Temporal and spatial variation of a winter soundscape in south-central Alaska

Abstract

Context Winter soundscapes are likely different from soundscapes in other seasons considering wildlife vocalizations (biophony) decrease, wind events (geophony) increase, and winter vehicle noise (technophony) occurs. The temporal variation and spatial relationships of soundscape components to the landscape in winter have not been quantified and described until now. Objectives Our objectives were to determine the temporal and spatial variation and acoustic-environmental relationships of a winter soundscape in southcentral Alaska.Methods We recorded ambient sounds at 62 locations throughout Kenai National Wildlife Refuge (December 2011-April 2012). We calculated the normalized power spectral density in 59,597 recordings and used machine learning to determine acousticenvironmental relationships and produce spatial models of soundscape components. Results Geophony was the most prevalent component (84 %) followed by technophony (15 %), and biophony (1 %). Geophony occurred primarily at night, varied little by month, and was strongly associated with lakes. Technophony and biophony had similar temporal variation, peaking in April. Technophony occurred closer to urban areas and at locations with high snowmobile activity. Biophony occurred closer to rivers and was inversely related to snowmobile activity. Over 75 % of sample sites had [1 recordings of airplane or snowmobile noise, mainly in remote areas. Conclusions The soundscape displayed distinct patterns across 24-h and monthly timeframes. These patterns were strongly associated with land cover Electronic supplementary material The online version of this article (variables which demonstrate discrete acoustic-environmental relationships exhibiting distinct spatial patterns in the landscape. Despite the predominance of geophony, the presence of technophony in this winter soundscape may have significant negative effects to wildlife and wilderness quality.

Comparisons Between Autonomous Acoustic Recordings and Avian Point Counts in Open Woodland Savanna

“…According to this last sound classification, several scientists have proposed grouping sounds into 3 main categories by their biological, geophysical, or human/machine origins. These sounds have been respectively dubbed biophony, geophony, and anthrophony (or synonymously anthropophony), with technophony existing as a subcategory of anthrophony for ''human-made sounds generated from machines and technology'' (Krause 1987, Pijanowski et al 2011a, Mullet et al 2016). …”

“…While biodiversity indices have typically been based on periodic inventories conducted only during specific biological periods (e.g., breeding season for birds), soundscape approaches allow for continuous data collection and exploration of processes occurring outside traditional monitoring windows. For example, winter soundscape monitoring, as pioneered by Mullet et al (2016), could allow for the development of more detailed yearly phenologies of bird activity. Additionally, automated measurement of archived recordings supports high-volume analyses, but it also facilitates standardization of measurements across datasets, which is necessary for large-scale comparative analyses.…”

Traffic noise impacts on urban forest soundscapes in south‐eastern Australia

“…Geophony can influence the calling behaviour of some vocalizing fauna (Towsey et al 2014a) and can influence the results of acoustic indices (Sueur et al 2008;Depraetere et al 2012;Mullet et al 2016). Therefore, we identified and removed all files from our analysis that were predominantly recordings of rain, high wind and/or other confounding factors (e.g.…”

“…By studying the sounds which emanate from a landscape (also known as the soundscape), we can examine variation in sounds over space and time and how these sounds relate to anthropogenic activities and ecosystem processes (Pijanowski et al 2011a,b). Sounds present in the landscape may be differentiated as those produced by organisms (biophony), all geophysical sound, such as rainfall or wind, referred to as geophony (Pijanowski et al 2011a,b) and sounds that are generated by human technology, such as traffic noise, known as technophony (Gage & Axel 2014;Mullet et al 2016). The field of ecoacoustics is a growing discipline which focuses on answering ecological questions and addressing pressing biodiversity issues by studying soundscape patterns (Sueur & Farina 2015).…”

Passive acoustic monitoring as a potential tool to survey animal and ecosystem processes in freshwater environments

“…Passive acoustic monitoring has particularly strong potential in low visibility environments such as dense forests or underwater, because sound propagation is not as strongly impacted by obstacles as other sensing methods such as netting or visual detection. Passive acoustic monitoring has so far been used in terrestrial habitats such as tropical and temperate forests (Depraetere et al., ; Malavasi & Farina, ; Rodriguez et al., ), urban areas (Pieretti & Farina, ), and plains (Mullet, Gage, Morton, & Huettmann, ); and in marine habitats such as open ocean (Parks, Miksis‐Olds, & Denes, ; Ruppé et al., ), coral reefs (Bertucci, Parmentier, Berten, Brooker, & Lecchini, ), and coastal waters (Felisberto et al., ; McWilliam & Hawkins, ). Although there is a wealth of studies on bioacoustics of freshwater animals, mainly looking at behaviour (e.g.…”