Healing of the Sundarbans following Sidr
Cyclone Sidr hit areas showing disturbed and undisturbed forest stands for systematic sampling in which line transects and plots are positioned at a definite interval to capture the maximum diversity and environmental conditions.
This article examines the possible environmental problems that the forest might face after Sidr devastation and looks at management approaches to address them. The Sundarbans mangrove is the salt-tolerant forest ecosystem like the other coastal mangroves of Southeast Asia, and is the last large wilderness area of significant natural beauty in Bangladesh with a number of critically endangered animal species, such as the world renowned Royal Bengal Tiger, marine turtles, estuarine crocodiles, dolphins, and several rare bird species. With the recognition of the Sundarbans as a world Heritage Site, conserving and promoting biodiversity of this unique forest is an imperative. However, severe cyclonic disaster of November 15 over the eastern part of Sundarbans has disrupted the species-rich productive part of the forest that represented varieties of economic, social and environmental values. Environmentally, Sundarban mangrove ecosystem is a vital shelterbelt for protection against tidal waves, storms and cyclones. The dominance of tree species that composite in this wet-land ecosystem not only serves a strong wind break but also its ecologically adapted root systems act as a anchor against frequent river bank erosion. While the ecological successions following the degree of salinity had greatly influenced the distribution of species and stand-height from 10m to more than 15m in the eastern part of the Sundarbans, following cyclone Sidr, the stand-height has drastically reduced in severely damaged areas. Environmental aspect of cyclone Sidr however suggests much delaying of the recovery process for the original composition and its structure. But question is that, do mangroves survive in the environmental disaster? Or, does it require re-establishment? Mangroves survive well in the environmental disaster as the forests rely on some natural disturbance to maintain its biodiversity. But if the ecological factors become extremely adverse then the regenerations are much delayed. Re-establishment of mangrove species under the normal situations also showed unsuccessful and was not environmental friendly. Studies on Timber Stand Improvement (TSI) in the Sundarbans which included 'enrichment planting', 'assisted natural regeneration (ANR)' and 'golpata plantation' showed less than 50 percent of the physical target of TSI achieved and the condition of plantations and survival of seedlings not satisfactory. The high cost of TSI and its justification in the mangrove forest has therefore become a debatable issue. Only rare and endangered tree species such as, Passur, Dhandul, Amur can be re-established through a pilot study where natural regeneration is impossible. But what happened in the case of ANR? In the name of ANR, forest stands were thinned, non-timber ground cover and climbers having biodiversity value have so far been damaged or removed without clear understanding of ecological consequences. Based on the above facts, the man made attempt in healing the cyclone affected areas of Sundarbans is of no consequence, and no success history is also available. The only way is to encourage natural regenerations by keeping the forest undisturbed, threat free. This conforms to the aerial photographs flowing cyclone Sidr in which patches of comparatively dense forests have been tremendously decelerated by the wind velocity through tree boles and crowns keeping the inner side of forest almost intact. This learning is important as historically illegal felling of timber and over-harvesting of plants and aquatic resources and their effects on biodiversity have been the subject of many newspaper articles. The recent cyclone Sidr attack over the forest and its vicinity could have been much less if human induced damage of the forest would have been under control. Reports are available on how the core problem “Sundarbans biodiversity resources in depletion” is caused by different factors. Out of the nine factors that were identified as the main causes behind the depletion, the major one was the insufficient capacity to manage the resources in a sustainable way. For example, fish stock assessment in the Sundarbans done by Aquatic Resource Division of Forest Department showed severe stock depletion due to catching of juveniles and use of destructive nets. The Chakaria Sundabans of southeastern part of Bangladesh vanished some decades ago due to over harvesting and illegal. But once it was full of biodiversity-rich flora and fauna. Forest formation after natural disturbance possesses inherent resistance against the natural calamities as compared to man made creation of new habitat and thus natural diversity makes the ecosystem stable. There are some possible effects of cyclone Sidr on plant species diversity. Recoveries of plant species diversity in cyclone-hit wetlands are highly variable due to intensity of disturbance. In heavily damaged compartments, the species of low abundance may even become extremely rare or become extinct, and the number of individuals of dominant species may be drastically reduced, affecting structure of the forest. However, spatial and temporal heterogeneity following Sidr may increase total species diversity particularly at intermediate frequencies of disturbance. A year after tropical cyclone Larry crossed the far north Queensland coast, the World Heritage areas were found recovering better than the adjacent forest landscapes, because the Heritage areas, were quite well protected. Cyclone Sidr might also extend the top-dying of Sundari trees. Studies on top-dying Sundari have detected some indications which relate to the ecological conditions of the affected area. Top-dying was predominant in areas with high sedimentation rate where the number of pneumatophores (breathing roots) were significantly less. This suggests the low redox potential, which is a measure of soil aeration, in the top-dying areas. Canopy openness was also found responsible for enhancing the severity of top-dying. As such, in the Sidr affected forest floor where heavy sedimentation have been accumulated and the original soil physical structure and canopy closure is severely disrupted, the changing microclimates there could enhance the severity of top dying. Management approachesConducting cyclone Sidr damage assessments: Meanwhile, a very rough idea on the damage to flora and fauna is available as per report published in many newspapers. In the past there was no intensive study on the cyclone hit areas of Sundarbans. FD should now mobilise their field staff to assess damage done by Sidr to the residual stands by systematic sampling with appropriate statistical precision. Systematic sampling may be stratified also to capture maximum variation in the environmental conditions. By classifying various types of Sidr injury to trees, the results can be summarised as percentage intact, lost (smashed or dead) and damaged (trees that survived after injury) for trees of more than 1.5m height. Measurements must be done at three different size classes: saplings, poles and timber. Regeneration status of different plant species should also be registered along with habitat types. This data base of Sidr injury might influence the FD's existing inventory in stock analysis and understanding biodiversity status (abundance and rarity) of the residual stands as additional contribution. Holistic approach of resource management: It may be mentioned here that the existing management plan of the forest is not based on the ecosystem and biodiversity approach, rather the plan guides commercial production of timber and other forest products. As a result, past management inventory targeted the species of low abundance for felling and thus gradually they become rare and extinct from the ecosystem. The recent devastation of Sidr strongly suggests revising the management plan with due consideration of ecological and biodiversity parameters so that all species of plants are equally cared. Support integrated resource management :The management of Sundarbans should be more intensive, integrated and continuous, and can not be always donor based. Long-term integrated management plan for all aquatic and terrestrial resources must be developed for a period of 20 years or so with the aim of securing funds from the revenue budget. FD's existing capacity should be broadened in terms of trained manpower to manage the resources in a sustainable way. Provision of hardship allowance is of vital importance to build up morality of the field staffs. People living in the impact zone are to be identified properly and engaged in different income generating activities through funding from PKSF to reduce their dependency on Sundarban resources. Policy reform: Improvements to natural resource management policies affecting forest conservation should be given the highest priority. The recent widespread devastation by the cyclone Sidr of the eastern part of Sundarbans and its likely occurrence in future strongly suggest existing management system should be more oriented towards ecological and conservation approach. The Forestry Master Plan prepared for the period 1993-2012 emphasized the critical need for effective policy, legislation and improvement mechanisms for conservation, protected area management, wildlife management and biodiversity. Policies should also give priority to establish field based and well integrated research units with support system and build up human resource capacity to conduct research. Nowadays, emphasis is being placed to integrate biodiversity and ecological aspects into forest management planning, policy and research issues. Dr. Saiful Islam is Director, Forest Academy, Chittagong. Former Project Director, Sundarban Biodivesity Conservation Project.
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