Pakistan Journal of Biological Sciences

Year: 2008 | Volume: 11 | Issue: 3 | Page No.: 373-379
DOI: 10.3923/pjbs.2008.373.379

A Survey on the Faunal Diversity of Savar Upazila, Dhaka, Bangladesh

Md. Eftekhar Hossain, Mohammad Mamun Chowdhury and Kazi Farhed Iqubal

Abstract:

A survey was conducted during January to December 2006 to assess the status of faunal diversity of Savar Upazila, Dhaka, Bangladesh. A total of 30 species of birds, 24 species of winter birds, 7 species of reptiles, 3 species of amphibians, 15 species of mammalians and 32 species of fishes were recorded. Relative abundance of those species were determined. Of the birds, House Sparrow (Passer domesticus) was abundant while Blyth's Kingfisher (Alcedo hercules), Rock Eagle Owl (Bubo bengalensis), Hooded Pitta (Pitta sordida), Black-headed Oriole (Oriolus xanthornus), White-winged Duck (Cairina seululala) and Duck (Anser indicus) were rare. The relative abundance of winter bird could not be assessed because of their migratory habit. Striped keelback (Amphiesma stolata) and Common Smooth Water Snake (Enhydris enhydris) were very common while Black pond turtle (Geoclyms hamiltonii) and Pond tortoise (Melanochelys trijuga) were recorded as endangered. Common Toad (Bufo melanostictus) were abundant but Bull Frog (Rana tigrina) was rare. Asiatic Wild Dog (Cuon alpinus) and House Mouse (Mus musculus) were abundant while Common Otter, Large Indian Civet, Irrawaddy River Dolphin, Indian Hare were rare. Carpu, Silver carp, Tilapia, Nilotica were abundant while, Freshwater Garfish, One stripe spinyeel and Grey Featherback were rare. Landfilling, deforestation, poaching, industrial effluents and current jal were identified as major threats to the faunal diversity of Savar area.

Keywords: Bangladesh, faunal diversity, relative abundance, birds, reptiles, amphibians, mammalians and fishes

INTRODUCTION

Biodiversity is a key component for sustainable environment. But pressures on the environment caused by economic development and other human activities make it difficult to protect natural areas that are large enough to accommodate entire ecosystems. On the other hand ecosystems need to be treated with care, because they provide goods and services that are vitally important for human well being (Graham, 2004). In this context, precise and regular information on wildlife abundance and trends needs to be generated to ensure that management schemes are adaptive and allow for a sustainable use of wildlife populations (Kremen et al., 1994; du Toit, 2002). Several years back, most of the areas of Savar were sanctuaries for avifauna, wildlife and fisheries, which made it rich in faunal biodiversity and a well functioning ecosystem existed. But now, the vast land of Savar upazila including low lying areas and wetlands are under the process of encroachment for building a number of residential model cities and industries as Savar upazila has some standard opportunities for living and excellent communication system with Dhaka city. The ongoing transformation of the areas of Savar may bring unpredictable changes, which can lead to ecological disaster and socio-economic shifting. The current study was therefore carried out to assess the faunal diversity, which may serve as a database for the future conservation action plan.

MATERIALS AND METHODS

Savar upazila is situated at a distance of about 24 km to the Northwest of Dhaka metropolis. It lies between latitudes 23 45.5` N to 24 02` N and longitudes from 90 11` E to 90 20.5` E with an area of 280.13 sq km. The Upazila consists of one municipality, 9 wards, 11 union parishads, 175 mouzas and 321 villages (Fig. 1). The data collection was based on direct observation on the animals in the field. Different survey methods i.e., plot counting for amphibians and reptiles, transect line counting and block counting for birds and mammals and catch assessment, market survey and information on gears for fishes were used according to MOEF (2001). During

observations, necessary equipments: color coated binoculars, telescope, sound tracker, digital still camera and camcorder, tape recorder, nets, traps and spotlights were used. Rivers, canals and wetlands were accessed by a motorized boat while the other areas were covered by foot. Fauna were identified upto species level according to Khan (1982), Grewal (2000), IUCN (2000a), Rahman et al. (2000) and Rahman (2000). Besides local people were interviewed and questionnaires were distributed among them to know the existence and assess the status. The study was conducted from January to December 2006.

AND DISCUSSION RESULTS

A total of 30 species of birds belonging to 9 orders and 17 families were recorded from the study area (Table 1). Of these, 30 species, 9 species were both forest and wetland dwellers, 7 species forest dwellers, 7 species were both wetland and agricultural land dwellers, 5 species both forest and agricultural land dwellers while only 2 species were agricultural land dwellers. Only House Sparrow (Passer domesticus) was abundant while Black-rumped Flameback, Roseringed Parakeet, Rock Pigeon, Red Collared Dove, Indian Pond Heron, Great Egret, Indian Robin, Red vented Bulbul and Common Myna were very common, Grey-capped Pygmy Woodpecker, White-breasted Waterhen, Grey Heron were common, Rufous Woodpecker, Common Kingfisher, Brahminy Kite, Yellow-throated Laughing thrush, Spot-throated Babbler were fairly common, Indian Cuckoo, Crested Serpent Eagle, Black Kite, Golden-fronted Leaf Bird were few, Common Tailorbird, Baya Weaver were very few and Blyth`s Kingfisher, Rock Eagle Owl, Hooded Pitta, Black-headed Oriole, White-winged Duck, Duck were rare. According to IUCN (2000b) country status, Blyth`s Kingfisher (Alcedo hercules) was the only endangered species and 3 other species were critically endangered i.e., Yellow-throated Laughing thrush (Garrolax galbanus), Spot-throated Babbler (Pellorneum albiventre) and

White-winged Duck (Cairina seululala). So, considering both status, Blyth`s Kingfisher and White-winged Duck need immediate conservation. On the other hand, the locally rare species should be taken into account for conservation measures.

It was observed that during the months from October to May, several thousands of winter birds visited wetland areas of Savar and in respect of other places in Bangladesh, Savar was being chosen by the winter birds as their suitable habitat. A total of 24 species of birds

belonging to 1 order and 2 families were found during the study period (Table 2) but their relative abundance could not be assessed as they were absent in Summer and data on their IUCN country status was unavailable.

Table 3 shows that only 7 species of reptiles were found in the study area. Of the 7 species, 2 species belongs to the order Testudines, 2 species belongs to the order Lacertilia and 3 species belongs to the order Serpentes. All the 3 species of snakes were found in pond, wetland and agricultural land. Common Garden Lizard and Common Skink were found at forest and agricultural land while 2 species of turtles were pond dwellers. Striped Keelback and Common Smooth Water Snake were very common, Chekered Keelback was common, Common Garden Lizard and Common Skink were very few, while Black pond turtle (Geoclyms hamiltonii) and Pond tortoise (Melanochelys trijuga) were rare which were also reported by IUCN (2000b) as endangered.

Table 4 shows that only 3 species of amphibians found in the study area. Common Toad (Bufo melanostictus) were abundant whereas Cricket Frog (Limnonectes limnocharis) was fairly common and both of them were forest, wetland and agricultural land dwellers. Relatively the abundance of Bull Frog (Rana tigerina) was alarmingly rare and confined in forest areas though IUCN (2000b) reported it as not threatened (NO).

A total of 15 species of Mammals were recorded from Savar area (Table 5) of which 7 species were forest, agricultural land and wetland dwellers, 5 only forest dwellers, 2 both forest and agricultural dwellers while only Irrawardy River Dolphin were found in river. Asiatic Wild Dog and House Mouse were abundant, Asiatic Jackal, Bandicoot Rat, Indian Field Mouse and Swamp cat were common, Bengal Fox and False Vampire were fairly common, Common Mongoose and Malayan Giant Squirrel were very few, Common Otter, Large Indian Civet, Irrawaddy River Dolphin, Indian Hare were rare. According to IUCN (2000c) status, out of the 15 species Asiatic Jackal (Canis aureus), Bengal

Fox (Vulpes bengalensis), Common Mongoose (Herpestes edwardsi) were vulnerable, Oriental Small-clawed Otter (Aonyx cinerea), Large Indian Civet (Vivma zibetha), Indian Hare (Lepus nigricollis) were endangered, Asiatic Wild Dog (Cuon alpinus) Common Otter (Lutra lutra) and Irrawaddy Dolphin (Orcaella brevirostris) were critically endangered. The wild fauna were more prone to extinction and this may be due to the destruction of their habitat for urbanization and agricultural purposes.

Table 6 provides a list of fishes recorded from Savar. A total of 32 species was recorded from the study area. Of these 7 species were exotic and 10 species were found in both flood plain and river, 6 species in both flood plain and pond, 7 species in flood plain, river and pond, 5 species in only flood plain and 4 species were found in only pond. Carpu, Silver carp, Tilapia, Nilotica were abundant, Grass carp, Bighead carp and Thai Sarpunti were very common, Striped Gourami, Meni, Elongate Glassy Perchlet, Striped Snakehead, Spotted Snakehead, Asiatic Snakehead, Tengra mystus, Tengra, Rohu, Catla, Mrigal, Olive barb, Punti, Titpunti, Indian River Shad were common, Baicha, Climbing perch, Singi, Magur, Gutum, Indian Carplet were fairly common, only Blackline Rasbora was very few, Freshwater Garfish, One stripe spinyeel and Grey Featherback were rare. The locally designated rare species were also vulnerable according to IUCN (2000d). Only Dankina (Rasbora rasbora) was recorded as endangered by IUCN (2000d).

The location of Savar made it suitable for urbanization and industrial growth but vulnerable for the ecosystem. Various anthropogenic factors might have negative impact on the faunal diversity of that area. Land reclamation (filling of the wetland) and deforestation were the major factors, which might contribute to the threats of faunal diversity. Land filling resulted in the fragmentation of natural habitats and affected the movement of water between different aquatic habitats. Also large-scale garbage dumping on the wetlands and low lying areas was a serious problem for both the soil and water ecosystem. Industrial effluents and agro-chemicals contributed to the pollution of the wetlands, which would have serious negative impact on the faunal diversity. Poaching of winter birds was of great concern. Some professional poachers were engaged in preying winter

birds as well as local birds and they also collected the eggs of the birds from the wetlands. Rahman et al. (2000) observed that several types of winter birds were killed, trapped and distributed by local people, hunters and therefore, a large number of them are unable to return to their native country which was also true for the winter birds of Savar area. Sarker and Sarker (1983, 1985) reported that turtles were caught and consumed by the local people and eggs were prayed upon by Bengla Fox, Large Indian Civet, Asiatic Jackal and dogs which agreed with the situation prevailed during the study period. Local people also killed Common Garden Lizard and Common Skink as they considered them lethal and poisonous. A number of Chekered Keelback and Common Smooth Water Snake were killed by fishermen during fishing operation. There was a trend to use current jal (banned fishing net) among the fishermen to catch fishes, which might decline the fish diversity in the area in near future. In winter season, arrival of migratory birds and decrease in water level caused the decline in fish population. Several wetlands and aquatic habitats were filled for construction of residential areas, which contributed to the decline in fisheries. Also, culture of exotic fishes and their intentional and accidental release in the floodplain posed risks to the decrease in the population of indigenous fish species.

CONCLUSION

Bangladesh has 388 bird species, 109 species of reptiles, 22 species of amphibians, 110 species of mammals and 266 species of fishes (IUCN, 2000b) but Savar has only 30 species of birds, 24 species of winter birds, 7 species of reptiles, 3 species of amphibians, 15 species of mammals and 32 species of fishes which is relatively low contrasting the number of species found around in Bangladesh. Faunal diversity is important in maintaining ecosystem functioning and natural balance but it is now decreasing due to various factors like trapping, shooting, netting and destruction of habitats. To conserve the faunal diversity several measures should be taken immediately. Wetlands should be protected. Shooting and use of traps and nets should be prohibited. Use of pesticides also should be banned and Integrated Pest Management (IPM) should be practiced. Incorporation of NGO`s with the different Government agencies should be done. A mass awareness program should be launched for the local communities to conserve the fauna. Afforestration and declaration of several areas as Sanctuary would obviously contribute to the conservation of faunal diversity.

REFERENCES