DIVERSITY IN ANGIOSPERM FLORA OF TEKNAF WILDLIFE SANCTUARY , BANGLADESH

Teknaf Wildlife Sanctuary has been explored to assess angioperm diversity using traditional taxonomic techniques during 2010 to 2011. The assessment has resulted in recording of total 535 angioperm species under 103 familiies and 370 genera. For each species scientific name, Bangla name (whenever available), family and habit are provided. Of 535 species, 178 represented by herbs, 110 by shrubs, 150 by trees, 87 by climbers and 10 by epiphytes. In Magnoliopsida (dicots), Fabaceae is the largest family represented by 38 species, while in Liliopsida (monocots), Poaceae is the largest family represented by 29 species. Introduction Teknaf Wildlife Sanctuary, previously declared as game reserve in 1983 under the Bangladesh Wildlife (Preservation) (Amendment Act, 1974), is located in the Teknaf and Ukhia Upazilas of Cox’s Bazar district near Myanmar border. Geographical position of the reserve is in between 2052”-2109” N and 9208”-9218”E (Rosario, 1997). The Reserve is bordered by the Bay of Bengal to the south and west, the Naf River to the east and Monkhali and Thainkhali to the north. The reserve is locally managed by three range offices (Teknaf, Whykhong and Shilkhali ranges) and ten forest bits. The total area of the reserve is about 11651 ha (Green, 1987). Teknaf wildlife sanctuary in past supported mixed evergreen and semi-evergreen forests which over the period have been substantially altered due to heavy biotic pressure. The topography of sanctuary is very undulating and covered with a linear hill range (elongation north to south reaching an altitude up to 700 m), gently sloping to rugged hills and cliffs running down the central part of the peninsula, with a north-south length of nearly 28 km and an east-west width of 3-5 km. The range has several projections running towards east and west and interspersed by valleys, gullies and streams. These are crossed by numerous streams flowing down to the Naf river in the east and the Bay of Bengal in the west. Most of the streams are seasonal and dry up during off-monsoon season. The hills of the Sanctuary are composed of upper tertiary rocks (Pliocene and Miocene epoch) with 3 representative geological series: Surma, Tipam and Dhupitila (Choudhury, 1969). The soils vary from clay to clayey loam on level ground, and from sandy loam to coarse sand on hilly land (Choudhury, 1969). The sanctuary area enjoys a moist tropical maritime climate and rainfall is frequent and heavy during the monsoon season (May to October) ranging between 130 mm to 940 mm. Temperature ranges from 15oC to 32oC, whereas humidity ranges from 27% to 99% (BBS, 2011). As the Government commitment to the Convention on Biological Diversity (CBD), Taxonomists have already started to assess and document the floral diversity of different protected areas of Bangladesh. There are a few reports available on the Teknaf Wildlife Sanctuary. A list of Corresponding author, Email: zashim07@yahoo.com ACF, Teknaf Wildlife Sanctuary


Introduction
Teknaf Wildlife Sanctuary, previously declared as game reserve in 1983 under the Bangladesh Wildlife (Preservation) (Amendment Act, 1974), is located in the Teknaf and Ukhia Upazilas of Cox's Bazar district near Myanmar border.Geographical position of the reserve is in between 20 0 52"-21 0 09" N and 92 0 08"-92 0 18"E (Rosario, 1997).The Reserve is bordered by the Bay of Bengal to the south and west, the Naf River to the east and Monkhali and Thainkhali to the north.The reserve is locally managed by three range offices (Teknaf, Whykhong and Shilkhali ranges) and ten forest bits.The total area of the reserve is about 11651 ha (Green, 1987).
Teknaf wildlife sanctuary in past supported mixed evergreen and semi-evergreen forests which over the period have been substantially altered due to heavy biotic pressure.The topography of sanctuary is very undulating and covered with a linear hill range (elongation north to south reaching an altitude up to 700 m), gently sloping to rugged hills and cliffs running down the central part of the peninsula, with a north-south length of nearly 28 km and an east-west width of 3-5 km.The range has several projections running towards east and west and interspersed by valleys, gullies and streams.These are crossed by numerous streams flowing down to the Naf river in the east and the Bay of Bengal in the west.Most of the streams are seasonal and dry up during off-monsoon season.The hills of the Sanctuary are composed of upper tertiary rocks (Pliocene and Miocene epoch) with 3 representative geological series: Surma, Tipam and Dhupitila (Choudhury, 1969).The soils vary from clay to clayey loam on level ground, and from sandy loam to coarse sand on hilly land (Choudhury, 1969).The sanctuary area enjoys a moist tropical maritime climate and rainfall is frequent and heavy during the monsoon season (May to October) ranging between 130 mm to 940 mm.Temperature ranges from 15ºC to 32ºC, whereas humidity ranges from 27% to 99% (BBS, 2011).
As the Government commitment to the Convention on Biological Diversity (CBD), Taxonomists have already started to assess and document the floral diversity of different protected areas of Bangladesh.There are a few reports available on the Teknaf Wildlife Sanctuary.A list of important timber yielding plants of the Teknaf game reserve has been mentioned in the forestry master plan of Cox's Bazar south division (Cowan, 1923).Many years later, Khan et al. (1994) has made an assessment work on Teknaf game reserve to focus on ecologically and economically important plant species.Although co-management issues of Teknaf game reserve have been studied by several authors (Bari and Dutta, 2004;Molla et al., 2004), little is known about the floral diversity of the sanctuary.The sanctuary is very rich in flora and represents different ecosystems including hill forest, mangrove formation and sandune.Conservation significance of the sanctuary is also high because of the presence of Asian threatened elephant population.Currently floral diversity of the sanctuary is under threat due to various pressure including anthropogenic activities and the presence of Rohynga refugee along the eastern border.For making proper conservation and management plans of the sanctuary before its complete degradation, data on the floral diversity is essential.In order to provide such information, in the present study an attempt has been made to document diversity of angiosperm flora of Teknaf Wildlife Sanctuary.

Materials and Methods
Specimen collections have been made in the Teknaf wildlife sanctuary at 2-months intervals between November 2010 and December 2011.The collections covered all habitats of the study area including hilltops, slopes, foothills, valleys, sand dune and wet areas including mangrove stretch along the Naf river.Special attention has been given to locate the species already listed as threatened categories in the country.Fertile plant specimens (flowering or fruiting specimens) were collected and processed using standard herbarium techniques (Hyland, 1972;Alexiades, 1996).The plant specimens were identified by consulting different Floras and literature, viz., Hooker (1872Hooker ( -1897)), Prain (1903), Uddin and Hassan (2004), Siddiqui et al. (2007) and Ahmed et al. (2008aAhmed et al. ( , 2009a)), and by comparing with the herbarium specimens available at Dhaka University Salar Khan Herbarium (DUSH) and Bangladesh National Herbarium (DACB).For updated nomenclature of the species, Siddiqui et al. (2007) and Ahmed et al. (2008aAhmed et al. ( ,b, 2009a,b,c) ,b,c) were followed.Threatened categories of plants were confirmed with the help of Khan et al. (2001).Some noxious exotic plant species were also identified comparing with the reports of Islam et al. (2003), Hossain and Pasha (2004) and Akter and Zuberi (2009).Cronquist (1981) system of classification has been followed to determine the families.Voucher specimens are deposited at DUSH.

Results and Discussion
A total of 535 angiosperm species (wild and cultivated) have been identified and presented based on the present study (collection and observation) in the Teknaf Wildlife Sanctuary.These species have been assigned to 103 families and 370 genera.For each species scientific name, Bangla name (when available) and family name are provided (Table 1).46% of the total species are represented by 15 families, whereas the rest 54% by 87 families.In Magnoliopsida (dicots) Fabaceae is the largest family represented by 38 species, while in Liliopsida (monocots) Poaceae is the largest family represented by 29 species.Each of 31 families is represented by only one species.Of 535 species recorded here, herbs are represented by 178 species, 110 by shrubs, 150 by trees, 87 by climbers and 10 by epiphytes including parasites.Nineteen species including one gymnosperm (Gnetum oblongum) listed as threatened in the Red Data Book of the country have also been detected in this sanctuary (Khan et al., 2001).
Once, the Teknaf area has been classified as hill forest dominated by evergreen and deciduous trees.Currently maximum area of the forest has been degraded and denuded and exposed to sun.During the field observations and discussion with foresters and local people, we could identify a number of threats to plant diversity.These are illegal logging, political influence in illegal logging and encroachment, Rohynga pressure, brikfield in sanctuary area, cutting of plantlets for betel leaf cultivation, new road constraction, fragmentation, over ambitious foresters, unadequet manpower in the forest department in terms of forest area and minor products collections including fire wood.All such threats are enough to eliminate remaing plant diversity from the sanctuary.
For the sustainable conservation of angiosperm diversity in Teknaf wildlife sanctuary, the following recommendations have been made.Database for all species need to be made first, otherwise we will loss some of the plants before their introduction to science.Set priority for species those are sensitive to disturbance and locate them in the habitat using Greographical Information System (GIS) technique.Much effort should be given to increae their number using different propagation techniques either in situ or ex situ conditions.Effort should be made to give alternate source of income for forest products dependent people.Forest and biodiversity protection act should be implemented for over ambitious people who destroy in different ways the ability of ecosystems to support biodiversity.In 2010, the status of area has been shifted to the wildlife sanctuary because of the presence of Asian wild threatened elephant.A small part of the sanctuary has also been declared as nature Reserve Park to gain public support for biodiversity conservation.The present list of plant biodiversity (535 species) is still considered as preliminary.There might be some more species yet to be listed and few specimens remain unidentified.Based on the field observations and present preliminary results it may be concluded that the sanctuary is rich in the plant diversity and the sanctuary is the home for so many threatened plant species in context of Bangladesh.Field observation also confirmed that regeneration of tree species in the habitat is severely hampered because of anthropogenic pressure and minor product collections.Invasive species such as Urena lobata, Mikania cordata, Chromolaena odorata etc. are another challenge to future regeneration of forest trees in the disturbed areas.The study suggests for further long term research to focus all aspects of plant biodiversity to help in making proper management plan for this sanctuary.

Table 1 . List of species recorded in Teknaf wildlife sanctuary (* means
cultivated).