Changing light conditions due to human activities represents an important emerging environmental concern. Although changes to natural light conditions can be independently detrimental, in nature, organisms commonly face multiple stressors.
To understand the consequences of altered light conditions, scientists exposed an amphibian model to control and anthropogenic light conditions: intensified daytime illuminance and artificial light at night. They found that light at night has a detrimental effect on amphibian populations.
Binghamton University Assistant Professor of Biological Sciences Jessica Hua said, “Research on the effects of light pollution has recently seen a surge in popularity. It’s difficult to find any place on Earth that is not affected by even minimal light pollution. We recognized a gap in the research and realized that not much was known about how light pollution can impact amphibians. Since amphibians are sensitive to environmental changes, they make great models for studying how pollution of any type can impact other species.”
During the study, scientists exposed wood frogs to a control and two anthropogenic light conditions: intensified daytime illuminance and artificial light at night (ALAN). They found that both the intensified daytime illuminance treatments and the ALAN treatment decreased hatching success in tadpoles. Tadpoles that were reared in the ALAN treatment, on the other hand, were larger, less active, more sensitive to road salt pollution and had more parasites.
Scientists found that the exposure to light at night time could make amphibians more susceptible to the effects of additional stressors, like road salt and parasites.
Graduate student Grascen Shidemantle said, “This is concerning since these are common stressors that many amphibians have to cope with. The light at night on itself might not have too much of a negative effect on its own, however, since wildlife rarely encounter just one stressor in their natural habitat, the combination of light pollution with additional stressors may have negative impacts on amphibian populations.”
Shidemantle is considering looking at how light pollution impacts other organisms in wetland ecosystems that amphibians might interact with, such as damselfly larvae which are common predators of tadpoles. She received a grant from the National Science Foundation this year to further explore the effects of light pollution on amphibians.
Shidemantle said, “It is critical to understand how humans impact wildlife so that we can make more responsible decisions about how we proceed with activities such as urbanization and construction. Also, it is likely that these effects of light pollution extend beyond just amphibians–the impacts on amphibians may have indirect effects on other organisms that amphibians interact within their ecosystem.”
The study is published in the journal Environmental Pollution.