Biodiversity conservation: Challenge and opportunity

Mohammed Solaiman Haider

Star

Bangladesh was claimed as very rich with its huge biological resources. Now-a-days, this claim is getting pale, as the rate of destruction on biodiversity is knowing no bound. As the rate of biodiversity loss is looming large, the nature loving people are raising their concern apprehending the catastrophic imbalances waiting ahead of us.

We have to curb the situation for the greater sake of the present generation and the generations to come. The prosperity of the country will always be depending on how much we are being able to maintain and conserve our precious biological diversity. Because, diversity of ecosystems and their rich floral and faunal resources have made Bangladesh resilient to natural calamities and the rich biodiversity of this land with moderate tropical climate makes it soothing for the human habitation. The richness of species diversity, health of ecosystems and habitats has been declined in recent decades for a number of reasons.

Ecosystem diversity under continuous pressure
The ecosystem diversity which made the country the bounty of nature is getting fragile day after day. The increasing population of Bangladesh continues to put pressure on existing forest resources resulting over exploitation. Bangladesh's forests have decreased significantly in terms of both area and quality over the last few decades. The annual deforestation rate is estimated to be around 3.3%

In the Ganges-Brahmaputra floodplain area, about 2.1 million hectares of wetland have been lost to Flood Control, Drainage and Irrigation development projects (FCDI). Human interference in the wetlands have been damaging the fragile ecosystem and the long-term sustainability of the wetlands. For instance, in the southwest brackish water coastal plains of Bangladesh, farmers used to have a single paddy crop during monsoon when surface saline layer depletes due to heavy rainfall and for rest of the months the field left for grazing. The practice of this culture evolved and enriched by local knowledge for centuries. However, in the last two decades, this entire practice has been abandoned to provide space for more profitable shrimp farming practice. As a result, local ecosystems became threatened because of changed water exchange system, rapid siltation of the channels and continuous inundation of land with saline water.

In the haor areas, large scale settlement was initiated at the mid-20th century from surrounding densely populated regions and since then the resources of the haor basins are being exploited at an increasing rate causing adverse effects. Continuous large scale exploitation of aquatic vegetation and fruits like Makna (Euryale ferox), Singara (Trapa bispinosa), Lotus, Lily, Hogla (Typha elephantina) has caused serious degradation of the quantity and quality of the habitat required for fish and migratory birds in the haor areas. Similarly, embankment constructed for FCDI projects reduce floodplains and obstruct fish movement and migration from rivers as well as beels to the remaining floodplains for feeding and breeding. As a result, many fishermen have lost their livelihood.

As a whole, degradation of wetlands has caused several problems including extinction and reduction of wildlife, extinction of many indigenous wild and domesticated rice varieties, loss of many indigenous aquatic plants, herbs, shrubs and weeds, loss of natural soil nutrients, loss of natural water reservoirs and of their resultant benefits, increase in the occurrence of flooding and degeneration of wetland based ecosystems, occupations, socio-economic institutions and cultures.

Our Mangrove Ecosystem, the Sundarbans shows a general trend of reduction of commercially valuable species like the Sundari and Gewa and increase of less valued smaller tree species. This might be because of the changed scenario of the salinity regime in the eastern part due to decreasing freshwater influx from the Gorai River. The vegetation community in the western region found to be more stable as the hydrological regime in this area remained stable.

The area of settlement and consequently homestead vegetation is growing gradually for the last few decades. Moreover, tree density of the homestead has also increased in the recent past. However, the quality of the homestead ecosystem has declined rapidly, because of the commercialization of the land. Species diversity reduces drastically with rapid increase of commercially valuable species. Loss of plant species diversity also reduces the quality of wildlife habitat by reducing food sources and other microhabitats essential for supporting the integrity of the food chain.

Two most notorious AIS, Chromolaena odorata and Lantana camara are occurring side by side in all forest lands in the country.

The major rivers bring in large concentrations of pollutants from agricultural pesticides and industrial waste that damage fish spawning and nursery areas, cause fish kills and lead to possible changes in tropic structure.

High levels of pesticides can be found along the coast, especially near cities and ports. Input of freshwater from upstream and silt influence the pollutant dilution and salinity of the coastal and estuarine waters as well as coastal circulation patterns. It is also seriously endangering the existence of the existing corals islands. Other than this, huge population burden and associated poverty, unsustainable fishing practices and a decline in income from fisheries are contributing to crisis generation. Other economic activities are tourism and the mining of coral and sand for construction also hampering the marine environment. Other issues of ecosystem health that are common throughout the coast are: environmental stresses on the Bay of Bengal's water quality; the degradation of many of the coral, mangrove, wetland and seagrass bed habitats that support fisheries; and the use of harmful fishing gear affecting the long-term sustainability of the fisheries resources

Recent research findings have indicated a rising trend of imbalance and indiscriminate use of agricultural inputs, which has already created threat to the proper functioning of the country's' agroecosystems. Land degradations due to over utilization, landuse change and construction of various man-made infrastructures have aggravated this situation in most of the agroecological regions of the country.

Species diversity declining
For a small country like Bangladesh, the species richness is relatively large but population sizes of most of the species are gradually declining. Thirteen species of vertebrates are so far extinct from Bangladesh. Among these, Pink-headed Duck suffered global extinction; all other species are locally extinct. Virtually all mammalian wildlife species of the country are endangered in a way or another. It is evidential that mammals are the most endangered group of wildlife. Most of the larger mammals are either extinct from the country or on the verge of being so

List of extinct vertebrates from Bangladesh
Of the birds that have extinct from Bangladesh, only one species (Pink-headed Duck) has become globally extinct. The remaining 29 species of birds have been extinct locally, but continue to occur elsewhere in the region.

Population amphibians and reptiles are shrinking fast due to the destruction of their habitats. It is highly probable that many amphibian species may become extinct even before the discovery of their presence in Bangladesh.

Invertebrate population and diversity in the country is reducing. Although many studies have not yet been carried out in this regard but indiscriminate use of agricultural chemicals, especially chemical fertilizers, herbicides and pesticides are the main cause of declining trends of invertebrate population of the country.

Floral diversity shrinking progressively
Common conception about floral diversity loss is fairly established, although no scientific surveys for this purpose have conducted in the recent past. The number of angiosperm flora describes in the recently published Encyclopaedia of Flora and Fauna is 3,611. At least one fourth of these species are very rare and many not seen or collected after its first collection about 100 years or before. Many of the endemic floras have not been collected or reported since they were first described. Bangladesh National Herbarium published a Red Data Book of Vascular Plants of Bangladesh (2001) listing 106 species of threatened plant species of various categories. A second volume of Red Data Book of Vascular Plants of Bangladesh is under preparation.

Genetic diversity eroding as a result of Green Revolution
Genetic diversity of different crops and cereals are declining sharply. In the name of green revolution, new high yielding varieties are introduced from early Seventies. Out of thousands of rice varieties, the farmers now commonly use only about 25 varieties. Similar kind of declining trend has been occurred in other cultivated crops varieties as well. Reduction in number of species and decline of wild flora and fauna is also a common trend like elsewhere in the world.

For wild flora and fauna, declining trend is mostly attributed to habitat loss. Fragmentation of forest and other natural areas caused great loss of species diversity as well as its genetic resources. Reduction of population size and fragmentation of habitat forced the wildlife to inbreed causing genetic erosion.

Threats to biodiversity
There are many drivers of biodiversity loss, among which some are direct and dynamic while the others are indirect. Direct threat includes landuse change, habitat destruction, introduction of invasive alien species etc. On the other hand, indirect threats are economic system and policy of the country; unsustainable exploitation of resources and weak management system; gaps in spatial information, lack of public awareness etc.

* Change of landuse (High population growth and natural resource consumption)

The pressures that brought change in the landuse in both terrestrial and aquatic environments include, demand for increased agricultural lands, collection of fuelwood and non-timber forest products by the local communities. More and more natural habitats are converting into human habitations due to high growth of population and economic activities. As a small country with high population and limited natural resources, it is obvious that the competition for these resources is immense. At present, the country has 85 thousand hectares of agricultural lands, of which 1% is being converted annually to other land use patterns. Urbanization is another major concern for the country, causing rapid shrinkage in agricultural lands. Development of

infrastructures such as communication networks and flood control and irrigation infrastructures are also bringing rapid change in the landuse.

* Fragmentation and loss of habitat
Fragmentation of habitats has been extensive and continues to occur at a rapid rate across the country. Habitat fragmentation typically reduces total habitat area, size of individual habitat patches, and proximity of habitat patches, and it can increase the amount of habitat edge. Reduction in the area of suitable habitat can result in population declines for most of the species by simply reducing adequate space for territories and other critical resources. Changes in habitat patch size, proximity of habitat patches, and the amount of edge-habitat also can affect wildlife populations by negatively affecting reproductive success, survival, and/or immigration rates in the remaining habitats.

* Change in hydrological regime
Reduction of upstream flow is one of the major causes of concern for reducing biodiversity of the country. Additionally, changes in land use and development of numerous flood management infrastructures have also played key role to change the hydrological cycle of the country. Other infrastructures such as roads and railways have also created obstacles for the waterways. These changes in hydrological regime not only reduced the fish production by changing the migration routes and spawning grounds but also influencing negatively the habitat quality of many other aquatic and terrestrial wildlife by changing the water availability for their existence. Reduction in the availability of freshwater is posing severe threat to the species composition and biodiversity of Sundarbans, the largest mangrove in the world.

* Pollution
With the increase of industrial units across the country without having effective waste management practices, the pollution level for both terrestrial as well as aquatic habitat is on the rise. Many of these industries are dumping their waste directly into neighbouring agricultural fields or water bodies. The situation is extremely bad for water bodies near all the major cities of the country. The situation is further worsened because of the release of untreated sewage from most of the cities. Agricultural run-off, growing use of agricultural chemicals such as fertilizers and pesticides, are major source of pollutant across the country posing potential threat to the genetic resources to be faded out.

* Uncontrolled tourism
The development of unplanned and uncontrolled tourism is becoming one of the major threats for the degradation of biodiversity at hot spots. For example, the biodiversity of St. Martin's island, Lawachara National park and Madhabkundu Ecopark have been facing a continuous threat from unmanaged or poorly managed tourism.

* Unsustainable agricultural practices
Introduction of high yielding varieties coupled with hybrid seeds are causing sharp decline in the country's crop genetic resources. Changes in agricultural system are the main causes of genetic erosion in agricultural biodiversity. Out of more than 10,000 rice cultivars only 22 are mostly used now, leaving behind the vast genetic resources accumulated through the painstaking work of our farmers. With the advent of High Yielding Varieties (HYVs), farmers have stopped using most of these old varieties that they used to possess earlier. Slush and burn practice in the hilly area is also not sustainable in present form. Traditionally it was done in a long 5-7 years return period, but with present population growth, the return period shrinks to 2-3 years making the area vulnerable to be denuded and thus exposed to landslide and erosion. This small return period also do not provide enough time to re-vegetate the area to support the wild flora and fauna.

* Invasive alien species
A large number of non-native species have been introduced in Bangladesh with various purposes including agriculture, horticulture, forestry, animal husbandry, fisheries development, pet animal and ornamental aquarium species. Although some of them escapes in the wild and adapted with local condition, but many of them became invasive. Many exotic turtle species have been introduced to natural water bodies by the aquarium shops. Most of the identified alien invasive species found in Bangladesh are plant species and are known worldwide for their invasiveness. Two of the most common are Chromolaena odorata and Lantana camara; these two cryptic invaders are established in our forest floor and out-competing our local species, especially in the open areas of forest margins.

* Climate change
Bangladesh is one of the most vulnerable countries to climate changes, variability and extreme events and the country is suffering from severe impacts because of its low-lying nature and dense population. The coastal zone including the world's largest stretch of mangrove ecosystem, the Sundarbans (has been declared in 1997 as Ramsar Site), is facing a serious threat of loss of biodiversity due to change in climate. Northward penetration of the salinity front due to climate change would result in salinity induced succession problems in the Sundarbans and as a result, the symbiotic process in the entire ecosystem would change completely. Since the rate of these changes are much higher compared to the rates at which forest species migrate to suitable places, the size of the (actual) forest will be less compared to its present size. Forests and agricultural systems are vulnerable to increased incidents of disease and pest outbreaks as a result of changing climatic conditions. Moreover, with the ensuing threat of climatic changes, the existing agroecosystems of the country could be under heavy pressure to feed the population.

The increased salinity in the estuarine region would also change the species composition of freshwater fishery, as many freshwater fish are sensitive to salt water. The coastal zone would also be negatively impacted, as increasing water level would lead to considerable habitat loss in the short term.

A wide range of mammals, birds, amphibians, reptiles, crustaceans, and above all the Royal Bengal Tiger will face extinction in Bangladesh due to climate change. For some species there will no longer be anywhere with a suitable climate to survive; in other cases they may be unable to reach distant regions where the climate is suitable. Other species may survive elsewhere only to face new threats, notably if the new area is covered by crops or urban sprawl.

Climate change over the past 30 years has produced numerous shifts in the distribution and abundance of species worldwide. Climate change can affect the distributional area of each species independently. Climate change has already produced shifts in the distribution of some species, such as amphibians, grasses, migratory birds and butterflies.

* Lack of knowledge and awareness
Lack of information and knowledge generally leads to gaps in awareness. Gaps in awareness have been identified at various levels. To start with, most people do not even know that there are so many species of organisms occurring in Bangladesh. Most of the people do not know that there are laws that ban hunting and trade in wild animals, there are laws that protect certain species and ecosystems and that there are laws that are meant to control environmental pollution.

* Legal and institutional systems that promote unsustainable exploitation
A number of laws have been come into force in last four decades those are directly or indirectly addressing the issue of biodiversity conservation. Bangladesh Environment Conservation Act 1995 is one that has clear mandate to conserve overall environment along with biological diversity and ecosystems. To fulfil the mandate of the Environment Act, the Department of Environment (DoE) is not yet strengthened enough with adequate work force and other facilities. To deal with the three basic obligations of the Convention on Biological Diversity (CBD) viz., conservation of biological diversity, sustainable use of its components and fair and equitable sharing of benefits arising out of uses of genetic resources, the institutional setup at the policy level is not mainstreamed and sensitized. Outdated bureaucracy in the governance and administrative arena is not yet supportive enough for knowledge-based conservation and management of biodiversity in Bangladesh.

Overall, there is a lack of integration of environmental considerations in planning resulting in the absence for a truly integrated land and water management. Due considerations on environmental issues were farsighted off the development activities like roads and highways development, polders and embankments development, barrage and dam construction.

Excessive climatic uncertainty, fishing and overexploitation of coastal resources, water quality deterioration, mangrove destruction for shrimp pond excavation, lack of public awareness and rampant rural poverty, institutional and legal limitations, cyclones, etc. are some of the major problems which need to be addressed on a priority basis for conserving our biological resources.

Way forward
Bangladesh is globally, committed to conserve its Biodiversity as the country is a party to the Convention on Biological Diversity (CBD) and signatory to the Convention on International Trade on Endangered Species of Wild Flora and Fauna (CITES), UNESCO World Heritage Convention and Ramsar Convention on Globally significant Wetlands. Our traditional knowledge to conserve biodiversity. We have got rich traditional knowledge to conserve biodiversity. We have also an uprising generation to come up with knowledge-based resource management. The much thing we need is our policy level endeavor to implement effective action plans to conserve biodiversity. Biodiversity conservation should be placed on the high of the agenda of the government. Rules-regulations should be formulated or in some cases be updated with the core concept of conservation and sustainable use of the components of biodiversity. Bangladesh, in 2004, has developed National Biodiversity Strategy and Action Plans (NBSAP).

Bangladesh has enacted environment conservation act and rules and regulations. Environmental Impact Assessment has been made mandatory for development interventions which have much impact on the environment. Bangladesh has nineteen nationally designated protected areas comprising approximately 2,458 km2, which is 1.66 percent of land area of the country. These include ten national parks, eight wildlife sanctuaries and one game reserve.

Bangladesh has so far declared 9 areas significant in biodiversity and environment conservation, as ecologically critical areas (ECAs). Government has already undertaken project initiatives towards conserving some of these important areas. United Nations declared 2010 as the International Year of Biodiversity. To commemorate the year, government has chalked out various events of public awareness. Government is going to submit the Fourth National Report to the Convention on Biological Diversity. Bangladesh has finalized the Fourth National Report on implementation of the Convention on Biological Diversity, which came up with Biodiversity Program of Action (BPA) 2020. BPA covered the immediate and urgent needs of activities to be implemented towards strengthening biodiversity conservation in the country. Government and the development partners should come forward to implement BPA ensuring ecosystem approach and people's broader engagement in biodiversity and natural resources management.

The author is Deputy Director (Technical), Department of Environment.

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