What evidence exists on the effects of anthropogenic noise on acoustic communication in animals? A systematic map protocol

Background: Noise pollution is an intense, widespread anthropogenic disturbance that can have highly detrimental impacts on natural populations, communities, and ecosystems across the globe. One major way through which noise can affect wildlife is by masking acoustic signals that animals rely on and, in doing so, hindering inter- A nd intraspecific communication among individuals. In response, many animals change their vocal behavior in an attempt to overcome the signal- A nd cue-masking effects of noisy environments. This can be done by changing the amplitude of the vocal output, shifting its frequency, or changing its temporal structure. However, to date, we still know very little about the ecological contexts of signal modifications in animals or their fitness consequences. We present a protocol for a systematic map aiming to collect and characterize all research done on animals' signal modification in response to anthropogenic noise. The map will increase our understanding of the consequences of noise pollution on animal communication and may guide the development of new mitigation tools to alleviate any negative effects. The map will also allow us to identify gaps in the literature and highlight possible future research areas. Methods: We will collect information about different types of acoustic modifications in response to noise as well as information about the noise's source and properties. The map will also include the ecological context of the signal modification and the fitness consequences of the modification, if measured. We will search both commercially published literature and grey literature, and conduct the searches in academic journal databases, online search engines, and specialist websites. Articles will be screened for inclusion at title, abstract and full-text levels and will then be critically appraised for study robustness and validity. Data will then be extracted and coded according to categories informed by consultation with stakeholders. Data will be summarized in a quantitative manner, accompanied with a narrative review that will map our knowledge on how animals change their vocalizations in response to noise pollution as a function of their taxa, geographic location, noise pollution source, and vocalization type.