Abstract
Construction of new Linear Transport Infrastructure LTI (roads, motorways, railways) leads to habitat destruction and may constitute areas of risk (mortality) and/or restrict the movement of species in surrounding habitats. Amphibians are strongly affected by these effects. Recent projects have implemented impact mitigation measures to improve the ecological transparency of these structures using the sequence “Avoid Reduce Compensate (ARC)”. During the construction of a new High Speed Railway “Bretagne–Pays de la Loire HSR” in North-West France inaugurated in 2017, measures under the ARC sequence have been implemented. This thesis aims to evaluate measures of the ARC sequence that would allow amphibian communities to carry out the movements needed for population functioning (seasonal migration and dispersal). It was carried out as part of the HSR environmental observatory (CIFRE EPHE-EGIS contract in partnership with EIFFAGE). The thesis is based on two approaches: (1) monitoring of movements by Capture-Marking-Recapture conducted in five areas including reduction measures (installation of a tunnel under the high-speed line) and compensation measures (creation of new ponds) for three newt species (marbled newt Triturus marmoratus, great crested newt Triturus cristatus and alpine newt Ichthyosaura alpestris). The recaptures of individually marked animals reveal exchanges between ponds located on either side of the high-speed line (use of tunnels) and colonisation of new breeding sites. (2) Homing experiments to study tunnel crossing behaviour. RFID antennas placed in three tunnels (1x1m) and of variable length (from 18.5 to 40 m) made it possible to detect the movements of individuals tagged with PIT-tags (spiny toad Bufo spinosus, I. alpestris, T. marmoratus, T. cristatus, water frogs of the Pelophylax lessonae - P. kl. esculentus system), agile frog Rana dalmatina and fire salamander Salamandra salamandra). A great inter-individual and specific variability of movements is observed, and varies according to the length of the tunnels. Acoustic enrichment (Broadcasting of amphibian calls in the tunnel) improves the movements (rate and speed crossing, distances travelled) of Pelophylax and T. cristatus. The thesis shows the need for a significant effort (number of marked animals) to show the presence of (rare) exchanges between breeding sites, and the use of tunnels and ponds as mitigation measures. The development of a method for evaluating movements in tunnels (RFID marks and antennas) will make it possible to test different factors (lengths, substrates, etc.) to improve their use and effectiveness. Acoustic enrichment appears to be a promising method to complement the implementation of small wildlife passages.