Current state of road ecology in Japan


Recently, "Roadd ecology" has become widespread worldwide. However its term and concept are not well known in Japan despite there are many conservative constructions and road business operators have given carefull considerations for wildlife. For future development of road ecology in Japan, it is necessary to clearly grasp the information concerning road and wildlife. Our aim of this research is to understand current state and suggest future problems of road ecology in Japan.


The data base "CiNii" operated by National Institute of Informatics was used for searching domestic research papers relating to road ecology. In 2013, we selected following six keywords concerning wildlife and traffic (excluding traffics by ship and plane): "Road kill", "Eco-road" which was term coined to denote the road giving consideration for environment, "Habitat + Conservation measures", "Train + Wildlife", and "Rail kill". We retrieved papers with above keywords and identified the tendency of subject matter, issue year, target species, and study site.


We found a total of 136 papers published from 1981 to 2012. There were 62 papers hits for " Eco-road", 31 for "Road kill", 28 for "Road + Conservation measures", 15 for "Train + Wildlife", three for "Habitat fragmentation", and no hits for "Rail kill".The number of issued papers has tended to rise in recent years. Only eight papers were published in second decade; 1992-2002 and in the third decade; 2003-2012. As for target species of research, all papers were distributed into eleven items. There were most hits for large-sized mammal (19), and plant (15) and insect (7) follow it. Studies were mostly conducted in Hokkaido (25 papers) and limited in several regions.


It was thought that the reason why "Eco-road" had most hits was the word used widely in road construction and conservation without relation to target species. Keywords concerning train had few papers however study of train and wildlife will be increased because many collisions with large-sized mammal have been found on newspaper in recently. The number of paper published has increased 10 times in several decades. We considered that enhancement of environmental preservation consideration of road business not only newly built road but also road widening affected increasing of number of study and paper published. As for the target species of the study, it might be a reason that countermeasures for road kills have been improved since magnitude of the damage by collision with large-sized mammals as deer has been well known. For the study area, the Hokkaido Development Engeneering Center holds workshop on the theme "wildlife and traffic" every year in Hokkaido and provide a platform for researchers of unique countermeasures (conservation for flying squirrels, bats, and crayfish). In conclusion, it is needed that more information about wildlife and traffic/road will be published and collected through various region for popularization of road ecology and maintaining a good relationship between human and wildlife in Japan.

Japan; published year; road ecology; target region; target species