Abstract
<jats:title>Abstract</jats:title> <jats:p>Early research in community ecology tended to focus on the density-mediated indirect effects described in previous chapters, but more recent research has revealed the prevalence of trait-mediated indirect effects across taxa and systems. Here, trait-mediated indirect effects also involve three or more species, but the pathways by which effects are transmitted from the initiating species to the receiving species are mediated by changes in phenotypic traits (e.g. behavioural anti-predator responses). Given that carnivores often exert strong top-down influence on other species, their behavioural adaptations to humans represent a potentially common trait-mediated pathway by which humans indirectly influence communities. This chapter will detail how humans initiate these indirect effects and discuss their implications for community dynamics and ecosystem structure and functioning. The chapter discusses such concepts in a manner that categorizes humans as ‘apex’ predators, and the degree to which humans inhabit this role can replace or modify the effects of non-human apex predators. We also emphasize that approaches to studying trait-mediated effects by humans onto carnivores must consider flexibility in trait expression as organisms adaptively respond to different environmental contexts (e.g. changes in resource quality or consumer pressure).</jats:p>