Light and noise together were not consistently worse than their sum
WHAT THE EVIDENCE SAYS
A systematic search retrieved 6,018 records; 30 studies directly examined artificial light at night with anthropogenic noise, with 16 eligible for the interaction meta-analysis. The absolute departure from additivity was detectable, yet the pooled directional interaction was not significant. Both light and noise showed negative main effects, and responses varied among biological outcomes.
WHY IT MATTERS / OUR READ
The design lesson is to examine multiple exposures together without assuming every co-exposure is synergistic. A null directional interaction does not excuse either pollutant; it warns against making a one-size-fits-all claim about their combination.
CAVEATS / UNCERTAINTY
Only 16 papers entered the interaction meta-analysis, with geographic and taxa/outcome imbalance. A significant magnitude of nonadditivity does not imply a consistent worsening; communication outcomes differed from other outcomes, and study designs varied.
SOURCE
Biodiversity and Conservation — 2026 meta-analysis
View original evidence ↗
A synthesis across taxa found harmful individual disturbance effects but no universal direction for their interaction.
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