IENE 2016

Development of “techniques for environmentally harmonious coexistence” is essential for achieving conservation of biodiversity while human activities obstruct global environment.

We have studied and built bridges that arboreal animals could use to pass over roads since 1988. We built a dormouse bridge over a toll road in Yamanashi Prefecture in 1998. The bridge also serves as a traffic signal. To make it easy for dormice to pass, we incorporated the following measures into the bridge structure: (1) a metal net enclosing the bridge to keep away natural enemies, (2) plates on the bridge floor to shield the bridge from car light at night, (3) ivy and branches placed in the bridge in order for dormice to move easily inside, (4) nest boxes as shelters, (5) approaches from woods to branches for access to the bridge, and (6) trees planted around both ends of the bridge for dormice to use as feed and nest materials. We found that dormice made nests inside the bridge and crossed over the road, squirrels also used the bridge to cross and Japanese wood mice and Japanese great tits made nests.

To achieve environmental conservation, it is essential to “popularize” means that can be used globally. Hence, we studied and developed low-cost and simply designed “animal pathways” (hereafter “pathway”) that arboreal animals can utilise easily.

We studied pathway materials in 2004 to determine whether dormice would walk over noncorrosive, man-made wires and what an appropriate wire diameter would be. We found a diameter of six millimeters optimal.

We studied pathway structure again in 2005. A triangular model made of wire was placed in a large cage accommodating dormice to observe how the dormice used the model. An aluminum roof was also provided to prevent icicle development. The dormice used the model.

We built an improved animal pathway over a city road in Hokuto City on 2007. The pathway included the following measures: (1) shelters, (2) an aluminum roof to keep the bridge from snow, (3) space for squirrels, (4) a rope for dormice, which walk on the downside, (5) cider bark wrappings around utility poles, (6) video cameras for monitoring. Dormice, wood mice, squirrels, martens used. The arboreal animals used the pathway 1510 times in 2670 hours (about 111 days). Because this is the first pathway of its kind for arboreal animals, there is no similar usage data available for comparison. Japan now has a total of 6 pathways, the fourth of which is also used by Japanese flying squirrel used another. This evidence showed that most Japanese arboreal mammals used pathways.