SOUND-TRANSMISSION AND ITS SIGNIFICANCE FOR ANIMAL VOCALIZATION .1. TEMPERATE HABITATS
SOUND-TRANSMISSION AND ITS SIGNIFICANCE FOR ANIMAL VOCALIZATION .1. TEMPERATE HABITATS
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DOI：
10.1007/bf00299740
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发表时间：
1977-01-01
影响因子：
2.3
通讯作者：
MARLER, P
中科院分区：
文献类型：
--
作者：
MARTEN, K;MARLER, P
1.在纽约达奇斯县的开阔地、落叶混交林和针叶林中测量了声传播。白色噪声和纯音的衰减是在靠近扬声器的一个麦克风和100米远的另一个麦克风之间测量的，在相同的高度。过量衰减（E.A.在离地面0.15、1、2、5和10 m处获得了相对于频率的噪声（dB/100 m）。通过方差分析，估计了高度、频率和生境对声传播的影响。2.高度和频率对声传播的影响大于生境。声源靠近地面（15厘米和1米）的所有频率衰减比在更高的高度。E.A.作为声音频率的函数，在所有的栖息地基本上是相似的。在所有的声源高度上，频率越低，声音传播的越好，除了靠近地面的地方，低于2 kHz的声音被过度衰减。与野外和森林相比，树木改善了3 kHz以下频率的传播，尤其是接近地面的频率。3.可以预测这些生境中动物声音传播距离最大化的一些一般趋势。当动物在离地1米以上的地方发声时，频率越低，声音传播的距离越远。在接近地面的地方，为了最大化传输距离，低频也是首选，但频率必须高于衰减的低音范围，其限制在一定程度上随栖息地而变化，从而形成莫顿的“声音窗口”。这种衰减最小的频率“窗口”，只发生在靠近地面的地方，在森林中往往比在开放的栖息地中要低一些。然而，对于在测试的栖息地产生声音的动物来说，栖息地的高度和声音频率比栖息地更重要，因为它们决定了声音能传播多远。
1.Sound transmission was measured in open fields, mixed decidous forest with and without leaves and coniferous forest in Dutchess County, New York. Attenuation of white noise and pure tones was measured between one microphone close to a loudspeaker and another microphone 100 m away, at the same height. Graphs of excess attenuation (E.A. in dB/100 m) against frequency were obtained at 0.15, 1, 2, 5, and 10 m above the ground. An analysis of variance was conducted to estimate effects of height, frequency and habitat.2.Height and frequency affect sound transmission more than habitat. With a sound source close to the ground (15 cm and 1 m) all frequencies were more attenuated than at greater heights. The patterns of E.A. as a function of sound frequency were basically similar in all habitats. At all source heights the lower the frequency the better the sound carried, with the exception that close to the ground, sounds below 2 kHz were excessively attenuated. Comparing open field and forest, trees improved transmission of frequencies below 3 kHz, especially close to the ground.3.Some general trends can be predicted for maximization of transmission distances of animal sounds in these habitats. For an animal vocalizing higher than 1 m above the ground, the lower the frequency the further the sound travels. Close to the ground, low frequencies are again preferred for maximization of transmission distances, but the frequencies must be pitched above a range of attenuated, low-pitched sounds, the limits of which vary to some extent with habitat, creating the ‘sound window’ of Morton. This ‘window’ of least-attenuated frequencies, only occurring close to the ground, tends to be pitched somewhat lower in forest than in open habitats. However, for an animal producing sounds in the habitats tested, perch height and sound frequency are more important than the habitat in determining how far the sound will carry.