looking for

Habitat Depletion and Over Exploitation: BIODIVERSITY DEPLETION

The people of Bangladesh largely depend on fish to meet their protein needs, especially the poor in rural areas, several decades ago there was an abundance of fish in this country. But recently, capture fish production has declined to about 50 per cent, with a negative trend of 1.24 per cent per year (Ahmed, 1995b). Despite the constant depletion of the river, canal, and flood plain habitats for years, Bangladesh still holds the worlds most diverse and abundant inland fisheries. But the availability of many species that were very popular locally has been drastically decreased, and some are no longer found in the country. The physical loss, shrinkage, and modification of aquatic habitats for fish, prawn, turtle and other aquatic organisms are said to be the major factors involved in depleting fish varieties. Such loss or shrinkage of aquatic habitats has been the result of thousands of physical structures, dikes, and drainage systems that have been constructed in Bangladesh in an effort to control floods, cyclones, and other natural calamities. These structures have disrupted the natural flow of waters in closed rivers, diverted rivers, and have dried up water bodies.

The extensive irrigation schemes for agricultural fields, and indiscriminate use of agrochemicals are changing the feeding and breeding grounds of many fish species. Discharge of pollutant into water bodies (rivers, canals, ponds, etc.) from industries, and over-fishing (especially of juvenile and brood fishes) are highly responsible for the destruction of fish species throughout the country.

In Bangladesh, 22 species of Amphibians have been recorded (Table -1). Some of these are economically important and thus are being exploited commercially. Until the early eighties many traders in the country were exporting frog legs in large quantities. Most of the frogs were collected from the wild, and exported as a frozen food item. This practice also causes insect and predator populations to be affected.

The depletion of reptilian fauna in the country is noteworthy. Reptiles are environment friendly as they eat many agricultural pests, and help control their numbers. However, turtles, tortoises, snakes, lizards, and crocodiles are exploited economically because of a tradition of making useful commodities from their body parts, e.g., bones, skins, etc. Therefore, most of them are in high demand by traders in these items, and are over-exploited.

Mammals and Other wildlife:
The mammalian fauna of Bangladesh is the most highly affected from their habitat destruction and over exploitation. Very exceptionally people in Bangladesh use some wildlife species. Most of them are used either a food (e.g. birds, deers, wild boars, etc.), or as commodity (e.g. medicine, handicrafts, etc.), or as pet (e.g. turtles, lizards, snakes, parakeets and hill Mayna, etc.). However, the country is yet to formulate appropriate policies and guidelines to manage the utilization of these biological resources in a sustainable manner. Most of them are exploited in an unsustainable way, and hence, a number of wildlife species have become threatened.