A dramatic global rise in wildlife mortality due to vehicle collision has boosted a wide interest across disciplines to mitigate this impact through the installation of structures such as overpasses, underpasses, fences, etc. These structures can restore connectivity and improve population viability, even though research has found that some structures need to increase their effectiveness. So, it is more important than ever for optimal planning initiatives to be more precise, resilient, and adaptable enough to work for a wide range of species and taxa.

Underpasses are a useful tool to enable wildlife to move across landscapes with roads. Not all ground-dwelling species of wildlife will find underpasses to their liking, but many do. Underpasses are also not a panacea for impacts on wildlife. And we shouldn’t use their effectiveness as a justification to run highways through pristine areas. They’re a tool to minimise impacts of road projects that have wide community support.

Demand-controlled LED street lights are only fully illuminated when there is traffic and dimmed in the absence of traffic. In our study, dimming reduced the light on average by 35%. Effects of dimmed light on the abundances of nocturnal insects and bats were generally beneficial as fewer insects went into traps and fewer bat signals were recorded when the lights were dimmed.

We calculated that the effects of roads on the critically endangered western chimpanzee extends to an average of 17.2 km from major roads and 5.4 km from minor roads. Our results enable development planners, government regulators, project funders and conservationists to better avoid and mitigate road impacts on chimpanzees.

Conservation landscapes are often frequently visited by tourists wanting to interact with wildlife, which can also increase threatening processes such as wildlife-vehicle collisions. Understanding how roadkill rates change with increasing tourism, and wildlife abundances concurrently, could help to identify successful mitigation measures which could be implemented pre-emptively.

There are more than 1,400 species of bats worldwide and they play critically important roles in ecosystem health. We conducted an international systematic review and found that many species of bats are significantly impacted by barrier effects due to the presence of roads, by mortality due to collision with vehicles, and by habitat loss and decreased activity due to habitat alteration.

Hedgehogs are among the most common victims of roadkill across Europe and most European hedgehog species are in decline. We undertook a comprehensive literature review to identify the impacts of road mortality on the viability of European hedgehog populations, potential mitigation solutions, and remaining knowledge gaps.

On the megadiversity island of Sumatra, Indonesia, a mining corporation has gained government approval to construct a major, 88-kilometer-long road that would cut across the Harapan Rainforest, one of the last surviving tracts of lowland rainforest on the island. We use strategic land-use-planning methods to identify alternate routes for the road that have far lower environmental and economic costs than the road being currently planned.

We used custom-built cameras and image recognition software to evaluate the use and effectiveness of a tunnel and fence system for amphibians at a road mitigation site in England. Over four years, we found high rates of use of the tunnels, no roadkill, colonisation of newly-built ponds and a substantial increase in the population size of several species, including the nationally protected Great Crested Newt.

This study aimed to clarify the level of agreement between potential movement corridors and areas of high predicted road mortality in order to identify optimal locations for mitigation. We recommend considering both approaches in parallel.

Bird collisions with overhead powerlines is one of the most significant human causes of bird mortality worldwide, with estimates in the millions of birds killed annually and contributing to the decline of many species. We undertook a comprehensive literature review and identified the factors that increased bird collision risk with power lines, the existing mitigation measures, and remaining knowledge gaps.

A republished article from The Conversation. An analysis of the ecological effects of fencing on ecosystems around the world.

In order to reduce wildlife-vehicle collisions, is it better to use a few long, or many short, fences (FLOMS)? We devised an adaptive plan for prioritizing road sections for fencing, based on roadkill hotspots and coldspots, considering multiple scales and the FLOMS trade-off.

Many populations of amphibians are declining rapidly across Asia and road kill is a significant cause. In this project, we designed and tested a range of culverts to identify amphibian-friendly options to mitigate roadkill and barrier effects of roads.

To reduce wildlife mortality from train collisions, we invented a warning system that emits flashing lights and bell sounds prior to the arrival of a train. A test of this system showed that animals fled earlier from trains in the presence of warning signals.

Jaguars together with other neotropical species only used purpose-built wildlife underpasses under a highway in Mexico, even when ‘large enough’ drainage structures were available. Drainage structures may work as crossings for some species but can’t substitute proper wildlife underpasses.

The Hazel Dormouse is an arboreal mammal in Europe that are reluctant to cross at ground level. This study examines a bridge crossing structure, which shows its effectiveness for dormice in the UK.