Climate change is breaking Earth's beat

International audienceForests, deserts, rivers, and oceans are filled with animal vocalizations and geological sounds. We postulate that climate change is changing the Earth's natural acoustic fabric. In particular, we identify shifts in acoustic structure that all sound-sensitive organisms, marine and terrestrial, may experience. Only upstream solutions might mitigate these acoustic changes

Unsupervised classification to improve the quality of a bird song recording dataset

Open audio databases such as Xeno-Canto are widely used to build datasets to explore bird song repertoire or to train models for automatic bird sound classification by deep learning algorithms. However, such databases suffer from the fact that bird sounds are weakly labelled: a species name is attributed to each audio recording without timestamps that provide the temporal localization of the bird song of interest. Manual annotations can solve this issue, but they are time consuming, expert-dependent, and cannot run on large datasets. Another solution consists in using a labelling function that automatically segments audio recordings before assigning a label to each segmented audio sample. Although labelling functions were introduced to expedite strong label assignment, their classification performance remains mostly unknown. To address this issue and reduce label noise (wrong label assignment) in large bird song datasets, we introduce a data-centric novel labelling function composed of three successive steps: 1) time-frequency sound unit segmentation, 2) feature computation for each sound unit, and 3) classification of each sound unit as bird song or noise with either an unsupervised DBSCAN algorithm or the supervised BirdNET neural network. The labelling function was optimized, validated, and tested on the songs of 44 West-Palearctic common bird species. We first showed that the segmentation of bird songs alone aggregated from 10% to 83% of label noise depending on the species. We also demonstrated that our labelling function was able to significantly reduce the initial label noise present in the dataset by up to a factor of three. Finally, we discuss different opportunities to design suitable labelling functions to build high-quality animal vocalizations with minimum expert annotation effort

New indices to characterize drawing behavior in humans (Homo sapiens) and chimpanzees (Pan troglodytes)

Techniques used in cave art suggest that drawing skills emerged long before the oldest known representative human productions (44, 000 years BC). This study seeks to improve our knowledge of the evolutionary origins and the ontogenetic development of drawing behavior by studying drawings of humans (N = 178, 3- to 10-year-old children and adults) and chimpanzees (N = 5). Drawings were characterized with an innovative index based on spatial measures which provides the degree of efficiency for the lines that are drawn. Results showed that this index was lowest in chimpanzees, increased and reached its maximum between 5-year-old and 10-year-old children and decreased in adults, whose drawing efficiency was reduced by the addition of details. Drawings of chimpanzees are not random suggesting that their movements are constrained by cognitive or locomotor aspect and we cannot conclude to the absence of representativeness. We also used indices based on colors and time and asked children about what they drew. These indices can be considered relevant tools to improve our understanding of drawing development and evolution in hominids

A multilevel statistical toolkit to study animal social networks : the Animal network toolkit Software (Ants) R package

publishedVersio

Explosive breeding in tropical anurans: Environmental triggers, community composition and acoustic structure

Background: Anurans largely rely on acoustic communication for sexual selection and reproduction. While multiple studies have focused on the calling activity patterns of prolonged breeding assemblages, species that concentrate their reproduction in short-time windows, explosive breeders, are still largely unknown, probably because of their ephemeral nature. In tropical regions, multiple species of explosive breeders may simultaneously aggregate leading to massive, mixed and dynamic choruses. To understand the environmental triggers, the phenology and composition of these choruses, we collected acoustic and environmental data at five ponds in French Guiana during a rainy season, assessing acoustic communities before and during explosive breeding events. Results: We detected in each pond two explosive breeding events, lasting between 24 and 70 h. The rainfall during the previous 48 h was the most important factor predicting the emergence of these events. During explosive breeding events, we identified a temporal factor that clearly distinguished pre- A nd mid-explosive communities. A common pool of explosive breeders co-occurred in most of the events, namely Chiasmocleis shudikarensis, Trachycephalus coriaceus and Ceratophrys cornuta. Nevertheless, the species composition was remarkably variable between ponds and for each pond between the first and the second events. The acoustic structure of explosive breeding communities had outlying levels of amplitude and unexpected low acoustic diversity, significantly lower than the communities preceding explosive breeding events. Conclusions: Explosive breeding communities were tightly linked with specific rainfall patterns. With climate change increasing rainfall variability in tropical regions, such communities may experience significant shifts in their timing, distribution and composition. In structurally similar habitats, located in the same region without obvious barriers, our results highlight the variation in composition across explosive breeding events. The characteristic acoustic structure of explosive breeding events stands out from the circadian acoustic environment being easily detected at long distance, probably reflecting behavioural singularities and conveying heterospecific information announcing the availability of short-lived breeding sites. Our data provides a baseline against which future changes, possibly linked to climate change, can be measured, contributing to a better understanding on the causes, patterns and consequences of these unique assemblagesThis research was supported by the Labex CEBA (Centre d’Étude de la Biodiversité Amazonienne), which provided fnancial and logistic support for the data collection. JSU was supported by COLCIENCIAS (Doctoral Scholarship of the Colombian government, 2014 call #646). DLL was supported by a Global Marie S. Curie fellowship (European Commission, program H2020, EAVESTROP–661408), a postdoctoral grant Atracción de Talento Investigador (Comunidad de Madrid, CAM, Spain, 2016-T2/AMB-1722), and acknowledges funding provided by the Ministerio de Economía, Industria y Competitividad (CGL2017-88764-R, MINECO/AEI/FEDER, Spain). None of the funders had any role in the design, analysis, interpretation of results or writing the manuscrip

Freshwater ecoacoustics as a tool for continuous ecosystem monitoring

Copyright by the Ecological Society of AmericaPassive acoustic monitoring is gaining popularity in ecology as a practical and non-invasive approach to surveying ecosystems. This technique is increasingly being used to monitor terrestrial systems, particularly bird populations, given that it can help to track temporal dynamics of populations and ecosystem health without the need for expensive resampling. We suggest that underwater acoustic monitoring presents a viable, non-invasive, and largely unexplored approach to monitoring freshwater ecosystems, yielding information about three key ecological elements of aquatic environments – (1) fishes, (2) macroinvertebrates, and (3) physicochemical processes – as well as providing data on anthropogenic noise levels. We survey the literature on this approach, which is substantial but scattered across disciplines, and call for more cross-disciplinary work on recording and analysis techniques. We also discuss technical issues and knowledge gaps, including background noise, spatiotemporal variation, and the need for centralized reference collection repositories. These challenges need to be overcome before the full potential of passive acoustics in dynamic detection of biophysical processes can be realized and used to inform conservation practitioners and managers

Rapid Acoustic Survey for Biodiversity Appraisal

Biodiversity assessment remains one of the most difficult challenges encountered by ecologists and conservation biologists. This task is becoming even more urgent with the current increase of habitat loss. Many methods–from rapid biodiversity assessments (RBA) to all-taxa biodiversity inventories (ATBI)–have been developed for decades to estimate local species richness. However, these methods are costly and invasive. Several animals–birds, mammals, amphibians, fishes and arthropods–produce sounds when moving, communicating or sensing their environment. Here we propose a new concept and method to describe biodiversity. We suggest to forego species or morphospecies identification used by ATBI and RBA respectively but rather to tackle the problem at another evolutionary unit, the community level. We also propose that a part of diversity can be estimated and compared through a rapid acoustic analysis of the sound produced by animal communities. We produced α and β diversity indexes that we first tested with 540 simulated acoustic communities. The α index, which measures acoustic entropy, shows a logarithmic correlation with the number of species within the acoustic community. The β index, which estimates both temporal and spectral dissimilarities, is linearly linked to the number of unshared species between acoustic communities. We then applied both indexes to two closely spaced Tanzanian dry lowland coastal forests. Indexes reveal for this small sample a lower acoustic diversity for the most disturbed forest and acoustic dissimilarities between the two forests suggest that degradation could have significantly decreased and modified community composition. Our results demonstrate for the first time that an indicator of biological diversity can be reliably obtained in a non-invasive way and with a limited sampling effort. This new approach may facilitate the appraisal of animal diversity at large spatial and temporal scales

So Small, So Loud: Extremely High Sound Pressure Level from a Pygmy Aquatic Insect (Corixidae, Micronectinae)

To communicate at long range, animals have to produce intense but intelligible signals. This task might be difficult to achieve due to mechanical constraints, in particular relating to body size. Whilst the acoustic behaviour of large marine and terrestrial animals has been thoroughly studied, very little is known about the sound produced by small arthropods living in freshwater habitats. Here we analyse for the first time the calling song produced by the male of a small insect, the water boatman Micronecta scholtzi. The song is made of three distinct parts differing in their temporal and amplitude parameters, but not in their frequency content. Sound is produced at 78.9 (63.6–82.2) SPL rms re 2.10−5 Pa with a peak at 99.2 (85.7–104.6) SPL re 2.10−5 Pa estimated at a distance of one metre. This energy output is significant considering the small size of the insect. When scaled to body length and compared to 227 other acoustic species, the acoustic energy produced by M. scholtzi appears as an extreme value, outperforming marine and terrestrial mammal vocalisations. Such an extreme display may be interpreted as an exaggerated secondary sexual trait resulting from a runaway sexual selection without predation pressure

Les mutations contemporaines du droit de l’animal

Le droit de l’animal a connu des mutations d’ampleur au cours des vingt dernières années. Il s’est structuré en champ disciplinaire autonome, a pris une importance croissante dans le débat public et a fait l’objet de réformes remarquées. Le présent ouvrage rend compte de ces évolutions en publiant les actes d’une université d’automne qui s’est tenue à la faculté de droit d’Aix-en-Provence en octobre 2021. Il rassemble les contributions des auteurs – juristes, politistes et historiens – autour de sept thématiques : le droit de l’animal comme champ disciplinaire ; les mots du droit de l’animal ; la fabrique du droit de l’animal ; droit de l’animal et participation démocratique ; droit de l’animal, droits fondamentaux et droit constitutionnel ; la représentation des animaux devant les juridictions et l’action au nom et pour le compte d’un animal ; juridictions pénales et animaux. Le lecteur pourra apprécier, en les parcourant, l’intérêt et la richesse d’une matière en plein essor, particulièrement en phase avec les préoccupations de son temps

Une nouvelle espèce de Cigale du Mexique (Los Tuxtlas, Veracruz), et étude de son émission sonore (Homoptera, Auchenorhyncha, Cicadoidea)

A new Cicada species from Mexico (Los Tuxtlas, Veracruz) and description of its sound production (Homoptera, Auchenorhyncha, Cicadoidea). Dorisiana sutori, a new cicada allied to D. amoena n. comb., is described as being from the region of Los Tuxtlas (Veracruz, Mexico). An audiospectrographical representation of the calling song is provided. The sound emission is a long succession of uniformly schemes each composed of two syllables (A and B) with very distinct spectral features. We suppose that the syllable A with low sharply tuned spectral components is used by females for long range localisation of the calling males and that the syllable B with broad high frequency band is used for short range localisation.Dorisiana sutori, nouvelle espèce de Cigale proche de D. amoena n. comb., est décrite de la région de Los Tuxtlas (Veracruz, Mexique). Son émission sonore, ou cymbalisation, est analysée. Celle-ci est formée par la succession invariable de modules composés de deux motifs (A et B) aux caractéristiques fréquentielles opposées. Les motifs A, à fréquence basse et spectre étroit, sont supposés être utiles aux femelles pour s'orienter à longue distance vers les mâles alors que les motifs B, à fréquences hautes et spectre large, seraient analysés pour les localiser à courte distance.Una nueva especies de Cigarra de Mexico (Los Tuxtlas, Veracruz) y analysis de sus producciones sonoras (Homoptera, Auchenorhyncha, Cicadoidea). Se describe Dorisiana sutori de la región de Los Tuxtlas (Veracruz, Mexico), una nueva especie de cigarra cerca de D. amoena n. comb. Se analizan aspectos bioacústicos de las producciones sonoras (o cimbalización). Esta está formada por la sucesión invariable de módulos compuestos de dos subpartidas diferentes (A y B) con características de frequencias opuestas. Se establece la hipótesis de que a las hembras les es útili las subpartidas A (espectro estrecho y bajas frequencias) para orientarse a larga distancia hacia los machos, mientras que las subpartidas B (espectro ancho y altas frecuencias) serían analizadas para localizarlos a corta distancia.Sueur Jérôme. Une nouvelle espèce de Cigale du Mexique (Los Tuxtlas, Veracruz), et étude de son émission sonore (Homoptera, Auchenorhyncha, Cicadoidea). In: Bulletin de la Société entomologique de France, volume 105 (3), août 2000. pp. 217-222