River dams are often criticised for blocking fish migration, but they can also create major obstacles for one of the world's largest amphibians. Rather than removing every small dam standing in the way, researchers in Japan tested an unusual alternative: specially designed ladderways that allow giant salamanders to climb over river barriers.
The approach, described in a 2016 study published in the International Journal of River Basin Management, showed that carefully designed "salamander ladders" could help reconnect fragmented river habitats without dismantling existing infrastructure. The findings suggest that relatively simple engineering solutions may support wildlife conservation where dam removal is not practical.
Why river dams are a problem for Japanese giant salamanders
The Japanese giant salamander (Andrias japonicus) is among the largest amphibians on Earth, with some individuals growing well over a metre in length. The species is found only in Japan and has been designated a Special Natural Monument because of its ecological and cultural importance.
