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Contact Information

Joseph A. Burns CWB
National Transportation Ecology Program Leader
Watershed, Fish, Wildlife, Air, Rare Plants
1400 Independance Ave SW - MS1121
Washington, D.C. 20250-1121
(202) 205-0919

Sandra Jacobson
Wildlife Biologist
USDA Forest Service
Pacific Southwest Research Station
(541) 678-5240


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How to Use the Glossary

One of the most difficult things biologists face when beginning to work on a highway development project is the daunting new terminology. Sometimes the terms appear to be easy enough but the subtleties are important. Compare the meaning of the terms ‘culvert’ or ‘permeability’ among a group of biologists and engineers: they are decidedly different.

The Wildlife Crossings Toolkit helps bridge gaps in understanding. The tools in this section define and sometimes graphically depict common terms used by engineers and transportation departments on highway projects.

Glossary of Terms

The glossary will be useful for biologists and engineers. Some terms are illustrated.

Common Types of Wildlife Crossing Structures (Terminology)

This section graphically depicts several major types of wildlife crossing structures. It is not a recommendation (for example, one way gates are NOT recommended but are still commonly used).

Terrestrial Wildlife Crossing Structure Types (by Function)

Animals of different species perceive infrastructure elements like enclosed culverts or open bridges very differently. This section provides a handy way of synthesizing some of the ways that animals perceive infrastructure elements. An easy way to look at this is that many animals will tend to be intimidated by an unfamiliar element (such as an enclosed culvert) based on their anti-predator adaptations. So the types of structures that animals are most likely to feel comfortable in using tend to work with their anti-predator adaptations rather than against them.

An example might be small nocturnal species that use cover to hide from predators; these species tend to adapt to small enclosed culverts readily. Contrast this with those species, such as deer, that use their vision and hearing to detect predators and their swift running abilities to avoid them; these species tend to prefer structures with high visibility and minimal obstructions to escape.

Page Last Modified: February 18, 2014

Additional Information

Want a quick primer on how to describe a wildlife crossing structure? Here’s what the International Conference on Ecology and Transportation recommend for describing structures and some other common road ecology terms.

Proposed Recommended Terminology for ICOET2011 Presentations, Papers and Posters (pdf)