IENE 2016

Large-scale Transportation Infrastructures (LTIs) influence the biological functioning of ecosystems by modifying gene flow across landscapes. LTIs can have different effects depending on the type of infrastructure, species under study and the landscape structure.

Most studies estimate the effects of one single LTI because measuring the real impact of several LTIs is hard to achieve (cumulative effects), especially when several species are followed.

Recently, thanks to the development of landscape ecology and the growth of computing possibilities, there is a multiplication of modeling tools which are very useful to quantify the effects of LTIs. However, most of these tools were neither confirmed with empirical data neither applied to LTIs issues.

In this context, the goal of our study is to compare the capacity of different modeling tools to evaluate correctly the effects of several LTIs on four common and abundant species with different mobility capacities (an amphibian, a snake, a butterfly and a ground beetle).

Five different cumulative LTIs parallel to each other were studied in a 240km² limestone Causse study site dominated by dry grasslands, forests and agricultural lands in the South-West of France. Species were monitored, throughout this landscape in 2015 and 2016. Empirical data were obtained with genetic tools (microsatellite primers) completed with mark-recapture studies.

Aims of the project will be presented as well as preliminary mark-recapture results for the butterfly Maniola jurtina and the amphibian Alytes obstetricans. The effects of LTIs on the functional connectivity of these species will be discussed.