PLENARY 3 – Thursday 24


PLENARY 3 – Thursday 24

The Future Belongs to Those Who Can Hear It Coming (a paraphrase of a David Bowie aphorism.)

Bernie Krause

Wild Sanctuary
PO Box 536, Glen Ellen, CA

Since I first engaged with the ecology of sound fifty-three years ago, the density and diversity of wildlife acoustic signatures has diminished markedly. At some sites, as a direct consequence of anthropogenic climate change and other exploitive human endeavor, the biophony can no longer be heard in any form. This essay of personal thoughts on my evolution to ecoacoustics is framed by the title, a paraphrase of the late David Bowie aphorism. Bowie’s deeply profound observation speaks to a host of insights that flow from it. Most important, we can no longer disregard the cries of wild organisms and human ensembles living closely connected to the natural world, those begging for relief from the relentless corporate assault on the earth’s finite resources that have otherwise sustained them from the beginning. It is an onslaught now transmitted all too eloquently through the otherwise life-affirming voices of the natural world, its biophonies and geophonies, as these critters struggle for purchase. Will this descent toward silence be the world-wide outcome of Bowie’s prediction? What can be done to alter this course? And who among us will take the lead?

O35- Songs of a fishing bat: echolocation call variation of the greater bulldog bat across the Neotropics

  • Arias-Aguilar, A., Bird and Mammal Evolution, Systematics and Ecology Lab, Graduate Program in Animal Biology, Universidade Federal do Rio Grande do Sul, and Brazilian Bat Research Society, Brazil.
  • Rodríguez-Herrera, B., Escuela de Biología y Centro de Investigaciones en Biodiversidad y Ecología Tropical, Universidad de Costa Rica.

Ramos Pereira, M.J., Bird and Mammal Evolution, Systematics and Ecology Lab, Graduate Program in Animal Biology, Universidade Federal do Rio Grande do Sul and Brazilian Bat Research Society, Brazil; Centre for Environmental and Marine Studies, Universidade de Aveiro, Portugal.
Climate is a crucial factor for the evolution of bat echolocation calls, mostly due to its effect on atmospheric sound absorption. Indeed, according to the Sensory Drive hypothesis species’ echolocation call frequencies will vary along the latitudinal gradient in response to different conditions of atmospheric attenuation. The lineages of Neotropical fishing bats are perfect models to test this hypothesis. So, here, by means of acoustic monitoring and analysis, echolocation calls from bat populations of the greater bulldog bat, Noctilio leporinus, from North, Central and South America will be used to test if differences in humidity and temperature across the geographic and climatic ranges of the species will result in different call frequencies. Despite the fact that in the last years the use of acoustic monitoring has increased in the Neotropical region, studies on echolocation behaviour are still very scarce. Indeed, the variation in the echolocation calls of the greater bulldog bat along its geographic distribution has never been studied. The results of our study will shed light on how bats adapt their echolocation behaviour to local weather conditions and on the subsequent implications for lineage diversification. Ultimately, this will potentially help us understand how other bats will cope with present and future climate changes and to identify priority populations and habitats for conservation efforts.

O36- Bats of the neglected Brazilian-Uruguayan savanna: occupancy, diversity and conservation

  • Costa, Cíntia Fernanda da., Programa de Pós-Graduação em Ecologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brasil; Brazilian Bat Research Society.
  • Ramos Pereira, Maria João., Programa de Pós-Graduação em Biologia Animal, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brasil; Centre for Environmental and Marine Studies, Universidade de Aveiro, Aveiro, Portugal; Brazilian Bat Research Society

The conversion of open habitats into monoculture forest systems or their degradation through intensive use for agriculture and livestock production affects the activity, diversity and occupation of organisms at different spatial scales. The BrazilianUruguayain savanna is the least officially protected of all Brazilian biomes. There is a significant gap of knowledge on bats of these South American grasslands, especially in what concerns aerial insectivores. Indeed, no acoustic monitoring has ever been made in the region, knowingly the best method to detected this guild, that potentially makes up the majority of bat fauna of the region. We monitored 75 sites placed 1.5 km apart, from November 2019 to January 2020. We calculated different landscape metrics to determine the degree of connectivity in each site. The sites were grouped into scarcely, medium and highly connected, composing the classes of land-use in concentric spatial buffers from 100 m to 1000 m around each sampling site. We sampled bats using automated sound-detectors (Audiomoths), programed to record cuts of 15 seconds every two minutes, for five days in each site. We also coupled automated temperature and humidity sensors to each active Audiomoth to obtain detailed information on the weather conditions associated with each sound record. We obtained over 20,000 hours of recordings, and presently the acoustic data is being processed in the laboratory. Using the history of detection and non-detection of each species, we will build hierarchical occupation models, using the landscape variables as occupancy predictors and the microclimatic variables as detection predictors. Our results should contribute to fill several knowledge gaps on bat occupancy, ecology and diversity patterns in the Brazilian-Uruguayan savanna. In parallel, we should be able to increase the acoustic library of Brazilian bat calls allowing the expansion of the horizons of bioacoustics research in the country.

O37-Acoustic measures of bird communities in a thinned and burned coastal plain pine forest

  • Cahalan, G. D., The Nature Conservancy, Maryland, USA.
  • Landau, D., The Nature Conservancy, Maryland, USA.

In the face of climate change and urban development land managers are faced with increasingly difficult choices on how to maintain the biological integrity of protected areas.  To support the decisions made by protected area managers, tools and methods to quickly measure and assess trends and outcomes from management actions are needed.  Our current study in an Atlantic seaboard coastal plain forest examines how prescribed fire and timber harvesting impact bird diversity and singing activity using a soundscape analysis.

In 2008 The Nature Conservancy started to restore sites planted in loblolly pine (Pinus taeda L.) using controlled burns and timber harvests at the Nassawango Creek Preserve, a protected conservation area.  This area is visited by a high number of migratory birds and has been designated an Important Bird Area by the Audubon Society.  This setting allowed us to compare bird communities in thinned and burned stands to unmanaged areas with similar forest types.

We found a higher quality soundscape as measured by the mean normalized difference soundscape index (NDSI) in the thinned and burned site with lower mean trees per hectare.  In addition, the thinned and burned forest had higher mean acoustic complexity and bioacoustic indices (ACI and BI).  We also found that since 2005, the population of prairie warbler (Setophaga discolor) declined at the unburned site as the canopy closed and became more homogeneous.  In contrast, prairie warbler continues to persist in nearby burned forest of approximately the same age.  Prescribed fire combined with targeted timber management can increase the available habitat conditions required by different species of birds in a loblolly pine plantation.

O38-  Monitoring vessel use and characterizing acoustic species assemblages in the soundscapes of two Australian marine parks

Jessica A. McCordic1*, Annamaria I. DeAngelis1, Logan Kline2, Candace McBride3, Giverny Rodgers3, Timothy J. Rowell1, Jeremy Smith3, Jenni Stanley4, Andrew Read5, Sofie M. Van Parijs1

1 Northeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 166 Water Street, Woods Hole, MA 02543, USA

1* under contract to Northeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 166 Water Street, Woods Hole, MA 02543, USA

2 University of Maine, 5755 Nutting Hall, Orono, ME 04469, USA

3 Parks Australia, GPO Box 787, Canberra, ACT, 2601, Australia

4 University of Waikato, School of Science, New Zealand

5 National Marine Science Centre, Southern Cross University, 2 Bay Drive, Coffs Harbour NSW 2450, Australia

Soundscape ecology characterizes acoustic interactions within an environment, integrating biological, geological, and anthropogenic sound sources. In this study we assessed the overlap of biological sound sources and vessel transit in time and frequency to establish a baseline measure of soundscapes within two marine National Park Zones (NPZs) along the east coast of Australia: Cod Grounds Marine Park and Solitary Islands Marine Park. Although transit through the areas and general use is permitted, fishing and other extractive activities are prohibited within the NPZs, and acoustic recordings were originally used to inform park managers of vessel activity patterns. This study presents a noninvasive, high resolution method of simultaneously assessing human activity and the presence of multiple species. In each of the NPZs, recorders were deployed twice during the austral winter (33–35 days, 2018 and 60-69 days, 2019) and once during the austral summer (35–71 days, 2018–2019) to determine whether the soundscape of each site exhibited seasonal differences in anthropogenic or biological sound sources. The resulting acoustic recordings allowed us to determine hourly presence of sounds throughout the recording periods between 20 Hz and 24 kHz in frequency. Biological sources at both sites included dolphins, continuous snapping shrimp, diel patterns of fish choruses, and seasonal presence of singing humpback whales. Anthropogenic sources were largely dominated by vessel transit, which was further classified into distant vessels and closer approaches likely within the NPZ. Additional deployments are forthcoming in more remote marine parks aimed at understanding patterns of vessel use and soundscapes throughout diverse habitats.

O39- Assessing soundscape disturbance through hierarchical models and acoustic indices: a case study on a shelterwood logged northern Michigan forest

  • Doser, J., Department of Forestry, Michigan State University, East Lansing, USA
  • Finley, A., Department of Forestry, Michigan State University, East Lansing, USA
  • Kasten, E., Clinical and Translational Sciences Institute, Michigan State University, East Lansing, USA
  • Gage, S., Department of Entomology, Michigan State University, East Lansing, USA

Assessing the effects of disturbances on wildlife is a necessary conservation task. The soundscape is a critical habitat component for acoustically communicating organisms, but the use of the soundscape for assessing disturbance impacts has been relatively unexplored until recently. Here we present a broad modeling framework for assessing disturbance impacts on soundscapes, which we apply to quantify the influence of a shelterwood logging on soundscapes in northern Michigan. Our modeling approach can be broadly applied to assess anthropogenic disturbance impacts on soundscapes. The approach accommodates inherent differences in control and treatment sites to improve inference about treatment effects, while also accounting for extraneous variables (e.g., rain) that influence acoustic indices.

Recordings were obtained at 13 sites before and after a shelterwood logging. Four sites were in the logging region and nine sites served as control recordings outside the logging region. We quantify the soundscapes using common acoustic indices (Normalized Difference Soundscape Index (NDSI), Acoustic Entropy (H), Acoustic Complexity Index (ACI), Acoustic Evenness Index (AEI)) and Welch Power Spectral Density (PSD) values. We build two hierarchical Bayesian models to quantify the changes in the soundscape over the study period.

Our analysis reveals no long-lasting effects of the shelterwood logging on the soundscape as measured by the NDSI, but analysis of H, AEI, and PSD suggest changes in the evenness of sounds across the frequency spectrum, indicating a potential shift in the avian species communicating in the soundscapes as a result of the logging. Multiple model validation techniques (i.e., comparison of parameter estimates and the widely applicable information criterion (WAIC)) reveal our proposed hierarchical Bayesian models outperform more simple models used for hypothesis testing. Acoustic recordings, in conjunction with this modeling framework, can deliver cost efficient assessment of disturbance impacts on the landscape and underlying biodiversity as represented through the soundscape.

O40- Passive acoustic monitoring for identification and location of a migratory fish spawning areas in a tropical Andean river.

  • Muñoz-Duque, S., Natural and Exact Sciences Faculty, University of Antioquia, Medellín, Colombia.
  • López-Casas, S., The Nature Conservancy, Bogotá, Colombia
  • Jiménez-Segura, L., Natural and Exact Sciences Faculty, University of Antioquia, Medellín, Colombia.
  • Rivera-Gutiérrez, H., Natural and Exact Sciences Faculty, University of Antioquia, Medellín, Colombia.

Hydropower expansion poses multiple threats to biodiversity of rivers around the world. One of the most notable aspects is the loss of migratory fish spawning areas due to fragmentation and changes of the environmental characteristics in such areas, affecting fish recruitment. To apply comprehensive management strategies for migratory fish in rivers basins impacted by hydroelectric development, it is necessary to identify and locate their spawning areas. These areas of importance for fish reproduction have been identified, among other techniques, through passive acoustic monitoring (PAM), however there are very few cases of PAM application in tropical river systems. Our objective in this project was to bioacoustically characterize spawning sounds of a migratory fish species (Prochilodus magdalenae) and validate PAM to identify and locate spawning areas of this fish in the Magdalena River Basin, Colombia. As a result of our project, the spawning sounds for this species was characterized and two spawning sites were successfully located in the Magdalena River Basin. Train of pulses presented a dominant frequency, train duration, total number of pulses by train and interpulse interval values of 399 Hz, 2.3 s, 48.6 pulses and 49.0 ms, respectively. It is concluded that through PAM spawning areas of Prochilodus magdalenae can be located in the Magdalena River Basin. A greater number of soniferous fish species could be bioacoustically characterized in the area, providing important data that helps to prioritize conservation and management efforts for spawning key areas.

O41- Musical use of nature sounds – Perspectives from the second part of the 20th century

  • Supervie, Armelle., Institut de Systématique, Évolution, Biodiversité (ISYEB), Muséum national d’Histoire naturelle/ CNRS/ Sorbonne Université/ EPHE, 57 rue Cuvier, 75005 Paris, France
  • Éco-Anthropologie (UMR 7206), Muséum national d’histoire naturelle/ CNRS/ Univ. de Paris, Musée de l’Homme, 17, place du Trocadéro, 75016 Paris, France
  • Battesti, Vincent, Éco-Anthropologie (UMR 7206), CNRS/Muséum national d’histoire naturelle/Univ. de Paris: Musée de l’Homme, 17, place du Trocadéro, 75016 Paris, France
  • Sueur, Jérôme, Institut de Systématique, Évolution, Biodiversité (ISYEB), Muséum national d’Histoire naturelle/ CNRS/ Sorbonne Université/ EPHE, 57 rue Cuvier, 75005 Paris, France

Ecoacoustics has been developed as a unique mix of science and arts. Here, we aim at understanding and exploring why and how nature soundscapes are embedded in musical practices. More specifically, we worked on the concept of “musicality”. Why are nature sounds considered to be more musical than anthropophonic sounds? How does the use of nature sounds in music since the second part of the 20th century deconstruct and question the concept of “musicality”? These essential issues about the interweaving of music and sounds from the environment, which transcend cultural boundaries, have been addressed by a study based on a review of musicological, ecoacoustics and ethnographic literature, and on interviews with field recorders and composers using nature sounds in their music. We identified three ways of considering musicality: as an acoustic structure, as a human process, and as a listening posture. We challenged the hypothesis that nature sounds possess an intrinsic structural musicality. We thus discussed the concept of harmony, melody, and rhythmic of natural sounds. We then questioned the way in which natural sounds are transformed into music, analysing the different processes, steps, and artistic styles of producing. Eventually, we discussed whether a specific posture of listening leads to finding musicality in nature sounds. We exposed different types of listening described by various authors, and commented on the notions of imagination, abstraction, and realism in the Western concept of musicality. The combination of ecology and social sciences leads to a unique interdisciplinary and creative approach to understanding how environmental sounds and music are connected.

O42- The rise and fall of Biophony and the drivers of the acoustic space 

  • Sugai, L.S.M., Terrestrial Ecology Group, Science Faculty, Universidad Autónoma de Madrid, Madrid, Spain
  • Desjonquères, C., Terrestrial Ecology Group, Science Faculty, Universidad Autónoma de Madrid, Madrid, Spain
  • Silva, T.S.F, Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, UK
  • Siqueira, T., Instituto de Biociências, Universidade Estadual Paulista (Unesp), Rio Claro, Brazil
  • Llusia, D., Terrestrial Ecology Group, Science Faculty, Universidad Autónoma de Madrid, Madrid, Spain

Ecoacoustics targets the properties and dynamics of environmental sounds as its main analytical unit. Biophony, being the collection of animal sounds, is perhaps the most enigmatic component of soundscapes. It contains multifaceted information about biodiversity, ranging from the identity of organisms to the output of eco-evolutionary processes. Here we begin by presenting the raise of research of animal ecology with passive acoustic monitoring in terrestrial ecosystems. We synthesize main aspects in almost two decades of research for distinct biological groups, research subjects, geographical distribution, and survey designs. Next, we address traditional hypotheses addressing the acoustic component of ecological communities that are considered theoretical backgrounds in ecoacoustics. Our approach combined species composition, phylogenetic, acoustic parameters, and body-size relationships of anuran signaling assemblages across gradients of environmental heterogeneity in the Pantanal wetlands of Brazil. First, we found little support for the hypotheses of acoustic partitioning and acoustic adaptation in structuring the acoustic space of assemblages,

arguing for the fall of these traditional hypotheses. Second, fine-temporal variation in community-wide activity was associated with environmental heterogeneity and phylogenetic relatedness, suggesting potential trade-offs between spatial and temporal partitioning. Altogether, our findings underscore the importance to address the ecological context of communities to better comprehend the dynamics and drivers of the biophonic component of soundscapes.