Artificial night light and anthropogenic noise interact to influence bird abundance over a continental scale

Abstract

The extent of artificial night light and anthropogenic noise (i.e., “light” and “noise”) impacts is global and has the capacity to threaten species across diverse ecosystems. Existing research involving impacts of light or noise has primarily focused on noise or light alone and single species; however, these stimuli often co‐occur and little is known about how co‐exposure influences wildlife and if and why species may vary in their responses. Here, we had three aims: (1) to investigate species‐specific responses to light, noise, and the interaction between the two using a spatially explicit approach to model changes in abundance of 140 prevalent bird species across North America, (2) to investigate responses to the interaction between light exposure and night length, and (3) to identify functional traits and habitat affiliations that explain variation in species‐specific responses to these sensory stimuli with phylogenetically informed models. We found species that responded to noise exposure generally decreased in abundance, and the additional presence of light interacted synergistically with noise to exacerbate its negative effects. Moreover, the interaction revealed negative emergent responses for several species that only reacted when light and noise co‐occurred. Additionally, an interaction between light and night length revealed 47 species increased in abundance with light exposure during longer nights. In addition to modifying behavior with optimal temperature and potential foraging opportunities, birds might be attracted to light, yet suffer inadvertent physiological consequences. The trait that most strongly related to avian response to light and noise was habitat affiliation. Specifically, species that occupy closed habitat were less tolerant of both sensory stressors compared to those that occupy open habitat. Further quantifying the contexts and intrinsic traits that explain how species respond to noise and light will be fundamental to understanding the ecological consequences of a world that is ever louder and brighter.

Nine‐banded armadillo (Dasypus novemcinctus) activity patterns are influenced by human activity

“…We assume that higher levels of L50 sound correspond to higher human presence and activity in an area. Although this sound layer estimated sound levels during the summer, it has been used for studies exploring animal response to noise in the winter (Wilson et al, 2021 ) and Buxton et al ( 2017 ) noted that this layer is valid for winter use but that overall sound levels may be lower in winter. We extracted the L50 sound value for the location of each camera.…”

The power of large‐scale community science in addressing anthropogenic change

“…We urge for the aggregation of big datasets in more diverse and rapidly urbanizing parts of the world, such as tropical regions, which differ in a history of development, primary productivity, and other environmental characteristics (Breuste et al, 2009). Community science is a powerful tool in urban ecology as spe- (Wilson et al, 2021). Nonetheless, these data are invaluable for providing fine-scale observations over a large range of environmental conditions using a standardized protocol.…”

“…Dissecting the variation that emerges from large-scale correlative analyses, like those presented in Wilson et al (2021), is the first step toward generating more specific top-down hypotheses.…”

“…For example, Wilson et al found that species with a preference for closed habitats were less tolerant of light and noise pollution than those with a preference for open habitats and propose that this might be explained by correlations between habitat preference and matched sensory traits, such as light gathering ability or the frequency of species' vocalizations. To test these hypotheses, we need better knowledge of hearing sensitivity and measurements of eye geometries that serve as a proxy for light sensitivity (Hall & Ross, 2007), as our current knowledge on this topic is extremely limited and is far from categorizing population variation across a gra- (Wilson et al, 2021), is critical to avoid overfitting models, misinterpreting correlations, or overlooking complex/ambiguous relationships among variables.…”

“…Especially as urban areas increase, where anthropogenic changes are highly concentrated and overlapping, investigating how multiple stressors interact to affect individuals and populations is a current research priority. Wilson et al (2021) levy the power of human interest in wildlife to study the effects of human-generated pollution. The authors provide a timely and novel continent-level study that addresses the interaction of light and noise pollution on species abundance and response using community science.…”