Adam Gebb: Wildlife Road Crossings Are Essential for Creating Conservation Networks

Human development has fragmented most ecosystems into small, vulnerable patches, many of which are now under additional stress from rapid climate change. As a result, the essential migration pathways of countless species have been disrupted, contributing to a growing wave of extinctions.

"The very infrastructure that connects our communities is disconnecting wildlife," explains Adam Gebb in his paper Wildlife Road Crossings. A conservation strategist and environmental leader, Gebb is committed to addressing landscape connectivity challenges through collaboration with Indigenous and rural communities. He currently serves as Executive Director of the Andes Amazon Conservancy.

Expanding Infrastructure Cuts Off Wildlife from Critical Habitat

From rural byways to multi-lane highways, roads act as physical and ecological barriers—isolating wildlife populations, increasing mortality rates, and disrupting the movement of mammals, insects, and the plant communities they depend on. Plant migration is driven by rising temperatures, forest succession, and the shifting patterns of their insect pollinators. Insects, in turn, form the foundation of terrestrial ecosystems. They play critical roles in nutrient cycling, pollination, seed dispersal, and maintaining soil health. Insects also help regulate species populations and serve as a vital food source for countless animals, making their mobility and survival essential to overall ecosystem resilience.

Insect Decline Threatens Ecosystems and Agriculture

Over the past 40 years, insect populations have declined by an estimated 45% due to a range of environmental stressors, many of which also disrupt critical migratory cues. This alarming trend threatens ecosystem health and global agriculture. As climate change reshapes temperature and moisture patterns, insects' reduced ability to migrate and adapt poses a significant risk to humanity.

Wildlife Road Crossings Reconnect Isolated Habitats, Increasing Their Resilience

While wildlife migration bridges are effective in increasing connectivity for large mammals, they do not address the broader evolutionary dynamics of insects and plants. These structures recreate less than 1% of the landscape connectivity that once existed, leaving countless species at risk of decline or extinction. Furthermore, they are exceedingly costly. It's imperative to devise viable solutions for small towns and states in the US and around the world, which struggle to afford even basic infrastructure maintenance.

Wildlife Road Crossings (WRCs) are emerging as a critical yet underutilized tool for restoring habitat connectivity and slowing localized extinction, especially in rural communities. Wildlife bridges must be complemented by widespread WRCs to maintain the migration patterns that underpin resilient natural communities.

Many WRCs occur naturally or can be established with minimal intervention, making them a scalable and cost-effective solution for building conservation networks. These crossings allow a wide range of species—from mammals to pollinators—to move across fragmented, human-modified landscapes and access the resources they need to survive.

The Ideal Wildlife Road Crossing

According to Adam Gebb, for WRCs to be effective, they should have specific characteristics. Native forests should be maintained right up to the road on both sides to help the movement of mammals, insects, and plants. Mature trees can provide additional canopy connectivity for insects. Successful WRC networks should link diverse ecological communities to maintain higher long-term biodiversity.

Gebb recommends maintaining at least 500 meters of undeveloped habitat along either side of the road to minimize edge effects. Crossings as narrow as 50 meters can still be effective, but are more vulnerable. Signs help raise public awareness, and during peak migration, community volunteers are invaluable in assisting amphibians and reptiles as they cross.

Strategically located WRCs create the vital links required for conservation networks in a roaded world, helping to maintain biodiversity, support ecosystem services, and build long-term resilience in the face of environmental change. Investing in these crossings now is a practical and effective way to protect the natural systems that sustain us all.

About Adam Gebb

For over 30 years, Adam Gebb has led environmental research and advocacy at the intersection of community land use planning and wildlife migration. Since 2018, he has worked in close collaboration with Indigenous nations of the Ecuadorian Amazon to redefine landscape connectivity to include wildlife migration, human food sovereignty, and the protection of freshwater resources. His pioneering work is reshaping the face of conservation in the Andes-Amazon region.

Explore Gebb's insights in Wildlife Road Crossings to understand why these overlooked connections are essential to ecological resilience and the future of biodiversity conservation. Read the full paper here: https://open.substack.com/pub/adamgebb/p/wildlife-road-crossings-wrcs