The impact of anthropogenic noise on wetland habitats above and below the waterline
Sound production and natural soundscapes are an important but poorly studied ecological component in wetland habitats. Animals use sound for a variety of reasons such as, to detect or deter predators and coordinate their movements. In terrestrial ecosystems, many taxa (e.g. Orthoptera, Hymenoptera, Coleoptera) have been shown to use sound to attract mates or delineate territorial boundaries. Given the importance of sound for animal communication, it is important to understand what impacts anthropogenic noise may have on the soundscapes of a variety of habitats. My research has investigated the differences in the above, and below water, soundscapes of wetlands with varying amounts of exposure to anthropogenic noise from roadways. For this soundscape study a total of 14 sites were utilized and recordings were collected at three different times a year for 24-hour periods. Soundscapes for above and below the water were recorded simultaneously.
The above water average power ranged from 38.9db to 83.8db. The below water average power ranged from 48.6db to 82.2db. Overall, the frequency band 0-5Khz had the highest overall power. A main difference between the disturbed (near roads) and undisturbed (further from roads) habitats was the composition of soundscapes. Soundscapes of disturbed habitats had a larger amount of anthropogenic noise, such as traffic and construction noise. While undisturbed soundscapes were composed mostly of natural sounds, such as animal calls and rain. With the importance of sound use by wetland organisms such as birds, frogs, fish and invertebrates understanding the impact of anthropogenic sounds should be a part of conservation management. Excessive anthropogenic noise, either in power or particular frequency bands, could mask animal communication or cause stress to organisms. Developing and maintaining a healthy soundscape should be a part of the management and development of natural habitats to ensure the health of all populations.