Effects of bird migration on the temporal patterns of the wetland soundscape in the downstream region of the Tumen River Basin of China

doi:10.17520/biods.2022337

Abstract

Abstract:

Aims: Bioacoustics may provide an effective method for monitoring changes in wetland bird activity and soundscape, yet phenological and seasonal patterns remain poorly understood. In this study, we examine the seasonal and diel soundscapes, as well as the utility of bioacoustics in detecting changes in songbird phenology in the downstream region of the Tumen River Basin of China.

Methods: Between November 2020 and December 2021, 91,988 acoustic recordings were collected at 10 sites from the Jingxin Wetland, a stopover ground for numerous migratory bird species. For each sample, we record the acoustic complexity index (ACI), bioacoustic index (BIO), acoustic evenness index (AEI), normalized difference soundscape index (NDSI) and power spectral density (PSD) values.

Results: Our analysis show that seasonal shifts and bird migration have a significant effect on the composition and diversity of wetland soundscape. The 1-2 kHz daytime vocal signals of wild geese dominated the soundscapes of two migration periods (February-April and October-November), resulting in a significant decrease in NDSI and a significant increase in PSD at 1-2 kHz. Acoustic indices are sensitive to bird migration, but changes in bioacoustics were less abrupt in the fall, suggesting that spring recordings are better suited to indicate phenology. Summer birds and insects dominated the soundscape of non-migration period.

Conclusion: We find that the soundscape of the Tumen River’s downstream wetland exhibits clear annual and diurnal rhythm. Our experiment demonstrates the use of multiple acoustic indices in conjunction can effectively monitor changes in migratory bird phenology, particularly the time and population size at which wild geese fly back north in the spring. Furthermore, we conclude that acoustic recordings, in combination with acoustic indices, may be a useful method for tracking shifts in songbird communities caused by climate change.

Key words: ecoacoustics, soundscape monitoring, acoustic indices, power spectral density, Tumen River’s downstream region, bird migration

Shizheng Wang, Yifei Sun, Zhenzhen Li, Yue Shu, Jiawei Feng, Tianming Wang. Effects of bird migration on the temporal patterns of the wetland soundscape in the downstream region of the Tumen River Basin of China[J]. Biodiv Sci, 2023, 31(1): 22337.

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URL: https://www.biodiversity-science.net/EN/10.17520/biods.2022337

https://www.biodiversity-science.net/EN/Y2023/V31/I1/22337

Figures/Tables 9

References 56

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示意图 Schematic diagram	声学指数 Acoustic indices	声景格局 Soundscape pattern	参考文献 References
时频图 Spectrogram	声音复杂度指数(ACI): 音频中相邻时间窗声强的变异性, 值的范围 > 0。Quantifies the sound complexity for estimating the variability of the intensities between time samples within a frequency band. Range = [0, +].	高值代表高水平的鸟类活动; 低值代表持续性的昆虫噪音。High values represent higher levels of bird activity, while low values represent consistent insect noise.	Pieretti et al, 2011
频谱图 Spectrum	生物声学指数(BIO): 声谱图中2-11 kHz范围内超过分贝阈值部分的面积, 值的范围 > 0。Estimates the area under curve of the mean spectrum above a specific decibel (dB) threshold within 2-11 kHz. Range = [0, +].	高值代表生物声丰富, 大量频段被占据, 最高声和最安静频段差异大; 低值代表在2-11 kHz之间很少有声音。High values represent higher levels of biophonic, in which many frequency bands are occupied, and significant disparity between the loudest and quietest bands; low values represent no sound between 2 and 11 kHz.	Boelman et al, 2007
	声音均匀度指数(AEI): 表示声信号强度在不同频段的均匀度, 计算Gini系数来表示声信号强度在每个1 kHz频段的不均等程度, 值的范围为0-1。Measures the evenness of the acoustic activity distribution estimating the Gini coefficient on the signal proportion in each 1 kHz band. Range = [0, 1].	高值代表少数频段由高的声强主导; 低值代表多个频段被占据或者所有频段没有声学活动。High values represent high sound intensity in a restricted range of frequencies; low values represent either high or no acoustic activity across all frequency bins.	Villanueva-Rivera et al, 2011
	标准化声景差异指数(NDSI): 人造声(1-2 kHz)与生物声(2-11 kHz)频段间声信号功率的比率, 值的范围为-1至1。The ratio of signal power in the frequency bands between anthrophony (1-2 kHz) and biophony (2-11 kHz). Range = [-1, 1].	高值代表高水平的生物声, 而低值代表人造声为主。High values represent higher levels of biophonic activity, and minimal noise in 1-2 kHz.	2012

示意图 Schematic diagram	声学指数 Acoustic indices	声景格局 Soundscape pattern	参考文献 References
时频图 Spectrogram	声音复杂度指数(ACI): 音频中相邻时间窗声强的变异性, 值的范围 > 0。Quantifies the sound complexity for estimating the variability of the intensities between time samples within a frequency band. Range = [0, +].	高值代表高水平的鸟类活动; 低值代表持续性的昆虫噪音。High values represent higher levels of bird activity, while low values represent consistent insect noise.	Pieretti et al, 2011
频谱图 Spectrum	生物声学指数(BIO): 声谱图中2-11 kHz范围内超过分贝阈值部分的面积, 值的范围 > 0。Estimates the area under curve of the mean spectrum above a specific decibel (dB) threshold within 2-11 kHz. Range = [0, +].	高值代表生物声丰富, 大量频段被占据, 最高声和最安静频段差异大; 低值代表在2-11 kHz之间很少有声音。High values represent higher levels of biophonic, in which many frequency bands are occupied, and significant disparity between the loudest and quietest bands; low values represent no sound between 2 and 11 kHz.	Boelman et al, 2007
	声音均匀度指数(AEI): 表示声信号强度在不同频段的均匀度, 计算Gini系数来表示声信号强度在每个1 kHz频段的不均等程度, 值的范围为0-1。Measures the evenness of the acoustic activity distribution estimating the Gini coefficient on the signal proportion in each 1 kHz band. Range = [0, 1].	高值代表少数频段由高的声强主导; 低值代表多个频段被占据或者所有频段没有声学活动。High values represent high sound intensity in a restricted range of frequencies; low values represent either high or no acoustic activity across all frequency bins.	Villanueva-Rivera et al, 2011
	标准化声景差异指数(NDSI): 人造声(1-2 kHz)与生物声(2-11 kHz)频段间声信号功率的比率, 值的范围为-1至1。The ratio of signal power in the frequency bands between anthrophony (1-2 kHz) and biophony (2-11 kHz). Range = [-1, 1].	高值代表高水平的生物声, 而低值代表人造声为主。High values represent higher levels of biophonic activity, and minimal noise in 1-2 kHz.	2012

声学指数 Acoustic indices	2-4月 Feb.-Apr.	5-7月 May-July	8-9月 Aug.-Sept.	10-11月 Oct.-Nov.	12月至次年1月 Dec.-Jan.	P
声音复杂度指数 Acoustic complexity index (ACI)	4,530.52 ± 17.78^a	4,622.86 ± 28.88^a	4,523.64 ± 22.69^a	4,449.51 ± 7.54^b	4,413.08 ± 7.26^b	< 0.001
生物声学指数 Bioacoustic index (BIO)	10.38 ± 0.48^c	12.22 ± 0.47^b	14.15 ± 0.52^a	8.32 ± 0.19^d	7.15 ± 0.20^e	< 0.001
声音均匀度指数 Acoustic evenness index (AEI)	0.90 ± 0.01^b	0.83 ± 0.01^c	0.78 ± 0.01^d	0.90 ± 0.01^b	0.92 ± 0.01^a	< 0.001
标准化声景差异指数 Normalized difference soundscape index (NDSI)	-0.04 ± 0.07^c	0.46 ± 0.05^b	0.88 ± 0.01^a	0.10 ± 0.06^c	0.40 ± 0.04^b	< 0.001

声学指数 Acoustic indices	2-4月 Feb.-Apr.	5-7月 May-July	8-9月 Aug.-Sept.	10-11月 Oct.-Nov.	12月至次年1月 Dec.-Jan.	P
声音复杂度指数 Acoustic complexity index (ACI)	4,530.52 ± 17.78^a	4,622.86 ± 28.88^a	4,523.64 ± 22.69^a	4,449.51 ± 7.54^b	4,413.08 ± 7.26^b	< 0.001
生物声学指数 Bioacoustic index (BIO)	10.38 ± 0.48^c	12.22 ± 0.47^b	14.15 ± 0.52^a	8.32 ± 0.19^d	7.15 ± 0.20^e	< 0.001
声音均匀度指数 Acoustic evenness index (AEI)	0.90 ± 0.01^b	0.83 ± 0.01^c	0.78 ± 0.01^d	0.90 ± 0.01^b	0.92 ± 0.01^a	< 0.001
标准化声景差异指数 Normalized difference soundscape index (NDSI)	-0.04 ± 0.07^c	0.46 ± 0.05^b	0.88 ± 0.01^a	0.10 ± 0.06^c	0.40 ± 0.04^b	< 0.001

声学指数 Acoustic indices	时段 Period	白天 Day	夜晚 Night	W	P
声音复杂度指数 Acoustic complexity index (ACI)	2-4月 Feb.-Apr.	4,612.30 ± 25.94^a	4,460.47 ± 12.26^b	368	< 0.001
	5-7月 May-July	4,656.94 ± 37.25^a	4,596.90 ± 24.96^a	446	0.38
	8-9月 Aug.-Sept.	4,554.53 ± 37.00^a	4,494.61 ± 15.23^a	163	0.20
	10-11月 Oct.-Nov.	4,484.44 ± 8.30^a	4,417.02 ± 8.51^b	291	< 0.001
	12月至次年1月 Dec.-Jan.	4,443.98 ± 8.55^a	4,383.45 ± 6.25^b	366	< 0.001
生物声学指数 Bioacoustic index (BIO)	2-4月 Feb.-Apr.	11.71 ± 0.52^a	9.22 ± 0.49^b	317	< 0.001
	5-7月 May-July	12.85 ± 0.48^a	11.65 ± 0.50^a	497	0.09
	8-9月 Aug.-Sept.	12.88 ± 0.60^b	15.41 ± 0.49^a	57	< 0.01
	10-11月 Oct.-Nov.	9.47 ± 0.24^a	7.25 ± 0.20^b	308	< 0.001
	12月至次年1月 Dec.-Jan.	7.66 ± 0.22^a	6.67 ± 0.19^b	306	< 0.01
声音均匀度指数 Acoustic evenness index (AEI)	2-4月 Feb.-Apr.	0.95 ± 0.06^a	0.68 ± 0.06^b	71	< 0.001
	5-7月 May-July	0.81 ± 0.01^b	0.83 ± 0.01^a	218	< 0.01
	8-9月 Aug.-Sept.	0.78 ± 0.01^a	0.79 ± 0.02^a	117	0.70
	10-11月 Oct.-Nov.	0.88 ± 0.01^b	0.92 ± 0.01^a	63	< 0.01
	12月至次年1月 Dec.-Jan.	0.91 ± 0.01^b	0.93 ± 0.01^a	73	< 0.001
标准化声景差异指数 Normalized difference soundscape index (NDSI)	2-4月 Feb.-Apr.	0.00 ± 0.07^a	-0.09 ± 0.08^a	228	0.58
	5-7月 May-July	0.52 ± 0.05^a	0.40 ± 0.05^a	482	0.14
	8-9月 Aug.-Sept.	0.85 ± 0.02^a	0.90 ± 0.01^a	79	0.07
	10-11月 Oct.-Nov.	0.03 ± 0.07^a	0.16 ± 0.07^a	127	0.28
	12月至次年1月 Dec.-Jan.	0.35 ± 0.05^a	0.44 ± 0.03^a	148	0.17