Variation in escape response of Himalayan marmots (Marmota himalayana) under different human disturbances

Abstract

AbstractWe measured flight initiation distance (FID) and distance fled (DF) of Himalayan marmots (Marmota himalayana) from three populations suffering different human disturbances when they are near (<5 m) and away from (>5 m) a potential refuge to analyze the effects of varied disturbance intensity on their FID, DF, and the interaction between the two parameters. We found that: (1) highly disturbed individuals have shorter FIDs and smaller standard deviation of FID relative to undisturbed individuals, but there was no difference between lowly disturbed and undisturbed individuals. The diversifications arise possibly because extensive disturbance enhances the risk perception threshold of highly disturbed marmots but their lowly disturbed congeners; (2) the DF of highly disturbed individuals was shorter than undisturbed individuals, possibly because heavy disturbances drive reproductive pairs to dig more burrows in the habitat, resulting in the reduced inter‐burrow distance and thus decreased DF. No similar diversifications were observed between lowly disturbed individuals and individuals in the other two populations, possibly because reproductive pairs from low disturbance population concentrate their burrows, resulting in shorter DF when they are near their burrows, but longer DF when they are farther away; and (3) unlike lowly and undisturbed marmots, FID of highly disturbed individuals under different DFs differed significantly, potentially because shorter inter‐burrow distance reduced their flight costs, resulting in more tolerance of human proximity. Nevertheless, the DF‐derived risk perception threshold of undisturbed and lowly disturbed individuals drives them to prioritize fleeing when threatened. Generally, the escape response of Himalayan marmots under different human disturbances is determined by the interaction between predation risk and flight costs.