Spotlight on Bright Lights

When I started grad school I made a pact with a friend that we would get out of the city and see the stars in the night’s sky at least once a month.  Grad school got busier and it didn’t really happen but the reason for this pact in the first place is light pollution.  Artificial lights on at night in cities and towns cause light pollution, which prevents us from easily viewing the stars.  One has to drive far away from large urban centers to see anything besides Orion’s belt and a few of the other brightest stars. 

Light pollution effects our enjoyment of nature, but the larger question is, what does it do for wildlife that live with it all the time?  Nocturnal species, which are awake at night are particularly vulnerable.  Researchers have spent a lot of time looking at how artificial lights at night impact wildlife and there are many examples of negative effects.  For example, some birds migrate long distances using the stars and the moon for navigation.  Bright lights can distract them from their correct course and they can crash into buildings and towers and die. 

Alternatively, some birds become disoriented and fly around in circles until they die from exhaustion.  But it’s not only birds that can feel these negative effects.  Female sea turtles come onto land to lay eggs but they don’t come ashore if there are too many artificial lights.  And it’s a double whammy for sea turtles because when they are successful at laying eggs on shore the hatchlings have to get back into the ocean.  These hatchlings use stars and moonlight to orient themselves back to the water but sometimes they are distracted by streetlights and go off in the wrong direction.  When this happens predators can easily pick them off as a tasty snack.  To help with this problem people have found a solution.  They can shield the side of the lights that is closest to the ocean or even turn off the lights during the sea turtle breeding season. 

Artificial lights at night can influence wildlife in other ways besides disorientation.  Have you ever been blinded by a bright light or distracted by the lights of a passing car?  This type of light can distract you from what you are trying to work on at the moment.  And even change your behavior if you were to avoid the light altogether.  Artificial light at night can change the behavior of animals and even prevent them from doing behaviors that they need to do in order to survive. I am particularly interested in looking at how artificial light at night might affect the forging behavior of nocturnal endangered species in California.  San Bernardino kangaroo rats (Dipodomys merriami parvus) and Pacific pocket mice (Perognathus longimembris pacificus) are endangered nocturnal species and need to spend a lot of time collecting seeds, which they eat as food.  They store as many seeds as they can in their burrows and eat them throughout the year.  Both of these species need open space and native habitat but unfortunately, these species live in areas currently threatened by development and urban expansion.  The habitats in which they live in are becoming increasingly impacted by humans. 

The research project that I am working on involves experimentally exposing kangaroo rats and pocket mice in their respective habitats to artificial lights at night and measuring how their behavior compares under artificial conditions to their behavior with just moonlight.  The goal of the research project is to learn all that we can about free living kangaroo rats and pocket mice and their behavior to better understand the actions that people will need to take to protect their species.  Our experiments are ongoing, so stay tuned to see what we discover.