Data from: The sound of recovery: coral reef restoration success is detectable in the soundscape

1. Pantropical degradation of coral reefs is prompting considerable
investment in their active restoration. However, current measures of
restoration success are based largely on coral cover, which does not fully
reflect ecosystem function or reef health. 2. Soundscapes are an important
aspect of reef health; loud and diverse soundscapes guide the recruitment
of reef organisms, but this process is compromised when degradation
denudes soundscapes. As such, acoustic recovery is a functionally
important component of ecosystem recovery. 3. Here, we use acoustic
recordings taken at one of the world’s largest coral reef restoration
projects to test whether successful restoration of benthic and fish
communities is accompanied by a restored soundscape. We analyse recordings
taken simultaneously on healthy, degraded (extensive historic blast
fishing) and restored reefs (restoration carried out for 1–3 years on
previously-degraded reefs). We compare soundscapes using manual counts of
biotic sounds (phonic richness), and two commonly used computational
analyses (acoustic complexity index [ACI] and sound-pressure level [SPL]).
4. Healthy and restored reef soundscapes exhibited a similar diversity of
biotic sounds (phonic richness), which was significantly higher than
degraded reef soundscapes. This pattern was replicated in some automated
analyses but not others; the ACI exhibited the same qualitative result as
phonic richness in a low-frequency, but not a high-frequency bandwidth,
and there was no significant difference between SPL values in either
frequency bandwidth. Further, the low-frequency ACI and phonic richness
scores were only weakly correlated despite showing a qualitatively
equivalent overall result, suggesting that these metrics are likely to be
driven by different aspects of the reef soundscape. 5. Synthesis and
applications: These data show that coral restoration can lead to
soundscape recovery, demonstrating the return of an important ecosystem
function. They also suggest that passive acoustic monitoring (PAM) might
provide functionally important measures of ecosystem-level recovery – but
only some PAM metrics reflect ecological status, and those that did are
likely to be driven by different communities of soniferous animals.
Recording soundscapes represents a potentially valuable tool for
evaluating restoration success across ecosystems, but caution must be
exercised when choosing metrics and interpreting results.