海拔梯度对山噪鹛鸣声的影响

The Effects of Elevation Gradient on the Birdsong of Garrulax davidi

环境因素是鸟类鸣声特征分化的重要驱动力.海拔梯度对鸟类鸣声特征的影响少见报道.以我国特有种山噪鹛(Garrulax davidi)为对象,通过分析其鸣声的声学复杂度指数、声学多样性指数、声音均匀度指数、声学丰富度、生物声学指数、声学熵、振幅指数、标准声景差异指数、频峰数等特征,发现声学多样性指数与声学熵随海拔梯度增加先升高后降低,其最大值分别出现在海拔1718米和1646米处.声学均匀度指数随海拔梯度增加先降低后升高,最小值产生在海拔1783米处.这表明中海拔地区山噪鹛鸣声变异无序度最高而均匀度最低,也意味着中海拔地区鸟类物种多样性比高海拔与低海拔地区更丰富.其原因可能与中海拔地区较高的植物物种多样性有关.研究有助于揭示海拔梯度对山噪鹛鸣声的影响规律,加深对鸣禽响应环境变化的理解.

Environmental factors are vital driving forces for the differentiation of birdsongs.The influence of elevation gradients on birdsong is little reported.Here,we calculated nine acoustic indices of Garrulax davidi,including acoustic complexity index(ACI),acoustic diversity index(ADI),acoustic evenness index(AEI),acoustic richness(AR),bioacoustic index(BI),acoustic entropy index(H),amplitude index(M),normalized difference soundscape index(NDSI)and number of peaks(NP).We used regression models to analyze the relationship between acoustic indices and elevation gradients.The results showed that two indices,i.e.,ADI and H,increased along with the rise in elevation gradient and decreased after the peak.The peak of elevation gradient in ADI was 1718 m.Meanwhile,the peak of the elevationgradient in H was 1646 m.The AEI declined along an increase in elevation gradient and rose after the bottom point(1783 m).These results indicated that bird diversity was more abundant in the middle elevation area.It might be due to the higher plant species diversity in this area.This study helps us reveal the influence of elevation on birdsongs of Garrulax davidi and understand the response of birds to environmental changes.