SRCE: Level 3 linear fragmenting elements

The linear infrastructures taken into account in the analysis of the Regional Ecological Coherence Schema (SRCE) for the Pays de la Loire are essentially transport infrastructure, composed of road and rail networks. Several criteria make it possible to describe the fragmentary nature of this type of work: road traffic, width or number of tracks, track equipment: the presence of closure essentially. Linear infrastructures have been classified according to their fragmenting potential and an ecological disturbance zone has been associated to indicate disturbances generated in nearby natural and semi-natural environments. __Origin__ Sources: Daily traffic of all types of vehicles combined (2008, DREAL Pays de la Loire), Number of tracks per section (2008, DREAL Pays de la Loire, CETE), Rail traffic (2010, RFF), Presence of closure on the railway network (2010, RFF), Ensemble of the linear railways (IGN, BD TOPO), Large infrastructure projects (DREAL Pays de la Loire). Linear network prioritisation: The more widely discussed and documented “traffic density” criterion appears to be the main criterion for prioritising different classes of fragmentation. The criterion “number of tracks” was rejected as its own impact on the mortality of different species is poorly documented. The criterion “equipment” was used only for railways, as roads were not informed. Associated ecological disturbance zone: Once the linear was qualified, a buffer zone was associated to quantify its “fragment potential”. Ideally, the identification of areas of ecological disturbance associated with anthropogenic elements should be assessed according to the nature of nearby habitats. Given the complex nature of certain biodiversity reservoirs (associated with several sub-trames), and for the sake of simplification, the potential for disturbance has been qualified according to the nature of the structure. This “buffer band” allows the ecological disturbance associated with the structure to be represented surfacically, and thus to calculate the degradation status of biodiversity reservoirs. Level of fragmentation 3: Road traffic of the DREAL Pays de la Loire (in number of vehicles per day) providing moderate traffic links. __Partner organisations__ DREAL Pays de la Loire [See this page on geo.data.gouv.fr](https://geo.data.gouv.fr/fr/datasets/337529e9548295989eea316a71d34782d9e7f110)