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Acoustic Complexity of vocal fish communities: a field and controlled validation
Get PDFThe Acoustic Complexity Index (ACI) is increasingly applied to the study of biodiversity in aquatic habitats. However, it remains unknown which types of acoustic information are highlighted by this index in underwater environments. This study explored the robustness of the ACI to fine variations in fish sound abundance (i.e. number of sounds) and sound diversity (i.e. number of sound types) in field recordings and controlled experiments. The ACI was found to be sensitive to variations in both sound abundance and sound diversity, making it difficult to discern between these variables. Furthermore, the ACI was strongly dependent on the settings used for its calculation (i.e. frequency and temporal resolution of the ACI algorithm, amplitude filter). Care should thus be taken when comparing ACI absolute values between studies, or between sites with site-specific characteristics (e.g. species diversity, fish vocal community composition). As the use of ecoacoustic indices presents a promising tool for the monitoring of vulnerable environments, methodological validations like those presented in this paper are of paramount importance in understanding which biologically important information can be gathered by applying acoustic indices to Passive Acoustic Monitoring data
Indications of dynamic effects on scaling relationships between channel sinuosity and vegetation patch size across a salt marsh platform
Get PDFSalt marshes are important coastal areas that consist of a vegetated intertidal marsh platform and a drainage network of tidal channels. How salt marshes and their drainage networks develop is not fully understood, but it has been shown that the biogeomorphic interactions and feedbacks between vegetation development and channel formation play an important role. We examined the relationships among tidal channel sinuosity, marsh elevation and roughness, vegetation type (pioneer, Elymus athericus or Phragmites australis) and patch size at different spatial scales using a high‐resolution vegetation map (derived from aerial photography) and lower‐resolution satellite imagery processed with linear spectral mixture analysis (LSMA). The patch size distribution in all vegetation types corresponded to a power law, suggesting the presence of self‐organizational processes. While small vegetation patches are more dominant in pioneer vegetation, they were present in all vegetation types. The largest patch size is restricted to E. athericus. We observed an inverse logarithmic relationship between channel sinuosity and vegetation patch size in all vegetation types. The fact that this relationship is observed in both pioneer and later successional stages suggests that after the establishment of a drainage network in the dynamic pioneer stages of salt marsh development, the later stages of salt marsh succession largely inherit the meandering pattern of the early successional stages. Our study confirms recent evidence that no significant changes in the specific features of tidal channel networks (e.g., channel width, drainage density and efficiency) take place during the later stages of salt marsh development
On the implementation of an integrated platform for phytoplankton automated observation in European coastal waters: a JERICONEXT (H2020) Joint Research Action
Get PDFOp speurtocht met de metaaldetector - een onderbenutte informatiebron in de archeologie, toegepast op vroegmiddeleeuws Kust-Vlaanderen
Get PDFOp Vlaamse velden kom je ze al eens tegen: vrouwen of (meestal) mannen met een metaaldetector, begeesterd door de archeologische artefacten die ze hopen aan te treffen in de ploeglaag. Velen van hen beoefenen de hobby al jaren, en legden op die tijd aanzienlijke collecties aan. Lange tijd was hobbymetaaldetectie in Vlaanderen, zoals in vele Europese landen, verboden. Archeologen beschouwden deze hobby als een vorm van plundering, en het contact tussen de erfgoedsector en de detectiegemeenschap verliep dan ook lange tijd stroef. Nu komt daar gelukkig verandering in. Met het in voege treden van het nieuwe decreet Onroerend erfgoed kunnen detectieliefhebbers sinds 1 april 2016 vrijelijk hun hobby beoefenen. En dat levert boeiende, nieuwe kennis op
WEATHER-MIC – How microplastic weathering changes its transport, fate and toxicity in the marine environment
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