Abstract
Human activities catalyse risk avoidance behaviours in wildlife across taxa and systems. However, the broader ecological significance of human-induced risk perception remains unclear, with a limited understanding of how phenotypic responses scale up to affect population or community dynamics. We present a framework informed by predator-prey ecology to predict the occurrence of non-consumptive effects (NCE) and trait-mediated indirect effects (TMIE) of anthropogenic disturbances. We report evidence from a comprehensive review of the different types of human-induced behavioural and physiological phenotypic changes and their influence on vital rates and population parameters in wildlife. Evidence for human-induced NCEs and TMIEs is mixed, with half of published studies finding a relationship between human activities, phenotypic change and population outcomes. The net effects of anthropogenic NCEs and TMIEs depend on the mismatch between the phenotypic response and the lethality of human activity. However, strong research biases in taxa, systems, human disturbance types and demographic measures prevent unified inference about the prevalence of population responses to human activities. Coexistence with and conservation of wildlife requires additional research linking human-induced phenotypic change to population and community outcomes.
Demographic costs of behavioural and physiological responses to human activities are often inferred yet rarely tested. Existing literature on such effects is highly biased and limited. Future work in this area should draw from predator-prey theory and can inform conservation and management of wildlife.image