Artificial light at night (ALAN), a pollutant closely linked to urbanization, is rapidly increasing worldwide. ALAN poses growing ecological challenges by altering wildlife movement and habitat use. However, many species have distinct and sometimes flexible behavioral responses to ALAN. Caracals (Caracal caracal) are an adaptable terrestrial carnivore capable of inhabiting urban areas yet are also sensitive to humans. We investigated how ALAN influences caracal movement, habitat selection, and foraging behavior using GPS collars and behavioral data at night. We assessed the role of direct and indirect ALAN, including total upward radiance, public streetlights, and urban skyglow, on adult (n = 17) and subadult (n = 7) caracals of both sexes using integrated step selection functions (iSSFs) to evaluate movement and habitat selection and resource selection functions (RSFs) to examine habitat selection while foraging (i.e., kill sites). We found that caracals avoided direct ALAN, as upward radiance strongly drove movement patterns. Caracals simultaneously selected areas closer to urbanization, and subadults had greater tolerance to ALAN than adults. Additionally, the interplay between urbanization and age class indicates a complex relationship in which ALAN and urbanization both constrain and potentially benefit caracals. We also found that caracal foraging was primarily influenced by direct ALAN via public street lighting, with avoidance of highly illuminated areas. Our findings illustrate that artificial light sources influence distinct yet interconnected behaviors. ALAN is a pollutant that will continue to impact wildlife and therefore disentangling how and where ALAN influences species, and the relative importance of direct and indirect ALAN, can inform mitigation and conservation strategies.
Hickling et al. (Wed,) studied this question.