A preliminary assessment of bat diversity and people’s attitude towards their conservation in Baksa District, western Assam

· Articles
Authors

U. Saikia1*, A. R. Boro2 & P. K. Saikia3

1Zoological Survey of India, Risa Colony, Shillong-793003
2Department of Zoology,Pandu College, Guwahati
3Department of Zoology, Gauhati University, Guwahati
boroanand7@gmail.com
*Corresponding author:Uttam Saikia, email: uttamzsi@gmail.com

Abstract

Field studies were conducted in Baksa district of western Assam to assess the bat diversity and their conservation opportunities especially in the anthropogenic landscape. We report the presence of 14 bat species in 10 genera and 4 families from the study area which is likely to go up with intensive surveys. The bat genus Tylonycteris is being reported for the first time from Assam. Since many of the bat species encountered are found in anthropogenic environment, they remain vulnerable to persecution and protecting bat populations in human landscape remains a big challenge. However, it also throws us an opportunity for conservation as educating the villagers about the importance of bat and persuading them to live in harmony can go a long way in conservation of this little known but ecologically important group of animals.

Keywords Bat diversity, threats, conservation, Baksa district, Assam

Introduction

The bat (Mammalia: Chiroptera) fauna of the north eastern part of India is exceptionally diverse with at least 70 species, including a few newly described and recently reported species (Bates and Harrison, 1997; Thabah and Bates (2002); Sinha, 1999; Ruedi et al. 2012a, 2012b). This constitutes well over fifty percent of the total bat species diversity (123 species) from India (Ruedi et al. 2012; Sanecha and Dookia, 2013). However, compared to the north eastern region as a whole, the bat diversity of the state of Assam is seemingly poor at 30 species (Bates and Harrison, 1997; Sinha, 1999; Boro et al. 2013; Boro and Saikia, 2015) which may partly be attributed to the lack of field studies in the state. Despite the tremendous ecological role of bats in maintaining a healthy ecosystem, they are one of the least understood and explored mammalian group especially in the north-east Indian context. In this backdrop, the authors initiated a series of preliminary field surveys in Baksa district of western Assam to assess the bat diversity of the area especially in the anthropogenic environment and to assess the threat faced by them. Located in the northwestern part of Assam, Baksa is one of the newest districts of Assam. It is bordered by Bhutan in the North, Udalguri district in the East, Barpeta, Nalbari and Kamrup district in the South and Chirang district in the West, Baksa district covers an area of approx. 2400 sq. km. Vegetation is dominated by tropical moist deciduous type and interspersed with semi-evergreen forest.

Methodology

The field surveys were conducted between February, 2012 to July 2013 in five localities of Baksa district (Map1) namely Goreswar (approx.26°31’55″N, 91°43’17″E) Balahati Village (approx.26°32’53″N, 91°42’02″E), Tamulpur (approx.26°37’15″N; 91°34’08″E), Salbari (approx. 26°39’14″N; 91°05’16″E) and Basbari area (approx. 26°44’04″N, 91°01’32″E) adjacent to Manas National Park. Two mist nets were set in a suitable area close to human habitation in the evening hours (approx between 5-9 pm). An estimated 60 netting hours were spent in all the five localities. A total of 17 voucher specimens were collected from mist netting and also by opportunistic methods and with the help of local people. They were euthanized, preserved in 70 percent alcohol and later identified in the laboratory of Zoological Survey of India, Shillong. To comprehend the attitude of the locals regarding conservation of bats in their vicinity, randomly 10 persons in each locality were asked to reply a simple questionnaire of five questions regarding 1. Whether bats are present (observed roosting, foraging etc) in their vicinity 2. Any observable change in the number of bats in the recent past (last 10-15 years) 3. Whether people hunt bats for consumption 4. Instances of persecutions of bats by villagers and 5. Whether people are willing to live in harmony with bats. The responses of the fifty respondents were recorded and augmented with field observations.

Results and discussion

During the field surveys, a total of 24 specimens were caught (seven released in the field after obtaining measurements) that were identified into 12 species in four families. One species namely Pteropus giganteus was observed in the field and one specimen of the genus Tylonycteris was captured but managed to escape during measurements. Hence the species identity of this specimen could not be established. Thus, the present species inventory comprises 14 species under 9 genera and 4 families as listed in Table 1.

Table 1

Sl. No.

Family

Species

IUCN Conservation status

1

Pteropodidae

Pteropus giganteus (Brunnich, 1872)

Least Concern

2

Rousettus leschenaultii (Desmarest, 1820)

Least Concern

3

Cynopterus sphinx (Vahl, 1797)

Least Concern

4

Megadermatidae

Megaderma lyra (E. Geoffroy, 1810)

Least Concern

5

Megaderma spasma (Linnaeus, 1758)

Least Concern

6

Emballonuridae

Saccolaimus saccolaimus (Temminck, 1838)

Least Concern

7

Taphozous melanopogon (Hardwicke, 1825)

Least Concern

8

Vespertilionidae

Scotophilus heathi (Horsefield, 1831)

Least Concern

9

Scotophilus kuhlii (Leach, 1821)

Least Concern

10

Pipistrellus tenuis (Temminck, 1840)

Least Concern

11

Pipistrellus coromandra (Gray, 1838)

Least Concern

12

Tylonycteris sp.

-

13

Myotis muricola (Gray, 1846)

Least Concern

14

Myotis horsfieldii (Temminck, 1840)

Least Concern

Among these species, the bare-rumped sheath tailed bat Saccolaimus saccolaimus has and the Horsfield’s Myotis Myotis horsfieldii have recently been reported from Assam (Boro et al. 2013; Boro and Saikia, 2015). The report of Myotis horsfieldii from the study area also constitutes the second known record of this species from the northeastern India (Boro and Saikia, 2015). The genus Tylonycteris commonly known as bamboo bats consists of three species of which two namely, T. pachypus and T. robustulaare known from some of the states of Northeast India (Bates et al., 2008a, 2008b). However, this genus has not been recorded from the political boundary of Assam till date and our photographic example constitute the first report of this genus from Assam. However, species identity of our photographic specimen being uncertain at present, it remains open for future investigations. Considering the limited survey area and that too in anthropogenic landscape, this represents significant bat diversity which is expected to go up considerably with further intensive surveys.

The analysis of questionnaire data, although far from being representative, reveals some interesting facts with significant conservation implications. Out of the fifty respondents, over half of them reported the presence of bats in their vicinity and twenty four percent reported a declining trend in bats over a period of 10-15 years in their locality. Apparently many bat species do well in anthropogenic environment and some even preferring to live in close proximity to human dwellings. However, the extent of their tolerance to changing habitat parameters is a question of intensive research. Thirty eight percent of the people interviewed revealed occasional killings of bats for consumption (for purported medicinal property of bat meat) and a staggering sixty percent reported persecution of bats in their vicinity. Thus, killing and persecution possess a serious threat to the survival of bats in the study area. Surprisingly, sixty four percent of the respondents told that they do not have any negative attitude about bats and are willing to live with them in their vicinity.

It is apparent from the above discussions that although the ever increasing human pressure on the environment and consequent deterioration of habitat quality is clearly taking a toll on bat populations across the regions, a few bat species are able to cope with the changing environment to some extent. Though instances of killing or persecution of bats in the study area is not uncommon, a majority of the people do not seem to associate bats with negative attitude and are willing to live in harmony with them. This gives a silver lining in the grim biodiversity conservation scenario of this region as educating people about the myriad ecological services rendered by these animals and persuading them to protect them can go a long way in future conservation efforts . Unfortunately, the Indian Wildlife Protection Act, 1972 or any other wildlife law of the country is yet to provide any legal protection to bats (except for two species) and we can only hope this happens sooner than later.

    

Acknowledgement

The authors are grateful to the Director, Zoological Survey of India (ZSI) Kolkata, and the Officer-in-Charge, ZSI, Shillong and the Principal, Pandu College, Guwahati for institutional support. Field support provided by Bharat Boro of Balahati village is gratefully acknowledged.

References

Bates, P.J.J. and Harrison, D.L. 1997 Bats of the Indian Subcontinent. Harrison Zoological Museum, The Kent, UK.

Bates, P., Francis, C., Rosell-Ambal, G., Heaney, L., Molur, S. and Srinivasulu, C. 2008a. Tylonycteris pachypus. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 27 May 2014.

Bates, P., Francis, C., Rosell-Ambal, G. and Heaney, L. 2008b. Tylonycteris robustula. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 27 May 2014.

Boro, A., Saikia, U. and Saikia, P.K. 2013 First record of Saccolaimus saccolaimus (Temminck, 1838) (Chiroptera: Emballonuridae) from Assam, NE India. Small Mammal Mail: 5(1):2-3

Boro, A and Saikia, U. 2015 The Horsfield’s Myotis, Myotis horsfieldii (Temminck, 1840) (Chiroptera: Vespertilionidae); an addition to the bat fauna of Assam Small Mammal Mail 7(1):13-14

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