Abstract | Vidence-based development of a commercial arboreal wildlife bridge to prevent habitat fragmentation and isolation

The ever-expanding global transport network has the potential to fragment and isolate habitats utilised by arboreal species. Evidence-based, effective mitigation is essential to maintain ecological connectivity in such situations. Although a number of ‘wildlife bridges’ have been installed to facilitate arboreal habitat connectivity, many are expensive and ineffective, highlighting the requirement for further research to determine affordable and reliable alternatives.

This presentation details the development of an affordable wildlife bridge with proven effectiveness in enabling arboreal species to travel through fragmented habitats. The design is based upon research undertaken in Japan and the UK, which confirmed the effectiveness of this unique design of arboreal crossing structure.

The Japanese study determined the most suitable bridge materials, structure and design to facilitate habitat connectivity across a highway for Glirulus japonicas. This design also proved effective for other arboreal species including Pteromys momonga, Sciurus lis, Apodemus argenteus and Martes melampus.

This success influenced a UK trial to assess whether this proven design could be effectively transferred into a European context. A bridge adapted from the original Japanese design was installed, connecting two areas of Muscardinus avellanarius habitat fragmented by a railway.

A combination of exclusion fencing and motion-activated cameras were installed to determine whether the species would utilise the bridge and, if so, whether a preference was demonstrated for crossing the bridge as opposed to crossing at ground level. M. avellanarius demonstrated a strong preference for crossing the habitat gap via the bridge, with bridge usage also exhibited by Sciurus vulgaris.

Following the proven effectiveness of the design Animex International, in collaboration with Highways England, People’s Trust for Endangered Species, municipal councils and Natural England, has developed a cost-effective, durable and Highways compliant structure for a wide range of construction mitigation projects.

The structure will ensure such projects provide ongoing arboreal habitat connectivity.

Bio | Sophie Hughes

Sophie Hughes holds a Bachelor of Science degree in Environmental Science from the University of Manchester, UK and a Master of Science degree in Biodiversity Conservation from Bournemouth University, UK. Sophie is a Consultant Ecologist and Wildlife Bridge Advisor with Animex International. Animex specialises in combining biological understanding and engineering insight to provide bespoke ecological mitigation solutions around the globe. Sophie has particular experience in the provision of ecological mitigation associated with development and infrastructure schemes. One of her main areas of work concerns the reduction in wildlife highway mortality whilst preventing associated habitat fragmentation.