Conserving our biological diversity
MAY 22 is observed as the International Day for Biological Diversity (IDB) all over the world. The theme for the IDB in 2009 is Invasive Alien Species -- one of the greatest threats to biodiversity, and to the ecological and economic well-being of society and the planet. The theme provides the parties, which have signed the Convention on Biological Diversity (CBD) and those dealing with invasive alien species, opportunity to raise awareness of the issue and increase practical action to tackle them.
According to the CBD, biological diversity means the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems, and the ecological complexes of which they are part; it includes diversity within species between species, and of ecosystems.
What are invasive alien species and why are they a big threat to biodiversity, ecology and economy? What measures and steps should be taken to tackle the problem?
According to various studies, invasive alien species are plants, animals, pathogens and other organisms that are non-native to an ecosystem, and which may cause economic or environmental harm or adversely affect human health. In particular, they impact adversely upon biodiversity, including decline or elimination of native species -- through competition, predation, or transmission of pathogens -- and the disruption of local ecosystems and ecosystem functions. For instance, native to the Amazon basin, water hyacinth has invaded tropical habitats worldwide blocking waterways, decimating aquatic wildlife and the livelihood of local people and creating ideal conditions for disease and its vectors.
Suggestions made by the experts to tackle the problem globally, include: preventing the establishment of potentially invasive species through customs checks, inspection of shipments, and setting quarantine regulations to try to limit the entry of invasive species; developing economic tools and incentives for the prevention of introductions; and educating the general public and raising their awareness.
The CBD, which was signed by representatives of more than 150 countries including Bangladesh at the Earth Summit in Rio de Janeiro in June 1992, "places a duty on States Parties to conserve biological diversity within their jurisdiction, as well as outside their jurisdiction in certain cases."
Biological resources and diversity form the basis of both the ecology and economy of Bangladesh. Its rivers and other inland water bodies, its marine water bodies, forests provide habitats for its fauna and flora. According to Bangladesh State of the Environment Report- 2001, there are nearly 10,000 species of plants, animals, and microbial organisms -- a good percentage of which are found in abundance. But that does not provide any room for complacency.
A number of species of fauna and flora are endangered or critically endangered. Available studies suggest that there are 54 species of inland fishes, 8 amphibians, 58 reptiles, 41 resident birds, and 40 mammals, which are threatened throughout the country. Among the marine and migratory species of animals 4 fishes, 5 reptiles, 6 birds and 3 mammals are threatened. Among the plants, 96 seed-bearing plant species are threatened.
The depletion of biodiversity is the result of various kinds of human development interventions and activities, especially in the areas of agriculture, forestry, fisheries, urbanisation, industries, chemicals, minerals, transport, tourism, and energy.
More important and relevant to the topic is the introduction of some invasive alien species. A study on Sunderbans shows that over the past decades, invasive species have spread significantly in the mangrove ecosystem. Of the identified 23 invasive species, 19 are native or naturalised to Sunderbans mangrove. The study thus suggests that invasion in Sunderbans is still at controllable stage.
Available sources suggest that introduction of alien invasive species of flora and fauna were deliberate in Bangladesh, primarily, to increase productivity to meet the needs of a huge population. However, some of them were introduced for decorative or ornamental purposes. Almost all of the alien invasive species in Bangladesh possess the characteristics of high growth rate.
To conclude, the rich biological diversity of Bangladesh is crucial for survival and progress of her people. So, the need for conservation of her native fauna and flora can hardly be over emphasised. Extreme care is also required to introduce any alien species.
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