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5/28/2010
Human Elephant Conflicts
The Sri Lanka elephant (Elephas maximus maximus) has shared a special cultural bond with people of Sri Lanka over 25 Centuries. Elephants are featured prominently in Sri Lanka history, Culture, religious faiths and folklore Symbolizing qualities like physical strength, intelligence, dexterity, loyalty and responsibility. IUCN Red List Rank is endangered.
Based on remote sensing studies, elephant range I Sri Lana Constitutes approximately 2% of the current global range. However, estimates of elephant numbers by leading international experts suggest that over 10% of the total Asian Elephant population is found in Sri Lanka.
Ecologically, Asian elephants are an ‘edge species’, which means that the best habitat for them is at the boundary between the forest and open habitats. Tall, closed canopy forests- such as mature tropical rainforests and evergreen forests – are not ideal habitats for elephants. Most of the growth in such forests happens up in the canopy which is beyond the reach of elephants – the undergrowth is sparse due to the low light falling inside.
The number of wild elephant that can be supported by a given extent of land varies on the type of its vegetation. A large extent of global Asian elephant habitat in countries such as Myanmar, Laos and Malaysia is covered in closed canopy rain forests. Examples in Sri Lankan dry evergreen forest in the National Parks of Wilpattu, Wasgamouwa and Yala (Block 5). In closed canopy forests both in Sri Lanka and in other countries, a single elephant needs around 5 to 10 square Kilometers or 1200 to 2400 acres of area. However, if Such Forests are disturbed and converted to a mosaic of regenerating forests and grassland Savanna patches, the pioneer species of shrubs and grasses provide abundant fodder for elephants. In such regenerating forests grassland habitats, a single elephant on average needs only one third to one fifth of a square kilometer, or around 50 to 80 acres.
It is believed that elephants came to Sri Lanka over 3 million years ago, through a land bridge connection that existed at the time with India. In comparison, the first humans arrived in the island only about 50000 years ago. Because of the tropical climatic conditions in Sri Lanka, the entire island would have been covered in mature, closed canopy natural forests for millions of years. In such conditions, elephants would have been found at low densities in both wet zone rain forests and dry zone evergreen forests. Sri Lanka has few natural lakes, and elephants would have had to depend on rivers and streams for water. The seasonality of dry zone rivers would have had a further negative impact on elephant numbers in the dry zone.
This situation changed completely after the humans arrived and started their settlement, and especially with the advent of irrigated agriculture. For thousands of years, people have been converting mature closed canopy forests in the dry Zone into agricultural fields. They have been damming rivers, tributaries and streams to make numerous reservoirs or tanks. While shifting agriculture practiced for elephants, irrigated agriculture was a permanent form of land use which excluded elephants.
Around 13th Century AD, the civilization in the dry Zone Gradually declined, and the centre of civilization slowly shifted to the wet zone. From the 16th century, the country came under colonial rule, during which periods the wet Zone became densely populated. Large scale land use changes took place due to the growing of cash crops, while the targeted killing of elephants practically eliminated tem from the wet zone. Today, the last wet zone elephants are found in the remnant forests of the Peak Wilderness.
Meanwhile, the regenerating secondary forests in the largely abandoned dry zone, along with the thousands of tanks built during the ancient hydraulic civilization, provided an ideal elephant habitat. The low intensity shifting agriculture practiced in the dry Zone also maintained the habitat in optimal condition for elephants.
After political independence in 1948, the land use patterns changed once again. With rapid human population growth, successive governments turned to redeveloping the dry zone for agriculture. Large scale irrigation projects that dammed major rivers and diverted water to newly constructed reservoirs, brought extensive areas of the dry zone once again under irrigation agriculture. These involved resettling people from the crowded wet zone in the newly opened up areas of the dry Zone.
Conflict between humans and elephant is not a new phenomenon; elephant have been raiding crops since time immemorial. However, the reverence people had for elephants in Sri Lanka historically ensured its peaceful co-existence and made them tolerant of the occasional intrusion. In recent times however, human settlements have been encroaching further and further into elephant habitat, and the incidence of crop-raiding has increases phenomenally, leading to the destruction of crops, human homes and lives. Most of the large scale clearings of jungle for agriculture have not given due consideration to the ecological needs of the elephant and other wildlife. As people have suffered escalating losses to elephant, their tolerance has given way to anger and frustration. Every year hundreds of acres of agricultural crops, considerable number of houses and other property are destroyed by elephant looking for food.
On average every year about 100 – 150 elephants die in Sri Lanka due to intense human-elephant conflict. Conflict is widespread through the elephant habitat. The reason for conflict too varies from region to region. It is unlikely that just one solution will help resolve human elephant conflict. New ideas should tired out as pilot projects and refine to suit legal issues. It is important to involve the local people from the very beginning. Consideration should be given to their plight as well as to the elephant’s if these projects are too succeeded. Public participation is crucial not only to resolve human elephant conflict but also to ensure the long term survival of the Sri Lankan elephant. A farmer who can reap the benefits of his labor would be more benevolent towards the elephant than one whose life, family, property and crops are under constant threat from it.
Management Strategies
Both within and outside National Parks authorities are required to take decisions in the light of presently inadequate knowledge or information. This continues to be so especially in the case of elephants, their habitats, and the human population. This continues to be so especially in the case of elephants, their habitats, and the human populations around them, and the problems that manifest themselves as a result of these interactions.
The approach of “Adaptive Management” where actions are designed to provide information on the state and function of the ecosystem under management, has been advocated, but rarely practiced by essentially conservative wildlife managers. A more confident approach to management and research coupled with improved models and genuine interest in finding how systems work would appear to be the way forward. This could best be achieved by avoiding such concept as fixed equilibrium, embodied by the obsolete term “carrying capacity” and giving greater scope to ecological processes within at least some parts of the elephant range.
Variety in management strategies would generate spatial and temporal heterogeneity, allowing greater species diversity and providing the possibility of experimental treatment blocks. Research on other components of elephant habitat systems Such as the habitat requirements and vulnerabilities of other animals and plant species and on the influence of fire and other episodic disturbance factors should be undertaken. Whatever the approach adopted, management should have clear goals and objectives which do not conflict. Measurable objectives, Such as limits of acceptable change broad or narrow should be identified so that research can have a target and management can be informed on the progress or otherwise towards its goals. Many small elephant populations, habitats, plant and animal communities still exist outside protected areas and they also deserve attention, in the context of fast diminishing forest cover and species including elephants, following the rapidly increasing human population in the island. Specific problems that need attention include impact of elephants upon the habitats are their long term viability, the loss of habitats for its fragmentation due to human nativities incidence of crop damage by elephants and economics loss involved , and the growing conflict between elephants, people and other forms of land use, such as agricultural and agro forestry.
Conflict between people and elephants has now developed to huge proportions; there is an urgent need either to reduce the level of conflict or to increase the levels of human tolerance, or both. Protection of new habitats and linking them with the larger National Parks by establishing jungle corridors, creation of buffer zones or multiple land use areas in the periphery of National Parks, where elephants now free range , Payment of reasonable compensation for rope damage and man slaughter by elephants, providing employment and engaging local communities for park development works, creation of an auxiliary game guard system involving local communities to help farmers to scare away persistently crop raiding elephants to patrol and gather information. In multiple lands use areas of buffer zones are some of the ways and means of reducing the existing level of conflict and increasing the levels of human tolerance. Use of power fences by state and private sector agencies to keep away elephants from raiding their large plantations and by cultivation societies of farmers to protect large extent cultivated under tank irrigation too should be advocated and actively promoted by the DWLC. The use of power fences to control elephant egress is being restored to in many countries both in Asia and Africa with different measures of success. Given the present advancement of technology, well applied and maintained power fences can act as a powerful deterrent to elephant entry and trespass. Cost effectiveness of power fences is an aspect that is often neglected in many countries. Cost benefits analysis of power fences are important prerequisite for their promotion among development agencies and farmers, as an effective and acceptable elephant management tool.
5/21/2010
heavy rains and resulting floods that lashed Sri Lanka over the last two weeks
Over 500,000 people are affected in Sri Lanka floods
Over 500,000 people have been affected by the heavy rains and resulting floods that lashed Sri Lanka over the last two weeks, the Sri Lankan government has said.
“The number of IDP’s (internalls displaced) affected by the floods is 18,908. A total of 220 houses had been destroyed and 1039 partially damaged in the Anuradhapura,Nuwara Eliya and Mannar Districts. In Angulana 64 houses were washed away due to the floods.”
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5/19/2010
5/18/2010
Can we learn something???????
India’s power sector: private players do a good job, prices to go up!
Given this trend ,there will soon be a new market-driven power production from the growing clout of these players.
Accordingly, we also need to redraw the new power production policy that would enable the private sector players more and more in the years to come.
We need to exploit our own natural resources, hydropower/thermal and alternative energy sources. Somehow our power sector debate has been pushed on a queer path. It doesn’t seem to be a fashion to talk of our own natural resources, hydro power and thermal power from coal. It is now a sort of fashion to talk of the distant civil nuclear power as the new energy supplies.
Also, we don’t seem to put any emphasis, lest it be mistaken, as relying on the biggest players like Reliance and Tatas in the current political environment where the emphasis should be on aam aadmi, rather than business with no nonsense!
Anyway, there are new energy sources, gas, petroleum and also much collaboration with foreign suppliers, from Iran to Russia.
This is the time or age of natural gas and petroleum exploration and thus , the right time to design foreign policy that takes care of our energy sources.
Unfortunately, there is not much public discussion or debate on this.
In parliament most MPs also don’t seem to be talking in any depth on any basic issues like power deficit or energy sources.
Repeatedly, we are talking about price rise, especially about the rise of prices of petroleum.
Since most of our petroleum is imported, we run a heavy subsidy bill. Thus, the news remains politically motivated and the substantive side of the energy and power supplies and deficits do not get adequate exposure.
With the private players, like Jindal steel, Tata power, Lanco Infratech. Adani power, Torrent power, the total capacity
addition fell short of by a third of the 14,507 mw target set for 2009-10.
Our Prime Minister never talks and hence the people at large also don’t get a fairly balanced discussion on the country’s inherent strengths. We seem to be talking too much about high profile areas like civil nuclear power, as if it is the only source of power and do not focus on what is in reach and within India’s capabilities. No one talks about the still untapped potential from our natural resources, like hydro power, coal sector power, wind power etc.
Also, some policy decisions that paid off like the role of the private sector power producers is left unmentioned or the real achievers left unhonoured.
There is also the mindset to focus on the public sector power companies like NTPC and NHPC.
NHPC MD Mr.S K Gag says in a recent interview that India is endowed with abundant hydropower potential of about 149 gw (giga watts) of which only 25% has been developed so far. The remaining untapped potential gives ample opportunities to hydropower developers. NHPC alone is executing 11 new projects with an aggregate capacity of 4,622 mw, which will enable the company to become 9,500 mw plus company. This is good news.
After 2013, NHPC has set a new target of 12 more projects with aggregate installed capacity of 5,322 mw during the XI Plan. NHPC is presently operating 13 hydro projects. Total installed capacity is 5175 mw. NHPC is seeking clearances for projects about 10,000 mw.
NHPC can also pursue the thermal power generation option; it has a jt venture company for this. The MD narrates the details of the joint ventures in Madhya Pradesh alone.
There is also a mini tidal power project in West Bengal.
There is the other biggest PSU, the NTPC, thermal power generating giant. NTPC and NHPC are the two giants and they hold the key to attain targets under the government’s long term vision. NTPC’s performances are very disappointing, just 990 mw added in 2009-10.
5/08/2010
Forest Fires
Sri Lanka's forests are one of the country's richest natural resources, supporting a huge diversity of plant and animal species providing forest products to support local livelihoods. Over the years the forested lands have been deceased drastically due to number of causes. These include clearing for agriculture and large development projects, selective felling of timber, and recently, introduction of invasive species. apart from these factors forest fires can be considered as an agent for forest degradation.
Tropical rain forests in their undisturbed state are nearly fire proof. The stratification structure of the forest helps to keep wetness inside the forest. As tropical forests are opened up for logging and agriculture, they become very fire prone, and produce more died wood than under natural condition and provide fuel for future fires. After a forest is burnt, more light and space is available for grasses and other vegetation to grow on the fores floor. This vegetation dries out more quickly and easily burns. Creating conditions for annual fires.
Knowledge on effect of fire to the forest to the forest is very important for managing degraded forest and plantations. Generally it affects the composition, structure and pattern of vegetation of the landscape. The forest manager faces a complex challenge in managing fire to achieve beneficial effect and avoid unwanted results. Even attempts to eliminate harmful fire can cause undesirable consequences such as increased risk of fire and declining ecosystem health. Thus. it is important that the immediate and long term effects of fire be understood and integrated into forest restoration program.
Causes of Forest Fire
Forest fires are caused by natural as well as man made caused. Many forest fire starts from natural causes such as lighting which set trees on fire. High atmospheric temperatures and dryness offer favorable conditions for a fire to start. Man made fire is caused when a source of fire like naked flame, cigarette, electronic spark or any source of ignition comes into contact with inflammable material.
Even though natural forest fires are not common in Sri Lanka, there are some forest fires which are created by human. These human activities are significant in savanna grasslands because it is an effective tool to prepare lands for agricultural activities. Other than this, some cattle farmers set fire to the grassland for obtaining young leaves to feed their cattle. Not only grassland but also forest plantations such as Pinus and Eucalyptus in dry and low humidity areas are very sensitive to fire. The number of fires reported annually ranges from 50-200 depending on the prevailing weather conditions in Sri Lanka.
Types of Forest Fire
There are to type of forest fires:
1 Surface fire, and
2. Crown fire.
Surface Fire
A forest fire may burn primarily as a surface fire, spreading along the ground as the surface litter on the forest floor and is engulfed by the spreading flames.
Crown Fire
The other type of forest fire is crown fire in which the crown of trees and shrubs burn. Often sustained by a surface fire. A crown fire is particularly very dangerous in a coniferous forest because resinous material given off burning logs burn furiously. On hill slopes, if the fire starts downhill, it spreads up fast as heated air adjusted to a slope tends to flow up the slope spreading flame along with it. If the fire starts uphill there is less likelihood of it spread in downwards.
Damage of the fire to the ecosystem and their subsequent recovery depend on various factors such as fire behavior, fire duration, the pattern of fuel consumption, and subsurface heating. Fire can damage or kill trees through effects on tree species has different vulnerability to fire, which can vary on different site.
fire have both positive an negative effects to the environmental. Most of the public attention inclines to its negative effects. These include the destruction of vegetation, the loss of plants and animal, threats to biodiversity, and erosion in mountain areas when soil is exposed. Moreover fires can create favorable sites for invasive plant species to become established and flourish.
The positive impacts of fire and less widely appreciated. In place where decay is constrained by dry and cold climates, fire plays a dominant role in recycling plant debris. apart from that, fire can induce germination of dormant seeds of some species. Germination of some hand seeds can occur only after fire ruptures seed coat., allowing water to enter. Some seeds require dry heat to induce germination, but are killed by low temperatures if they have imbibed moisture.
Managing forest fire
Wildfire prevention refers to the preemptive methods of reducing the risk of fires as well as lessening its severity and spread.Effective prevention techniques allow supervising agencies to manage air quality, maintain ecological balances, protect resources, and to limit the effects of future uncontrolled fires.Policies may permit naturally-caused fires to burn to maintain their ecological role, so long as the risks of escape into high-value areas are mitigated.However, prevention policies must consider the role that humans play in wildfires, Sources of human-caused fire may include arson, accidental ignition, or the uncontrolled use of fire in land-clearing and agriculture.
Wildfires are caused by a combination of natural factors such as topography, fuels, and weather. Other than reducing human infractions, only fuels may be altered to affect future fire risk and behavior. Wildfire prevention programs around the world may employ techniques such as wildland fire use and prescribed or controlled burns. Wildland fire use refers to any fire of natural causes that is monitored but allowed to burn.Controlled burns are fires ignited by government agencies under less dangerous weather conditions.Vegetation may be burned periodically to maintain high species diversity, and frequent burning of surface fuels limits fuel accumulation, thereby reducing the risk of crown fires. Using strategic cuts of trees, fuels may also be removed by hand crews in order to clean and clear the forest, prevent fuel build-up, and create access into forested areas. Chain saws and large equipment can be used to thin out ladder fuels and shred trees and vegetation to a mulch. Multiple fuel treatments are often needed to influence future fire risks, and wildfire models may be used to predict and compare the benefits of different fuel treatments on future wildfire spread. However, controlled burns are reportedly "the most effective treatment for reducing a fire’s rate of spread, fireline intensity, flame length, and heat per unit of area" according to Jan Van Wagtendonk, a biologist at the Yellowstone Field Station. Additionally, while fuel treatments are typically limited to smaller areas, effective fire management requires the administration of fuels across large landscapes in order to reduce future fire size and severity.
Building codes in fire-prone areas typically require that structures be built of flame-resistant materials and a defensible space be maintained by clearing flammable materials within a prescribed distance from the structure. Communities in the Philippines also maintain fire lines 5 to 10 meters (16 to 33 ft) wide between the forest and their village, and patrol these lines during summer months or seasons of dry weather.Fuel buildup can result in costly, devastating fires as new homes, ranches, and other development are built adjacent to wilderness areas. Continued growth in fire-prone areas and rebuilding structures destroyed by fires has been met with criticism. However, the population growth along the wildland-urban interface discourages the use of current fuel management techniques. Smoke is an irritant and attempts to thin out the fuel load is met with opposition due to desirability of forested areas, in addition to other wilderness goals such as endangered species protection and habitat preservation. The ecological benefits of fire are often overridden by the economic and safety benefits of protecting structures and human life.For example, while fuel treatments decrease the risk of crown fires, these techniques destroy the habitats of various plant and animal species. Additionally, government policies that cover the wilderness usually differ from local and state policies that govern urban lands.
5/07/2010
5/06/2010
5/05/2010
Forestry n Environmental Science Society
Notice
Hi friends now you can become a member of young Scientist association by filling on line forum in www.youngscientistsrilanka.org and there will be a meeting on coming Saturday 9.30am at Physics dept.
5/01/2010
Leaf Feeder attack on Mahogany
Xylosandrus compactus
Black twig borer, Xylosandrus compactus has been identified as a serious insect pest in mahogany nurseries.
The Larva
The Pupa
Adult moth
The Leaves damaged by larvae
Typical Leaf web made by larva
Early stage of attack
Bushy appearance of crown due to larval feeding
Black twig borer, Xylosandrus compactus has been identified as a serious insect pest in mahogany nurseries.
Nature of damage
The larvae feed on young tender leaves and other soft tissues of the terminal portion of the host seedling. They skeletonize the leaf or sometimes entire leaf is eaten.During sever infestations, tender part of most seedlings in the nursery was damaged by the larval feeding.
As a result repeated defoliation and damage to the apical shoot, the affected seedlings exhibit symptoms of die-back in tips and several axial buds start growing and this gives a bushy form to the crown of the seedling.
Infections could be easily noticed due to the presence of webbed frass with dried veins of the leaves made by larvae on the foliage. Larvae are nocturnal feeders.
Description of the pest
Larvae are about 3.5 to 4.5cm long when full grown. The color is dull brown in the older larvae with dark lateral strips on the both surfaces.
When about to pupate, the larvae rappel to the ground and pupate on the ground litter.Pupa is reddish brown in color and 2cm long. Pupation takes place within 5-8 days. The moth is brownish grey in color and 1.5-2cm in wingspan. The moth is nocturnal and hides in the vegetation during the day time.
Economic importance
A heavy defoliation reduces the vigor of the seedlings, thereby making it more susceptible to other pests especially for black twig borer damage. Then reduces the quality of seedlings.
Management
Hand collection of larval webs and destroying them will often provide satisfactory control in nurseries.
Any foliar spray used to control lepidopteron larvae can be applied to minimize the damage. Spraying the insecticide to the foliage at the beginning of first signs is most effective.
The Larva The Pupa Adult moth The Leaves damaged by larvae Typical Leaf web made by larva Early stage of attack Bushy appearance of crown due to larval feeding
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