Bats in the Himalayas: Establishing a paradigm for long-term acoustic monitoring in a montane ecosystem.
Rohit Chakravarty and Dr. Anand Krishnan
Indian Institute of Science Education and Research-Pune
We received our SM4BAT recorders and an Echo Meter Touch 2 Pro in early February, and have been hard at work getting them tested and recording bats in Pune, prior to fieldwork in the Himalayas. First, we tested each of the recorders overnight on the IISER Pune Campus, and recorded a great deal of bat activity as the weather warms up! We have trained a student volunteer, Ram Mohan, in the use of these bat detectors and in basic analytical tools, and he will play a major part in this season's fieldwork. To get our educational and outreach activities started, we also conducted a bat walk on campus using the Echo Meter Touch 2 Pro. During both these activities, we identified and recorded calls of at least five bat species, including the Indian pipistrelle (Pipistrellus coromandra), the greater yellow house-bat (Scotophilus heathii) and the Egyptian free-tailed bat (Tadarida aegyptiaca).
All the other equipment for fieldwork has also been procured, and RC has now left for the Himalayas in Uttarakhand to begin our first field season. This work will last until mid-June at least, and will involve both our student volunteer and two field assistants (both of whom will also be trained in the use of recorders). Fieldwork from now on will focus on identifying suitable recording sites at four different elevations and getting acoustic data. Bat activity is likely to pick up by late March, so hopefully we will gather useful data on distributions and activity patterns soon!
In mid-March we were into the most anticipated leg of our project: field work! We reached Kedarnath Wildlife Sanctuary on 13 March and conducted fieldwork up till 15 May. After nine days of reconnaissance, we had finalised our recording sites. In order to have coverage of various habitat types and species, we placed our recorders in three habitat types: forest, forest edge and open areas. Our sampling locations also covered an elevational gradient from 1400 to 3700 m above sea level. Depending on the area of the sampling location and the habitat heterogeneity at various elevations, we had up to three spatial replicates of each habitat type. A breakdown of our recording sites is given in the following table. We recorded for two consecutive nights at each recording site. Assuming the night length to be 10 hours on an average, we collected roughly 760 hours of acoustic data!
During the course of fieldwork, we trained our field assistants Zareef Khan Lodha and Baseer Baniya Gujjar. Zareef and Baseer are from a small village in Uttarakhand and have been assisting biologists for the last five years. We have trained them in all aspects of bat research, and they are now well-trained not only in setting up bat detectors but also in identifying different genera of bats from recordings!
We are now back at IISER Pune and we have started analysing the recordings. Our intern, Ram Mohan is playing an important role in this step. Preliminary checks suggest that we have recorded about 15 species of bats across the elevational gradient, including the highest elevation record of the European Free-tailed Bat (Tadarida teniotis). We also have possibly the first recordings of social calls of bats from the Himalayas. We cannot wait to unravel more exciting distribution and activity patterns!