Physics?based model to predict the acoustic detection distance of terrestrial autonomous recording units over the diel cycle and across seasons: Insights from an Alpine and a Neotropical forest

1. Passive acoustic monitoring of biodiversity is growing fast, as it offers an alternative to traditional aural point count surveys, with the possibility deploy long-term surveys in large and complex natural environments. However, there still a clear need evaluate how frequency-and distancedependent attenuation sound well ambient level impact detection distance soniferous species environments over diel cycles across seasons. This great importance avoid pseudoreplication provide relevant indicators, including richness, abundance density. 2. To address issue distance, we tested field-based protocol Neotropical rainforest (French Guiana, France) Alpine coniferous forest (Jura, France). standardized repeatable method consists recording session directly followed by experiment using calibrated white noise broadcast at different positions along 100 m linear transect. We then used laws reveal basic physics behind propagation attenuation. 3. demonstrate that habitat two kinds forests can be modelled exponential decay law dependence on frequency distance. also report attenuation, first approximation, summarized single value, coefficient habitat. 4. Finally, show predicted knowing contribution each factor, habitat, pressure amplitude bandwidth characteristics transmitted sound. 1 mostly depends may vary factor up 5 cycle These results reinforce take into account variation when performing passive producing reliable indicators.