Glossary of Key Terms

This glossary provides definitions for key terms used throughout the Biodiversity & Infrastructure Handbook, supporting consistent understanding across disciplines such as ecology, engineering, transport planning and policy.

Definitions are based on legal texts, reference documents and expert agreement, and cover essential concepts related to wildlife and traffic, habitat fragmentation, ecological connectivity, mitigation measures, monitoring, green infrastructure and nature-based solutions. The glossary helps practitioners interpret technical guidance and supports clear communication between stakeholders involved in infrastructure projects.

If you are new to transport ecology or working in a multi-disciplinary team, the glossary can serve as a quick reference before exploring detailed handbook chapters. Terms will continue to evolve as the handbook is updated through expert collaboration and user feedback.

Last update: October 2023 – How to cite

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There are currently 3 names in this directory beginning with the letter U.
Underpass
Structure (including its access points) which allows one linear transport infrastructure to pass under another. See also 'Wildlife underpass'.
Unpaved road
A road not covered by any artificial material such as asphalt or concrete. See also 'Paved road'.
Upgrading
Improvement or rehabilitation of the infrastructure network, during which measures are generally implemented to reduce environmental impacts before upgrading such as storm basins, or acoustic screens. It may also include measures to reduce barrier effect and wildlife mortality. See also: 'Defragmentation'.