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Vol. 53, 2014
Influence of microclimate on the activity of Royle's pika in
the western Himalaya, India
Sabuj
Bhattacharyya1,2*, Bhupendra Singh Adhikari1 and
Gopal Singh Rawat1
1Department
of Habitat Ecology, Wildlife Institute of India, P.O. Box # 18,
Chandrabani, Dehradun, India
2Current address: Centre for Ecological Science,
Indian Institute of Science, Bangalore 560012, India
Abstract
Background: A central aim in
ecological research is to improve understanding of the interactions
between species and their environments; these improvements will prove
crucial in predicting the ecological consequences of climate change for
isolated montane species, such as Royle's pika. We studied the
influence of habitat microclimatic conditions on the activity patterns
of Royle's pika in the period May to August (2008 to 2011) within six
permanently marked plots deployed along an attitudinal gradient (2,900
to 3,680 m) within the Kedarnath Wildlife Sanctuary, India. Pika
activity was recorded through direct observation during the period from
0600 to 1900 on each observation day and normalised as the percentage
of individuals observed in an hourly interval relative to the maximum
number of individuals sighted in a particular plot during the
observation day. Microclimatic data in pika habitat were recorded
across the altitudinal zones using automatic data loggers, a soil
thermometer and a hygrometer deployed within the site during each
observation interval.
Results: Using linear mixed effect models, we
simulated pika activity as the number of active versus inactive
individuals with logical alternate combinations of habitat
microclimatic parameters, altitudinal zone and daily time interval. The
pika had a bimodal activity pattern with high activity in the morning
and evening hours and low activity during midday hours. The best fit
candidate model demonstrated that pika activity increased with ambient
humidity and decreased with increasing temperature.
Conclusions: The reduction of
activity due to an increase in temperature was significantly higher in
the subalpine zone (2,900 to 3,200 m) than in the alpine zone (3,400 to
3,680 m). Thus, Royle's pika avoids heat stress by reducing activity
during warm midday hours and taking shelter in microclimatically
favourable cooler talus habitat. We showed that changes in habitat
microclimatic conditions (specifically, increases in temperature) might
significantly restrict Royle's pika daytime activity.
Key words: Activity; Kedarnath Wildlife
Sanctuary; Microclimate; Pika; Thermal stress.
*Correspondence: E-mail: bhattacharyyasabuj@gmail.com
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