High microphone signal-to-noise ratio enhances acoustic sampling of wildlife

PeerJ

article

Kevin F.A. Darras¹  Franziska Deppe¹  Yvonne Fabian¹  Agus P. Kartono³  Andres Angulo¹  Bjørn Kolbrek⁴  Yeni A. Mulyani³  Dewi M. Prawiradilaga⁵ 

[1]Agroecology, University of Göttingen

[2]Agroscope FAL Reckenholz, Swiss Federal Research Station for Agroecology and Agriculture

[3]Department of Forest Resources, Conservation and Ecotourism, Bogor Institute of Agriculture

[4]Celestion International

[5]Museum Zoologicum Bogoriense Research Centre for Biology-LIPI Jl

关键词: Automated sound recorders;    Bats;    Birds;    Sound detection spaces;    Detection range;    Autonomous recording units;    Signal-to-noise ratio;    Ecoacoustics;    Microphone self-noise;    Soundscape;   

DOI  :  10.7717/peerj.9955

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

BackgroundAutomated sound recorders are a popular sampling tool in ecology. However, the microphones themselves received little attention so far, and specifications that determine the recordings’ sound quality are seldom mentioned. Here, we demonstrate the importance of microphone signal-to-noise ratio for sampling sonant animals.MethodsWe tested 12 different microphone models in the field and measured their signal-to-noise ratios and detection ranges. We also measured the vocalisation activity of birds and bats that they recorded, the bird species richness, the bat call types richness, as well as the performance of automated detection of bird and bat calls. We tested the relationship of each one of these measures with signal-to-noise ratio in statistical models.ResultsMicrophone signal-to-noise ratio positively affects the sound detection space areas, which increased by a factor of 1.7 for audible sound, and 10 for ultrasound, from the lowest to the highest signal-to-noise ratio microphone. Consequently, the sampled vocalisation activity increased by a factor of 1.6 for birds, and 9.7 for bats. Correspondingly, the species pool of birds and bats could not be completely detected by the microphones with lower signal-to-noise ratio. The performance of automated detection of bird and bat calls, as measured by its precision and recall, increased significantly with microphone signal-to-noise ratio.DiscussionMicrophone signal-to-noise ratio is a crucial characteristic of a sound recording system, positively affecting the acoustic sampling performance of birds and bats. It should be maximised by choosing appropriate microphones, and be quantified independently, especially in the ultrasound range.

【 授权许可】

CC BY