03288nas a2200301   4500008004100000022001300041245010500054210006900159260001600228300001100244490000800255520235700263653001602620653002402636653003202660653002002692653003202712653002002744100001702764700001902781700002702800700002202827700002502849700002202874700002502896700002402921856004102945       2019                        eng d  a1470160X00aAn optimised passive acoustic sampling scheme to discriminate among coral reefs’ ecological states0 aoptimised passive acoustic sampling scheme to discriminate among  cJan-12-2019  a1056270 v1073 a<p>In the present era of rapid global change, innovative monitoring methods can greatly enhance our ability to detect ecological disturbances and prioritise conservation areas in a timely and cost-effective manner. While Passive Acoustic Monitoring (PAM) has recently emerged as a promising tool for monitoring ecological states in marine environments, the specifics of how to apply this method remains poorly defined. In this study we examined how different combinations of sampling settings (frequency bandwidth, time of sampling (day/night), and sample duration) influenced the ability of two acoustic indices, the Sound Pressure Level (SPL) and the Acoustic Complexity Index (ACI), to discriminate different ecological states (ecostates) of coral reefs. We applied an iterative approach to select the most efficient and consistent combinations of sampling settings to use for these two acoustic indices, depending on the stability of their discriminating power across different time scales (successive days, moon phases, and seasons), and the minimum sampling effort required for reliable ecostate assessment. The ability of SPL and ACI to discriminate ecostate-specific soundscapes was more stable and required less sampling effort at nighttime. For indices calculated in the higher frequency band (&gt;2 kHz), very short recording times (&le;20 min divided into 5 s samples) were sufficient to discriminate ecostates, whereas longer recording times (&ge;200 min divided into 5 min samples) were necessary when using indices calculated in the lower frequency bands (&lt;1 kHz). An optimised sampling scheme, i.e. the group of the five best combinations of settings to discern among coral reef ecostates, was determined at Reunion Island, Indian Ocean, then tested at New Caledonia, Pacific Ocean. Here, the classifications obtained through visual surveys and with the optimised acoustic sampling scheme were congruent. The concordance of our results with visual fish counts confirms the potential of ecoacoustics to rapidly and reliably characterise coral reefs&rsquo; ecostate, allowing managers to prioritise conservation areas among numerous sites, and detect ecological changes over time. Our study provides clear guidelines for monitoring soundscapes by means of the ecoacoustic indices most widely used in the marine realm.</p>
10aCoral reefs10aEcoacoustic indices10aEcological state (ecostate)10aMarine habitats10apassive acoustic monitoring10aSampling scheme1 aElise, Simon1 aBailly, Arthur1 aUrbina-Barreto, Isabel1 aMou-Tham, Gérard1 aChiroleu, Frédéric1 aVigliola, Laurent1 aRobbins, William, D.1 aBruggemann, Henrich  uhttps://bio.acousti.ca/it/node/5735102838nas a2200313   4500008004100000022001300041245009400054210006900148260001600217300001100233490000800244520191200252653001702164653001602181653002402197653002802221653003202249653001502281100001702296700002702313700001802340700002402358700001902382700001702401700002002418700002102438700002402459856004102483       2019                        eng d  a1470160X00aAssessing key ecosystem functions through soundscapes: A new perspective from coral reefs0 aAssessing key ecosystem functions through soundscapes A new pers  cJan-12-2019  a1056230 v1073 a<p>The functioning of tropical coral reefs is imperilled by climate change, overfishing, and decreasing water quality. Maintaining their capacity to provide goods and services will critically depend on our ability to monitor their functioning at appropriate spatial and temporal scales. Given the constraints of traditional methods to respond to those needs, the potential of complementary tools such as Passive Acoustic Monitoring (PAM) is emerging. Coral reef soundscapes (i.e. ambient sound) encompass sounds produced by numerous organisms. Soundscape characteristics quantified by ecoacoustic indices have been found to reflect general ecosystem properties, such as diversity and abundance of fishes, and coral cover. The present study tested, on the virtually pristine coral reefs around Europa Island, South-West Indian Ocean, the capacity of acoustic indices to assess key ecosystem functions. Soundscapes were recorded during 2 h, and ecosystem functions were evaluated using video footage of the fish assemblages and underwater photogrammetry of the benthic landscapes. We found significant and strong correlations between six ecoacoustic indices and six key ecosystem functions, including habitat features and fish assemblage characteristics. The six ecoacoustic indices were representative of several combinations of frequency, amplitude and time analysis domains, highlighting the diversity of the functional information conveyed by soundscapes. Our findings reveal that a 2 h daytime recording on a coral reef could provide sufficient acoustic information to characterise major ecosystem functions of a site. This should facilitate the detection of functional disturbances at temporal and spatial scales adapted to the rapidity of upcoming climate changes. Our results also highlight the potential of ecoacoustics to bring novel and relevant insights in the functioning of ecosystems.</p>
10aconservation10aCoral reefs10aEcoacoustic indices10aKey ecosystem functions10apassive acoustic monitoring10aSoundscape1 aElise, Simon1 aUrbina-Barreto, Isabel1 aPinel, Romain1 aMahamadaly, Vincent1 aBureau, Sophie1 aPenin, Lucie1 aAdjeroud, Mehdi1 aKulbicki, Michel1 aBruggemann, Henrich  uhttps://bio.acousti.ca/it/node/57345