Divergent ecological responses to typhoon disturbance revealed via landscape-scale acoustic monitoring

Abstract

Climate change is increasing the frequency, intensity, and duration of extreme weather events across the globe. Understanding the capacity for ecological communities to withstand and recover from such events is critical. Typhoons are extreme weather events that are expected to broadly homogenise ecosystems through structural damage to vegetation and longer-term effects of salinization. Given their unpredictable nature, monitoring ecological responses to typhoons is challenging, particularly for mobile animals such as birds. Here, we report spatially variable ecological responses to typhoons across terrestrial landscapes. Using a high temporal resolution passive acoustic monitoring network across 24 sites on the subtropical island of Okinawa, Japan, we found that typhoons elicit divergent ecological responses among Okinawa's pristine forests, as indicated by increased spatial variability of biological sound production (biophony) among forested sites. However, no such post-typhoon shift in variability was observed among developed urban or agricultural sites. This indicates that natural forests have a diversity of pathways through which communities can respond to typhoons, whereas land use development produces communities more constrained in their disturbance responses. That is, spatial insurance effects among forest communities may provide resilience to typhoons at the landscape scale, but this spatial insurance was diminished by habitat degradation through land use development. Though site-level typhoon impacts on soundscapes and bird detections were not particularly strong, we nevertheless revealed spatial heterogeneity in typhoon responses, owing to the data resolution afforded to us by monitoring at scale (high temporal resolution, broad spatial extent). Our findings underscore the importance of natural forests in insuring ecosystems against disturbance, and demonstrate the potential of landscape-scale acoustic sensor networks for documenting the understudied ecological impacts of unpredictable extreme weather events.

Passive acoustic monitoring provides a fresh perspective on fundamental ecological questions

“…Beyond geographical remoteness, PAM can also enable data acquisition during seasons of heightened inaccessibility, such as during floods or rainy seasons, which often coincide with important life‐history stages for vocalising birds and mammals (Szymański et al, 2021). Similarly, parts of ecosystems that are typically hard to study, such as forest canopies or the deep sea, or areas undergoing dramatic disturbance such as gas exploration or extreme weather events, become more accessible (Deichmann et al, 2017; Gomes et al, 2020; Gottesman et al, 2021; Ross et al, 2023). Such disturbances and other temporary alterations to ecosystems or soundscapes frequently provide invaluable ‘natural experiments’ for testing ecological hypotheses (Derryberry et al, 2020).…”

“…the U.S. Northeast Passive Acoustic Sensing Network [NEPAN]: Van Parijs et al, 2015, the Australian Acoustic Observatory: Roe et al, 2021, and the Okinawa Environmental Observation Network [OKEON]: Ross et al, 2018), there is increasing opportunity to address fundamental questions concerning global environmental change and disturbance ecology through a mechanistic lens (e.g. Gottesman et al, 2021; Ross et al, 2023).…”