As humans proliferate, we have penetrated deeper into wildlife habitats, creating a widespread increase in ambient noise with our devices, traffic, and industry. A growing body of research has shown how noise pollution negatively affects the behavior of animals, but one study suggests that the detrimental effects have also seeped into plants.
To investigate the long-term ecological effects of persistent noise, the researchers chose the Rattlesnake Canyon habitat management area in New Mexico. Dominated by forest plants, the area in the southwestern United States contains a high density of natural gas wells, some of which are coupled to compressors that run continuously and generate chronic noise of up to 100 decibels. That’s as strong “as standing next to the speakers at a Black Sabbath concert or standing right next to the train tracks as the train passes,” said Dr. Jenny Phillips, who was lead author of the study while in California Polytechnic State University in San Luis Obispo. Other wells lack compressors.
Vegetation and human activity in both types of wells are similar, so in 2007 a group of researchers compared vegetation in both contexts and found that noise pollution disrupted the natural community in two ways: seedling dissemination and germination (known as recruitment) from the forest. species, stone pine, declined as the community of animals that feed and disperse the plant’s seeds were adversely affected. Meanwhile, hummingbirds thrived amid the noise, prompting more pollination of the flowers.
Twelve years later, the researchers sought to assess the long-term ecological impact of this noisy ecosystem. They re-examined the plots after initial data collection to determine if previously reported patterns for pine nut seedlings persisted, but also included analyzes of another tree species, the Utah juniper, as well as other flora. However, of those 115 plots initially surveyed, some had switched from noisy to quiet because the compressors had been removed and vice versa.
In terms of the pinion, the researchers found that the seedlings were found less in noisy areas (in line with the 2007 findings) and the seedlings (plants between two and 12 years old) had also grown more slowly in the persistently noisy environment. The same pattern was observed in juniper plants.
However, when looking at the plots that were previously noisy but quiet, they saw more recruitment of juniper than pine nut, according to the study published in the journal Proceedings of the Royal Society B.
This uneven recovery rate could be attributed to the different seed dispersers for each plant, Phillips said.
The California bush jay eats the seeds of the pine nut, but also buries them to save for later. Then they forget about the seeds and that is what makes the forest regenerate.
“What we think is potentially happening… is that jays are intelligent birds, they have episodic memory and can recall negative experiences. So if they explored an area a couple of years ago and if it’s noisy, then they would remember it and they wouldn’t go back to that area, “he said.
Juniper seedlings were dispersed more frequently by mammals and other birds for whom the noise was not as disturbing, he added.
“We really don’t have the ability to say how severe the impacts are. [of noise pollution] They are, especially if you look at the ecosystem level, ”said Sarah Termondt, a co-author of the study at Texas A&M University.
“If you are changing the ability of a seed to grow somewhere because a bird is no longer dropping that seed there, that could change the habitat of a large number of species.”