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Sunday, 17 May 2009

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Climatic chaos and vanishing potatoes

Palitha Wijethunga: Increase in temperature good for potato cultivation

There are no cascading waterfalls among the dark green hills; or does any glittering stream carry crystal cold water. During January-March dry season much of the beautiful harmony of nature has been carried away with the time; however, it was not so even during dry seasons two or three decades ago. Instead, there was the hum of some hundreds of water pumps echoing among the hills; misty dark greenery was replaced with hundreds of brown coloured terraced vegetables fields, one upon the other on the steep hills.

This is Nuwara Eliya, the country's famous cool capital, known as Little England, is also the country's potato capital since the country's best potatoes are produced here. It is a matter of some more decades before the crop is doomed in the cool climes as Nuwara Eliya is getting hot! Future generations would not be so fortunate as to taste crunchy, crispy, Nuwara Eliya potatoes!

Temperature gap

Of course, Nuwara Eliya is getting hot, simply every one feels it, residents, visitors and so do the scientists! According to the Meteorological Department statistics, each passing year the minimum night time temperature in Nuwara Eliya increases by 0.025 degrees and the temperature in Nuwara Eliya will increase by 2.5 degrees during the next century! "By then, potatoes could not be grown in Sri Lanka," warned Dr. Punyawardane, Head, Agro-Climatology Unit, Agricultural Department, Kandy.

D.M.S. Sunil:Potato should not be cultivated in Nuwara Eliya

"You can grow potatoes in Kandy, but without any tubers, it would be just an ornamental plant, here," he commented. He explained that there should be a difference of eight degrees between the day time maximum and the night time minimum temperatures to grow potatoes and it is less than eight in Kandy; however, which is around ten in Nuwara Eliya, he said. "The more the difference the better the potatoes," he said.

He said that the temperature gap is gradually narrowing down in Nuwara Eliya at an alarming rate of 0.025 degrees per year. "As a result the potatoes would be smaller, number of potatoes per plant would be less and it would not be crispier," he noted.

"The reduction in the yield could be partially due to the increase in the temperature," expressed Dr. Punyawardane, due to this significant annual increment in the temperature, which is the highest in the country. He added that the high soil erosion and poor quality seeds contributed to drastically reduce the yield. The crop was first introduced in the country in the 1950s and the harvest then had been twentyfold, he said.

Downpour and higher temperature

Palitha Wijethunga (41), Vijayabhapura, Kandapola, cultivated around one acre of potatoes for 20 years also has evidence that the climate in Nuwara Eliya, has changed. "North-East Monsoons may come 1-2 months early or late." He recollected that the continuous showers the Monsoon had been replaced by heavy downpour for a few hours and longer consecutive dry periods. "Now it's changed. Sometimes it would rain for a week and sometimes not at all and there would be sudden downpours which would destroy cultivation," he explained how the weather in the highlands had changed. "We have not had a proper rainy season since mid December last year."He pointed out that the temperature in Nuwara Eliya too had gone up.January and February supposed to be the coldest months of the year, was not cold as before. "Look, now people do not wear warm clothes. I am wearing just a shirt," he elaborated.

Poor quality seeds

Potato plant

Along with those changes in the climate, the crop yield too has come down. "Definitely, there is a reduction in the yield," however, he said that there were some other contributory factors, such as the use of the poor quality seed potatoes had affected the yield.

"The more the rain, more are the diseases, that attack the potato cultivation."

Poor yield

D.M.S. Sunil of Lady McCullum Drive, Nuwara Eliya said if the climate is good he could fetch a good harvest of 500kg of potatoes from 50kg of seed potatoes. Usually, the average amount was around 300-400kg.Drought is worse than 5-6 years ago and the yield is poor. Rain is less but there is a lot of "Akal Wehi," untimely rains which are not expected that would erode fertile top soil and destroy vegetable plants.Nuwara Eliya is a mountainous terrain, therefore, growers should level the steep slopes for the cultivation; these are narrow bed upon bed as you see it from a distance.

These terraced fields are quite vulnerable to heavy rains. A kilogram of potato was sold at Rs. 60 over 15 years ago, when one a kilogram of rice was just around 10-20 rupees. Now a kilo of rice and potatoes are sold at Rs. 60. He said that Indian Potatoes are available in the heart of country's potato production districts may be for the first time."People do buy them because they are cheaper."

Mahaweli project

He pointed out that drastic consequence of the climate change that occurs in Nuwara Eliya area, which is an important water shed of the Mahaweli river, the country's longest river, key to the electricity generation and the agriculture in the dry zone. "One of the reasons for the implementation of the Mahaweli Project was that the river carried a substantial amount of water even during a drought.

P.A. Appuhamy Senarathne: Fears prolonged drought

But there was only a little water in the reservoirs down stream as virtually thousand water pumps sprayed water out of streams that fed the river and vaporize it into the cold dry air.

Not a single stream carried water down stream during the dry season.There was a dearth of water in areas such as Welimada and Kotmale which lie below Nuwara Eliya.

No wonder the reservoirs downstream lacked water he explained.He believed that ideally the potato cultivation should be stopped in Nuwara Eliya.

If one is concerned of the country's future and only a few would lose their livelihood, but the country would conserve its vital life blood. After all, the cultivation has not contributed much to the development of the area.

Severe drought

P.A.Appuhamy Senarathne (72) of Magoda, Ruwaneliya, said the unbearable cold when he first settled in 1972 has been considerably changed and that he only needs a shirt during the day time.

But even I was young I had to put on number of clothes.

A plot being prepared for potato cultivation.

"The people just left lands granted by the government because it was so cold." This year we had ground frost even in December, which we usually have in January-February and the dry period is longer than usual and from last December we did not have rain.

The wells were dried and people do not have water even for drinking. "This could be first time that wells ran dry.

We never had such a drought before.Nuwara Eliya water was just like crystals, we used to drink water from streams, which are now polluted, he recollected.

He too agrees that the potato yield is poor due to number of reasons; that seeds are of poor quality, poor soil which is not fertile because of decades of erosion.

Also the higher cost of fertiliser makes people use less fertilizer. He also alleged that the agricultural officers never visited their cultivations.Would climate change and global warming, change the future of potatoes in Sri Lanka?

(This article was written under the aegis of CSE Media Fellowships)


Butterflies, charming but self-armed!

Everyone, young or old, likes butterflies and is enchanted by their presence. But how many of them know that some butterflies are perfumed and smell of verbena, lemon or pineapple or that some butterflies have evolved protective coloration or resort to rues against the attacks by predators? Have you ever heard of the butterflies which in their larval stage cohabit with the ants being tended by them in their nests or of larvae showing cannibalistic tendencies.

Well, these are some of the aspects in the interesting life history of the "Scaly-winged Tribe" that should make the study of butterflies more alluring than simply observing them in the field and feasting one's eyes on their beauty.

Once, some years ago, I observed a Common Mime or Lankeswara butterfly hovering about a cinnamon shrub in the garden. I went down with my magnifying glass in hand to investigate. A closer look revealed that it had laid half a dozen tiny, yellowish-green eggs on tender leaves and the stem I collected from two of the eggs placed in an empty jam bottle with a tight-fitting stopper.

I examined the eggs every night in the light of my table lamp and on the forth day they hatched and the larvae started to eat the egg shells, their first meal. The new-born larva was spiny and dark-brown in colour with the centre of body buff-white. At first the larvae relished the tender cinnamon leaves but later on they switched to a diet of the leaves of Litsea longifolia "Ratkeliya" which I offered them. The half-grown larva was brown and ochreous with greasy-looking marks and looked exactly like a bird's dropping. Perhaps, in the wild it would have been probably overlooked by an enemy owing to its resemblance to an inedible object. When the larva was nearly full-grown it assumed a coloration of gaudy black, yellow and red, which the entomologists describe as a "Warning coloration" usually seen among insects with poisonous or repellent features that repulse the enemies from attacking them.

On the 13th day after hatching from eggs, both the larvae stopped feeding and got ready to pupate on the sticks I provided for them. The next day the changeover was completed round about 11 in the night, a process which took them almost thirty hours.

On pupation the larva retuned to the device of resembling an inedible object once again, but this time it assumed the form of a short, snapped-off dead twig; the base of the pupa being so shaped that it appeared to have grown out of the stick to which it was anchored. The pupa as a whole was brown to dark brown in colour with pencil marks of a lighter shade and measured 39 mm. by 8 mm. The adult butterfly emerged 14 days late.

Experiments on the metamorphosis of the Common Mime Chilasa clytia lankeswara butterfly point to the fact that when the adult butterfly emerges, whatever its sex, whether it was the typical brown form or the striped black and blue dissimilar form, it mimics three butterflies of the Euploeas family and three of the Danaus species. The butterflies of both these groups are known to be distasteful to the birds and their colour schemes are of the warning type.

It is presumed that the two colour forms of the Common Mime take advantage in the protection conferred by this warning coloration. This is further advanced by the fact that both forms have two distinct styles of flight-one, used when they are alarmed or pursued by an enemy, in the ordinary, swift and dodging flight of the Swallow-tail family to which it belongs, the other is the slow, sailing, careless style of flight always used by both the Euploea and Danaus groups of butterflies. The second is the style adopted while feeding and playing and especially, by the female, while laying her eggs. Under these circumstances, it is hardly possible to distinguish between the mimic and its models in the field, even for a trained observer.

However, no direct observations appear to be on record to indicate whether the Common Mime possesses poisonous or repellent qualities rendering it unedible to its natural enemies or whether these qualities fluctuate in agreement with the changes in its life history, between the two types of coloration.

It has been found that beyond being very tenacious of life all butterflies of the Danaid species, i.e. Tree Nymp, Glassy Tiger, Blue Tiger, Blue Glassy Tiger, Dark-blue Tiger, Common Tiger and Common Indian Crow, Double-banded Crow, Great Crow and King Crow and three of the Papilio group i.e. Ceylon Rose, Crimson Rose and Common Rose are protected by the possession of unpalatable body juices, because in their larval stage they feed on poisonous plants, hence once an enemy has tried to eat anyone of them it will have either died or will never try again. The colouring patterns in such cases are usually so conspicuous that the enemy is pre-warned not to attack.

The protective devices occur not only in the adult stage but also in the larval and pupal stages. The larva is frequently coloured to harmonize with the surroundings, it may be armed with spines or possess threatening markings, which together with definite gestures, give it superficially a terrifying look. Others who are brightly coloured, and fed by day and exposed to view possess distasteful qualities and exhibit warning patterns as the adult butterflies do. On the other hand, the larvae who are supposed to be palatable escape detection by hiding during daylight hours and venturing out to feed at night.

The larvae of certain butterflies of the Lycaenidae family have evolved a curious system of protection in conjunction with ants. The ants tend and protect the larvae and receive in return sweet juices which are emitted from glands of the larvae. In certain cases the larva when nearly full grown is taken away by the ants to their nests where it is fed and looked after until it pupates at leisure and emerges from the nest as a full-fledged butterfly in due course.The Lycaenidae are a large family in Sri Lanka mostly of small sized butterflies, consisting of 81 species.

The larvae of this species possess specialized organs that are known to exude a sweet fluid much relished by ants.

The Apefly butterfly Spalgis epeus epeus of this family apart from its normal diet of vegetable is known to feed in its larval stage on Mealy Bugs or small insects, but displays a strong tendency towards cannibalism, occasionally eating brethren of the same brood.

Sometimes, a larva which in its early stage feeds on flowers and plants may later wonders away and meets an ant, which is attracted by the sweet honey like fluid the larva exudes. The ant moves the small larva to its nest where from being a vegetarian the larva turns carnivorous, feeding for the rest of its larval life on the young of the ants, until it is ready to pupate.

In other cases it is believed the female butterfly lays her eggs in close proximity to an ant's nest and after the tiny larvae hatch out they are taken by the ants into the nest and treated somewhat on the lines the humans treat milch cows.

Another interesting feature in this widespread family is that the male butterflies of some species possess either scent pouches or patches of specialized scent-producing scales on their wings. The glandular cells which contain the scent secrete a volatile fluid or essence which in certain circumstances flows into the scales and eventually passes off by evaporation as an odorous vapour...

There is evidence to believe that scent-producing structures are the exclusive property of the male butterflies, hence we may feel pretty certain that their chief function is to charm or attract members of the opposite sex at the time of courtship. That these perfumed male insects are really irresistible to the females of their kind has been proved again and again by interested observers of insect-life in many countries.

With some species the scent tufts emit a strong perfume not unlike that of pineapple, while the scent scales of some others are known to give forth a fragrance which has been likened to that of the lemon verbena plant.

Meanwhile, many kinds of butterflies and moths often notable for their gaudy coloration give out disgusting smells, especially if they are alarmed or touched.


"Pathan-ala" extinct?

******

Family: - Asclepiadaceae

Scientific Name:- Brachystelma lankana

Dassanayake & Jayasuriya.

Sinhalese Name:- Pathan-ala

Status:- Critically Endangerd, Endemic

******

* Brachystelma lankana highly restricted to Knuckles region (Endemic), belongs to Asclepiadaceae family, with only one species is recorded from Sri Lanka.

* It is a small herb simple stem or with a few branches. Consisting one tuber underground, with small leaves tapering at both ends and laceolate in shape.

* Small flowers have lobed petals. Fruits are long and elongated.

* According to the 2007 Red List of Threatened Fauna and Flora of Sri Lanka Patan-ala is critically endangered species. It was protected under the Flora and Fauna Protection Ordinance. This species will be extinct due to over collection, habitat destruction, etc...

Reference:

1.Dassanayake, M.D. and Fosberg, F.R.(eds.)(1983) A revised handbook to the flora of Ceylon. Amerind, New Delhi.

2. IUCN Sri Lanka and the Ministry of Environment and Natural Resources (2007)The 2007 Red List of Threatened Fauna and Flora of Sri Lanka, Colombo, Sri Lanka.

Pic and text: Dilup Chandranimal

IUCN (The International Union for

Conservation of Nature)

Sri Lanka-Country Office

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