Boise State University, Boise, ID, USA.
California Polytechnic State University, San Luis Obispo, CA, USA.
Nat Commun. 2021 May 24;12(1):3029. doi: 10.1038/s41467-021-22390-y.
Natural sensory environments, despite strong potential for structuring systems, have been neglected in ecological theory. Here, we test the hypothesis that intense natural acoustic environments shape animal distributions and behavior by broadcasting whitewater river noise in montane riparian zones for two summers. Additionally, we use spectrally-altered river noise to explicitly test the effects of masking as a mechanism driving patterns. Using data from abundance and activity surveys across 60 locations, over two full breeding seasons, we find that both birds and bats avoid areas with high sound levels, while birds avoid frequencies that overlap with birdsong, and bats avoid higher frequencies more generally. We place 720 clay caterpillars in willows, and find that intense sound levels decrease foraging behavior in birds. For bats, we deploy foraging tests across 144 nights, consisting of robotic insect-wing mimics, and speakers broadcasting bat prey sounds, and find that bats appear to switch hunting strategies from passive listening to aerial hawking as sound levels increase. Natural acoustic environments are an underappreciated niche axis, a conclusion that serves to escalate the urgency of mitigating human-created noise.
自然感官环境尽管具有很强的系统结构潜力，但在生态理论中却被忽视了。在这里，我们通过在高山河岸带两个夏季播放白水河流噪声来检验强烈的自然声环境通过掩蔽作用形成动物分布和行为模式的假设。我们使用光谱改变的河流噪声来明确测试作为驱动模式的机制的掩蔽效应。使用两个完整繁殖季节在 60 个地点进行的丰度和活动调查的数据，我们发现鸟类和蝙蝠都避开高音量区域，而鸟类避开与鸟鸣重叠的频率，而蝙蝠则更普遍地避开更高的频率。我们在柳树中放置了 720 个粘虫幼虫，并发现强烈的声音水平会降低鸟类的觅食行为。对于蝙蝠，我们在 144 个夜晚进行了觅食测试，包括机器人昆虫翅膀模拟和扬声器播放蝙蝠猎物的声音，发现随着声音水平的增加，蝙蝠似乎会从被动聆听转变为空中捕食的狩猎策略。自然声环境是一个被低估的生态位轴，这一结论加剧了减轻人为噪声的紧迫性。
