From harnessing fire to inventing the light bulb, humans have a long history of lighting up the night. Despite the long history of humans introducing artificial light to nocturnal environments, the widespread impacts of light pollution have largely been ignored. Studies that have investigated communities’ response to artificial light typically do so by comparing lit and unlit areas and fail to address how naïve communities respond to the introduction of artificial light. Through experimental manipulation, our study addresses this shortcoming by investigating a community previously unaffected by ecological light pollution and monitoring the community’s response to the introduction and subsequent removal of artificial light. Using an array of landscaping lights placed above pitfall traps, we tracked an arthropod community over fifteen consecutive nights with a five-night pre-light period, five-night during-light period, and five-night post-light period. By investigating changes in the community at the taxonomic and trophic level we can identify artificial light as a mechanistic driver of community change. Additionally, by tracking the community through time we display the speed and magnitude of change it causes.
Results/Conclusions
Our results show an overall increase in arthropod abundance in response to light. However, this increase is not uniform across trophic levels with detritivores, predators, scavengers, and parasites increasing in abundance but herbivores decreasing in abundance. Within these trophic levels, families such as Agelenidae, Carabidae, and Lycosidae show affinity to light by significantly increasing in abundance when light is on. In contrast, other families such as Armadilidididae and Tingidae are highly reduced in the presence of light. This study also indicates that the community response to artificial light is rapid. The observed change in community is seen immediately upon introduction of artificial light and once light is removed the community rapidly returns to a pre-disturbed state. This study highlights a change many communities will experience as light pollution spreads to new environments and suggests the role lighting may have in altering global communities and creating ecological traps