Although much focus has been on the passage of fish, many other organisms are affected by culverts and other barriers designed without consideration for natural processes and AOP, including small aquatic organisms such as salamanders (USFS 2006, Schrag 2003). In general, a culvert that is impassable for fish may also pose a barrier to aquatic organisms including those with weaker swimming abilities.
This document specifically addresses improvements in AOP. However, planners, ecologists, biologists, and engineers recognize that expanding wildlife connectivity and improving climate resilience, as well as reducing infrastructure repair and maintenance costs, overlap with improvements to AOP. Therefore, this guide also acknowledges these goals.