基于声学指数的神农架国家公园声音多样性动态变化

Exploration of dynamic changes of sound diversity based on acoustic index in the Shennongjia National Park,China

【目的】评估声学指数在神农架国家公园内对动物声音多样性动态变化的响应,探究神农架国家公园声音多样性的变化特征,为当地生态保护提供量化依据。【方法】在神农架国家公园较大区域内部署了9个声音采集点,连续采集了2021年5—7月的样点声音数据,采用生态声学的方法,从声音数据中提取了声学复杂度指数(ACI)、生物声学指数(BI)、归一化声景差异指数(NDSI)3个声学指数,并探究这3个声学多样性指数夏季的动态变化特征。【结果】ACI指数在夏季变化的总体趋势并不显著,BI指数呈双峰变化趋势,NDSI指数呈3峰或4峰变化趋势;经Mann-Kendall突变性检验的结果表明,气候和人为干扰是引起指数值突变的主要原因;日变化结果显示ACI指数不能很好地反映日变化趋势,但BI指数和NDSI指数具有明显的日变化趋势,且变化趋势符合物种黎明/黄昏合唱的习性;声学指数随海拔梯度的空间变化结果表明,ACI、BI指数在中海拔区域具有最大值,且ACI指数与海拔相关性较强,NDSI指数没有显著的变化趋势。【结论】BI、NDSI指数能较好地反映动物声音多样性随时间动态变化趋势,气候变化和人为活动会造成声音多样性的突变。ACI指数能较好说明动物声音多样性随空间的变化,研究区域内声音多样性在中海拔区域最大。

【Objective】The study aims to evaluate the response of acoustic indices to the dynamic changes of animal sound diversity,further to explore the characteristics of the variation of animal sound diversity in Shennongjia National Park,China,in order to provide a quantitative basis for the local ecological protection.【Method】We deployed nine sound recording equipments in nine sampling sites in Shennongjia National Park,and sound recording data from May to July 2021 were obtained.A time series of eco-acosutic indices including acoustic complexity index(ACI),bioacoustic index(BI),normalized difference soundscape index(NDSI)were extracted from the recording data after noise reduction processing.Further the summer dynamic characteristics of these three acoustic diversity indices were analyzed.【Result】Results showed that the variation of ACI was not obvious during the recording period,while BI showed a double peak variation,NDSI index showed a triple or four peak variation.Results of the Mann-Kendall mutagenicity test showed that ACI only had a mutations at a few sampling sites,while BI and NDSI had mutation at most of the sampling sites.And the analysis of daily variations on the date of the index mutation suggested that weather and human disturbance are the main causes of the index mutation.Results of daily changes of acoustic indices showed that the variation of ACI was not obvious also,while BI and NDSI had a obvious diurnal variation trend,which was consistent with the species of dawn/dusk chorus.The spatial variation of acoustic indexes with altitude gradient indicated that ACI and BI have the maximum value in the middle altitude area,and ACI has a strong correlation with the altitude,while the NDSI has no obvious change.【Conclusion】Our results demonstrated that BI and NDSI could better reflect the dynamic changes of animal sound diversity over time,and the changes of animal sound diversity in Shennongjia National Park showed a multi-peak variation during the recording period,and weather and human activities would cause the abrupt change.The ACI can well explain the spatial variation of animal sound diversity,and the maximum diversity was found in the middle altitude area.