae and Hesperiidae.
The eleven families found in Sri Lanka are Danaidae, Satyridae, Amathusiidae, Nymphalidae, Acraeidea, Libytheidae, Riodinidae, Lycaenidae, Pieridae, Papilionidae and Hesperiidae.
Tuesday, November 27, 2007
Distribution of Tropical Rain Forests in Africa and Asia.
Around 150 to 200 years ago, tropical rain forests stretched as an unbroken green belt over the humid tropics, in three main blocks in the. Amazonian, African and Far-Eastern regions. Today they are greatly reduced and are in a fragmented state. The rain forests of Sri Lanka belong to the Far-Eastern group which includes the rain forests of South and South-East Asia. The centre of this block is the Malayan Archipelago stretching eastward to New Guinea. Although, the rain forests of south-west Sri Lanka share many features common to this group, they also contain elements that are peculiar to themselves alone.The origin of Sri Lankan rain forests . and their unique species composition i.e. a large proportion of endemics, have been explained in relation to the island's geological history. During the Paleozoic era. Sri Lanka was part of the Southern super continent or Gondwanaland. About 140 million years ago this continent began to break up and 55 million years ago, during the mid - Cretaceous period, the fragment known as the Deccan Plate which comprised India and Sri Lanka drifted off towards the equator to collide with the Northern continent of Laurasia. Under equatorial climatic conditions, a tropical community was established on the Dec-can Plate. These conditions however did not remain stable, for continuous fluctuations of climate and sea level in the tropics occurred during the Glacial and Inter-glacial periods. With the submersion of the land connection with the Indian subcontinent 20 million years ago, Sri Lanka separated out as an island. Since then, temporary land connections with the subcontinent have been formed from time to time. The Glacial periods have resulted in alternating climatic conditions of ever-wet and seasonally dry, cool weather prevailing on the island. .As these occurred, rain forests expanded over to the mainland and contracted back into the ever-wet pockets we have today.The rain forest species presently found in Sri Lanka therefore have affinities to Gondwanic flora and fauna as well as to those of the Deccan Plate. While some elements may have been maintained without change, others have evolved into new plants and animals. From a biogeographic point of view therefore the species found in the rain forests of Sri Lanka are of extraordinary interest, a fact which has still not been widely recognized. Together with the rain forests of the Mascarene Islands (Rodriguez, Reunion and Mauritius), East Madagascar, the Seychelles, and the Andamans, the rain forests of Sri Lanka represent* the few surviving links between the rain forests of one major block, (the African) and another (South-East Asian).
Rain Forest of Sri Lanka
Introduction
The legendary Sinharaja forest covers the steep hills and valleys of Rakwana in the south-western lowlands of Sri Lanka. It is the island's largest expanse of lowland rain forest and the only sizeable, undisturbed remnant. All that remains in the rest of the wet lowlands are the familiar, mist-laden forest patches scattered on hilltops and ridge crests, a mere shadow of the magnificent forests which once covered the entire southwestern sector of the country. Rain forests are the natural vegetation type of the island's ever-wet south-western cjuarter. which covers an area of around 22.500 square kilometres. These forests comprise both lowland rain forests of the hot humid lowlands below 1,000 metres in elevation, and the lower and upper montane rain forests of the cooler mountains, that occur between 1,000 and 2500 metres in elevation.
Climetic Conditions
Rain forests occur under equatorial conditions of constant temperature, high rainMl thai is well distributed the whole year round and suitable soil conditions. In Sri Lanka, the south-western region receives an annual rainMl between 2,500 and 5.000 millimetres and is devoid of a dry period The main sources of rain are the two monsoons that blow over the island, the south-west from May to Jury, and the north-east from November to January. It is the former however that brings the greatest amount of moisture. This wind is intercepted by the central hills of the island, resulting in precipitation on the hill slopes and lowlands of the south-western region.There is little variation in temperature, that of the lowlands being 27 °C to 30 °C while in the upper montane regions at round 1,800 metres in elevation, the temperature can drop to 16°C or 17°C.
The Importance of Rain Forests
The value of these forests is multifold. Of primary importance are the protective benefits they offer as watersheds and ameliorators of climate. The multi-storeyed vegetation of the forest, its leaf litter, root mat and humus-rich, porous top soil all help to trap moisture which accumulates and is then gradually released into rivulets and streams. Rain forests thus help to sustain perennial sources of water such as the major rivers. These forests also make the climate more equitable, the physiological functioning of individual plants helping to moderate temperature, humidity and the level of carbon dioxide in the atmosphere.Man has long recognised that the major benefit of the rain forest is as a source of timber. However continuous and rapid exploitation is fast reducing the available -timber potential of these forests. In Sri Lanka, most of the rain forests were depleted of select hardwoods such as calamander and ebony at the turn of the century. Today the depletion still continues in the lowland rain forests, where a range of light hard woods are being felled to support the plywood industry.
These forests make an important contribution to the national economy. In addition, they are also important to those people who live in, and along their fringes. These people are dependent on the forest for most of their basic needs of food, shelter and medicine. The forest to them is not merely a source of wood for fuel and timber but also a store-house of a host of useful products such as rattan, food, medicine and spices.One value of rain forests often ignored is their recreational value. Forests provide opportunities for human relaxation in surroundings that are peaceful, healthy and above all, beautiful.The protective and commercial value of forests is generally recognised by most people today. However, it is only the scientists perhaps who are aware of the biological importance of rain forests. In Sri Lanka, the rain forest ecosystem is the richest reservoir of flora and fauna of all ecosystems in the country. Furthermore, a high percentage of the plants and animals found in the rain forests are endemic to Sri Lanka and found nowhere else in the world. Of the 25 genera and 830 species of plants that are'endemic to Sri Lanka, i.e. 24% of the island's total flora, as much as 60% is found in the lowland rain forest, and of this 40% appears to be exclusively confined to it.The forests are therefore reservoirs of genetic materials or 'gene pools' and contain a wide variety of plants and animals which are directly or indirectly of use to man. Yet, many are underutilized, and a large majority are as yet unscreened and may perhaps become important in the future. These wild species can be used to breed new strains or improve existing strains of domesticated plants and animals that are of use to man. Many species such as rattan, wild cardamom and medicinal plants such as "went wel" are of commercial importance but are collected solely from the wild and therefore have great potential for domestication and genetic improvement' The fact that the Sri Lankan rain forests contain a high proportion of endemics makes them all the more valuable.The rich complexity of undisturbed rain forests also serves to illustrate the full potential of the land. The rain forest in an undisturbed state is a highly efficient biological system in which individual components are structurally and functionally arranged to maximise the use of the land. If fully understood therefore, these forests can serve as a yardstick for measuring the efficiency of man-made systems such as plantations, agro-forestry systems and agricultural farms. Although they have been unquestionably recognised as the most complex of all ecosystems, the interactions between their physical and biological components are little understood. Thus there is enormous potential for research and education in the rain forest. Much remains to be discovered of the origin, evolution and functioning of these forests. Fortunately, today the rain forest has become the focus of increased scientific speculation, and therefore, there is hope that it will be preserved for future generations.
The value of these forests is multifold. Of primary importance are the protective benefits they offer as watersheds and ameliorators of climate. The multi-storeyed vegetation of the forest, its leaf litter, root mat and humus-rich, porous top soil all help to trap moisture which accumulates and is then gradually released into rivulets and streams. Rain forests thus help to sustain perennial sources of water such as the major rivers. These forests also make the climate more equitable, the physiological functioning of individual plants helping to moderate temperature, humidity and the level of carbon dioxide in the atmosphere.Man has long recognised that the major benefit of the rain forest is as a source of timber. However continuous and rapid exploitation is fast reducing the available -timber potential of these forests. In Sri Lanka, most of the rain forests were depleted of select hardwoods such as calamander and ebony at the turn of the century. Today the depletion still continues in the lowland rain forests, where a range of light hard woods are being felled to support the plywood industry.
These forests make an important contribution to the national economy. In addition, they are also important to those people who live in, and along their fringes. These people are dependent on the forest for most of their basic needs of food, shelter and medicine. The forest to them is not merely a source of wood for fuel and timber but also a store-house of a host of useful products such as rattan, food, medicine and spices.One value of rain forests often ignored is their recreational value. Forests provide opportunities for human relaxation in surroundings that are peaceful, healthy and above all, beautiful.The protective and commercial value of forests is generally recognised by most people today. However, it is only the scientists perhaps who are aware of the biological importance of rain forests. In Sri Lanka, the rain forest ecosystem is the richest reservoir of flora and fauna of all ecosystems in the country. Furthermore, a high percentage of the plants and animals found in the rain forests are endemic to Sri Lanka and found nowhere else in the world. Of the 25 genera and 830 species of plants that are'endemic to Sri Lanka, i.e. 24% of the island's total flora, as much as 60% is found in the lowland rain forest, and of this 40% appears to be exclusively confined to it.The forests are therefore reservoirs of genetic materials or 'gene pools' and contain a wide variety of plants and animals which are directly or indirectly of use to man. Yet, many are underutilized, and a large majority are as yet unscreened and may perhaps become important in the future. These wild species can be used to breed new strains or improve existing strains of domesticated plants and animals that are of use to man. Many species such as rattan, wild cardamom and medicinal plants such as "went wel" are of commercial importance but are collected solely from the wild and therefore have great potential for domestication and genetic improvement' The fact that the Sri Lankan rain forests contain a high proportion of endemics makes them all the more valuable.The rich complexity of undisturbed rain forests also serves to illustrate the full potential of the land. The rain forest in an undisturbed state is a highly efficient biological system in which individual components are structurally and functionally arranged to maximise the use of the land. If fully understood therefore, these forests can serve as a yardstick for measuring the efficiency of man-made systems such as plantations, agro-forestry systems and agricultural farms. Although they have been unquestionably recognised as the most complex of all ecosystems, the interactions between their physical and biological components are little understood. Thus there is enormous potential for research and education in the rain forest. Much remains to be discovered of the origin, evolution and functioning of these forests. Fortunately, today the rain forest has become the focus of increased scientific speculation, and therefore, there is hope that it will be preserved for future generations.
THE REAL NATURE OF LANKA
The legendary Sinharaja World Heritage Site is the last remaining extensive primary Lowland Tropical Rainforest in Sri Lanka. It covers an area of about 11,187 ha, spread over an elevation range of 200-1150m above sea level. Sinharaja is located in the Southwest Lowland Wet Zone of the island, between latitudes 6°21'- 6°26'N, and longitudes 80°21'- 80°34'E. It lies between the tributaries of the Kalu Ganga (in the North) and the Gin Ganga (in the South) and extends over the administrative districts of Galle, Matara and Ratnapura, within the Southern and Sabaragamuwa Provinces. In general, the area consists of a rolling terrain with a series of ridges and valleys, whilst some parts of the eastern section of the forest consist of flat plains. About nine prominent peaks ranging from 575m to 1,170m are located within the forest, of which the Northeastern peak of Hinipitigala is the highest.
The mean annual rainfall in Sinharaja varies between 3,600 - 5,000 mm without a dry spell, and the mean annual temperature ranges between 19°C and 27°C. The Sinharaja forest is one of the most important watersheds on the island, with several streams draining into the 'Kalu Ganga' and 'Gin Ganga'rivers.
The Sinharaja forest is rich in biodiversity and contributes greatly towards Sri Lanka being recognized as one of the world's biodiversity 'hot spots', as identified by Conservation International. The vegetation of Sinharaja consists mainly of primary and secondary Tropical Lowland Wet Evergreen forest, with a few patches of Lower-Montane forests and grasslands in the higher altitudes. This diverse vegetation provides shelter to a rich composition of fauna, including a variety of vertebrate animals and countless numbers of lesser-known invertebrate animals. The vertebrate animals documented so far from Sinharaja represents about 50% of the native inland vertebrate animals, of which 35% are endemic to Sri Lanka, whilst about 35% are considered Nationally Threatened. The landscape in the periphery of Sinharaja shows marked human influence as it consists of tea and rubber plantations, rice fields, cinnamon cultivations and homesteads. About 40 villages are located around the forest reserve, and since historical times most villagers have been dependent on a variety of forest products for their daily subsistence. Between 1971 and 1977 the Western part of Sinharaja was subject to selective logging, where timber species were extracted for the production of plywood. Continuous protests from nature conservationists against the logging operations, resulted in a complete ban on logging in this forest in 1978, and an area of 8500 ha was declared an International Man and Biosphere (MAB) Reserve. In 1985 the Forest Department established a live boundary for the MAB reserve by planting Finns trees. An additional 2,687 ha of Sub-Montane Forest located on the Eastern side was included in the Sinharaja Reserve, expanding the total area to 11,187 ha. This entire area was declared a National Heritage Wilderness Area in 1988 and subsequently, UNESCO recognized it as the first Natural World Heritage Site in Sri Lanka. The administration and management of the Sinharaja World Heritage Site is vested with the Forest Department of Sri Lanka. At present, Sinharaja is the largest block of lowland rainforest left in Sri Lanka, occupying approximately 0.2% of the total land area of the island.
Monday, November 26, 2007
NATURE
The rounded world is fair to see, Nine times folded in mystery: Though baffled seers cannot impart The secret of its laboring heart, Throb thine with Nature’s throbbing breast, And all is clear from east to west. Spirit that lurks each form within Beckons to spirit of its kin; Self–kindled every atom glows, And hints the future which it owes.
There are days which occur in this climate, at almost any season of the year, wherein the world reaches its perfection, when the air, the heavenly bodies, and the earth, make a harmony, as if nature would indulge her offspring; when, in these bleak upper sides of the planet, nothing is to desire that we have heard of the happiest latitudes, and we bask in the shining hours of Florida and Cuba; when everything that has life gives sign of satisfaction, and the cattle that lie on the ground seem to have great and tranquil thoughts. These halcyons may be looked for with a little more assurance in that pure October weather, which we distinguish by the name of the Indian Summer. The day, immeasurably long, sleeps over the broad hills and warm wide fields. To have lived through all its sunny hours, seems longevity enough. The solitary places do not seem quite lonely. At the gates of the forest, the surprised man of the world is forced to leave his city estimates of great and small, wise and foolish. The knapsack of custom falls off his back with the first step he makes into these precincts. Here is sanctity which shames our religions, and reality which discredits our heroes. Here we find nature to be the circumstance which dwarfs every other circumstance, and judges like a god all men that come to her. We have crept out of our close and crowded houses into the night and morning, and we see what majestic beauties daily wrap us in their bosom. How willingly we would escape the barriers which render them comparatively impotent, escape the sophistication and second thought, and suffer nature to intrance us. The tempered light of the woods is like a perpetual morning, and is stimulating and heroic. The anciently reported spells of these places creep on us. The stems of pines, hemlocks, and oaks, almost gleam like iron on the excited eye. The incommunicable trees begin to persuade us to live with them, and quit our life of solemn trifles. Here no history, or church, or state, is interpolated on the divine sky and the immortal year. How easily we might walk onward into the opening landscape, absorbed by new pictures, and by thoughts fast succeeding each other, until by degrees the recollection of home was crowded out of the mind, all memory obliterated by the tyranny of the present, and we were led in triumph by nature.
These enchantments are medicinal, they sober and heal us. These are plain pleasures, kindly and native to us. We come to our own, and make friends with matter, which the ambitious chatter of the schools would persuade us to despise. We never can part with it; the mind loves its old home: as water to our thirst, so is the rock, the ground, to our eyes, and hands, and feet. It is firm water: it is cold flame: what health, what affinity! Ever an old friend, ever like a dear friend and brother, when we chat affectedly with strangers, comes in this honest face, and takes a grave liberty with us, and shames us out of our nonsense. Cities give not the human senses room enough. We go out daily and nightly to feed the eyes on the horizon, and require so much scope, just as we need water for our bath. There are all degrees of natural influence, from these quarantine powers of nature, up to her dearest and gravest ministrations to the imagination and the soul. There is the bucket of cold water from the spring, the wood–fire to which the chilled traveller rushes for safety, — and there is the sublime moral of autumn and of noon. We nestle in nature, and draw our living as parasites from her roots and grains, and we receive glances from the heavenly bodies, which call us to solitude, and foretell the remotest future. The blue zenith is the point in which romance and reality meet. I think, if we should be rapt away into all that we dream of heaven, and should converse with Gabriel and Uriel, the upper sky would be all that would remain of our furniture
These enchantments are medicinal, they sober and heal us. These are plain pleasures, kindly and native to us. We come to our own, and make friends with matter, which the ambitious chatter of the schools would persuade us to despise. We never can part with it; the mind loves its old home: as water to our thirst, so is the rock, the ground, to our eyes, and hands, and feet. It is firm water: it is cold flame: what health, what affinity! Ever an old friend, ever like a dear friend and brother, when we chat affectedly with strangers, comes in this honest face, and takes a grave liberty with us, and shames us out of our nonsense. Cities give not the human senses room enough. We go out daily and nightly to feed the eyes on the horizon, and require so much scope, just as we need water for our bath. There are all degrees of natural influence, from these quarantine powers of nature, up to her dearest and gravest ministrations to the imagination and the soul. There is the bucket of cold water from the spring, the wood–fire to which the chilled traveller rushes for safety, — and there is the sublime moral of autumn and of noon. We nestle in nature, and draw our living as parasites from her roots and grains, and we receive glances from the heavenly bodies, which call us to solitude, and foretell the remotest future. The blue zenith is the point in which romance and reality meet. I think, if we should be rapt away into all that we dream of heaven, and should converse with Gabriel and Uriel, the upper sky would be all that would remain of our furniture
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