TY - JOUR T1 - Gaps in terrestrial soundscape research: it’s time to focus on tropical wildlife Y1 - 2019 A1 - Marina D. A. Scarpelli A1 - Cezar Ribeiro, Milton A1 - Teixeira, Fernanda Z. A1 - Young, Robert J. A1 - Teixeira, Camila P. KW - bioacoustics KW - gap analysis KW - landscape KW - Noise KW - review KW - sound AB -

There has been a body of research examining the sounds produced in landscapes. These sounds are commonly defined as soundscapes, however, the term is often used in different contexts. To understand how the various meanings attributed to soundscapes, we identified how soundscapes are represented in the scientific literature and identified current knowledge gaps in soundscape research focusing on terrestrial environments. We conducted a quantitative review of published papers with the keyword soundscape available at Web of Science and Scopus databases. A total of 1,309 abstracts and a subset of about 5% (N=68) complete papers and reviews published from 1985 to 2017 were read and analysed, identifying types of sound, types of environment and focal species studied, as well as study regions and climates. By identifying the current focus of research, we also identified gaps and research opportunities. Research was biased towards temperate regions, terrestrial environments, and the impacts on humans in urban areas. Although most of the world’s biodiversity is concentrated in tropical wilderness areas, these regions had fewer studies attributed to them. Given the importance of tropical landscapes for biodiversity conservation, we strongly suggest that more research should be undertaken in the tropics, with a particular focus on wildlife in these regions. Furthermore, soundscape research (methods and tools) should increasingly target the anthropogenic impacts on wildlife, including behavioural and physiological changes, alongside the current focus on human-sound interactions and the approach used by bioacoustics methods.

UR - https://linkinghub.elsevier.com/retrieve/pii/S0048969719353963 ER - TY - JOUR T1 - Acoustic indices as rapid indicators of avian diversity in different land-use types in an Indian biodiversity hotspotAbstract JF - Journal of Ecoacoustics Y1 - 2018 A1 - Agnihotri, Samira A1 - Robin, V. V. A1 - Goel, Anurag A1 - Rohini Balakrishnan KW - diversity KW - landscape KW - passive acoustic monitoring KW - shade-grown crop KW - species richness KW - Western Ghats AB -

Passive acoustic monitoring is a potentially valuable tool in biodiversity hotspots, where surveying can occur at large scales across land conversion types. However, in order to extract meaningful biological information from resulting enormous acoustic datasets, rapid analytical techniques are required. Here we tested the ability of a suite of acoustic indices to predict avian bioacoustic activity in recordings collected from the Western Ghats, a biodiversity hotspot in southwestern India. Recordings were collected at 28 sites in a range of land-use types, from tea, coffee, and cardamom plantations to remnant forest stands. Using 36 acoustic indices we developed random forest models to predict the richness, diversity, and total number of avian vocalizations observed in recordings. We found limited evidence that acoustic indices predict the richness and total number of avian species vocalizations in recordings (R2 < 0.51). However, acoustic indices predicted the diversity of avian species vocalizations with high accuracy (R2 = 0.64, mean squared error = 0.17). Index models predicted low and high diversity best, with the highest residuals for medium diversity values and when continuous biological sounds were present (e.g., insect sounds >8 sec). The acoustic complexity index and roughness index were the most important for predicting avian vocal diversity. Avian species richness was generally higher among shade-grown crops than in the open tea plantation. Our results suggest that models incorporating acoustic indices can accurately predict low and high avian species diversity from acoustic recordings. Thus, ecoacoustics could be an important contributor to biodiversity monitoring across landscapes like the Western Ghats, which are a complex mosaic of different land-use types and face continued changes in the future.

VL - 2 UR - https://www.veruscript.com/journals/journal-of-ecoacoustics/acoustic-diversity-in-an-indian-hotspot/ JO - J. Ecoacoust. ER -