Suivi à long terme du déplacement d’une espèce en danger critique d’extinction : la Grande Mulette Pseudunio auricularius (Spengler, 1793)

As part of the construction of the South Europe Atlantic High Speed Line (LGV SEA), a translocation of a population of the very rare giant pearl mussel Pseudunio auricularius (Spengler, 1793) was carried out in 2012. During this translocation, 63 individuals were translocated to two nearby localities, located upstream of the impacted site. The paper details the technical choices made and the translocation protocol used. The 10-year follow-up shows differences in mortality between age groups, but not between sites. The translocated juveniles did not suffer any loss of individuals, whereas the adults showed a steady decline until t+48 months. This decrease is not statistically different from the control site. Major changes in the functionality of one of the translocation sites were observed, leading to the implementation of restoration measures. In this respect, long-term monitoring must allow for the follow-up of the translocated individuals as well as the integrity of the control sites.