The
distribution of Himalayan Newts, Tylototriton verrucosus in the Punakha-Wangdue Valley, Bhutan
Jigme Tshelthrim Wangyal 1 & Dhan Bahadhur Gurung 2
1 District Forest Office, District
Administration, Trashigang 42001, Bhutan
2 College of Natural Resources,
Royal University of Bhutan, Lobesa, Punakha 14001, Bhutan
Email: 1 jigmewangyal@gmail.com (corresponding
author), 2 dbg2006@gmail.com
Date of publication (online): 26 October 2012
Date
of publication (print): 26 October 2012
ISSN
0974-7907 (online) | 0974-7893 (print)
Editor:Sanjay Molur
Manuscript
details:
Ms # o3136
Received
25 March 2012
Final
received 05 October 2012
Finally
accepted 07 October 2012
Citation: Wangyal,
J.T. & D.B. Gurung (2012). The
distribution of Himalayan Newts, Tylototriton verrucosus in the Punakha-WangdueValley, Bhutan. Journal of Threatened Taxa4(13): 3218–3222.
Copyright: © Jigme Tshelthrim Wangyal & Dhan Bahadhur Gurung2012. Creative Commons Attribution 3.0 UnportedLicense. JoTT allows unrestricted use of this
article in any medium for non-profit purposes, reproduction and distribution by
providing adequate credit to the authors and the source of publication.
Acknowledgements:We would like to, in no particular order, thank the following individuals. Yeshi Phuntsho in Gasa and Punakha areas; Yeejay, Nima Gyeltshen and Dorji Namgay in Lamperi, Thinleygang and Dochula areas; Namgay Tshering (Gathpoo) in Sha areas. They have helped us collect and take
measurements of the specimens and have never denied befriending us even at the
middle of the nights. Sonam Dorji(GP), Baep Tshering and few
others accompanied us to the field in Thinleygangwhen in the College, our sincere thanks to them. AP Sonamof Goemkha Village, Toebisahelped us catch at least four species, thanks to his spirited search for the
animals. Thanks are also due to all people of the study areas. The first author
in particular is glad to receive the assistance of the RuffordSmall Grant for the study of this group of animals. Phurba Lhendup, WWF Bhutan programmeneeds a special mention for generously allowing me to use his camera during the
study.
ZooBank urn:lsid:zoobank.org:pub:2FF1568B-2804-400D-9574-3D366EE6C5F6
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The Himalayan Newt Tylototriton verrucosusis considered one of the most primitive species amongst living Salamanders (Das
1987) and is also the only salamander known from Bhutan. John Anderson, who described the species
in 1871, discovered the species in flooded rice fields near the small Chinese
town of Nantin.
Although a well studied
species, the Himalayan Newts’ occurrence is hardly known in Bhutan because of
poor reporting. After Frost (1985),
who reported the presence of the species without any specific location, Palden (2003), confirmed its occurrence in Thinleygang and Kabjisaareas. Other than these two
reports, there is no evidence to prove that the species has been ever studied
in Bhutan. However, outside Bhutan,
the species is reported from China, India, Nepal and Thailand.
Therefore, this study was
taken up in the Punakha-Wangdue PhodrangValley solely to look at the distribution and habitat of the species.
Materials and Methods
In this survey, a
time-constrained visual encounter search technique (Campbell & Christman 1982; Corn & Bury 1989) was used because of
the study areas’ diverse habitat types such as paddy fields, roadsides, river
banks and forests (Fig. 1). The
search area within the valley was not fixed as species encountered anywhere
within the valley was considered for distribution mapping.
Nocturnal road cruising and
opportunistic collecting was the primary method used for collection of
data. Rainy nights were taken as an
advantage to catch the newts that move along the roads. While short distances
were covered by walking, longer distances were covered using a car. Survey teams of two to three people used
a walk-and-turn method to survey all of the area within the study site. A team of two people was used for
scouring every paddy field and they walked in and around the entire field
looking for the species. The
observers used headlamps to continuously search the ground surface, only
stopping to gently turn objects that could be easily lifted and replaced
without significant disturbance to the forest floor in search of the animals.
The forest floor, on and
under fallen wood, under barks, exposed rocks, tree trunks and stumps were
searched for the newts and when encountered captured by hand. For further analysis, each individual
was placed in buckets with a small amount of water, wet leaves or moss and they
were weighed, measured, and released at their capture locations. A total of
about 80 adult newts were collected from different localities of Toebisa (n=37), Kabjisa (n=20)
and Kazhi (n=23).
A steel
ruler was used by laying it along the length of each salamander and total length and
snout-vent-length (SVL) were recorded to the nearest millimetre(mm). SVL was recorded from the tip
of the snout to the front of the vent (Corkran &
Thomas 1996) and the tail length was calculated. Each newt was weighed in the bag to the
nearest 0.1g with a branded spring scale and then each bag was weighed
separately after the animal was released. Garmin E-trek GPS was used to collect the geo-coordinates of all the species
collected and their major habitats.
The identification references
used in the field include Smith (1931, 1935, 1943), Daniels (2005), Yang & Rao (2008), Ahmed et al. (2009), Fei et al. (2010), and Vasudevan & Sondhi (2010).
Results
Frost (1985), without any
specific location, reported the presence of Himalayan Newts in Bhutan which was later confirmed by Palden(2003). After that, there was no reports on the species from Bhutan. However, the lack of reports did not
mean the species have gone missing. The newts did exist in the valley but without the attention of conservationists
and academicians. Therefore, this
study further confirms their presence.
This research showed that
quite a good number of the species survive in Toebisaand Kabjisa, PunakhaDistrict, from where it was reported to the world (Palden2003) for the first time. Kazhi, another study site under Wangdue Phodrang also had a good population of the
newts. The highest elevation at
which Himalayan Newts were detected was at 2679m, at LampelriBotanical Park, below Dochula while the lowest was atToebrongchu Zam,
1255m.
Sex ratio: To
look at the sex ratio, males and females were identified amongst the collected
specimens. The males carry a
vertical fissure in the anal region whereas the females bear a circular
opening, a clear distinction between the sexes keeping confusion out of
question. Of the 37 specimens from Toebisa, 21 were males, while in Kabjisaand Kazhi the number of males was 10 out of 20 and 13
out of 23 in their respective collections. While the sex ratio in Kabjisa is 1:1, the males exceeded females in Toebisa and Kazhi (Fig. 2).
According to a breeding study
conducted by Roy & Mushahidunnabi (2001), oviposition happen in May and June soon after salamanders
emerge from their hibernation with the first monsoon shower amongst the
permanent and temporary pools, shallow ditches, marshes and slow-moving
streams. In line with their
finding, it is fair to assume that mating and courting ends by July which means
the individual species are on their own. It can also be assumed that the sex ratio in the July collection could
be skewed due to the tendency of males and females staying in groups of their
own sex. An all male group of five
newts was collected from Thinleygang at the end of
July in 2009 (Image 1) which indicates that the
species had stopped courtship and that they were on their own, looking for food
and shelter.
Habitat affinity: Habitat occupancy was considered based on the number of species
that were collected from three different kinds of habitat in all three study sites (Table 1). The Himalayan Salamanders seemed to like
paddy fields, at least during the three months of June, July and August as most
of the specimens were caught from the paddy field in all three
study sites.
Since the study was conducted in July and
August, the specimen collection time probably must have coincided with the
phase of the species when it becomes aquatic. This is very much in consistence with
the findings of the studies on the species conducted by the researchers in
India who found the species becoming terrestrial once the rain ceased to fall
by the end of October (Das 1987). It is only during the rains that the species breeds and remains
active. Otherwise, the species is
known to be sluggishly terrestrial, inclined more towards land than water.
Individuals use paddy fields
for feeding and breeding while they use forests and roadsides only for
migration, because maximim numbers were collected in
paddy fields in all three study sites through the
survey in July and August (Fig. 3). Studies in India have confirmed its egg layingperiod as the last week of June on leaves of submersed aquatic plants. The eggs hatch by the middle of July and
by the last week of August they become big enough for a terrestrial life. This study conforms withDas (1987). However, the soil data
analysis result which showed the soil to be basiccould not be used due to nonavailability of past
records for comparative analysis.
Personal
observations of the animals over the last few years has revealed that the animals
are most active in June and July when the paddy plantation and weeding of the
fields happen. The newts of this
locality are very active by day, as many could be observed during the day in
the paddy fields. The villages of Lemjikha and Thinleygang in Toebisa Gewong were scoured mostly during the day as their paddy
fields provided the best possible sites for catching the salamanders in situ
for morphometric studies.
Association with other species: In this study, the Himalayan
Newts were found along with Polypedates cf. himalayensis in all three studysites. In Toebisa,
the species found alongside the newts included Xenophryscf. nankiangensis, Duttaphrynus melanostictus and Nanorana liebigii. In Kabjisa,
the associates included D. melanostictus, D.himalayanus and N. liebigiiwhile in Kazhi, the sympatric species included D. melanostictusand D. himalayanus.
The sympatric occurrences of Duttaphrynus and Ranatadpoles, juvenile D. himalayanus and foam
nests of rhacophorid frogs have been observed in
Nepal (Schleich & Kästle 2002). Similarly, the sharing of aquatic habitat with the metamorphosing Polypedates cf. himalayensiswas observed in Kabjisa. Many other sympatric species must have
been left out owing to the short duration of the study because the newts cover
extensive areas around the vast paddy fields where there are chances of getting
several species of other amphibians if a long termstudy is done.
Distribution: The salamanders were found in Kabjisa, Barp, Toep, Chhubu,Dzomi, Guma, Shengana, Talo, and southern Toewang in Punakha Dzongkhags. The species was not seen in Lingmukha while Goenshari was not surveyed.
In Wangdue Phodrang, the majority of the animals were observed
in Kazhi, Nahi and Thedtsho while Gewongs like Bjena, Nyisho, Gangtey, Phangyul and Rubeisa were not properly surveyed due to time
constraints. The rests of the Gewongs were not even visited.
This study also shows that
Himalayan Salamanders occur along small seasonal and perennial stream reaches
and paddy fields from 1255–2679m. Therefore, these habitats (streams and paddy fields) must be conserved. The traditional paddy farming must
continue for the survival of the species as the fields provide them food,
shelter and home. The distribution
map (Fig. 4) shows the areas where the species were found during the study. These areas are significant for
conservation of the Himalayan Newts.
Conclusion and Discussions
This study, being the first
of its kind in Bhutan is significant and is an attempt to find the habitats of
the Himalayan Newts in the Punakha-WangdueValley. The species was found to
use paddy fields, vernal pools, streams and forest
sides.
A look at the sex ratio
revealed that the males exceeding the females by a small margin, is not a
worrying factor for the species’ survival. By way of habitat affinity, the newts seemed to like the paddy fields,
at least during the summer when the fields are being worked for paddy
production. Almost all the
specimens came from the paddy fields. Looking at the association with other species, the Himalayan Newts were
found along with the Polypedates cf. himalayensis in all three study sites including
other species such as Xenophrys cf. nankiangensis, Duttaphrynus melanostictus, D. himalayanus and Nanorana liebigii.
Distribution wise, the study
showed that Himalayan Salamanders occur along small seasonal and perennial
stream reaches and paddy fields from 1255–2679 m. Therefore, these habitats (streams and
paddy fields) must be conserved. The traditional paddy farming must continue for the survival of the
species as the fields provide food, shelter and home for the Himalayan Newts.
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