Light pollution enhances ground-level exposure to airborne toxic chemicals for nocturnally migrating passerines

Authors: Frank A. La Sorte, Christopher A. Lepczyk, Myla F. J. Aronson

Year: 2022

Publication: Global Change Biology

Publication Link:

Keywords: air pollution, community science, light pollution, nocturnal migration, seasonal bird migration, toxic chemicals

Abstract: Anthropogenic activities generate different forms of environmental pollution, including
artificial light at night (ALAN) and airborne toxic chemicals (ATCs). Nocturnally
migrating birds are attracted to ALAN during migration and if ALAN occurs in unison
with ATC, the chances of ground-level ATC contamination occurring at stopover sites
could increase. Here, we document the relationship between ALAN and ATC within
the contiguous United States based on 479 toxic chemicals from 15,743 releasing
facilities. Using weekly diurnal estimates of relative abundance for 165 nocturnally
migrating passerine (NMP) bird species, we assess how the species richness and relative
abundance of NMP species are correlated with ALAN and ATC across the annual
cycle. The concentration of ATC increased with increasing ALAN levels, except at the
highest ALAN levels. The species richness of NMP species was positively correlated with ATC during the non-breeding
season and migration, and negatively correlated during the breeding season. The relative abundance of NMP species was negatively
correlated with ATC during the breeding and non-breeding seasons and the correlation
did not differ from zero during migration. Through the disorienting influence
of ALAN, our findings suggest large numbers of NMP species are being exposed to
higher ATC concentrations at stopover sites. Outside of migration, large numbers of
NMP species that winter along the US Gulf Coast are being exposed for an extended
period of time to higher ATC concentrations. Initiatives designed to decrease ALAN
during migration have the potential to reduce the acute and chronic effects of ATC
contamination, lower the maternal transfer of toxic chemicals to eggs, and decrease
the biologically mediated transport of toxic chemicals across regions. However, these
initiatives will not benefit species that experience prolonged ATC exposure during
the non-breeding season along the US Gulf Coast, a region that could be a significant
source of ATC contamination for North American birds.

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