PLENARY 1 – Wednesday 23

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Opening ceremony

PLENARY 1 – Wednesday 23

Long-term ecoacoustics: a plea for slow science

Jérôme Sueur, Institut de Systématique, Évolution, Biodiversité (ISYEB), Muséum national d’Histoire naturelle, CNRS, Sorbonne Université, EPHE, 57 rue Cuvier, 75005 Paris, France

Climate change is a fast event at the scale of geological times but a slow phenomenon at the scale of a researcher career. Assessing the impacts of climate change on natural systems requires an extensive amount of time over years to collect meaningful ecological data. Long-term remote monitoring is one mainstay of ecoacoustics. However, running ecoacoustic research programs over years is a challenge in terms of human resources, financial support, equipment maintenance, data saving, and results analysis. Here, I will introduce two long-term programs that we started at the same time in a cold forest in France mainland (Jura) and in a tropical forest in France overseas (Guyane). I will describe the local ecological context, the research framework, the field sampling protocol, data management, some preliminary results and future analysis. This will be the occasion of a plea for slow, relaxed, and aesthetical ecoacoustics.

O1- Acoustic niche partitioning in two tropical wet forest bird communities

  • Hart, P.J., Department of Biology, University of Hawaii at Hilo, USA
  • Paxton, K.,Department of Biology, University of Hawaii at Hilo, USA
  • Ibanez, T. Department of Biology, University of Hawaii at Hilo, USA
  • Tredinnick, G.,Department of Biology, University of Hawaii at Hilo, USA
  • Sebastián-González, E., Departamento de Biologia Aplicada, Universidad Miguel Hernández, Elche, Spain
  • Tanimoto-Johnson, A. Department of Biology, University of Hawaii at Hilo, USA

When acoustic signals sent from individuals overlap in frequency and time, acoustic interference and signal masking may occur. Under the acoustic niche hypothesis (ANH), signaling behavior has evolved to minimize overlap with heterospecific calling individuals through selection on signal structure and the sender’s ability to adjust the timing of signals. In this study, we examine the fine-scale use of acoustic space and the relevance of the acoustic niche hypothesis in two montane tropical wet forest bird communities (Costa Rica and Hawaii) that vary in bird species richness but have similar overall bird abundance. We used a null model approach to test the prediction that there are differences between observed and expected signal overlap in both communities and also that acoustic niche partitioning is greater in the species-rich community (Costa Rica) due to greater selection to reduce inter-specific signal overlap. As predicted under ANH, we found much lower overlap of acoustic signals in both bird communities than expected by chance. In addition, spectral and temporal overlap between different signals was very rare within one-second sound-slices examined for Costa Rica but occurred within approximately 37 % of those examined for Hawaii. These findings constitute the strong support to that there is competition for acoustic space in signaling communities, and this has resulted in temporal and spectral partitioning of the soundscape.

O2- Acoustic monitoring to evaluate environmental watering responses in the Koondrook-Perricoota Forest

  • Simon Linke 1 , Daniella Teixeira 1 , Katie Turlington 1 , Sarah Treby 2 , Jean Dind 2 , Jo-Anne Deretic 3, Paul Roe 4
  • 1Griffith University, Nathan, QLD, Australia
  • 2Forestry Corporation of NSW, Deniliquin
  • 3Goulburn-Broken CMA, Shepparton
  • 4QUT, Brisbane

This project successfully developed, tested and implemented call recognisers for eight species of frog in the Murray-Darling Basin. Recognisers for all but one species performed well and substantially better than many species recognisers reported in the literature .We achieved this through a comprehensive development phase, which carefully considered and refined the representativeness of training data, as well as the construction (amplitude cut-off) and the similarity thresholds (score cut-offs) of each call template used.

We demonstrated the utility of automated frog call detection to monitor ecosystem response at all watered sites. At most sites the response was almost instant – calls were close to a peak around one week after watering. The sharp response curves by the recognisers demonstrate the utility of multi-species call recognisers. This is demonstrated in the diagram below – as soon as water reaches a site, frog calls increase significantly. We tested this using a Linear Mixed Model, in which we contrasted watered and control sites – showing that only watered sites increase in activity.

While slightly more involved than building recognisers using commercial packages, the workflows ensure that a high quality recogniser can be built for which the performance can be fine-tuned using multiple parameters. Using the same framework, recognisers can be fine-tuned in future iterations. We believe that multi-species recognisers are a highly effective and precise way to detect the effects of ecosystem restoration – in this case environmental watering –  delivering a much sharper response signal than previous index based analyses.

O3- The Design of the Australian Acoustic Observatory

  • Paul Roe, QUT
  • Richard Fuller, University of Queensland
  • Paul McDonald, University of New England
  • Lin Schwarzkopf, James Cook University
  • David Tucker, QUT
  • Anthony Truskinger, QUT
  • David Watson, Charles Sturt University

The Australian Acoustic Observatory is a unique piece of infrastructure which will ultimately collect ecoacoustic data from 400 sensors around Australia. It is the first long term terrestrial acoustic observatory, and the only continental-scale acoustic array. Deployments have started and data is being collected. Sound data is continuously recorded and all data are being made freely available; the resulting dataset will be the largest ecoacoustic data set ever collected, 400 sensors by a five year initial project lifetime resulting in two millennia, two Petabytes, of sound. Unlike bioacoustics and single species studies, the research questions driving the observatory and associated data collection are broad-based and open-ended: to monitor biodiversity, phenology and species distribution, and to catalyse ecoacoustics research. The acoustic dataset represents a baseline data collection: the overall spatial temporal distribution of species is simply unknown. Given the general research questions and continental deployment there are many possible design options for such a unique infrastructure. This talk will outline the issues and challenges faced with designing an acoustic observatory and the reasons for the particular design decisions taken, including hardware, software, protocols, sensor location and people.

O4- Using false-colour spectrograms for survey of long-duration acoustic recordings for ecological studies of frog chorusing

  • Sheryn Brodie1*, Michael Towsey2, Slade Allen-Ankins1, Paul Roe2, Lin Schwarzkopf1.
  • 1 College of Science and Engineering, James Cook University, Townsville Qld Australia.
  • 2 QUT Ecoacoustics Research Group, Science and Engineering Faculty, Queensland University of Technology, Brisbane Qld Australia.

* Corresponding author email: sheryn.brodie@my.jcu.edu.au

Continuous recording of environmental sounds could allow long-term monitoring of vocal wildlife, and scaling of ecological studies to large temporal and spatial scales. However, such opportunities are currently limited by constraints in the analysis of large acoustic data sets. Computational methods and automation of call detection require specialist expertise and are time consuming to develop, therefore most biological researchers continue to use manual listening and inspection of spectrograms to analyse their sound recordings. False-colour spectrograms were recently developed as a tool to allow visualisation of long-duration sound recordings, intending to aid ecologists in navigating their audio data, and detecting species of interest. This paper explores the efficacy of using this visualisation method to identify multiple frog species in a large set of continuous sound recordings and gather data on the chorusing activity of the frog community. We found that, after a learning process, frog choruses could be visually identified to species with high accuracy. We present a simple R routine to interactively select short segments on the false-colour spectrogram for rapid manual checking of visually identified sounds. We contend these methods could be applied to analyse calling patterns in other chorusing species.

O5-Acoustic niche partitioning in frog assemblages

  • Allen-Ankins, S., College of Science & Engineering, James Cook University, Townsville, Australia.
  • Schwarzkopf, L., College of Science & Engineering, James Cook University, Townsville, Australia.

Acoustic signaling is an important communication method for many animal species. Given this, species usually occur in environments surrounded by many interspecific signals. These signals may interfere acoustically with one another, impeding the detection and localisation of conspecific signals. To avoid these costs, it has been suggested that animals should partition the acoustic niche to reduce acoustic competition. The aim of this study was to determine whether frog assemblages display evidence of acoustic niche partitioning. We used a null model approach to compare observed and expected levels of interspecific acoustic similarity in frog assemblages recorded across Australia over a one year period. We examined species 95% call frequency bandwidths, dominant call frequencies, and a combination of spectral and temporal call features. If frog assemblages are randomly assembled with regard to the spectral properties of their calls, then we would expect there to be no difference in acoustic similarity between observed assemblages and random assemblages. However, if they are partitioning the acoustic space, then we expect lower acoustic similarity between species calls in observed assemblages when compared to random assemblages. We found that most assemblages had lower acoustic similarity than random assemblages. Specifically, their 95% call frequency bandwidths overlapped less than expected, there was greater distance between their dominant call frequencies than expected, and there was greater distance between their calls when considering multiple call features than expected. These results are consistent with the acoustic niche hypothesis, suggesting that frogs partition the acoustic space to reduce competition.

O6- Are acoustic indices effective proxies of biodiversity? A meta-analysis

  • Alcocer, I., Terrestrial Ecology Group, Science Faculty, Universidad Autónoma de Madrid, Madrid, Spain
  • Lima, H., Global Change Ecology and Evolution group, Department of Life Sciences, University of Alcalá, Alcalá de Henares, Spain
  • Sugai, L.S.M., Terrestrial Ecology Group, Science Faculty, Universidad Autónoma de Madrid, Madrid, Spain
  • Llusia, D., Terrestrial Ecology Group, Science Faculty, Universidad Autónoma de Madrid, Madrid, Spain

As biodiversity decreases worldwide, the development of efficient tools to detect environmental changes becomes an urgent challenge for scientists. In this regard, the use of animal sounds has been suggested to be an important source to understand biodiversity along with its spatial and temporal changes. To extract biodiversity patterns from a massive quantity of passive acoustic recordings, acoustic indices emerged as a promising tool to characterize populations and communities. Since the development of the first acoustic indices, the efficiency of acoustic indices as a proxy of biodiversity have been explored for multiple taxa and ecosystems. However, we still lack a general synthesis that answers i) are acoustic indices good indicators of biodiversity, and if so ii) which acoustic indices perform better, iii) and in what circumstances. To shed light on these questions we collected data available in the literature and conducted a meta-analysis to evaluate how acoustic indices perform in estimating biological diversity. We found that acoustic indices exhibit a moderate but positive correlation with biodiversity. Sub-group analysis using the 7 alpha acoustic indices present on our dataset, revealed marked differences in their correlation with biodiversity. In addition, we explored the correlation variability across environments and different biodiversity metrics. Our findings highlight the limits and potential of synthesizing species diversity from environmental sound recordings and promote a debate on the generalization of acoustic diversity as a biological component. 

O7- Passive Acoustic Monitoring of Fishes in the Mediterranean Sea: from single species to whole communities monitoring

  • Marta Bolgan1, Marta Picciulin2, Lucia di Iorio3 and Eric Parmentier1
  • 1 Laboratory of Functional and Evolutionary Morphology (Freshwater and Oceanic sCience Unit of reSearch), Institut de Chimie B6c, University of Liège, Liège, Belgium.
  • 2 Department of Environmental Sciences, Informatics and Statistics, Ca’ Foscari; University of Venice, Venice, Italy
  • 3 CHORUS Institute, 115 rue des Alliés, Grenoble, France.

In the Mediterranean Sea, Passive Acoustic Monitoring of fish populations has been carried out since 2002; studies have focused on single species monitoring (mainly Sciaena umbra and Ophidion rochei), as well as on the monitoring of whole fish communities in a wide range of coastal environments. These studies have proved that the same species can be monitored over wide geographical and temporal scales thanks to the consistency of its acoustic signature, which can also be used to identify cryptic species which would otherwise go undetected. Recently, the monitoring of whole vocal fish communities has provided high resolution information on fish taxonomic richness and diversity. Furthermore, the allocation of acoustic resources within the community signal space and fish realised acoustic niches were found to change in relation with acoustic diversity and sonic-system morphology, introducing the concept of Acoustic Niche plasticity in acoustic fish communities. Recent investigations have started to shed lights on the possibility of extending the monitoring of vocal fish populations at depth greater than those usually considered. In this presentation, past and present studies are discussed at the light of future perspectives and recommendations for fostering the monitoring of vocal fish populations in our rapidly changing seas.

O8-Spatio-temporal distribution and acoustic characterization of the haddock (Melanogrammus aeglefinus, Gadiformes, Gadidae) calls in the arctic fjord Kongsfjorden (Svalbard Islands, Norway)

  • Buscaino G1*, Picciulin M2, Canale DE1, Papale E1,  Ceraulo M1, Grammauta R1, Mazzola S1.
  • 1 Bioacousticslab, National Research Council, via del Mare, 6, Torretta granitola (TP), Italy.
  • 2 Indipendent scholar.

*giuseppa.buscaino@cnr.it

In this study we analyzed the acoustic properties and the presence of haddock calls in the Arctic fjord Kongsfjorden (79° N – 12° E, Svalbard Islands, Norway) during one year. Data were collected with three autonomous acoustic recorders located in the inner, middle, and outer part of the fjord. The fjord is characterized by a gradient in the oceanographic conditions, from the inner to the outer parts of the fjord, reflecting changes from Arctic to Atlantic waters. Haddock sounds were more abundant in the outer compared to the middle fjord, whereas they were absent in the inner site. They were recorded from July to October, that is out of the spawning period. The call abundance revealed a strong periodicity and correlation with the cycles of neap tide (15 day) and tide (12 hour) in July and August, with a clear diel cycle (24 hour) in September and October. This result suggests that in this extreme enviroment, with 24 hour of light during summer, haddocks regulate their acoustic activity over the main available oscillating physical external driver, such as the tide during the polar summer; while, when the alternation light/dark starts, they shift the periodicity of their call to a diel cycle.

O9- #switchoffandlisten – acoustic ecology, ecoacoustics and listening practices towards inclusion with nature

  • Francisca Rocha Gonçalves
  • FEUP (Faculty of Engineering of the University of Porto)
  • INESC TEC (Institute for Systems and Computer Engineering, Technology and Science)
  • Supported by FCT – Foundation for Science and Technology

Acoustic ecology and ecoacoustics can be powerful tools to develop artistic approaches towards nature-connectedness. The psychological model for human inclusion with nature argues that individuals’ connection with nature will dictate their behaviours towards protecting it. In this sense, emotion is crucial when understanding environmental attitudes and behaviours. Moreover, an emotional affinity defined by the individual’s bond with nature is considered the basis for developing pro-environmental actions and commitments. The more time a person spends in nature, the more intimate their relationship becomes. This paper details artistic strategies for creating an underwater noise awareness campaign #switchoffandlisten. It explores listening strategies as tools to tune into a place. The goal is to reinforce emotional affinity and connectedness to nature through underwater listening workshops. We took the audience on boat tours for underwater listening while doing ocean soundscape recordings. By listening to ocean soundscapes with and without anthropogenic influence, the audience could feel the problem of noise pollution in a more grasping way while connecting emotionally to the underwater environment and their species. The outcome was a collaborative performance.

O10- Extreme vocalizations in songbirds : the case of the Mediterranean Flycatcher Muscicapa tyrrhenica

Jacques COMOLET-TIRMAN

UMS PatriNat (OFB – CNRS – MNHN), Muséum national d’Histoire naturelle, CP41, 36 rue Geoffroy Saint-Hilaire, 75005 Paris, France

Several kinds of vocalizations have been described in songbirds, including the following:

  • Territorial songs, meant to carry as far as possible (à soundscapes)
  • Alarm calls, also meant to carry some distance, with a supra-specific message
  • Vocalizations with a more intimate purpose (à sonotope) such as subsongs and nuptial songs

Territorial songs tend to be louder and often play a major role in soundscapes, whereas subsongs may be heard at close range only.

Most songbirds vocalizations remain well below 10 kHz. Among songbirds reaching high frequencies (for instance above 7 kHz), a classification test can be proposed, introducing the categories above further divided according to the regularity with which high frequency sounds are emitted, for instance (territorial songs):

  • Songs remarkable for their narrow frequency range such as Dendroica striata in North America or Regulus ignicapillus in Europe (note that both remain under 10 kHz).
  • Songs covering a wide frequency range and occasionally reaching high notes (13 kHz : Molothrus ater in North America).

Using these categories, we will discuss the song of the Spotted Flycatcher Muscicapa striata and the song of its sister species the Mediterranean Flycatcher Muscicapa tyrrhenica (recently split from the Spotted Flycatcher) which I had the opportunity to study in Corsica and in the Balearic Islands.

O11- How to determine the detection range of acoustic recorders in terrestrial environments?

  • Sylvain HAUPERTa, Frédéric SEBEb, Jérôme SUEURc
  • a Sorbonne Université, CNRS UMR 7371, INSERM UMR S 1146, Laboratoire d’Imagerie Biomédicale, Paris, France
  • b Université Jean Monnet, Laboratoire de neuro-éthologie sensorielle, Saint-Etienne, France.
  • c Muséum national d’Histoire naturelle, CNRS UMR 7205 ISYEB, Sorbonne Université, Paris, France, http://ear.cnrs.fr

Ecoacoustic research mainly relies on the use of passive recording devices which are deployed in complex natural environments. The detection range associated with each acoustic recorder should be evaluated 1) to avoid pseudo-replication and 2) to provide relevant proxies of biodiversity information such as species occupancy, species richness or evenness. To address this issue, we use a field-based protocol to determine the detection range of acoustic recorders in terrestrial environments. The method consists in a recording session of the ambient sound directly followed by a propagation test using a calibrated loudspeaker which is positioned away from the recording along a 100 m long transect by a 10 m step. The loudspeaker is used to play back a 80 dB SPL white noise sound. In addition a sound meter level is positioned at the recorder position to work as a calibrated reference. Such protocol was tested in a neotropical lowland rainforest (French Guiana, France) and in temperate cold mountain forest (Jura, France). The results show that the sound pressure level (SPL) of the soundscape plays a key role in the determination of the recorder detection range. The soundscape SPL varies significantly with frequencies and terrestrial environments. Sound attenuation process has been modeled as an exponential decay with two parameters depending on the propagation distance and the frequency band. Such model fit with the experimental data. Then, knowing the attenuation due to the spreading losses and the atmospheric absorption, it is possible to assess the part of the attenuation due to the environment (e.g. vegetation, ground and topography). Finally, combining the soundscape SPL with the attenuation model corresponding to the terrestrial environment, the utmost detection range could be estimated for a given frequency band and initial SPL of the source.

O12- Automatic detection of Meager’s (Argyrosomus regius) chorusing activity reveals natural rhythms and noise impacts

Manuel Vieira, Departamento de Biologia Animal and cE3c – Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Portugal; MARE – Marine and Environmental Sciences Centre, ISPA-Instituto Universitário, Lisboa.

  1. Clara P. Amorim, MARE – Marine and Environmental Sciences Centre, ISPA-Instituto Universitário, Lisboa; Faculdade de Ciências, Universidade de Lisboa, Portugal.

Tiago A. Marques, Centre for Research into Ecological and Environmental Modelling, , University of St Andrews, St Andrews, Scotland; Departamento de Biologia Animal, Centro de Estatística e Aplicações, Universidade de Lisboa, Portugal.

Paulo J. Fonseca, Departamento de Biologia Animal and cE3c – Centre for Ecology, Evolution and Environmental Changes; Faculdade de Ciências, Universidade de Lisboa, Portugal.

Many fish species rely on acoustic communication to fulfil several functions such as advertisement and mediation of social interactions. Therefore, Passive Acoustic Monitoring (PAM) can be a valuable tool to monitor activity and distribution of important soniferous fish species such as the meagre (Argyrosomus regius). However, PAM often involves extensive sound recordings and consequently automatic methods are invaluable tools to detect and extract relevant biological information. This study assesses the impact of boat passages on the vocal behaviour the meagre over four months in the Tagus estuary (Portugal). The Tagus estuary is an important breeding site for this species, but also holds important maritime harbours and a network of ferryboat connections. We used an automatic pattern-recognition methodology based on Hidden Markov Models to assess the occurrence of meagre choruses from continuous recordings. We further tested the impact of boat passages on meagre choruses by quantifying changes in chorus energy assessed with power spectral density. Meagre choruses were observed from 13h30 to 05h00 and were dominated by long-grunts and series of isolated pulses. The chorus onset was dependent on minimum water temperature, daytime length and lunar phase (generalized additive model, R2 = 0.74). Minimum temperature had the highest explanatory power (R2 = 0.66), with a non-linear correlation with chorus onset. On average we observed a significant reduction in the chorus energy related to the ferryboat passages. This study shows that PAM can be used to obtain relevant information on the meagre spatial and temporal use of spawning areas, and to assess the impact of boat noise on fish behaviour.

O13- SIMON | eco acoustic – Scientific Monitoring Data Management and Online Repository for Eco Acoustics

  • Köhler, Christian, science data management, ganzgraph, Bonn, Germany
  • Orth, Thorsten, web solution developer, ganzgraph, Bonn, Germany
  • Riede, Klaus, Zoological Research Museum Alexander Koenig, Bonn, Germany

Affordable and efficient acoustic logger like the AudioMoth pave the way for large scale audio monitoring. However, data handling and management remains challenging, especially in longrunning field studies. With SIMON we want to help monitoring projects to focus on their research without the need to create their own data management and storage solution.
SIMON is a combination of hard- and software tools to extract recorded data from the audio loggers and to store them in an online data repository, accessible by a set of APIs. A portable data collector based on a Raspberry Pi 4 automatically reads the audio data once connected to the audio logger, adds metadata like date, time and location and caches them in an internal storage. The data collector is equipped with a touch screen for easy handling and runs on a standard USB power supply including portable USB power banks. Once the data collector is connected to the internet via WiFi or cable, the cached audio files are automatically uploaded to the online repository for further processing.
The repository runs on a standard LAMP web server (Linux, Apache, MySQL, PHP). Besides the audio data itself, a database stores all available metadata in the Darwin Core format. Both audio and metadata are available online complying to the TDWG Access Protocol for Information Retrieval (TAPIR) for a seamless integration into existing systems.
A web based user interface for data annotation will be implemented in a future version. An automated signal detection based on individual threshold levels and an AI (artificial intelligence) animal sound detector will follow in our quest to provide a full integrated audio monitoring data management solution to the scientific community.

O14- Soundscape and landscape relationship in the tropical Andes. Can acoustic complexity reflect the landscape ecological integrity?

  • Sánchez-Giraldo, C., Grupo Herpetológico de Antioquia GHA, Instituto de Biología, Universidad de Antioquia, Medellín, Colombia.
  • Correa Ayram, C., Instituto de Investigaciones de Recursos Biológicos Alexander von Humboldt IAvH, Bogotá D.C., Colombia.
  • Daza, J.M., Grupo Herpetológico de Antioquia GHA, Instituto de Biología, Universidad de Antioquia, Medellín, Colombia

The tropical Andes, currently under severe land-use transformations and recognized as a priority region for biodiversity conservation, is in urgent need for rapid assessment of their landscape conditions in order to make informed decisions in management and conservation. Soundscape complexity has acquired a paramount role as a biodiversity monitoring tool as it may provide reliable information about the configuration and ecological integrity of the landscape. However, how soundscape complexity and ecological integrity are related in Andean environments, as well as the factors affecting this relationship require still a thorough understanding. We studied how the soundscape complexity reflects the ecological integrity of a heterogeneous landscape on the northern Andes of Colombia, and tested whether this relationship is affected by different spatial and temporal scales. We collected 16964 1-min acoustic recordings from 31 sampling sites between May-July 2018 and estimated nine acoustic indices (AIs) to quantify soundscape complexity. Additionally, from remote sensing data, we derived an ecological integrity index (EII) based on fragmentation, connectivity, and habitat quality indicators.
Mixed-effects models were fitted to assess the relationship between each AI and the EII, including the sampling site as a random effect. Five AIs were found associated with changes in the EII, indicating higher evenness of the acoustic activity and levels of the biophonic signals in sites with higher integrity. Relationships between AIs and the EII were stronger at a smaller spatial scale and responded to soundscape daily variation. The acoustic evenness index and the number of frequency peaks were the best indicators of the changes in ecological integrity. Both AIs can be integrated with remote sensing as a powerful tool for landscape monitoring and offer new perspectives for the understanding of soundscape spatial patterns. Our results show that soundscape analysis is a promising approach for the monitoring and conservation planning of acoustically unknown Andean landscapes.

O15- Application of a sample space for the characterization of shaded coffee plantation soundscape

  •  Juan Almedia
  • Universidad libre, Colombia

The plot of the frequencies that build soundscapes (power spectrum) has been used to show some of their distinctive characteristics. The application of a discretized sample space is proposed to describe, in a concise manner, the contribution of different frequency signals in a soundscape on a yearly scale. A sample space composed of frequency and intensity combinations was used to describe the shapes of power spectrums and their recurrence. The number of elements of the sample space was set so that each element had a low probability of being found in random samples. In this way, the statistical confidence in the occurrence and recurrence of the elements is increased, making it possible to validate traits in the soundscape. According to their occurrence, it was established that there are “base”, “temporary” and “sporadic” combinations of frequency-intensity. When the relative frequencies of the frequency-intensity combinations were plotted versus the number of analyzed power spectrums, it was observed that few combinations predominate in the soundscape. Further, the distribution of the relative frequencies of the combinations tends to stabilize with time; a potential function described the relative frequency of the combinations. It was found that a logarithmic accumulation curve described the relationship between the analyzed power spectrums and the detected combinations in each of the proposed frequency sections; such a function was useful to validate the sampling method.

O16-  Walking in the Footsteps of Stuart Gage: My Transformation into Ecoacoustics

  • Timothy C. Mullet, Ph.D.Kenai
  • Fjords National Park, U.S. National Park Service, Seward, Alaska U.S.A.

There was a time when I seriously thought that studying sound in the sub-freezing temperatures of Alaska’s snow-covered, subarctic winter was a fool’s endeavor. The field of Ecoacoustics was undefined at the time and the science of soundscape ecology hovered in the ambiguity of competing ideas, philosophies, and uncertainty. My efforts to understand sound’s role in nature felt distant and unobtainable as a doctoral student in 2009, and the methods to quantify sound and analyze it for ecological inference seemed beyond my imagination. Failure was imminent. Yet, a stroke of luck came to me in 2011 that would change my life, both personally and professionally, forever. Although I do not recall how I met Professor Stuart H. Gage, I vividly recall the impact he had on my development as a struggling Ph.D. student. Stuart was not only among the most brilliant minds I have ever encountered, his gentle nature, unwavering patience, and ability to connect with me intellectually and emotionally steered me in the direction of success. Together, we not only pushed the envelope of his own meticulously-thought out methodologies, but we accomplished what many thought was impossible. In a short time, Stuart introduced me to some of the greatest scientists and philosophers of the 21st century. I became both colleague and friend to Bernie Krause and Almo Farina, among many others. Stuart graciously introduced me to a community, a family, of like-minded scientists who not only embraced my ideas but fostered my individual growth to expand on their work in my own part of the world. Through Stuart, I became a contributing author to the first book on Ecoacoustics and an invited member to the International Society of Ecoacoustics. In his memory, I will present to you the story and the science of how Stuart changed my life and how Stuart helped me blaze a path to change the way we perceive and understand the natural world. I may fight back tears in the process. However, it will not simply be out of my sadness for losing him, but the joy and light he has brought to my life.

O17- Acoustic indices applied to biodiversity monitoring in a tropical rainforest of Costa Rica

  • Mónica Retamosa Izaguirre1, David Segura Sequeira2, Jimy Barrantes Madrigal1, Manuel Spínola Parallada1, and Oscar Ramírez Alán3†

1 Instituto Internacional en Conservación y Manejo de Vida Silvestre, Universidad Nacional, Costa Rica, mretamos@una.cr

2 Reserva Natural Las Arrieras

3 Escuela de Ciencias Biológicas, Universidad Nacional, Costa Rica

Acoustic monitoring is used to assess biodiversity across large spatial and temporal scales. Nevertheless, extracting meaningful information from large data sets might be exceedingly time consuming; for this reason, acoustic indices have been proposed as proxies for biodiversity monitoring. We examined the relationship between acoustic indices and bird indices in two sites at the Braulio Carrillo National Park (BCNP) with different environmental conditions (impact on the structure of the vegetation and exposure to vehicular noise along highway 32), and discuss the utility of acoustic indices as indicators for biodiversity monitoring in tropical rainforests. We sampled the soundscape and bird community (using point counts) in 12 sampling points per site, during four visits to each site from June 2017 to August 2018 . We recorded sounds continuously at dawn and dusk, and for 10 minutes each hour in between, during two consecutive days per visit; and conducted four bird counts per visit (dawn and dusk). We conducted a correlation analysis between 11 acoustic indices and 4 indices derived from bird point counts. We also used random forest to analyze the ability of all acoustic indices to predict each bird index. Alternatively, we assessed the value of acoustic indices to classify data according to the degree of forest perturbation related to highway 32. Bird abundance, richness, and diversity were positively correlated with complexity and acoustic evenness indices. However, the bird indices were negatively correlated with the acoustic diversity index. Predictions of bird indices using acoustic indices presented a low explained variance (range: 0.009 – 0.14) and a high normalized root mean square error (range: 0.22 – 0.82). The classification of the sites was conducted with a high average precision of 0.93 (sd = 0.08). Acoustic indices seem to be more promising for assessing ecological condition than levels of biodiversity in tropical rainforests.

O18- Does vegetation structure shape the acoustic features of Lincoln’s Sparrow songs?

Natalie V. Sanchez1, Branko Hilje2, Erin M. Bayne1

  1. 1. Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2R3, Canada
  2. 2. Council on International Educational Exchange, Monteverde, 60109, Costa Rica

Song variation within passerine birds has typically been explained by social interactions or local adaptations to a particular environment. In sparrows, there is evidence of songs adapting to certain vegetation structure even if theirs songs are simple or highly variable. For a less studied sparrow, the Lincoln’s Sparrow (Melospiza lincolnii), we aimed to describe the variation on its songs’ across different ecosystems in Alberta, Canada using autonomous recording units. To explain differences in acoustic features along the province, we used geographic location of songs and vegetation structure. For this, we first created a song catalog to classify song types and syllable types. Then, we measured the acoustic structure of songs and unique syllables found for each male using spectrogram and power spectra view. We performed multivariate analysis testing for the effect of space and vegetation on acoustic features. We identified 68 individuals, 69 songs and 127 syllable types. We did not find evidence of geographic structure in terms of song types demonstrating high syllable sharing across Alberta. Birds sang higher-frequency songs in open areas such as grass and shrubs. Finally, unique syllables were lower in frequency in coniferous forest (denser vegetation). Therefore, Lincoln’s Sparrow adjusted their songs by vegetation type. This study is a contribution to the understanding of song variation of a common sparrow at a large geographic scale.

O19- Eco-acoustic-arts: teaching qualitative ecoacoustics through sonic arts, birds & environmental sensitivities

  • Hellier Ruth
  • University of California Santa Barbara, California, USA

Teaching qualitative ecoacoustics through eco-acoustic arts opens up possible pathways for undergraduate students to develop deep and broad ecological sensitivities and knowledges. Focusing specifically on more-than-human birds sounds and engaging the core concept of ecoacoustics as the ecological investigation and interpretation of environmental sound, the course Sonic arts, birds & environmental sensitivities was created and taught within the context of a music department in a research university (University of California, Santa Barbara). Through the concept of sounding as an inspirational process to explore entanglements of scientific research and cultural formations, students used a range of qualitative and quantitative methods, practices and processes, including sensory ethnography, ethography, uses of ArcGIS (as sound mapping), and digital technologies. In particular, the course enabled students to undertake fieldwork during the COVID-19 lockdown, utilizing their own recording and listening technologies to engage with birds in their locale, translating these ecoacoustic data into embodied and emplaced knowledge, and into communicative, artistic responses. Recognizing the poetic-political potential of eco-acoustic-arts as activism, this course provides a model for analogous contexts in multiple educational settings integrating environmental arts and sciences.

O20- Zeuneriana marmorata and Uromenus annae (Insecta: Orthoptera): songs from the verge of extinction

Filippo Maria Buzzetti
Fondazione Museo Civico di Rovereto
Borgo Santa Caterina, 41
38068 Rovereto Tn

Zeuneriana marmorata (Fieber, 1853) and Uromenus annae (Targioni-Tozzetti, 1881) were once believed to be extinct or nearly so. Both are inserted in the IUCN Red List of European Orthoptera.

  1. marmorata ranges in the Adriatic coast of North East Italy and Slovenija inland. Its presence was

dramatically affected during the past by habitat loss and pesticide use. The remnant populations are now being studied by an international conservation project. The bioacoustic comparison of the male calling song from different populations is investigated to clarify any difference between populations. Uromenus annae is a striking species endemic of Sardinia (Italy) were it lives in scattered populations. Thought to be extinct, it has been rediscovered in 2018 and its male calling song has been recorded for the first time. This instigated further researches that found more living populations.