Spatio‐temporal scaling of biodiversity in acoustic tropical bird communities

Abstract

Automated analysis of acoustic communities is a rapidly emerging approach for the characterization and monitoring of biodiversity. To evaluate its utility, we should verify that such 'bioacoustics' can accurately detect ecological signal in spatiotemporal acoustic data. Targeting the 'Biological Dynamics of Forest Fragments Project' sites in Brazil, we ask: What is the relative contribution of the spatial, temporal and habitat dimension to variation in bird acoustic communities in a previously fragmented tropical rainforest? Does the functional diversity of bird communities scale similarly to space and time as does species diversity, when both are recorded by bioacoustics means? Overall, is the imprint of landscape fragmentation 30 years ago still audible in the present-day soundscape? We sampled forty-four sites in secondary forest and 107 sites in old-growth forest, resulting in 11 000 h of audio recordings. We detected 60 bird species with satisfactory precision and recovered a linear log-log relation between sampling time and species diversity. Sites in primary forest host more species than sites in secondary forest, but the difference decreased with sampling time, as the slope was slightly higher in secondary than primary forests. Functional diversity, as exposed by vocalizing birds, accumulates faster than does species diversity. The similarity among local communities decreases with distance in both time and space, but stability in time is remarkably high: two acoustic samples from the same site one year (or more) apart prove more similar than two samples taken at the same time but from sites situated just a few hundred meters apart. These findings suggest that habitat modification can be heard as a long-lasting imprint on the soundscape of regenerating habitats and identify soundscape-area and soundscape-time relations as a promising tool for biodiversity research, applied biomonitoring and restoration ecology.

Animal soundscapes reveal key markers of Amazon forest degradation from fire and logging

“…Independent of the ANH, consistent acoustic fingerprints among replicate sites and daily surveys suggest that network-based analyses of soundscapes may help differentiate among transient typologies of forest succession. These results corroborate previous reports based on acoustic studies of birds that soundscapes function as memory banks of Amazon forest modification (33), but this study goes further to demonstrate that soundscapes may be most valuable when collected as 24-hr records that capture more acoustically active taxa and their network-level interactions.…”

Acoustic monitors and direct observations provide similar but distinct perspectives on bird assemblages in a lowland forest of eastern Ecuador

“…NMS ordinations clearly indicated a separation between samples from the two plots, with annual samples from the same plot more similar to each other than to samples from the other plot, even after eliminating species recorded only once. Similarly, De Camargo, Roslin & Ovaskainen (2019) found that composition at a given point differed less between years than composition at different sites in the same year. The ordination also illustrated that composition changed across years in a similar way between plots—that is, direction of change in composition was similar even when the compositions differed between plots.…”

“…Acoustic monitors have proven to be useful for sampling bird species in a variety of habitats, including both temperate ( Celis-Murillo, Deppe & Allen, 2009 ; Depraetere et al, 2011 ; Cook & Hartley, 2018 ) and tropical ( Bueno et al, 2012 ; De Camargo, Roslin & Ovaskainen, 2019 ; Stevens et al, 2019 ) forests. They have been used to provide descriptions of bird species richness, community composition, and change in such communities over space and time ( Towsey et al, 2014 ; De Camargo, Roslin & Ovaskainen, 2019 ; Stevens et al, 2019 ). Recordings from acoustic monitors also have been used to develop acoustic indices that provide information on diversity, without identification of individual species ( Depraetere et al, 2011 ; Towsey et al, 2014 ; Aide et al, 2017 ).…”

Supplemental Information 1: List of species detected with acoustic monitors and/or by observations.

“…NMS ordinations clearly indicated a separation between samples from the two plots, with annual samples from the same plot more similar to each other than to samples from the other plot, even after eliminating species recorded only once. Similarly, De Camargo, Roslin & Ovaskainen (2019) found that composition at a given point differed less between years than composition at different sites in the same year. The ordination also illustrated that composition changed across years in a similar way between plots-that is, direction of change in composition was similar even when the compositions differed between plots.…”

“…Full-size  DOI: 10.7717/peerj.10565/ fig-6 DISCUSSION Acoustic monitors have proven to be useful for sampling bird species in a variety of habitats, including both temperate (Celis-Murillo, Deppe & Allen, 2009;Depraetere et al, 2011;Cook & Hartley, 2018) and tropical (Bueno et al, 2012;De Camargo, Roslin & Ovaskainen, 2019;Stevens et al, 2019) forests. They have been used to provide descriptions of bird species richness, community composition, and change in such communities over space and time (Towsey et al, 2014;De Camargo, Roslin & Ovaskainen, 2019;Stevens et al, 2019). Recordings from acoustic monitors also have been used to develop acoustic indices that provide information on diversity, without identification of individual species (Depraetere et al, 2011;Towsey et al, 2014;Aide et al, 2017).…”