Biology subjects

Authier, M.

Publications and source records attributed to Authier, M..

2 recordsLinked to original sources

bioRxiv2020

Prospective modelling of operational offshore windfarms on the distribution of marine megafauna in the southern North Sea

Intense development of Offshore Wind Farms (OFWs) has occurred in the North Sea with several more farms planned for the near future. These OFWs pose a threat to marine megafauna stressing the need to mitigate the impact of human activities. To help mitigating impacts, the Before After Gradient (BAG) design was proposed. We thus explored the use of the BAG method on megafauna sightings recorded at different distances from wind farms in the southern North Sea. We predicted intra-annual variability in species distribution, then correlated species distribution with the presence of operational OFWs and investigated the potential impact the operation of prospective OFWs may have on species distribution. Three patterns of intra-annual variability were predicted: species present most abundantly in spring, in winter or all year-round. We recommend that future OFW constructions be planned in summer and early fall to minimise impact on cetaceans and that offshore areas off northern France and Belgium be avoided to minimise impact on seabirds. Our prospective analysis predicted an increased or a decreased density with the operation of prospective OFWs. Prospective approaches, using e.g. a BAG design, are paramount to inform species conservation as they can forecast the likely responses of megafauna to anthropogenic disturbances.

ecology↗

bioRxiv2019

Combining single- and repeated-visit occupancy models to make the best of monitoring surveys

A major challenge in statistical ecology consists of integrating knowledge from different datasets to produce robust ecological indicators. To estimate species distribution, occupancy models are a flexible framework that can accommodate several datasets obtained from different sampling methods. However, repeating visits at sampling sites is a prerequisite for using standard occupancy models. Occupancy models were recently developed to analyze detection/non-detection data collected during a single visit. To date, single-visit occupancy models have never been used to integrate several different datasets. Here, we showcase an approach that combines two datasets into an integrated single-visit occupancy model. As a case study, we estimated the distribution of Bottlenose dolphins (Tursiops truncatus) over the North-western Mediterranean Sea by combining 24,624 km of aerial surveys and 21,464 km of at-sea monitoring. We compared the outputs of single- vs. repeated-visit occupancy models into integrated occupancy models. Integrated models allowed a better sampling coverage of species home-range, which provided a better precision for occupancy estimates than occupancy models using datasets in isolation. Overall, single- and repeated-visit integrated occupancy models produced similar inference about the distribution of bottlenose dolphins. We suggest that single-visit occupancy models open promising perspectives for the use of existing ecological datasets.

ecology↗