Acoustic luring/playbacks for restoration/recolonization

Question

Larissa Sugai and I were recently discussing the concept of acoustic restoration in terms of using acoustic 'lures' or playbacks to accelerate re-colonization of a restored/reforested/etc. area. There are a few papers addressing this concept, such as:

Znidersic, E., & Watson, D. M. (2022). Acoustic restoration: Using soundscapes to benchmark and fast‐track recovery of ecological communities. Ecology Letters, 25(7), 1597-1603.

Williams, B. R., McAfee, D., & Connell, S. D. (2021). Repairing recruitment processes with sound technology to accelerate habitat restoration. Ecological Applications, 31(6), e02386.

I am wondering if anyone has direct experience engaging in this type of acoustic restoration? Specifically, what equipment was used, how were recordings selected, and any evaluation or success metrics if possible (i.e., did it work, which I recognize is a difficult question to answer neatly).

I also recognize that there are an increasing number of papers that use acoustic monitoring for before/after comparisons for natural disasters (wildfire, cyclone, etc.), like those below, but I am more looking for folks that have used planned experimentation with acoustic luring for restoration.

(Gasc et al. 2018. Soundscapes reveal disturbance impacts: biophonic response to wildfire in the Sonoran Desert Sky Islands. Duarte et al. 2021. Changes on soundscapes reveal impacts of wildfires in the fauna of a Brazilian savanna. Gottesman et al. 2021. What does resilience sound like? Coral reef and dry forest acoustic communities respond differently to Hurricane Maria.)

Thanks!

Answer 1

Here is one example in the literature of experimental playbacks made on a coral reef, which was shown to increase fish colonization rates (in terms of settlement and retention). 6 week in-situ study. The discussion includes talk about combining such 'acoustic enrichment' with other active habitat restoration measures.

Gordon, T.A.C., Radford, A.N., Davidson, I.K. et al. Acoustic enrichment can enhance fish community development on degraded coral reef habitat. Nat Commun 10, 5414 (2019). https://doi.org/10.1038/s41467-019-13186-2

Answer 2

I know that there are several examples where this has been done with seabirds, specifically Caspian terns. It has been used both to recolonize abandoned habitat, and to try and "move" a colony away from an area to establish a colony elsewhere.

This open-access, relatively recent paper may provide the necessary background in the introduction to lead you to some of the earlier work of this type with seabirds:

Hartman, C. A., Ackerman, J. T., Herzog, M. P., Strong, C., & Trachtenbarg, D. (2019). Social attraction used to establish Caspian Tern nesting colonies in San Francisco Bay. Global Ecology and Conservation, 20, e00757.

Answer 3

Here is an extensive review on the subject broken down by taxa (Buxton et al. 2020). If you dig through the sources, you will find varying techniques and strategies, both for implementation strategies and post-implementation assessments.

https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.6922

To answer your specific question - equipment, recording selection, and evaluation will depend heavily on both the system and the goals.

For example, what do you define as success? Is it just a slight increase in abundance? Is it just the presence of a species? What kind of equipment can best transmit through the specific environment? What type of vocalizations are important for the specific animal group, etc.

Hopefully this review gives you some ideas. If you have a specific question with a specific habitat/taxa in mind, I could give more detailed advice.

Answer 4

Anderson et al 2021 measured larval recruitment in degraded and healthy habitats in the Florida Keys. From the paper:

They used a Lubell Labs 9196H underwater loudspeaker connected to a waterproof barrel containing an R-07 solid state WAV recorder, with a TOA CA-160 amplifier and a 12 V deepcycle battery to power the speaker and amplifier. Figure 2 in the paper includes photos and diagrams of their set-up.

They collected recordings at healthy and degraded sites, and then used root mean square sound pressure level over a 15 s clip in order to calculate the required voltage output for the speaker system to broadcast the recordings at approximately the same amplitude at which they were originally recorded.

The effects were measured by placing larval collectors (frayed rope attached to a mesh back within a PVC pipe tied to concrete blocks), and then counting individual larvae and taxa per collector.

An important step in their project was determining the detection range of the broadcast soundscape in different habitats and they discuss implications for restoration efforts. They also sampled in different lunar phases, which can be important for larval recruitment.

I wasn't personally involved in this study, but I really like it!