The effects of noise can reach organisms(生物体) without ears. Because of the way living things rely on each other, noise pollution may actually stop some forests from growing, a new study suggests. In a New Mexico woodland of pine trees, researchers found far fewer tree seedlings(小苗) in noisy sites than they did in quiet ones.
The study area is dotted with gas wells, some of which are quiet and some of which have compressors(压缩机) that create a constant noise. This allowed Jennifer Phillips, a behavioral ecologist at Texas A&M University-San Antonio and her colleagues to compare sites that were similar except for noise level. In areas that had been noisy for at least 15 years, the researchers found only about 13 pine seedlings, compared with 55 pine seedlings per hectare (公顷) in quiet areas.
The differences in plant growth were probably caused by changes in animal behavior, said Phillips. For example, noise might drive away certain pollinators(传粉昆虫) such as bees, bats and moths. In the case of pine trees, the problem was likely a lack of animals to disperse seeds. Pines depend on birds to carry their seeds away from the parent tree, and birds are known to avoid noise. The differences between the sites aren't yet obvious to someone walking through them, said Sarah Termondt, a botanist(植物学家) with the U.S. Fish and Wildlife Service who helped conduct the study. That's probably because pines are slow-growing, with most of the mature trees in such woodlands being over a century old.
The study raises questions about the future of the area. "If the noise stays there long term, are we going to lose this important ecosystem of the pine which supports so much wildlife?" said Phillips. The study was published today in the journal Proceedings of the Royal Society.
