Talk Amphibians and land transport infrastructure: from land management to ecological engineering

Linear land transport infrastructure can impact amphibians in different ways, either directly (loss and fragmentation of habitat, crushing,) or indirectly (habitat degradation by chemical or noise pollution, changing landscapes, reduction of genetic diversity).

This presentation details the services provided to humans by amphibians species, who are nevertheless under threats. It describes the main biological traits necessary for the implementation of effective protection measures in new project impact studies or modernization of existing infrastructure. It is illustrated by the French experience on amphibian crossings, dedicated to reduce the impact of ground transportation networks (road and rail) on these protected species.

Often invisible to motorists, hundreds of amphibian crossings have been built over the past three decades in France. Others are in the planning stage. These infrastructures, which result from cheap, ingenious DIY (do it yourself) by self-motivated volunteers, or cost sometimes hundreds of thousands of euros while involving the state, different public corporation and nature protection associations, belong to the history of road ecology. They have been through considerable changes, from specific two-way "amphibian" tunnels, to one way and small wildlife passages used by a greater number of species. Many questions still arise from the elaboration of new projects, especially when it comes to the modernization of existing roads, or the assessment of the effectiveness of these structures. This presentation aims at shedding a new light on some issues that have found no clear answers and solutions so far.

The comparative analysis of 30 years of experience and study questions conservation ecologists and road engineers : What are the amphibian species that benefit from these environmental engineering actions? How does the system affect population viability ? Will it systematically be followed up, and if so, what are the nature and duration of such follow-up? What are the studies able to assess the effectiveness of these infrastructures (tunnels, fences and rescues) ? Are there any functional differences depending on the size and shape of the crossings devices? What are the possibilities for innovation and the opportunities offered by the use synthetic materials, recyclable or not? What is the social acceptance of these devices, which are sometimes considerably costly? Thanks to the collaboration between road managers and scientific partners working on these issues (in behavioral ecology and / or population dynamics), are we now able to offer reproducible, effective and affordable solutions to respond to situations emerging from new projects or resulting from the modernization of existing infrastructure?

amphibians, land transport infrastructure, road mortality, road ecology, mitigation measures, toad tunnel, ecopassage, effectiveness assessment,