Long-term dim light during nighttime changes activity patterns and space use in experimental small mammal populations

Area of Science:

• Ecology
• Environmental Science
• Animal Behavior

Background:

• Artificial light at night (ALAN) is a growing global issue, disrupting natural light-dark cycles.
• The effects of low-intensity light pollution on wildlife are understudied.

Purpose of the Study:

• To investigate the impact of low-intensity artificial light at night (ALAN) on bank vole (Myodes glareolus) populations.
• To assess behavioral changes, survival, and physiological stress in response to light pollution over winter and early breeding seasons.

Main Methods:

• Eight experimental bank vole populations were housed in large grassland enclosures over seven months.
• LED garden lamps simulated low-intensity ALAN.
• Automated radiotelemetry monitored activity patterns and space use; live trapping assessed survival, body mass, and fecal glucocorticoid metabolites.

Main Results:

• Bank voles exposed to ALAN exhibited altered daily activity patterns and space use.
• Increased nocturnal activity was observed during half moon phases under ALAN.
• Larger day ranges were recorded during new moon phases in the ALAN treatment group.
• No significant differences were found in survival, body mass, or stress hormone levels.

Conclusions:

• Low-intensity artificial light at night can significantly alter animal behavior, specifically activity and space use in bank voles.
• These behavioral changes, even from subtle light pollution like sky glow, may have broader ecological consequences for species interactions.