Wetland biodiversity: A case study of
Tanguar Haor
By
dr.fourkan Ali
Wetlands
are of great importance to Bangladesh, About two-thirds of the country consists of wetlands
and 80% of all animal protein consumed consists of fish. The annual cycle of
monsoon floods followed by good agricultural harvest characterizes the way of
life for most of the country's 150 million people. Long ago, most of the
wetlands were formed, but nowadays freshwater wetland habitats (e.g. the beels,
jheels, and baors) are almost entirely herbaceous, due to a long history of
deforestation. As the population density in Bangladesh is one of the highest in the world, pressure on the
natural resources is great, and one can regularly read or hear about dwindling
fish stocks, falling of groundwater levels, and loss of forests and lack of
fuel-wood. Many wetland species have dwindled sharply in numbers and several
have become extinct altogether.
A
recent assessment of the status of freshwater fish in Bangladesh found that 54 species, out of a total of 260, are
threatened (MH. Khan, 1997). In the case of surface water resource management,
the international politics of water-sharing further complicates the issue.
Except
for the Sundarbans, which have been managed primarily as a production forest
for over 120 years and remain under forest cover; no Inland has any type of
active protection, To make the situation worse, Ire Ministry of Environment and
Forest (MoEF) is not equipped with the structure, man-power or funds to monitor
the few remaining areas of forest, let alone safeguard the country's natural
resources or secure a protected area system. Since independence, the area under
forest in Bangladesh has dropped from 18 % to just 4 % (Haider 1997), and
reportedly none of the sites incorporated in the national protected area pm is
in good condition or well-protected.
Under
the 'NCS implementation Project 1, Tanguar Haor -- a large floodplain lake area
in the north-eastern part of the country -- was identified as one of the four
main target areas for project implementation. Tanguar Haor was selected because
it is one of the country’s premier wetlands, identified in the Directory of
Asian Wetlands (Scott, 1989), and also listed as an internationally important
wetland by Scott and Rashid (1992). It is also one also the country’s most
productive inland fisheries sources. At the same time, it faces a host of
management challenges, due to hunting, over-fishing, habitual degradation and
competition between various forms of land use.
Description of Tanguar Haor
The Haor Basin - which includes Tanguar Haor - has a typical
tropical monsoonal climate characterized by the twice-yearly reversal of air
movement over the region. From December to March, air flows from the northeast,
while from June to September it flows from the south-west. These two periods of
air movement are called the north-east ml south-west monsoon, respectively
Rains are brought to the area mainly by the south-west monsoon, and this period
is often simply referred to S "the monsoon". Annual rainfall in the
region is high to very Netrokona, to the west of Tanguar Haor; has an average
annual rainfall of 2,971 mm (1961-90), while Sunamganj, to the east, has an
average; of 5,539 mm (1961-90) (NERR 1993L). The wettest months are June, July
and August, while the winter months - November to March – are relatively dry.
Hydro1ogy, water quality and siltation: Tanguar Haor forms part of the Surma-Baulai river
system, which is the third-largest tributary system of the river Meghna; it
links up with the Meghna at Kuliarchar. The average annual discharge rate of
the river Surma at Sylhet is 562.5 cubic meters per second. This varies from
less than 10 cubic meters per second in February to 1,458.7 cubic meters per
second in July (NERR 1995d). During the monsoon season, from June to September,
as much as 75 % of flood discharges are conveyed to the floodplain, and much of
the land in the Haor Basin is inundated to the depths of Z-3 meters. At Tanguar
Haor the water depth in the beels varies from 6-10 meters in the wet season, to
2-6 meters in the dry season; areas adjacent to the beels are flooded up to the
depths of4 meters (NERR 1993a).
The
main rivers in the northeast region experience much sedimentation during the
monsoon months and NERP (1993e) tentatively suggests that as much as 40 % of
the incoming sediment is deposited in the central part of the basin. Due to a
combination of topography and this sedimentation, river channels follow an
‘anastomosed’ pattern, consisting of highly meandering inter-linked channels.
Suspended sediment levels in the Surma river in Sylhet recorded between 1957
and 92 range between 4 and 1,947 milligram's per liter, averaging at 608, Total
annual sediment transported by the Surma averages at 3.7 million tons, with 82 %
carried during the monsoon months (NERP, 1993e).
The
baor system is mainly fed with
backflow waters stemming from the Surma-Baulai, Patnai and jadukata river
systems, Due to this ponding-up, waters are relatively free of suspended matter
and as a result, the waters are relatively transparent. Several hill streams
from the Meghalaya hills flow into Tanguar Haor; and these bring some Sediment
to the area. However; their volume is small compared to the backflow, and their
influence is relatively insignificant (NERE 1995e). An Exception to this fairly
rosy picture for Tanguar Haor regarding sedimentation is the river Jadukata;
which lies to the northeast. The Jadukata has produced the largest alluvial fan
in the northeastern region, and this river is subject to extremely high flash
floods with ms of up to 5,000 cubic meters per second (double the highest flood
on record of the Surma river in Sylhet). NERP (l993e) estimate that the total
annual sediment load is probably at least 150,000 cubic Gm about 15 years ago,
the river changed its course, with most of the 2 now flowing via its westerly
distributaries instead of via the southerly one, NERP (1993e) considers that
this change will increase sedimentation and affect Tanguar Haor.
Water
quality data for Tanguar Haor is lacking, but one does not need to know D0,
BOD, nutrient status and COD to determine if a water body is eutrophic,
mesotrophic or oligotrophic, There is ample biological information that is
indicative of nutrient-rich (i.e. eutrophic) waters: e.g., high to very high
densities of aquatic saprophytes, high fisheries production, and large numbers
of waterfowl. With a moderate annual influx of sediments, this can be
considered ‘natural’. Agricultural activity on the perimeter of the beels does
not appear to contribute in a major way to the nutrient status of these waters,
Most of the dung from cattle and buffalo are collected and used as fuel, and
only the higher grounds are moderately fertilized - mainly with urea, but also
with some TSP. Fields adjacent to die beels are not fertilized because,
according to the local people, these are already fertile enough due to incoming
sediments. Few pesticides are used at Tanguar Haor; and the most commonly used
in rice fields is Basudin, followed by Xydin, Basudin is an organic-phosphate,
commonly known as Diazinon, and it is highly and lethal for both fish and
birds.
The
back swamps and floodplain lakes that comprise Tanguar Haor a very important
function by storing flood-water and sediment. Hoods, water spills over the
levees into the back swamp and lakes, peak flow of the rivers is thus lowered.
Alternately after the flood has receded the back swamp and lakes drains into
the river; and this the flow downstream (Nishat, 1993) Flash floods usually
occur in April and early May while the more gradual monsoon floods occur in
June-August (Nishat, 1993).
Biological resource
Flora
of Tanguar Haor: A totals of 200-500 plant species in Bangladesh are judged to be wetland species for all or part of
their life spans (Nishat, 1995). Based on Karim (1993), NERP (19956) and BNH
(1997), it is estimated that a total of 200 wetland plant species occur in the
baor. This list also includes weeds of rice fields. A brief survey by the
Bangladesh National Herbarium NCS team (BNH, 1997) recorded only 78 plant
species at Tanguar Haor the actual number of species occurring at Tanguar Haor
is expected to be in the range of 120-150. In terms of habit, 200 wetland
species were recorded from Tanguar Haor during this case study, which include:
O Eleven
free-floating species, such as Pistia stratiotes (topapana) and Salvinia natans
(tetulapana);
O Thirty
eight anchored, submerged species, such as Potamogeton crispus (keorali) and
Aponogeton echinatus (ghechu);
O Five
suspended species, such as Utncularia aurea (chhotojanghi) and Cerato-phyllum
demersum (also known as chhotojanghi);
O Twenty
rooted species with floating leaves, such as Nymphaea riouchali (padma or sada)
and Ttapa maximowiczii (parriphal);
O Some
116 emergent species, such as Phragmites karka (nal khagra) and Polygonum
barbatum (bishkatali);
O Five
climbers, such as Clematis cadmia, Oxystielma secarnone (dudhi lata), and
Cuscuta australis (sarna lata); and
O Eight
swamp forest trees and shrubs, such as Barringtonia acu-tangula (hiial) and
Pongamia pinnata (koroch).
Recorded
species also include at least 12 exotic species: Alternanthera philoxeroides
(helencha), Cynodon dactylon (durba), Eichhomia crassipes (kochuripana),
Eupatorlum odoratum (assam lata), Hyptes capitata, Ipomoea fistulosa (dhol
lralmi), Ludwigia hyssopiflilia, Mimosa pudica laitabati), Paspalum oontugatum,
Rotala wallichii, Sagittaria guayanensis (muamia) and Sooparia dulcis
(bandhundi). The largest wetland plant families occurring in the haor region are
Poaceae (formerly known as Graminae), with 23 species, Cyperaoeae (11 species),
Asteraoeae (formerly known as Compositae, 10 species), Polygonaceae (9
Species), Acanthaoeae and Hydrocharitaceae (each 7 species), Lemnaceae,
Scrophulariaoeae and Solarraoeae (each 6 specia) and Nymphaeaceae and
Naiadaceae (each 5 species).
Plant
species that are listed by NERP (1995a) and Karim (1993) as threatened, rapidly
disappearing or rare in the Haor Basin and Bangladesh as a whole are:
O Barringtonfa acutangula (hijal),
O Clematis cadnria
O Crataeva nurvala (barun),
O Buryale ferox (makhna),
O Nelumbo nucifera (padma),
O Ottelia alismoides (panikola)
O Oxystelma secamone var secamorre
(dudhi lata)
O Pongamia pinnata (koroch),
O Rosa
clinophylla (formerly R. involucrata) (gunii kata), a.nd
O lypha spp. (egra or hogla).
Of
these, Euryala ferox (makhna), Nelumbo nucifera (padma) and the two Typha
(egra) species are now probably extinct at Tanguar Haor and probably rare in
other parts of the baor region.
The
Bengal Rose, Rosa clinophylla (gunji kata), which also occurs in parts of
India, was formerly common in Bangladesh but now it is rare, occurring only in
apart of Mymensingh district, and in the haor basin, Similarly the scrambling
herb Clematis cadmia was formerly a common element of homestead thickets and
scrubland, but now is quite rare in Bangladesh (pers. comm. Salar Khan, BNH,
1996). The asclepiad climber Oxystelma secamone var. secamone (dudhi lata)
occurs scattered in "dry river beds and semi-marshy places"
throughout eastern Bangladesh (Rahman & Wilcock, 1995), but is uncommon (pers.
comm., Md. Salar Khan, 1997). All three species - R. cllnophylla, C. cadmia and
O. secamone - are attractive and have potential as ornamentals.
Vegetation
types: The following (semi-) natural vegetation types can be identified at
Tanguar Haor:
Open-water
vegetation (e.g. in the beels), with submerged, suspended, flee-floating and
rooted floating plants. Common are Aponogetonaceae, Bydrocharitaceae,
Lemnaceae, lentibulariaceae, Menyanthaceae, Nymphaeaeeae, Pontederiaoeae,
Powmogetonaceae and Salviniaceae. At Tanguar Haor; Ceratophyllum demersum
(chhotoianghi), Hydrllla uuticillata (lcureli), Vallisneria spiralis (pata
ianghi) and Trapa mimowiczii (singara or paniphal ) are most common, while
Aponogeton sp. (gherhu), lpomoea aquatica (dhol kalmi), Lemna prpusilla
(khudipana), Luriwigia adsoendans (kesardarn), Marsilea umala (sushnisak),
Nymphoides indicum (panchuli), Sagittaria qttifolia (chhotokul), Spirodela
polyrhiza (khudipana) and Cl'icularia aurea (chhotojanghl) are also present,
Naiadaoeae and Symphaeaoeae are generally absent or uncommon.
Emergent
vegetation, dominated by Cyperaceae, Poaceae (Graminae) and Polygonaoeae, but
with many other species included. This vegetation, which occurs on the margins
of beels and other low-lying areas, can be 1-1.5 meters tall, but because of
intensive grazing and collecting of grass it is usually short-cropped and
stunted. At Tanguar Haor; Eleocharis atropurpurea (panichaise) and Hemarthria
protensa (dupi chailla or chailla) appear to be very common, along with many
other species of Oyperaceae and Poaoeae, Polygonaceae are also common and are
represented by nine species in the Haor Basin, with at least four or five
occurring at Tanguar Haor: lpomoea fistulosa (dhol kalmi) commonly occurs in
this vegetation type at slightly higher elevations. This vegetation type also
includes many species described by NERP (l993a) under "crop field
vegetation". Most of the latter species are weeds of rice fields, and
there appears to be enough overlap with ‘emergent vegetation' to justify the
lumping together of the two.
Reed Swamps (Pajuban): These occur in areas with a slightly higher elevation
than that of the emergent vegetation. Well-developed, mature reed vegetation
can attain a height of up to 6-7 meters, but this is seldom reached because of
clearing and burning, Common reed species in the baor region are Arundo donax
(baranal), Phragmites karka (nal khagra), Saccharum spontaneum (kash), Sclerosiachya
fusca (khuri) and Vetiverla zizanioides (chon or bena). mociated species are
the threatened Rosa clinophylla (gunji kata), and climbers such as
Clematis cadmia, Flcus heterophylla (baladumur) and the asclepiad Orrystelma
secarnone var. secarnone (dudhi lata).
Freshwater swamp forest: This vegetation type consists of evergreen trees,
which in a fully-developed stand would have a closed canopy and attain a
maximum height of 10-12 meters. However due to clearing, burning and lopping of
trees for fuel/material for fish entrenchments, few of any stands in the region
can be described as hilly developed and most are degraded. This vegetation is
dominated by Bar-ringtonia acutangula (hijal) and Pongamia pinnata (koroch),
commonly associated with Crataeva nurvala (barun), Phyllanthus disticha
(chitki), Rosa clinophylla (gunii kata), Salix tetrasperma (bias), ’l\‘ewia
nudlflora (gotagamar) and the climbers Ficus heterophylla (baladumur) and
Oxystelma secamone var secarnone (dudhi lata), At Tanguar Haor; the bat stand
off swamp forst is the Rangchi forest, in the south-westem part of the /mor,
which oonsists of more than 100 year old Barringtonia acutangula (hlial) and
Pongamia innata (koroch) trees. Virtually no natural regeneration is occurring
due to a combination of factors, such as the presence of a dense grass/herb
cover between the widely-spaced trees, fuel collection, grazing and clearing.
History of vegetation: The vegetation of Tanguar Haor is primarily secondary
in nature, modified by centuries of use and abuse. The natural climax
vegetation would be swamp forest on more elevated ground and along beel
margins, and mixed communities of submerged, floating and rooted-floating
vegetation in open water, Emergent herbaceous vegetation and reed beds would be
confined to small, unstable areas and be rather limited in area.
Thee
changes are not recent, and as Talukder (1995) reports, "By the 1770s,
almost the whole of the cultivable area of the haor basin came under the
plough", apparently by the late 18th century most of the changes in the
vegetation, notably the widespread disappearance of swamp forest, had already
taken place. Along with the swamp forest, a number of tree and shrub species
formerly occurring in the area may have become locally extinct. Reed beds may
have initially benefited from the demise of swamp forests, but as the demand
for thatch and fuel increased; this habitat type is also declining. According
to BCAS (1997) surveys in their three sample mouzas, forest areas have declined
from 18 % to 5% since 1971, and most of these areas have been convened into
agricultural land.
Faunal Diversity
Invertebrates: The wetlands of Tanguar Haor are inhabited by vast
numbers of invertebrates, including freshwater sponges (Porifera),
coelenterates, arthropods, annelids and mollusks. Several species of freshwater
sponge can be found clinging to the stems of various plants, bamboo poles and
piles, once floodwaters recede. These sponges soon die due to desiccation, but
not before they have reproduced, ensuring survival as a planktonic stage of
their life cycle. Tanguar Haor and adjoining wetlands are a prime habitat for
several species of mollusk, of which many hundreds of thousands can be seen in
the shallow waters in the floods. Most common are several species of the 2-3
cm-long gastropod snail Bellamya, large numbers of which line the baor shores
in the drier months, and the ‘pink-pearl’ freshwater mussel, Unio sp. Other
common mollusks include mussels such as Lamellidens sp., and the large
gastropod snail Pila ampullacea, which may measure up to 7-8 cm across. A
survey team from the Department of Zoology of the University of Dhaka
(DoZ, 1997) recorded a total of 12 butterfly species from the baor, of which
the most common are the Common Grass Yellow Eurema hecabe, the Brown Owl
Badamia exclamationis, African Monarch Danaus chrysipius and the African
Migrant Catopsila florella.
Fish: A total of 141 fish species were recorded by Nuruzzaman (1997) and/or
DoZ (1997). These include a total of nine under the case studies of exotic
introduced species: Aristichthys nobilis (Bighead Carp), Barbodes (Puntius)
gonionotus (Thai Silver Carp), Clarias garlepinus (African Magur),
Ctenopharyngodon idellus (Grass CUP), Cyprinus carpio (Common Carp, Mirror
Carp), Hypophthalmichthys mnlitrix (Silver Carp), Mylopharyngodon pisceus
(Black Carp), Oreochromis (Tilapia) mossambicus (Common Iilapia) and 0.
niloticus (Nile Tilapia). This total of 141 species represents more than half
of the 260 species of freshwater fish recorded in Bangladesh (Rahman, 1989).
Out
of the 141 species, 54 are listed as threatened (M.H. Khan, 1997), which
represents 39 % of the ichthyfauna of Tanguar Haor. Of these 54, three species
are listed by Khan as possibly extinct in Bangladesh, and their 'occurrence' at Tanguar Haor must be
regarded as tentative; these are Channa barca (gazar), Labeo boggut and Labeo
nandina (nandina). The fifteen species listed as critically endangered must
also be regarded as tentatively recorded at Tanguar Haor These are Bagarius
bagarius (baghair), Clupisoma garua (garua), Crossocheilus latius (kala bata),
Ctenops nobilis (naftini), Eutropiichthys vacha (bacha), Labeo boga (bhangan),
Mystus seenghala (guru), Notoptenrs chitala (chiral), Pangasius pangasius
(pangas), Rasbora elanga (elanga), Rasbora rasbora (leuzza darlraln), Rita rita
(rita), Rohtee ontio (chela), Silonia silondia (shilang) and Tor tor
(mahaseer). The most threatened group of fish appears to be migratory cyprinid
species.
Nunrzzaman
(1997) reports that fish species abundance has dropped from 135 in 1989-1990
(NERP studies) to just 112 species in 1997. When the DoZ (1997) data is added,
it increases from 135 to 141. Some of the species records are based on local
names given by fishermen. Almost half (49%) of the species recorded in Recorded
species are not abundant, being either rare, or with few or very few occurring.
Although It is usual that quite a few species occur at only low densities, when
this is the case for half of the species, this may be an indication that many
species are on their way out, i.e. they might become locally extinct within a
few years.
Amphibians and reptiles: During the aforesaid study 11 amphibian and 34
reptile species were recorded, the latter including 6 turtles, 7 lizards and 21
snake species. Many species are now extinct, threatened, or commercially
threatened, and these include mainly commercially valuable species, such as
turtles, monitor lizards, Bull Frog (sona bang) and Rock Python (azagar shap),
Of the species thought to be present, three species are classified by IUCN as
threatened. One is classified as Vulnerable (Rock Python, azagar shap), and two
as indeterminate -i.e. known to be either endangered, vulnerable or rare
(Spotted Pond Turtle or pura kaitta, Yellow Monitor Lizard or halud guishap). A
further four species, not classified as threatened by IUCN, are listed under
CITESI or II: Common Roof Turtle (kori kaitta), Peacock Softshell (jath kasim),
Spotted Flapshell (dhum kasim) and Bull Frog (sona bang).
Birds: A total of 208 bird species have been recorded at Tanguar Haor and
adjacent areas (MA, Khan, 1997), representing almost 30 % of the ml number of
species recorded in Bangladesh (690 species; M.A. Khan, 1997). Of these 208 species,
92 are water birds, 33 are reed land/grassland/marsh-dwelling passerine birds,
15 are birds of prey and 68 species are birds of village groves and/or foothill
forests. Out of the 28 species, 98 are migratory (of which 5 are vagrant), and
110 are resident species, i.e. they are found in the area all year round. With
92 water bird species, Tanguar Haor is particularly well-endowed compared to
other wetland areas in Bangladesh, During the winter months – usually October
to early April - Tanguar Haor is visited by many migratory water birds, especially
ducks (of which 20 species have been recorded) and coots.
Mammals: A list of 54 mammal species occurs in the baor basin.
Many species are either extinct, threatened, or commercially threatened,
including large ruminants; the larger predators; and commercially valuable
species such as otters (ud), Indian Pangolin (bon rui), Hispid Hare (khorgosh)
and Gangetic Dolphin (shushak), (the latter two occurring in areas adjacent to
Tanguar Haor), In the past, three species of Rhino occurred in the baor region,
namely the Sumatran, Javan and Great Indian Rhinoceros, but all have become
locally extinct a long time ago. The only mammal species occurring nowadays
that do not appear to be threatened are the Rufous-tailed I-Iare (shasak),
Irrawaddy Squirrel (badami katbiral), Indian Porcupine (Saiaru), numerous rats
(ilur), mioe (idur), bandicoot (dhari idur), bats (chamchika), jackal (shial),
mongoose (beji) and the Large Indian Civet (khatash).
Of
the species present, a total of three are classified by IUCN as threatened:
Vulnerable (Gangetic Dolphin, shusak), Indeteminate - known to be either
endangered, vulnerable or rare (Bengal Fox, khakshial) and one (Smooth-coated
Otter, mashrin ud) with Uncertain status. A further five species, not
classified as threatened by IUCN, are listed under CITES I or II: Indian
Pangolin (bon rui), Common Otter (ud), Small Indian Civet (ganda gakul), Jungle
Cat (iungli biral) and fishing Cat (messobag),
Evaluation of Tanguar Haor
Economic
importance of the baor: Benefits from wetlands are diversified, but not all of
these can be (directly) assigned a certain value or easily incorporated into an
economic context. Wetland benefits include:
a.
Products
# Biological resources
# Forage resources
# Agriculture resources
# Water resources
b.
Functions
# Groundwater recharge
# Groundwater discharge
# Flood control
# Shoreline stabilization, erosion control
# Sediment/toxicant retention
# Nutrient retention
# Biomass export
# Storm protection/windbreak
# Micro-climate stabilization
# Water transport
# Recreation/Tourism
c.
Attributes
# Biological diversity
# Uniqueness to culture/heritage
Tanguar
Haor provides many functions that benefit not only the people in and around the
baor, but also persons living downstream. The baor functions as a water storage
area, providing drinking water and irrigation water (specially for rice), while
helping to maintain river levels in the Patnai and Surma in the dry months, In
the wet season, it absorbs floodwaters, thereby mitigating the impact of floods
in downstream areas, and in addition recharging the areas ground waters. Silt,
especially from the Jadukata River, is deposited in the haor, and water quality
(of out flowing water) is thereby improved, Tanguar Haor provides a habitat for
a vast number of invertebrate, fish, amphibian, reptile, bird and mammal
species, including a number that are rare and/or endangered (see 3.2). These
functions, though of immense value, are difficult to quantify; and will not be
evaluated here. The same also holds for attributes, such as Tanguar Haor’s
scenic beauty, wilderness value, and the way in which it supports traditional
ways of life.
Tanguar
Haor`s directly used resources are easier to quantify than the other types of
benefits, although, because of lack of reliable data, much of this will have to
be inferred or estimated. Natural resources used, but not quantified are
additional plant products, such as edible seeds, medicines, thatching material,
shellfish, irrigation and potable water Crops planted on higher ground, such as
rabi crops planted on the kanda's, are not included as they are generally
planted outside the wetland area.
Conservation importance of Tanguar Haor
Last natural haor wetland: Most of the
natural wetland ecosystems in the baor basin have been convened and degraded,
and in the process, a large number of wildlife has been exterminated, while
others are threatened with extinction. Tanguar Haor, however is comparatively B
degraded, and the area still retains some of the natural features of the baor
wetlands. A well-defined catena a group of closely associated soils within a
given geographic zone or region that originated from me same or similar
material can be found, from the Meghalaya foothills to the deepest depression
within the beels, that retains water round the me Extensive areas with
submerged, floating and rooted floating vegetation occur and reed and
grasslands abound. In the post-monsoon and winter period, many of the banks and
levees are covered with lush, lofty and luxuriant growth of herbs, climbers and
shrubs, The last stronghold of swamp forest in the haor region occurs at
Rangchi, to the west of the baor, which has a vegetation dominated by
Barringtonia acutangula (hijal) and Pongarnia pinnata (koroch), Unfortunately
this forest now aces extinction due to commercial (over-) exploitation by the
Tanguar Haor leaseholder At the southeastern end of the baor there exist remarkable duars and a network of numerous canals.
A large natural lake occurs in the southeastern part of the haor, and the swamp
snub on its banks provides a unique habitat for wildlife, harboring the highest
concentrations of waterfowl and freshwater turtles.
Wetland of international impotence: Tanguar Haor; listed in the Directory of Asian
Wetlands (Scott, 1989) has been identified by Rashid & Scott (1992), NERP
(1995a) as a key wetland site of international importance, especially because
of its vital link in an international network of sites for migratory water
birds. The Government of Bangladesh is a signatory to the Ramsar Convention,
ratified on April N 1992, and Tanguar Haor has been proposed by various authors
(e.g. Scott & Rashid, 1992; MA Khan, 1997) for listing as a Ramsar site.
Tanguar Haor fulfils at least three of the criteria established for declaring a
wetland of international importance, as adopted by the Montreux Conference of
the Contracting Parties (Davis, 1994), each of which alone is sufficient for
proposing it as a Ramsar site. These three criteria met by Tanguar Haor are:
1.
Criteria for representative or unique wetlands, a wetland should be considered
internationally important if it is a particularly good representative example
of a natural or near-natural wetland, characteristic of the appropriate
biogeographically region. Tanguar Haor is one of the major last remaining
near-natural freshwater wetlands in the country and the region.
2.
General criteria based on plans or animals, A wetland should be considered
internationally important if it supports an appreciable assemblage of rare,
vulnerable or endangered species or subspecies of plant or animal, or an
appreciable number of individuals of any one or more of these species. Tanguar
Haor supports several endangered, vulnerable and threatened floral and faunal
species, such as numerous fish species, Pallas's Fish-eagle (kura), Baer’s
Pochard and the Bengal Rose (gunji kata), It is of special value for
maintaining the genetic and ecological diversity of a region because of the
quality and peculiarities of its flora and fauna, many of which are now extinct
elsewhere in the country It is also of special value as a habitat of plants or
animals at a critical stage of their biological cycle, as it is an important
spawning and breeding ground for fish, and has been widely recognized as one of
the important ‘mother fisheries' of the country,
3.
Specific criteria based on waterfowl. A wetland should be considered
internationally important if it regularly supports 20,000 waterfowl. Tanguar
Haor supports around 30- 40,000 waterfowl, on average, during the winter migratory
season.
Endangered species: Although there are no endemic species, Tanguar Haor
provides a habitat for many wildlife species that are globally threatened, are
listed in the CITES appendices, or recorded in the IUCN Red Data Book as
Endangered, Vulnerable, Rare or Uncertain (but thought to be one of the
aforementioned). In addition to the globally threatened species, Tanguar Haor
also harbors many species that have become regionally endangered, or are
endangered in Bangladesh. These include many species of fish, birds and
plants. Besides, Tanguar Haor harbors many plant species that have become rare
or have disappeared elsewhere in Bangladesh. These are mainly species associated with swamp
forests and seasonal wetlands, and include the Bengal Rose Rosa clinophylla
(gunji kata), the Swamp Clematis Clematis cadmia, and the asclepiad climber
Oxystelma secamone van secamone (dudhi lata). In all likelihood, many more
swamp plants occurring at Tanguar Haor are threatened elsewhere in Bangladesh, but this has not yet been recorded.
Breeding and mating site: Several freshwater turtles and resident waterfowl are
known to breed/nest on the levees of Tanguar Haor: These breeding freshwater
turtles incurred the Common Roof Turtle Kachuga tecta (kori kaitta), Spotted
Pond Turtle Geoclemys hamlltoni (pura kaitta), Spotted Flap shell Lissemys
punctata (dhum kasim), Bengal Eyed Turtle Morenia petersi (halud kaitta), and
the Peacock Soft-shell Aspideretes hurum (jath kasim), which lay their eggs in
vegetated levees. Breeding resident waterfowl include two species of jacanas,
bitterns, water-cock and Spot-bill Duck these birds nest in the reed vegetation
and emergent-floating vegetation present in the bam: Tanguar Haor also supports
at least four breeding pairs of the globally threatened Pallas's Fish-eagle
Haliaeetus leucorhyphus (kura).
Tanguar
Haor's most important features can be summarized as follows:
Conservation features:
O one of the last (semi-)natural
Haor’s in die country
O a potential Ramsar site, i.e. wetland
of international importance
O annually a refuge for
30-40,000(-60,000+) waterfowl
O harboring
one of the last remnants of freshwater swamp forest in Bangladesh
O providing
a habitat for globally threatened species, including 1 amphibian, 5 turtles, 2
lizards, 4 snakes, 10 birds and 6 mammals
O providing
a habitat for many species threatened in Bangladesh, including 55 fish, 51 birds and many wetland plant
species
O providing
a breeding area for many fish and birds, including the globally-threatened
Pallas‘s Fish-eagle (kura).
Iconomic features:
O supports one of the most productive
inland fisheries of Bangladesh
O highly
important to the livelihood of 46 villages (26,000 persons) in/adjacent to the
haor
O source
of livelihood for 2,000+ seasonal fishermen (+ families =5,000+ total) from
outside the district
O net
value of harvested wetland products in excess of Tk. 80 million annually
O of
immense value for floodwater retention, source of irrigation water groundwater
recharging
Natural features:
O the area is of great scenic beauty
O one of the last (semi-)natural areas
in lowland Bangladesh
O for
Bangladeshi standards, it has a high wilderness value, although the area is
seasonally much-visited by fishermen
O although
there are a large number of haors in Bangladesh, especially in Sylhet District, Tanguar Haor is
unique as it is the best representative of a natural baor ecosystem
Cultural features:
O the
Local Community at Tanguar Haor leads a very traditional way-of-life, in terms
of livelihood and access to maternities (no roads or electricity)
O the
area historically has one of the country‘s most important fisheries, already
renowned in the Zamindari colonial period
Main causes of resource degradation: Two main causes of resource degradation at Tanguar
Haor were identified as being: i) the Jalmohal leasing system, whereby 3 to
5-year leases foster a short-term approach to fisheries management, and a
mining of the resource; and ii) rural poverty, leading to over-utilization of
the non-fisheries resources. The latter was brought about by the decision,
taken by the leaseholder 10-12 years ago, to no longer use local fishermen in
the fishing industry but to employ seasonal labor from elsewhere, thereby
depriving the local economy of its main source of income. As a result, other
resources are over-utilized by a population trying to make their ends meet, and
the leaseholder has resorted to curbing (by force) the use of these resources
in order to prevent further habitat destruction.
Conclusion: Tanguar Haor is of outstanding conservation value,
being one of the last near-natural freshwater wetlands in the country It needs
special attention to manage this ham' on the basis of Ramsar guideline of wise
use of wetland resources. The following steps should also be taken to ensure
future conservation of Tanguar Haor:
i.
Involvement of local
villagers in commercial fisheries;
ii. Providing
access of local villagers to non-commercial fishing resources such as monsoonal
subsistence fishing, livestock grazing, duck keeping, grass and reed
collecting;
iii. Establishing
regulations to limit excessive use of these natural resources (based on
consensus within the community, rather than on imposition of levies or
threats);
iv. Community
development projects, to improve health and alleviate rural poverty:
v. Restoration
of the natural environment (e.g. replanting of swamp forest and reed beds, and
re-stocking of fish); and
vi.
Clear-cut roles for monitoring
and implementation.
Dr.Fourkan
Ali
Mob:
01711579267, Tel: 041 2832052
Email-
dr.fourkanali@gmail.com
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