The study was carried out for six long years. Leeches and ticks of the forests and super-secretive nature of herps--the collective nick for frogs, snakes, lizards and relatives--could not deter the painstaking work.
A group of passionate herpetologists did the seemingly impossible task at Lawachara National Park (LNP). They left no stone unturned. The 2011-2017 work reported 19 species of frogs and toads, 49 species of snakes and lizards, one limbless amphibian, one turtle and one tortoise—totalling about 71 species.
The study, featured in the journal Check List, created a stir among researchers, home and abroad alike. Of the jaw-dropping findings, 18 species appeared for the first time from the park area. In fact, 11 of them became new addition to the country's inventory.
The herpetologists teamed up for the study jointly initiated by two local nature-oriented NGOs - Creative Conservation Alliance (CCA) and Centre for Advanced Research in Natural Resources and Management (CARINAM), under the supervision of the Bangladesh Forest Department.
Lawachara National Park – at a glance
With an area of only 12.5 sq km, the national park is a semi-evergreen riparian forest, lying on low, flat hills. The park area, situated in Moulvibazar district, falls within a larger reserve, namely, West Bhanugach Reserve Forest (WBRF). Its periphery is surrounded by tea garden mosaics. Along with ethnic villages, millions of tourists also visit the park every year. The reserve forest is contiguous with anticlinal hill ranges of Tripura, India and subjected to heavy rainfall – annually about 4000 mm.
Herps of Bangladesh – the enigma
Amphibians and reptiles are not well-studied in the country. According to the present study, this paucity of data becomes evident when the scenario is compared to that of neighbouring India and Myanmar.
The first comprehensive attempt to detail out herpetofauna of northeast Bangladesh was made in 2008 by Dr Monirul H Khan, professor of zoology, Jahangirnagar University. However, unearthing the total diversity of the group is still far from complete. For example, in 2003, a similar study at LNP conducted by an NGO named Nature Conservation Management (NACOM) mentioned only 10 herps (four frogs and six reptiles). Use of these figures were common prior to these phenomenal findings; which made the park less significant in terms of conservation prioritisation.
How it all started
Shahriar Caesar Rahman, the lead researcher of the team, shared the story behind the work. The herp survey was initiated in parallel to their research on pythons in LNP. Through the Python Project, the research team came to learn about the biodiversity of the park. The extensive research then began with the discovery of the remains of various amphibians and reptiles lying dead on the road passing through Lawachara while pursuing the radio-tagged python.
Shahriar Rahman, with a goal to uncovering complete information about amphibians and reptiles in LNP, gathered a group of like-minded herpetologists. The team felt a hot-blooded drive to understand the lesser and much elusive cold-blooded critters.
The herp haven
Of the 71 species presented by the researchers, frogs and toads stood for 19 species, nearly reaching half of the country's total amphibian diversity. The study revealed a highly cryptic Caecilian, a type of limbless fossorial amphibian – first time from the country.
Snakes were dominant in the work, presented about 35 species. Many venomous species surfaced up including the mesmerising MacClelland's coral snake and the majestic king cobra. Two chelonian species, Assam leaf turtle and elongated tortoise, were observed by the researchers. The latter is globally Critically Endangered as described by the International Union for Conservation of Nature (IUCN).
There were mentions about 14 species of geckos, lizards and monitors. Suspecting an entire new species of grass lizard under genus Takydromus, the researchers are now working to describe it.
In pertinence to these sheer numbers, Shahriar Rahman described the research as modern and scientific. "Over time, we have seen each species with our own eyes, identifying them differently with different measurements of their bodies. We did not add any inferential information just by looking at the pictures," Shahriar said.
The contribution of BFD
The field officials were highly enthusiastic. Whenever snakes or lizards were caught from the rural areas around LNP, they were vigorously rescued by BFD authorities and the research team -- to be released later on. The roadkill specimens were shared with the researchers. These information were also included in the study, helping greatly to build up the database.
Not easy to identify
Herps, as hard to find one, are not easy to identify either. According to the research team, there were some limitations in the previous research works conducted in LNP leading to many misidentifications. Herp taxonomy is no commoners' plea. Frogs, snakes and lizards require different fine-scale body measurements (e.g. length of limbs, number of scales, etc), to be ensured with accurate identification; this information was presented in the current work.
A 2010 study at LNP, led by Dr AHM Ali Reza, currently an assistant professor at Delta State University in the United States, mentioned 45 species of reptiles and 15 species of amphibians. Twenty-three species of his study were not found in this present work. Shahriar Rahman said, "We have not found 23 species from the list which Dr Ali Reza presented in his research in 2010. In that study, it seemed to me that those 23 species had been misidentified. It's normal, as several herps are super-tricky to identify. Moreover, in the last ten years, taxonomy of several species has also been changed. Since we have worked at the field level, we have only added what we observed and able to identify correctly. So, we have omitted the names of those species."
There could be more!
According to the study, at least five more species are likely to live in the park area. The list of suspected species includes two species of kukri snakes, one keelback snake, one flying lizard and at least one frog from genus Minervarya. The researchers also stressed hope on many more species to pop up should there be more surveys.
A haven at a fine balance
Lawachara is not faring well. Amphibians and reptiles are very sensitive to various changes in the environment. In addition, many of these two classes of animals belong to fragile chains of ecosystem, vulnerable to stresses, which are dire in the park area. The team has expressed concern about the ongoing environmental crisis in the forest and the prolific loss of animal habitats. The number of trees in the forest has decreased drastically.
They have also noted the water crisis in the forest – a result of unplanned creation of culverts over streams and creeks. The use of pesticides in tea gardens near forests is another threat to the habitat-sensitive herps.
The severity of herp death is also of a grave concern – induced by the highway traversing the park. These might lead to the extinction of several species in the next 10 to 15 years, many without being brought under science spotlight. And, when the fragile branches of a food chain collapse, fall of the entire ecosystem becomes a matter of time.
When contacted, Rezaul Karim Chowdhury, Divisional Forest Officer (Department of Nature and Wildlife Conservation), Moulvibazar stressed his concern, "I have received the research paper. Bangladesh Forest Department is committed to secure the wildlife with a growing interest on less-known fauna. We will monitor the problems mentioned and take effective actions with a sense of responsibility to solve problems for wildlife."
Lastly, the work at Lawachara is an eye-opener to many extents. The staggering herp diversity of the park has just came in 2020, reminding us how little we know of our eastern forests. In the current trend, we have a tendency to overlook these forests assuming "empty" and "least diverse". In stark contrast, these habitats, the western cusp of the Indo-Burma Hotspot, are booming with life with many species from myriad of groups awaiting to be described.