Thesis Defense at CES on 28 July 2020 at 11:00 am titled "Distribution, activity budget and feeding ecology of Himalayan gray langur in Kashmir Himalaya" by Mehreen Khaleel from CES, IISc
Colobines are group of primates known to inhabit different habitats. These habitats pose diverse challenges which they have coped up physiologically and behaviourally. Primates in such environments are subjected to prolonged scarcity of food due to phenological variations and low temperature in winters. They are expected to allocate their time to various activities optimally in order to balance their energy requirements. One such primate inhabiting the harsh weather condition of Himalaya is Himalayan gray langur. Himalayan gray langur, Semnopithecus ajax, is little-known endangered primate, initially reported to be present in few parts of north-western Himalaya. To understand their survival strategies in these habitats one must know about the whereabouts of this species.
Therefore, I first accessed the spatial distribution and occurrence of Himalayan gray langur in Kashmir region. This was achieved by using well-structured questionnaire and on-ground surveys in the region. It was followed by identifying sites which face human-langur conflict. My results suggest a wider range of Himalayan gray langur in Kashmir which was previously thought to be restricted in a small range. Langurs were found distributed in the protected mountainous forest areas of Kashmir by showing a preference for broad-leaved deciduous and coniferous habitat types within 1600-3000 m. Conflict in the form of crop raiding was found in the villages around protected areas.
Based on the knowledge of the distribution of these primates in forests, I tried to address how this primate survives the seasonality and cold temperatures of Himalaya in the next chapters of my thesis. I have addressed this by investigating the behaviour patterns and the strategies they have adopted to balance the energy requirements. I used observational methods of instantaneous scans for different behaviour categories. My results suggest Himalayan langurs spend more time feeding during lean winter when high-quality food is less available and rest more during hotter months. Moreover, they have greater home range sizes in winter than in summer. These results suggest an energy maximizing strategy by these primates when resources are scarce by feeding more on less profitable food sources and expanding their home range size.
I further investigated the diet and feeding behaviour of langurs. They were found to shift their diet with seasonality. They feed on a variety of plant items ranging from bark, buds, young leaves, mature leaves, ripe fruits and seeds. I used resource selection functions to test for plant species preference. A seasonal preference for certain plant species and plant parts suggest that availability of plant parts influences their choices. From these results one can conclude that Himalayan gray langur has adapted to explore a variety of food sources other than leaves. This study helps us in understanding the ability of colobines to explore such versatile diets which has helped them colonize many habitats, one of them being the Himalaya.
Overall, this study provides a baseline information for conserving Himalayan gray langur through comprehensive understanding of its distribution, activity budget, home range, diet and feeding preference in Kashmir Himalaya. The current distribution serves as a base-map for various management policies towards the conservation of this high-altitude primate. Moreover, insights about the conflict will help managers in developing ideas to reduce and prevent conflict. Due to the presence of this species in the broad-leaved deciduous and coniferous forests of Kashmir, it becomes important to preserve and protect these habitats for its survival. The key findings of this study are expected to benefit directly towards the conservation of this species and in understanding the survival strategies of these high-altitude primates.