How can rail support biodiversity?

The potential to use rail schemes to minimise the impacts of climate change and improve ecological resilience remains untapped. Currently, the construction and operation of linear infrastructure is still associated with negative impacts that extend beyond the habitat loss within the construction footprint. These include: disruption or destruction of ecosystems and their function; the creation of a barrier to species movement; direct mortality of fauna (e.g. from train strike); ecosystem degradation through disturbance (noise, human activity); and permanent lighting impacting photosensitive species’ movements and migration.

Although some impacts are unavoidable, new and upgraded railways can be designed to create valuable green corridors that help to restore ecosystem function (in line with the targets of SDG 15: Life on land) and provide net gains for biodiversity33 – all of which ultimately benefits society.

The positioning of the railway route corridor within the wider landscape is important in achieving these targets. Each time a railway crosses a degraded river catchment, there is an opportunity to provide habitat restoration that will directly contribute to downstream flood resilience. The improvements can be expanded by creating temporary water storage to capture water for use during periods of drought and provide value to biodiversity. These interventions come at a price, but they reduce the need for costly infrastructure required to protect individual assets downstream. They also provide significant benefits to society as a whole, which must be acknowledged and accounted for at the start of a project.

The creation of biodiverse rail verges can provide long-standing habitat linkages between fragmented habitats that have been damaged by human activities such as urban and agricultural intensification. This facilitates fauna and flora movements, including microbes and invertebrates, and can improve ecological resilience on a landscape scale. Wildlife crossings above or below the route help to reduce the rail corridor’s barrier effect and crossing points can be linked to other infrastructure associated with the railway. For instance, vegetated bridges facilitate safe crossing points, provided they are of sufficient size and habitat quality for the targeted species.

Rail schemes can positively impact the environment, without putting an additional strain on stretched budgets. The traditional approach – compensation for damage caused – needs to be challenged. We need to start recognising how restoring nature can help to create long-term resilience of the transport infrastructure. The railways of the future may actually result in reforestation, instead of deforestation. Early engagement with ecological experts will help to determine the most cost-effective and beneficial solutions.