Utility of acoustic indices for ecological monitoring in complex sonic environments

With the continued adoption of passive acoustic monitoring as a tool for rapid and high-resolution ecosystem monitoring, ecologists are increasingly making use suite indices to summarise sonic environment. Though these often reported well represent some aspect biology an ecosystem, degree which they confounded by various extraneous conditions is largely unknown. We conducted aural inventory across 23 field sites in Okinawa identify number unique animal sounds present recordings. Using values ‘measured richness’, we then examined how performance 11 commonly-used varied range (including presence absence insect stridulations, audible wind or rain, human-related sounds). Our analysis identified both well- poor-performing indices, those that were particularly sensitive conditions. Only two reflected measured richness full examined. A few relatively insensitive conditions, but no index correlated with when masked sound from broadband stridulating insects. results demonstrate considerable sensitivity most commonly used confounding highlighting challenges working large datasets collected field. make practical recommendations based on study design, aim identifying greatest utility indicators biodiversity management world’s natural soundscapes.