Field evidence for interactive effects of artificial light at night and moon phase on sea urchin Paracentrotus lividus locomotion - Ferretti et al.: Dataset and R script

We investigated the nocturnal locomotor behaviour of the sea urchin Paracentrotus lividus, a key grazer of the Mediterranean coasts, in relation to ALAN and the moon phase. We hypothesised different ALAN effects under new versus full moon conditions. Low ALAN levels during new moon may mimic full moonlight, whereas higher intensities may mask natural full moon cues inducing disorientation, and/or negative phototaxis independently of moon phase.Field experiments were conducted under new and full moon phases across a gradient of ALAN intensities from coastal infrastructures. Sea urchin positions were marked at sunset and their movement was followed every hour until midnight. A total of 180 tagged individuals were monitored during nine sampling campaigns. Three response variables were obtained: path speed, maximum displacement, and straightness.Our results showed that animals moved more rapidly and covered greater distances as ALAN intensity increased, but only during full moon nights.