Noise pollution as a major disturbance of avian predation in Amsterdam

Trophic interactions play a key role in maintaining ecological balance. In
urban environments, avian predation has been demonstrated to be
particularly important due to its effects on community structure, pest
control, and nutrient cycling. As humanity relies upon ecosystem services
for sustenance, and with 70% of the global population projected to reside
in urban areas by 2050, understanding the impact of urbanization on avian
predation is becoming increasingly important. This study investigates the
impacts of urban microclimates, shaped by impervious surfaces and
green/blue infrastructure, and human-induced disturbances, on avian
predation in urban areas, with the aim of testing the increased
disturbance hypothesis. To assess the avian predation rate, plasticine
caterpillars were placed in Quercus robur trees in the city of Amsterdam
for a period of two months. The analyses evaluated the impact of
artificial lighting at night, human population density, the urban heat
island effect, impervious surfaces, vegetation, noise pollution, and water
bodies on predation rates. The results indicated a substantial increase in
predation during the second month, which was likely caused by an increase
in naïve fledglings or elevated ambient temperatures. Noise pollution was
identified as the most frequent and robust predictor of predation,
consistently leading to a reduction in predation rates, possibly due to
avoidance behavior. Other predictors exhibited substantial temporal and
spatial variability. The variables related to urbanization increased
predation in the initial month, suggesting that insectivorous birds prey
on areas with higher illumination and temperature. However, the effect
diminished in the subsequent month, potentially due to the increased
daylight hours or a reduction in heating effects. During the second month,
all predictors exhibited a negative effect on predation, thereby
supporting the increasing disturbance hypothesis. These findings
underscore the complex relationship between urban factors and avian
predation, emphasizing the necessity for mitigation efforts in urban
planning.