Presence of a small mammalian prey species in open habitat is dependent on refuge availability

• Published in: Mammal research Vol. 60; no. 4; pp. 293 - 300
• Main Authors: Bhattacharyya, S, Dutta, S, Adhikari, B S, Rawat, G S
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2015
• Subjects: Animal Ecology; Biomedical and Life Sciences; Evolutionary Biology; Fish & Wildlife Biology & Management; Life Sciences; Original Article; Zoology; Himalayan region; Kedarnath Wildlife Sanctuary; Pika; Habitat selection; Behavioural trade-off; Himalaya
• ISSN: 2199-2401; 2199-241X
• DOI: 10.1007/s13364-015-0234-0

Identifying cues used by animals to select habitat offers insights into ecological trade-offs-often, contrasting choices amongst physical environment to meet physiological demands, food/other resources and predator avoidance. We examined the relative influence of food and refuge on occurrence of Royle’s pika, a common high-altitude prey in western Himalaya. We sampled distribution of rock with different crevices size (anti-predation refuge), and vegetation cover (food) in 0.25-ha plots at 20 pika occupied sites each paired with a putative (talus habitat) but unoccupied site along 1080-m elevation gradient. We used logistic regression and information-theoretic approach to test the effects of these factors on habitat selection. We found that pika occurrence was determined by rock cover with small crevices (AICc-wt summation = 0.98 R ² = 0.77) in a positive way (β = 0.16 ± 0.03), whereas negligibly influenced by vegetation covers (AICc-wt range 0.01–0.21). Model incorporating rock cover with small crevices could accurately predict pika occurrence (93 % area under ROC curve). Since this species inhabit open habitats with high predation risk and heat stress, abundant rock cover with small crevices offers critical escape from predators apart from providing thermal refuge since temperature inside rock crevices are usually moderate compared to ambient conditions. It simultaneously allows animals to access larger foraging areas that perhaps reduce their dependency on local food availability. Thus, we demonstrate the relative importance of refuge over food in microhabitat selection by pika and highlight that concurrent large-scale rock extraction for developmental activities can adversely affect pika distribution.