Summaries of the eight phone interviews are presented below, while the full write-up of each interview can be found in Appendix A. Some issues that were common to all interviews are that cost was reported to be a prohibitive factor in building bigger and better crossings. Land acquisition and topography issues were also found to be common limiting factors in using the desired crossing technique. Agency collaboration was mentioned as an important element by all states, especially during the identification of hotspots and sensitive areas. Pre-construction monitoring was also found to be important in order to establish a baseline for monitoring. In most cases it was found that post-construction monitoring is not usually required and is therefore lacking, unless it is a condition of a permit (associated with a wetland or in the case of aquatics). It was also found that most states do not have separate cost tracking methods for the cost of maintaining crossing structures and fencing.
Literature review conducted throughout this research revealed that the issue of crossings for aquatic species has been rather well addressed through guidance and regulations. Some states indicated during the interviews that while semi-aquatic species most likely benefit from some of the practices applied to fish, non-fish species have not been the main focus in constructing these passages.
Specific to terrestrial species, most states noted that safety is very closely linked with minimizing terrestrial habitat fragmentation. If the minimization of habitat fragmentation can be shown to increase safety to motorists on the roads, the dedication of time, effort and funding to create adequate terrestrial passages is more likely to be widely accepted.
Terrestrial
Arizona Department of Transportation developed a process to address habitat fragmentation with its Wildlife Linkages program. The program included a Workgroup of nine public agencies and nonprofit organizations with the mission "To identify and promote wildlife habitat connectivity using a collaborative, science based effort to provide safe passage for people and wildlife". Arizona radio tagged hundreds of terrestrial species, including desert tortoise, and monitors their movements in order to identify hot spots both before and after construction of highways in order to determine success based on similar animal movements. Engineers at ADOT understand that each species reacts differently and that crossings are designed for different purposes. While the overall purpose of a crossing is to minimize disruption of habitat connectivity, it has been found that fencing and undercrossing provide the greatest ecological benefit to dollar cost, while also considering safety of motorists.
Florida has a wide variety of terrestrial species to consider in its program, from panthers to crocodiles, while also dealing with the obstacle of constructing crossings at sea level and frequently in wetlands. Fencing has been found to be beneficial, along with underpasses where practical. Florida has also been using Roadside Animal Detection System (RADS) which involves a sensor that activates a notification system to alert drivers when a panther or other large animal steps into the right of way. Florida also uses DNA studies and radio collaring in studying animal populations. Success is determined by whether the target species is using the crossing, the effectiveness of which is monitored by using motion sensor cameras. Success can also be measured by whether there was a reduction in roadkill in the area of the feature.
In contrast to growing states like Arizona and Florida, the Vermont Agency of Transportation (VTrans) has taken a different approach. Vermont has decided to focus on its existing infrastructure, rather than building new roads, via its "Road to Affordability" initiative. VTrans has developed a GIS model for habitat linkage so that they can assess their existing facilities and the few small projects that they do have that involve building new roadways. VTrans advocates for the use of longer and oversized bridge spans when doing bridge replacements. Since Vermont's few highways were built in the 1950's and 60's, wildlife was not monitored at that time to provide a baseline. However, for those crossings which do have baseline data, VTrans uses remote and digital infrared cameras, track beds/pads, visual monitoring, tagging and recapture.
Idaho is in the process of finishing up a very large crossing project, funded by stimulus dollars, which may be the first officially monitored project by the Transportation Department. This project will facilitate wildlife crossing for elk and deer in an area that has been identified as a safety concern due to the high number of collisions between motorists and wildlife. Idaho has also identified linkages and wildlife-vehicle collision locations which are being incorporated into a database. The practice of building bridges and culverts wider to accommodate passage has been found to be the technique that provides the greatest ecological benefit to dollar cost.
Aquatic (Non-Fish)
California's aquatic passages are designed in accordance with California Senate Bill 857, which amended California Fish and Game Code in 2005 to incorporate specific provisions regarding Caltrans' progress in removing barriers to fish passage, superseding the management of non-fish aquatics. However, anadromous fish and other aquatic species that use the same habitat such as amphibians and reptiles will benefit from some of the practices in California. Common practices include the use of culvert baffles, fish ladders and bridges instead of culverts. Caltrans has a Wildlife Crossing Guidance Manual and wildlife crossing website that provides methods for assessing proposed projects that focus on aquatic and semi-aquatic species permeability. Sites are monitored if required following an established mitigation and monitoring plan.
Since 2005, Connecticut DOT (ConnDOT) has incorporated new U.S. Army Corps of Engineers (ACOE) specific culvert crossing criteria into design of both new and replacement culverts. Channel work and rock work, including rock weirs and veins which incorporate natural streambed material back into the environment, have been found to be the most effective practices providing the greatest ecological benefit to dollar cost. Approximately 1/3 of ConnDOT projects involve the use of in-stream rock weirs or veins for bank or channel stabilization which also adds habitat value. While trout seem to benefit the most from these practices, any species including invertebrates that can utilize the structures will and do benefit. The gradation of natural material creates natural crevices for invertebrates to use. Monitoring is conducted if required by a permit.
For Georgia DOT (GDOT), the most commonly used aquatic habitat sensitive design features are a result of the US ACE (Savannah District) Regional Conditions which require GDOT to look at channel spanning using bridges as part of permit review process. GDOT has found that bridging is the technique that provides the greatest ecological benefit to dollar cost. Generally bridges benefit most species that Georgia deals with including trout, federally protected darters, freshwater mussels, flatwater salamander, bog turtle, and terrapin. But while bridging may be most beneficial it is also the most costly technique. No formal monitoring is performed.
Minnesota DOT's (MnDOT) liaison to the Department of Natural Resources (DNR) reported that MnDOT uses passage benches in bridges and finds them to be very beneficial, even for the local fisherman. They have been successful in showing that wildlife passages can benefit not only wildlife, but humans as well; in this case fishermen have used the benches for safe crossing under bridges. They have also had success with recessed culverts and have the state universities studying both the benches and the culverts to help MnDOT revise their design manual. MnDOT also has a detailed Best Practices Manual, developed with DNR, which directs the early agency coordination process. MnDOT's creation of the DNR-DOT liaison position can also be credited with promoting a successful agency-department relationship and coordination process.
Go to B. Screener Survey for Habitat Fragmentation Avoidance and Compensation