Ecol Appl. 2022 Apr 20:e2640. doi: 10.1002/eap.2640. Online ahead of print.
ABSTRACT
Animals perceive human activities as risky and generally respond with fear-induced proactive behaviors, to buffer the circadian patterns of lethal and nonlethal disturbances, such as diel migrations between risky places during safe nighttime and safer places during risky daytime. However, such responses potentially incur costs through movement or reduced foraging time, hence, individuals should adjust their tolerance when human activities are harmless, through habituation. Yet this is a challenging cognitive task when lethal and nonlethal risks co-occur, forming complex landscapes of fear. The consequences of this human-induced complexity have however rarely been assessed. We studied individual diel migration dynamics of chamois (Rupicapra rupicapra rupicapra, 89 GPS-tracked individual-years) from/to trails in the French Alps, in areas with co-occurring lethal (hunting) and nonlethal (hiking and skiing) disturbances, with different intensities across seasons. We developed a conceptual framework relying on the risk-disturbance hypothesis and habituation to predict tolerance adjustments of chamois under various disturbance contexts and across contrasted seasonal periods. Based on spatial and statistical analyses combining periodograms and multinomial logistic models, we found that diel migration in relation to distance to a trail was a consistent response by chamois (~85% of individuals) to avoid human disturbance during daytime, especially during the hiking and hunting periods. Such behavior unveiled a low tolerance of most chamois to human activities, although there was considerable inter-individual heterogeneity in diel migration. Chamois performed shorter diel migrations in areas highly disturbed by hikers. Interestingly there was an increased tolerance among the most disturbed diel migrants, potentially through habituation. Crucially, chamois which were most human-habituated during the hiking period remained more tolerant in the subsequent harvesting periods, which could increase their risk of being harvested. In contrast, individuals less tolerant to hiking performed longer diel migrations when hunting risk increased, and compared to hiking, hunting exacerbated the threshold distance to trails triggering diel migrations. No carry-over effect of hunting beyond the hunting period was observed. In conclusion, complex human-induced landscapes of fear with co-occurring disturbances by nature-based tourism and hunting may shape unexpected patterns of tolerance to human activities, whereby animal tolerance could become potentially deleterious for individual survival.
PMID:35443100 | DOI:10.1002/eap.2640
