The pinyon pine is one of the most important tree species in the American West, providing food and shelter for hundreds of wildlife species. But new research suggests that man-made noise may threaten the future of the pines.
According to a study published this week in the Proceedings of the Royal Society B, western scrub jays tend to avoid noisy areas, while mice were more likely to prefer noisy areas. Since scrub jays hide pinyon pine seeds to eat them later while mice completely consume them, this could affect the way the trees' seeds are distributed, if at all, in the future.
"There is a lot of evidence that the western scrub jay and the pinyon pine co-evolved," lead author Clinton Francis of the National Evolutionary Synthesis Center in Durham, N.C., told Audubon Magazine. "A single scrub jay in the fall, when a lot of these seeds are available, will collect and disperse hundreds, covering them under a few centimeters of soil. While they end up recovering lots of seeds, it's many of those forgotten seeds that end of becoming the future of the forest."
Francis and his fellow researchers conducted their study between 2007 and 2010 at Rattlesnake Canyon Wildlife Area in New Mexico, an area that is home to thousands of natural gas wells. Many of the wells use noisy compressors 24 hours a day to extract the natural gas and transport it through pipelines. The researchers found that quieter areas of the wildlife zone were more likely to contain scrub jays and four times more abundant with pinyon pine seedlings than loud regions. Meanwhile, the mice that thrived in the louder environments ate more seeds there, destroying them in the digestive process.
Even if the noise stopped today, the impact could be felt for many years to come since pinyon pines live for decades. "Fewer seedlings in noisy areas might eventually mean fewer mature trees, but because [the trees] are so slow-growing, the shift could have gone undetected for years," Francis said in a prepared statement. Meanwhile, a lower density of pinyon pines "would mean less critical habitat for the hundreds of species that depend on them for survival."
Not all birds avoided the noisiest areas. Over the course of the study, black-chinned hummingbirds were found to be five times more likely to visit loud areas compared to quiet sites. The birds are important pollinators for some plant species. Western scrub jays prey upon hummingbird nestlings, so the smaller birds may have moved to the noisy sites for their own safety.
"Our study shows that noise needs more attention — perhaps on par with other issues like habitat fragmentation or disturbance," said Francis.
Pinyon pine seeds are an important food source for songbirds, squirrels, black bears, deer, chipmunks and other wildlife, according to Utah State University. The seeds were a staple in Native American diets and are currently used in making a variety of sweets.