Septentrion Environnement strongly believes in the importance of sharing knowledge. Committed to an Open Science approach, the majority of our works are published under a Creative Common BY 4.0 license: they can be downloaded, shared and adapted freely, provided that the original work is cited.
2022
Internship and PhD dissertations
This M1 internship report focuses on the analysis of the data collected by voluntary divers in the framework of the participatory science program “CIGESMED for divers”. After 6 years of application of the program along French Mediterranean coasts , data exploitability and potential improvements applicable to the observation protocol are discussed here.
2021
Internship and PhD dissertations
2021
Internship and PhD dissertations
In the context of current global change, sessile marine organisms are among the most impacted. The increasingly frequent episodes of thermal anomalies are particularly fatal for Corallium rubrum and Paramuricea clavata. From a conservation perspective, understanding the life cycle of these species is a major research topic. Estimation of the growth of these species and their response to transplantation have been carried out several times using different methods. Here, it was shown that the transplantation of C. rubrum and P. clavata using two-component epoxy putty offers suitable results in terms of survival of the transplants and that photogrammetry allows robust measurement of population descriptors of these species.
2019
Internship and PhD dissertations
Following the creation of the Calanques National Park in 2012, which introduced no-take zones, a baseline state of red coral (Corallium rubrum) populations was investigated on 10 sites, giving the first insights; in 2018 this study was reiterated. During the course of this internship, using photogrammetry techniques, the comparison between the 2013 and 2018 photo series revealed a significant effect of the interaction between zoning and year on the population descriptors considered, reflecting the appearance of a reserve effect in 2018 which was absent in 2013. Populations in no-take zones show a maximum size and a basal diameter larger than outside populations, demonstrating efficiency of the Calanques National Park
management measures in maintaining its red coral populations. Among the sites studied, this study also allowed to quantify the impact of a harvesting episode in Castelvieil as well as an exceptional growth in South Riou. Finally, it provides elements for management strategies that can be implemented to conserve red coral populations and more generally the long-lived marine species across the Mediterranean.
2016
Internship and PhD dissertations
The protection of the marine environment is increasingly integrated into public policies. The research programs, coordinated by scientists, are part of multi-scale institutional strategies and action plans in favor of marine biodiversity. However, the temporality of the actions carried out by all of these stakeholders is not identical and makes the use of field data sometimes not optimized. To move towards sustainable management, managers express a need for data whose format is homogeneous in time and space. On the other hand, recreational divers show a real interest in contributing to the protection of the marine environment, by collecting field data. POLARIS is a pilot project that positions itself as a technical and educational platform dedicated to the acquisition of field data for the knowledge and protection of the marine environment.
2012
Internship and PhD dissertations
The aim of this PhD was to better understand the characteristics and consequences of the transformations of Mediterranean infralittoral fish (Teleostei) nursery habitats, in order to gather useful knowledge for management of coastal areas in Mediterranean regions. Among the seascape mosaic, Cystoseira forests, a threatened macrophytes-formed habitat, displayed higher densities of fish juveniles (notably Labridae and Serranidae) than alternate states of rocky bottoms photophilic biocenosis, namely Dictyotales and Sphacelariales bushland and barren grounds. The relatively higher nursery value of Cystoseira forests (for Symphodus spp.) and of the shallow heterogeneous blocks and pebbles gentle slopes (for Diplodus spp.) where consistent through space at both local (1 km) and regional (20 km) scales, although juvenile densities varied significantly in space between sites for a given nursery habitat. The spatial variability of juvenile densities, both across various habitats and among Cystoseira forests was notably related to habitat tri-dimensional structure (heterogeneity and complexity); this structure provided refuges for juveniles and influenced namely predation success of their predators. This experimental and observational study demonstrated that habitat human-induced transformations, such as forest fragmentation and cover density decrease critically reduced their nursery value for coastal fishes. Our results suggest that the fish productivity virtually lost in areas where forests have already disappeared may be considerable. Finally, these essential habitats were scarce and not homogenously distributed along the coast: in the case of Diplodus spp., less than 10% of the studied rocky shores displayed nursery habitats.
Furthermore, the present work highlighted that the current design of management measures did not take into account the spatial distribution of these nursery habitats and the connectivity between all essential habitats at each life stages. A conceptual scheme aiming at adopting such “seascape approach” is proposed, in order to better target conservation efforts and guarantee coastal fish assemblages’ replenishment.
