Biodiversity -- which way?
Gazi Nurul Alam
By a dictionary sense, Biodiversity is the total sum of flora and fauna in a given habitat that maintains a balanced environment. According to the view points of environmentalists, biodiversity indicates, with regard to the number, ecological status and frequency of all creatures living on this earth including plants and microorganism (bacteria). It is rather a common or popular term that refers to the variety and variability among living organisms and ecosystem complexes where they inhabit. So lastly biodiversity may simply be defined as the number of species of plants, animals and microorganism that live in a particular ecological niche. In a wider sense, the term biodiversity refers to genetic diversity, species diversity and ecosystem diversity.It is known to general people that the tropical and sub-tropical zones of the earth support the most diverse ecological conditions. Tropic of cancer passes across Dhaka-Narayanganj, thereby placing northern one-third of Bangladesh in temperate and southern two-third in the tropical zone, geograhically speaking. The presence of the mighty Himalays on the north and the direction of monsoon winds have tremendous impacts on Bangladesh enabling her to have ecological conditions of tropical nature and share the rich potential of fauna and flora. Bangladesh is approximately 147,570 square kilometers in area with an estimated total population of 138 million. It is very densely populated country of the world with more than 800 people per square kilometer. Bangladesh is uniquely endowed with rich and potential biodiversity which surprises the observers. Within its 56000sq miles it has a wide variety of biodiversity, the list of which is given below with comparative statement it shown with immediate neighbour India, and far away France and the world as a whole. Loss of biodiversity
Of course the loss of biodiversity is a global crisis, and such happenings are also common in Bangladesh. There is broadly any region on earth that is not facing ecological catastrophes. Of the 1.5 million species known to inhabit the world, one-fourth to one-third is likely to extinct within the next few decades. Biological extinction has been a natural phenomenon in geological history. But man's intervention has accelerated the extinction rate all the more. Between the years 1600 and 1950, the rate of extinction went up to one specie every 10 years. But currently it is perhaps one specie every year. Unfortunately, 18 or 20 important animal species became extinct from Bangladesh in 19th and early 20th centuries, even before we could realise what was going on and why. According to IUCN, Dhaka at lot of animal fauna are at high risk now. So they have been treated as endangered species. A list of endangered species of different animal groups, as prepared by IUCN is given below. Known Endangered
species species
Amphibia-19 8
Reptile-145 58
Birds-579 41
Mammals-199 40
Fishes-260 54
(Fresh water)
Plants 5000 27 The last century saw the extinction of six mammal species including the Javan Rhino, the swamp deer indeginous to Sundarbans and over 46 wildlife species have been listed as endangered (The Daily Star, Feb, 17, 2002). Furthermore, 40 species of animals has been listed as threatened with extinction. It is not more than twenty or twenty five years ago wild cats (Jungle cats) were available not only in woodlands but also in the in-situ. Now due to over population and infrastructure development this species has been exterminated. Also Gangatic Dolphins and Otters are also threatened mammals. Once upon a time, Bangladesh was unique for its various birds population of which 40 species are now threatened and 50 others are nearly threatened. The most endangered species of birds are white winged duck, camb duck, stork, crane, pheasant and patridge. Not only birds, fish resource of Bangladesh is also depleting for the same reason. It has been reported that fisheries catch has dropped by an average of 9 per cent every year over the past decade. Therefore Dr. Yousuf Ali, former Secretary of the Department of Fisheries writes that if the present trend continues, in 50 or 100 years there may be no open water fisheries production at all. Bangladesh has a rich variety of floral species also. Once upon a time, most of the Bangladesh's forest had a rich variety of floras but nowadays due to the deforestation, over harvesting, grazing, illegal felling, uncontrolled and wasteful commercial exploitation, floral species are depleting. Bangladesh has 4500 floral species out of which 80 species are endangered and 100 threatened. From a news report it is found that over-harvesting and top dying have caused a staggering 76 per cent decline in the number of Sundari trees. Diversity of native fish species is important to future employment and food self-sufficiency. But ongoing destruction of wetlands for agricultural use is a key threat to these species. Causes of loss
Factors affecting the loss of biological diversity include deforestation, forest conversion, agricultural and industrial pollution, irrigation, flood control developments, shifting land use and over exploitation of biological resources. Besides, almost all the terrestrial land is occupied by human beings, therefore the habitats of other lives are seriously hampered and they have to started decline. In the name of development work all over Bangladesh we care causing serious environmental degradation. Some of the salient causes for the degradation of biodiversity in both the terrestrial and aquatic ecosystem are given below: 1. Human interference for agriculture and settlement. 2. Unsustainable use of natural resources. 3. Hill clearing, cutting and destruction 4. Destruction of habitats of organisms 5. Illegal hunting of animals. 6. Traditional management practice. 7. Encroachment 8. Short sighted development efforts 9. Overexploitation. 10. Collection for zoos, studies and researches. 11. Loss of indeginous species by introduction of exotic species. But still we have a rich flora and fauna on our soil. We must save them with judicious approach to development. Suggested recommendations
The following steps may be taken for conservation of our valuable biodiversity: 1. Preparation of inventory of biodiversity including ecologically critical areas and protected areas. 2. Promoting environment friendly activities. 3. Preserving, protecting and developing natural resources. 4. Judicious exploitation of valuable biological resource. 5. Promoting participatory, community-based environmental resource management and environmental protection. 6. Ensuring active participation of the poor, especially women in environmental protection activities. 7. Strengthening the capabilities of public and private sectors to address environmental concerns. 8. Creating public awareness for participation in environment protection activities. 9. Conserving non-renewable resources and sustaining auto-and eco-generation of renewable resources. 10. Promoting sustainable environment management in pursuit of quality livelihood and alleviating poverty. 11. Discouragement of mono-culture. 12. Protection of domesticated plants and animal species in order to conserve indeginous genetic diversity. 13. Support for protecting traditional skills and knowledge for conservation. 14. Restriction on introduction of exotic species without adequate investigations. 15. Multiplication and breeding of threatened species through modern technique of tissue culture and biotechnology. 16. Protection and sustainable use of genetic resources/germplasm through appropriate laws and practices. 17. Conservation of biodiversity through network of protected areas including national parks, sanctuaries, biosphere reserves, marine reserves, gene banks, wetlands and coral-reefs etc. Gazi Nurul Alam is a senior biologist.
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