28th May 2000
Editorial/Opinion| Business| Sports|
Sports Plus| Mirror Magazine
By Tharuka DissanaikeWhat animal would you think is most threatened with extinction in Sri Lanka? The elephant? The leopard? The sloth bear?
It would surprise many that species most likely to disappear from the face of the country are several frog and toad types, a couple of lizards, certain freshwater fish like the 'Cherry Barb' and butterflies like the 'Ceylon Tree-brown'.
Of course, large mammals, birds and reptiles are affected by the rapid loss of forests, pollution and hunting. But the disappearance of the innocuous species of amphibians and insects paints a very grim picture of the extent of damage wrought upon nature by human activity.
"We believe that some of these species may have disappeared even before they were discovered and named," said Dr. Channa Bambaradeniya, Senior Programme Officer, IUCN (World Conservation Union). "The loss of wet-zone rainforests is the primary reason for the extinction of many of these species. Pollution of rivers and lakes, large dam- building and live-gathering threaten many freshwater fish."
The IUCN has recently published comprehensive lists of Sri Lanka's threatened fauna and flora. They include species of mammals, fresh- water fish, amphibians, reptiles, birds, land snails, fresh- water shrimps, freshwater crabs, dragonflies, butterflies and flowering plants.
The lists are extensive and classified neatly in the volume, 'The 1999 List of Threatened Fauna and Flora in Sri Lanka'. The IUCN plans to lobby with governmental authorities involved in forest and wildlife protection and even the Customs Department to use the lists as a guideline in preparing future conservation plans.
It was the first time such a comprehensive evaluation of Sri Lanka's biodiversity was conducted. Earlier, provisional lists of threatened species were based on a great deal of subjectivity. By this exercise, IUCN hoped to weed out the subjectivity and inject more objective and scientific criteria in determining threats to a species.
Two teams of academics and experts in their respective fields, developed a framework for the criteria. The criteria were reviewed in two workshops, which invited comments from other scientists and it was decided to use five factors to determine the intensity of threat. The distribution range was one, the situation of the habitat (protected by law or not) was another. The adaptability of a species was factored in as a plus point to its survival. Human impact and whether the species is endemic (only found in Sri Lanka) made up the other factors.
On these factors, eight criteria were developed. For a species to be qualified for evaluation there must be information to judge under at least four criteria. Any species that did not yield enough data to be considered under four criteria were listed separately as Data Deficient. These lists are valuable for scientists to base their future studies.
"Several interesting facts came to light through the evaluation," Dr. Bambaradeniya said. "Of the 690 plants that were listed as threatened, 131 species lack any record of existence after 1900. A further 27 species are not recorded after 1950. A possible assumption is that they have become extinct or very close to it."
Many endemic species are threatened. These include rare rainforest orchids, wet-zone tall trees like the Dipterocarpaceae, and Gordonia, a montane forest species with a scarlet flower. Loss of forest cover due to the population expansion in the latter half of this century has contributed to the disappearance of many plant species. Forest cover reduced from over 70 per cent in 1900 to less than 20 per cent today.
The tallied score for each species was averaged by the number of criteria used. Two main categories were developed- threatened and highly threatened. Highly threatened species are critically endangered and nearing extinction.
Sources for the study were published research during the past 100 years, unpublished information from reliable scientific sources and volunteered information during the participatory sessions when doors were thrown open to academia and researchers to bring in their own information.
"Largely, it is the endemic species that are highly threatened," Dr. Bambaradeniya said. "Of the endemic vertebrates, nearly 90 per cent are threatened. Endemic invertebrates, 66 per cent are threatened. This is largely because endemic species are very specialised to their habitat and diet. Also you cannot supplement dwindling populations by importing the species from abroad, as they are found only in Sri Lanka."
The data deficient lists are also extensive, pointing out that there is inadequate research on many species, which leads to dubious classification.
While loss of forests is a primary cause, many other factors affect the survival of species. Extensive, unregulated pesticide use is a major cause of river and lake pollution. Chemicals in these solutions are carried through the food chain, their toxicity accumulating in the higher species like predators.
Invasive, foreign species of plants and animals thrive in difficult conditions, their swelling populations pushing out more delicate local species. Good examples are the prolific water hyacinth, lantana in national parks and giant mimosa. 'The Golden Apple Snail' was imported by the aquarium trade to decorate fish tanks- today it has escaped down city drains to the marshes of Bellanwila and Attidiya. The carnivorous 'Clown Knife' fish grows to monstrous proportions in canals and streams that it has been thrown into, eating up other species. Many rare fish species are hunted live for aquariums and export.
Amphibians are especially sensitive to climatic changes. Temperature and rainfall changes can seriously impede their survival.
"Even activity done in the name of science, species collection, is a threat to the rare endemics "Dr. Bamba–radeniya said.
IUCN today contemplates over the future of the lists. An update every
four years would be ideal, Dr. Bambaradeniya said. The Union also hopes
to conduct awareness campaigns among conservationists, enforcement officers,
schools and the public.
Cruising down Madu Ganga
By Gamini G. PunchihewaAs we continued our cruise, we came upon several islets, some large, others small. Mr. Gunadasa de Silva pointed out 'Digaduwa','Periyaduwa', a large, lush stretch of land, second in size only to 'Kothduwa'.
Poet Ananda Rajakaruna extolling the attractions of Madu Ganga and her beautiful islets wrote thus:
" Nil Mal Bisau diya kelina Madu gange
Dupath hethathara maleka Menik wage,
Atharin pathara then thenwala Ivure dige,
Dagab Pelen Athivunu Lassanak Age."
"Queens like blue-hued flowers bathe and frolic in Madu ganga,
The 64 islets glitter like a necklace studded with gems,
Here and there on the fringes of her bank,
Graces a line of dagabas adding lustre and beauty."
Today, of the 64 islets the poet mentions only 23 remain. Among them are 'Maduwa', 'Nahaduwa', 'Vadaduwa', 'Pathamulla', 'Galmaduwa', 'Thihaduwa', 'Katuduwa', 'Gonaduwa', 'Miraladuwa', 'Appaladuwa', 'Periya'/Digaduwa', 'Marakkaladuwa', 'Naiduwa', 'Dimaduwa', 'Sathapaheduwa', 'Waladuwa' and 'Kothduwa'.
Going past a tiny, wooded isle called Sathapaheduwa, we saw a tiny shrine dedicated to God Kataragama. The name Sathapaheduwa is apparently a reference to the island's size which is likened to a five-cent coin. Each islet's name, we were told, has its own legend connected to it.
The Kadapawunaduwa, for instance, was once part of a larger island, while another isle that was once infested with snakes is called Naiduwa (Isle of Snakes). During World War II (1939-45), a German prisoner had lived here and is said to have collected many species of poisonous snakes for research he was conducting in the extraction of their venom. The poison was kept in sealed bottles and later sent abroad.
Boer prisoner ?
Dr. R.L. Brohier in his book "Seeing Ceylon" mentions the Boer prisoners of World War I. They were kept in Jaffna and Hambantota as they refused to sign the oath of allegiance to the British monarch. Among them was Henry Engelbrecht who opted to live out his life in Hambantota. He was later made the first Game Ranger of the Yala National Park, then known as the Yala Sportmen's Reserve.
Engelbrecht died in Hambantota and his remains were interred in the Hambantota cemetery by the seashore. Dr. Brohier mentions that some of the Boer prisoners were given asylum in Uragasmanhandiya off Elpitiya. Uragasmanhandiya lies close to the cluster of islands of the Madu Ganga near Bagula Ela. Could it be that Naiduwa's German prisoner was one of those Boers?
We also visited 'Gonaduwa', the isle where once sambar roamed. Its vegetation is dense and we saw several trees of medicinal value such as the Rukaththana (Astonia schoaris). Mr. Gunadasa said that over 50 years ago he had come across a kebellawa (ant-eater - Pangolin) here. The island is also the abode of the jungle cat - walbalala, he said.
Our next stop was the wooded isle of 'Polathuduwa' which was once a park and herbarium. From there we saw 'Meemalaguduwa' -Buffaloe island and 'Galmaduwa'.
Next : Around the mangroves
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