Reducing night lights in cities has ecological effects
Artificial light at night (ALAN) can cause plants to open their buds and sprout leaves earlier in the spring. ALAN can also cause trees to delay changing the color of their leaves in the fall. These changes can ripple through ecosystems, affecting pollinators, herbivores and insects that lay eggs on plants. ALAN also disorients many migrating birds and other animals.
Artificial light at night (ALAN) can influence plant growth cycles, potentially impacting ecosystems through changes in timing of spring and autumn. Two pairs of cities - New York City and Newark, New Jersey on one side, and Washington D.C. and Philadelphia on the other - were compared to evaluate the effectiveness of ALAN mitigation measures.
In cities where such measures were implemented, including New York City and Washington D.C., ALAN levels were reduced, particularly in the blue wavelength range. This reduction correlated with less advanced spring green-up and less delayed autumn leaf coloration in comparison to cities that did not implement such measures like Newark and Philadelphia.
The study suggests that satellite imagery can be a useful tool in evaluating the impact of ALAN mitigation efforts on urban ecosystems.
Written by urgent.news from Phys.org's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
