Creating Wildlife Corridors: Using existing infrastructure to improve wildlife connectivity across the strategic road network

Rethinking roads to increase biodiversity and improve wildlife connectivity

Habitat connectivity allows wildlife populations to move freely across the landscape to find food, mates, and nesting opportunities. This uninterrupted movement is essential for the genetic diversity, population stability, and resilience of our ecosystems. However, human development, such as the road network, has become a significant barrier to connectivity, leading to habitat fragmentation. This not only creates a barrier to the movement of wildlife but also increases the frequency of wildlife-vehicle collisions, posing risks to both animals and humans. Addressing these challenges requires innovative solutions that utilise the numerous existing overpasses and underpasses across the strategic road network and designing new projects with wildlife in mind.

The Impact of Roads on Habitat Fragmentation

In the UK, roads are one of the most prevalent sources of habitat fragmentation. They separate ecosystems into smaller, isolated patches, which can severely limit the movement of wildlife. This fragmentation has several negative impacts:

1. Restricted Gene Flow: Isolated populations may suffer from inbreeding and reduced genetic diversity, making them more vulnerable to diseases and environmental changes.
2. Increased Mortality: Animals attempting to cross roads are often struck by vehicles, leading to significant wildlife mortality rates and posing safety hazards for drivers.
3. Pollution: The presence of roads can lead to pollution, noise, and light disturbances, further degrading the quality of the habitat.

Utilising Existing Infrastructure for Wildlife Crossings

Existing infrastructure such as overpasses and underpasses can be adapted to support wildlife crossings, offering practical and cost-effective solutions that contribute to mitigating the impacts of roads. For example:

1. Retrofitting Culverts: Many existing underbridges can be modified to accommodate wildlife by adding natural substrates like soil and vegetation, implementing green walls, and installing mammal shelves and dormice bridges where culverts carry a watercourse under the road. These modifications can provide safe passage for a range of species including amphibians, reptiles, mammals, and insects.
2. Enhancing Bridges: Overbridges can be retrofitted with wildlife pathways such as strips of vegetation that connect the habitat on both sides, planters, green walls, manmade arboreal structures, and even complete the greening of disused bridges.

Designing New Wildlife-Friendly Infrastructure

Incorporating wildlife-friendly features into new infrastructure projects from the outset can significantly enhance habitat connectivity and reduce the environmental impacts of new projects. Key strategies include:

1. Integrating Wildlife Corridors: During the planning stages, identifying and preserving natural wildlife corridors can ensure that animals have safe passage across the landscape. This might involve modifying the design of crossing structures to include wildlife-friendly features such as mammal shelves and planting of native species at a fraction of the cost of large-scale green bridges.
2. Smart Road Design: Incorporating features such as wildlife detection systems in areas with high wildlife-vehicle collisions, reduced speed zones in high-traffic areas, and adequate signage that alerts drivers to wildlife on the road and reduces the likelihood of collisions.

Maintaining habitat connectivity is crucial for the health and sustainability of wildlife populations. As human development continues to expand, innovative solutions are needed to mitigate the impacts of roads and other infrastructure on our ecosystems. By retrofitting existing structures like bridges and culverts, and incorporating wildlife-friendly designs into new projects, we can create a balance between human needs and wildlife conservation.

The retrofitting of existing structures is more cost-effective than building new purpose-built green bridges. This means that a greater number of crossings can be implemented for the same price, increasing the likelihood of wildlife using these pathways and connecting a larger area of habitat.

By utilising existing infrastructure, the strategic road network can play a pivotal role in reducing fragmentation across the UK, protecting biodiversity, and improving road safety for people.

Animex is dedicated to reducing conflicts between biodiversity and transportation networks by implementing innovative and cost-effective solutions. We have worked on many projects globally that have led to the development of various products, best practice guidance and protocols.

Some of our most notable projects include:

• Developing and installing the only scientifically tested dormouse bridge designs across the UK.
• Identifying existing infrastructure suitable for improving wildlife connectivity in Devon and suggesting enhancements as part of the Network for Nature scheme.
• TRAX, a roadkill reporting app developed in collaboration with The Road Lab at Cardiff University.
• The Habitat Highway, an instant green modular bridge product designed to enable easy adaptation of existing infrastructure to enhance wildlife connectivity and increase biodiversity on the network.

Through the innovative adaptation of existing infrastructure and the integration of wildlife-friendly features in new developments, we have the power to reduce the adverse impacts of roads on our ecosystems and create a landscape that serves both wildlife and people. These efforts do not only enhance biodiversity but also make our road networks safer and more sustainable.