Use of linear transportation infrastructure rights-of-way as an ecological shelter: National asset estimate and stakeholder involvement

For a number of years, the rights-of-way (ROW) of several types of linear transportation infrastructure (LTI), such as roads, railways, waterways and power lines, have been regarded as possible shelter for biodiversity, notably local flora and entomofauna. For developing an informed general management policy of such an opportunity for species conservation and landscape connectivity, a fundamental prerequisite is to be aware of the ecological shelter potential available within LTI rights-of-way on a national scale. By considering the primary operating constraints of LTIs and their geometric characteristics, a GIS-based method was designed to approximate the linear extent and surface area of potential ecological shelter (PES), i.e. where actions could be implemented to provide sustainable shelter focused on local flora and entomofauna. At the scale of Metropolitan France, the minimum total surface area of PES amounts to 2,026 km 2 ; and its network spans over 88,094 km (39% power lines, 34% railways, 18% roads and 9% waterways). The State is the primary landowner of PES along operated networks (particularly railways) however over half of the assets (53.8%) fall under the responsibility of local authorities, concessionary companies and private landowners (notably power lines). These findings highlight the necessary involvement of State together with LTI operators, local stakeholders and landowners through partnerships aiming to implement the ecological shelter function of rights-of-way.