NCDOT Presentation Highlights

NCDOT Wildlife Crossings

Findings

• Monitoring suggests limited wildlife use of culverts and no bear use.
• Wildlife crossing behavior changes with time. Wildlife does not always cross where signed on the road.
• Human use of wildlife crossings has potentially negatively impacted wildlife use.

Participant Discussion Highlights

Image Source: NCDOT

Black Bear Research Efforts

Researchers tracked and trapped bears for 8 years, collaring 61 bears, about half male to female. Specimens were monitored every 20 hours. Researchers recorded 5,500 locations and 40 den visits. 33 of the 61 collared bears were killed through road kill or legal/illegal harvest. Bears remaining in the sanctuary fared better.

Findings

• I-40 presents a definite barrier. Increased traffic volumes lead to fewer road crossings. This study showed 13 recorded crossings, all male and primarily nocturnal, though exact locations are unknown. Research never recorded a bear location within 300 meters of I-40.
• Black bears are intelligent adaptable omnivores and agencies need to accommodate this adaptability in their plans. Bears change behaviors to survive.
• Females incorporated a large stand of oak trees as part of their home range. This adaptation is motivated by the availability of acorns which dictates their movement and can lead to mortalities from crossing I-40.
• Culverts provide good bear crossings, but require larger box culverts.
• Roadway infrastructure consisting of bridges and tunneling rather than crossing and cutting have contributed to thriving populations of brown bear and wolves in populated areas in the Alps.
• Reasons bears are thriving in the area include:
  • Millions of acres of uninhabited forest land,
  • Matured forests producing acorns,
  • Adaptability of the species, and
  • Management agencies’ actions and bear sanctuaries.

Participant Discussion Highlights

Elk Research Efforts

25 elk were released in GSMNP in 2001 and 27 were released in 2002. The 2003 release was cancelled. Elk were radio collared and put in acclimation pens for 2 to 3 months before releases. Calves were radio collared.

There were 5 years of monitoring post-release. Research predicted the population would stabilize or decrease due to the cancelled third release and/or calf mortality rates (mainly due to the need to adapt to predation by bears). Researchers established a bear relocation program to increase calf survival, moving 15 bears in 2006 to the edge of the park, 12 in 2007, and 22 in 2008.

The National Park Service (NPS) has management responsibility. Current research efforts with NCWRC, NPS, Eastern Band of Cherokee Indians (EBCI), University of Tennessee (UT), and U.S. Geological Survey (USGS) are estimating elk population based on DNA assessments. Sampling will continue for 3 years.

Findings

• The herd has a small home range. The core population is in the Cataloochee area and a satellite population is in the Cherokee area. Elk could move across I-40 as the population increases due to suitable habitat on either side of I-40.
• Survival rates are reasonable for adult males and females, but there is a low recruitment rate for calves (though it is improving). Rates improved over time (2006-2008 results), but the population is still vulnerable. Follow-up studies and new population estimates are needed.
  • The cause for increased survival rates is due to elk adapting to local surrounds and resources, the bear relocation program, and elk adapting to bears when rearing young. Meningeal worm is still impacting the herd but mortality rates are below what is sustainable for the population.

Participant Discussion Highlights

Elk Collar Study Research Efforts

Five elk were collared March/April 2018, 3 female and 2 male (1 male road mortality), to collect information on elk roadway behavior. These elk were targeted due to their potential higher probability of larger movements and interactions with roadways and the I-40 corridor. Collars provide hourly fixes on location, and will give 20 minute fixes on location if elk are within 500 meters of I-40 and US 19 to provide details on elk road crossings.

Image Source: Wildlands Network

Findings

• Elk tend to travel along slopes less than 40° which can help determine where elk use the landscape.
• Elk used structures in the area. Research should investigate synergy between camera and collar data.
• Movements can be individualistic and many factors contribute to behavior differences.
• More spatial and temporal data is needed from more elk to understand movement patterns and guide crossing location installations.
• Wildlands Network is interested in sharing data with NCWRC on 10 collared elk to answer questions about home range and movement patterns, and address road elk interactions and behaviors.

Participant Discussion Highlights

Proposed Camera Trap Study Presentation Highlights

WVC mortalities are underreported, and reporting is not centralized. Data collection needs to improve.

Project Goal – increase the understanding of black bear and elk movement patterns, mortality, and permeability within the highway corridor.

Long-term Goal – improve wildlife’s ability to cross I-40 and improve public safety.

Research Objectives –

1. Assess mortality hotspots to understand where animals are attempting to cross. Methods will include surveying to describe road aspects, using wildlife cameras, and compiling a master database from other sources.
2. Assess crossings at grade to understand where animals “prefer” to cross. Use cameras along randomly selected 500 meter segments of the corridor to understand animal distribution and landscape use. Some areas across the Gorge may be prohibitively steep to put out cameras. Cameras will be placed closest to a forested ridgeline in an area with the least slope using existing wildlife trails/paths when possible.
3. Assess use of existing structures to confirm use. The focus will be on structures with a reasonable expectation of usage based on literature and existing knowledge. Other tracking methods like DNA will be considered.
   • The study area is mainly Federal lands with some private land. Connecting large landscapes is one of highest national priorities for wildlife conservation.
   • The project will require permitting (ROW encroachment permits, State and federal wildlife permits), collaboration on mortality data collection, and consultation of subject matter experts. The agency still needs to apply for permits.

Participant Discussion Highlights

US 64 Widening Research Efforts

Research focused on highway permeability for wildlife while maintaining the usability and access of the roadway. Studies assessed the potential impacts of widening US 64 on species of interest and wildlife in general to understand landscape use and determine wildlife crossing locations.

The National Wildlife Refuge (NWR) System Improvement Act of 1997 provides a process for determining compatible uses for refuges. A compatibility determination, required for permitting refuge use, is when the use of a refuge will not interfere or detract from the purpose for which the refuge was established.

The project faced management issues and competing needs:

• US 64 provides unique habitat areas for species, namely the red-cockaded woodpecker and red wolf.
• Being located on NCWRC Game Lands used by the public, designs needed to maintain access points along the roadway but not allow black bear entry.
• Designs needed to provide the ability to retain the hydraulic connection to the waterfowl impoundments.
• The project needed to account for DOT standards and driver expectation.

Findings

• Identified candidate crossing structure locations for large and small crossings based on the black bear, red wolf, and general wildlife impact studies.
• Installed 73 structures total. Only 1 large pipe crossing was installed. Crossing structure height was constrained by maintaining a church and community center driveway access.
• Fencing was not buried at these crossings. Future installations will bury fencing to prevent gaps.

Participant Discussion Highlights

CO WVC Reduction Efforts – Background

CO deals with different types of conflicts depending on the season: herd migrations with large, high magnitude movements across roadways and winter range where individuals linger on and near roadways throughout both day and night. CO has some of the largest elk and mule deer herds in North America. 74 percent of WVC in CO are mule deer. Elk are also hit.

CDOT data sources to determine critical locations for WVC reduction treatments include:

• Law enforcement crash reports. Law enforcement data is known to be underreported and is estimated to be about half to a third of WVCs.
• DOT carcass removal data. DOT maintenance staff record species and location of wildlife carcasses on and near roadways which can be input into GIS. Maintenance staff do not remove or record carcasses in the ROW far from the roadway or in the woods when injured animals wander off and die. Data is considered underreported due to carcasses not recorded.
• Other data from other agencies, researchers, and universities.

Project Scoping Considerations

WVC Countermeasures and Treatment Options

• Crossing structures. Overpasses may be used more often by certain wary species, but underpasses are typically more feasible.
• Designate small species crossings to maintain roadway permeability for wildlife with limited movements and ranges.
• Exclusion fencing treatments are required with crossing structures.
  • Consider the fence end. Ensure animals are not circumventing the fence end.
  • Use escape ramps to give animals caught on the street side of fencing a safe place to exit. Install escape ramps where animals are naturally moving. Consider the ramp height.
• Vegetation management reduces attractions to the roadway while maintaining motorists’ line of site. Do not create foraging areas in the ROW.
• Reduce speed limits. This may cause pushback; consider implementing nighttime speed reductions.
• Be creative with signage, both permanent and seasonal. Motorists are sign-numb, especially commuters. Consider flashing lights at at-grade crossings.
• Be innovative. Stay on the cutting edge of research to determine mitigation options that work and that don’t.
• Engage local communities to garner public support. Install cameras immediately, regardless of monitoring plans, and share images with local media to prove to the public that construction was worthwhile.

Banff National Park Case Study – Background

Parks Canada maintains sections of the Trans Canadian Highway (TCH) running through national parks. With Park Canada’s mandate to protect resources for current and future generations, project goals were to improve motorist safety, reduce wildlife mortality, maintain habitat connectivity, and increase traffic level of service—all of equal priority.

TCH runs through Banff, home to many iconic species, and creates a high barrier to wildlife movement. TCH was twinned, creating 4 lanes to increase capacity. The project was completed in phases over 30 years with the team learning from one phase to the next using context sensitive designs.

Mitigation measures reduced WVC and promoted connectivity. In total, 83 kilometers of highway were twinned, 42 wildlife crossing structures were installed providing a crossing every 1.5-2 kilometers, and 166 kilometers of fencing was installed. Wildlife mitigation costs were about 30 percent of the overall budget.

Project Scoping Considerations

WVC Countermeasures and Treatment Options

• Fencing and crossing structures must be used together. Fencing is mandatory to address mortality issues and crossing structures are mandatory to address connectivity. Fencing guides animals to the crossings.
  • Fencing – consider the alignment. Monitoring found sheep were precluded from using rock faces as an escape route and were being killed by wolves.
  • Crossing structures – consider species preference to overpasses or underpasses when selecting crossing types. Generally, big works best.
• Charged fences and electromats are good deterrents to keep animals out of the ROW. Electromats are less effective with snow.
• Cattle guards, electrified or not, are not effective and can fill with snow/salt brine.
• Escape routes are required to allow animals trapped inside the corridor to escape.
• Consider other methods to increase permeability, such as including small openings in Jersey barriers to allow small species to cross.
• Take advantage of topographic features. Manipulate the landscape to achieve desired outcomes.
• Be prepared to adapt and use adaptive management. Animal behavior changes and is not always what is expected.
• Monitor treatments and allow enough time to capture changes in animal behavior. Be prepared to monitor for a long time. Some species may use a crossing structure before construction is complete but others may take years to incorporate crossing structures into their movement patterns.

Lessons Learned

• Sharing results changed the public perspective from lack of support to full support of the project.
• Mixed human and wildlife crossings do not work. Pedestrian connectivity should be considered separately. Pedestrian walkways were included above the roadways and have self-closing gates to prevent animal access.
• Crossings are not prey traps for predators, but may be used by humans/hunters.
• Fencing prohibited bears’ digging and climbing efforts, but bears gained access through a weak connection between the fence and apron.
• Total or 100 percent exclusivity is difficult to achieve. Pre-post mortality data shows improvement. There was an 80 percent reduction in WVC and a 95 percent reduction for elk and deer WVCs, but coyote WVCs increased because they can get under the fence.

Participant Discussion Highlights

Ecological Impacts of Roadways

All need to be addressed, not just road mortalities and barrier effect.

Image Source: Western Transportation Institute

1. Loss of wildlife habitat around the road where animals cannot and should not live.
2. Road mortality.
3. Barrier effect as animals will not cross the roadway.
4. Decreased habitat quality due to pollution, disturbances, lighting, and other factors. Impacts can extend from yards to miles, depending on the parameter and species.
5. Ecological function in the ROW can provide habitat for invasive plant species.

Steps to compensate for ecological impacts include:

• Avoid. Determine if the mode of transportation can be rerouted to avoid impacts. Consider avoidance measures immediately in the planning process.
• Mitigate.
• Compensate. Provide offsite mitigation to create new or larger habitat patches and promote connectivity.

Human Safety and WVC

WVC present safety concerns. Larger animals lead to a higher probability of human injury or fatality. There are 1-2 million large mammal-vehicle collisions/year (mostly white-tailed deer, mule, elk, and moose) costing $6-12 billion/year. The total number of crashes (all types) are stable from the 1990s, but WVCs are increasing with time.

Highway upgrades to improve driver safety can inadvertently increase driver speeds, leading to increased WVCs, requiring implementation of mitigation measures.

Project Scoping Considerations

• Define objectives and purpose first to determine what information is needed. Then consider data types and sources and how they can be used. Outcomes will differ based on different objectives.
• Safety focuses on reducing collisions with large game. Biological conservation focuses on species and habitat, indiscriminate of size or safety. Direct road mortalities are the main concern for protected amphibians and reptiles, but most mitigation measures are for ungulates and large mammals.

Data Sources and Uses

• Species and spatial data accuracy are important considerations when identifying hotspots. Consistent search and reporting efforts are critical.
• Applications are available to track data on dead and live sightings, such as the Federal application ROaDS (Roadkill Observation and Data System). Consider public safety in citizen science efforts.
• Crash data is reported by law enforcement, representing larger scale crashes with a minimum damage threshold. This provides a better description of what happened and where, but accounts for 30 percent of carcass removal data and often lacks species information.
• Carcass removal data is collected by maintenance, but doesn’t include animals that die outside the corridor.

WVC Countermeasures and Treatment Options

• Fencing is the main mitigation measure, with the primary function to keep animals off the highway and reduce collisions. Fencing also promotes connectivity by guiding wildlife to safe crossing locations. Study results show fenced areas had less WVC than non-fenced control areas. Fence end runs can increase WVCs.
• Crossing structures are required to allow safe passage. Crossings are for species and individuals that approach highways. Some will never approach highways and so cannot benefit from crossing structures by definition.
• Consider target species. Structure use does not mean it is appropriate for the target species. Camera data can be used to determine the acceptance ratio of crossing types by different species to identify best options for species.
• Continue monitoring until usage is stable to accurately capture use and interpret if it meets the objectives. Wildlife use increases as animals learn crossings provide safe passage. Study results showed deer and black bear use doubled over 5 years and continued to increase.

Study Results – Effectiveness

• Fencing longer road segments can reduce WVC by 80 to 100 percent. Shorter segments can reduce about 50 percent. Results are highly variable from location to location.
• Monitoring results showed more deer and bears crossed through the structure than ever crossed at-grade, showing that a combination of fences and wildlife crossing structures can increase habitat connectivity.
• Large mammal use of large underpasses (7 meters wide) is 146 percent higher than at random locations in the area. However, if the objective is to have the same number of movements under the highway compared to what moves in the immediate vicinity, 41 percent of the highway needs to be permeable with these structures.

Cost-Benefit Analysis (CBA)

Implementing mitigation measures can be less expensive than continuing to allow large mammal-vehicle collisions. Property damage estimates from WVC with large mammals and economic estimates for human injuries and fatalities range from $6,000 to $30,000 per collisions for deer, elk, and moose. CBA shows that only a small number of avoided collisions pays for mitigation measures. The model is currently based on human safety parameters, but can be expanded to include other parameters such as biological considerations, conservation value, tourism, and hunting abilities.

Participant Discussion Highlights

Camera Trapping – Uses

• Camera trapping is an easy way to monitor crossing structure activity before and after modification to evaluate the effectiveness of mitigation measures.
• Regular monitoring efforts and mortality data improve modeling by locating hotspots and determining parameters influencing animals’ use of landscapes.
• Mortality and carcass data provide information for conservation as well as safety (collisions and injuries). Consider what camera monitoring data will show that other data is not already capturing.

Camera Trapping Limitations and Challenges

• Cameras monitor microhabitats. Cameras only capture a small area in front of them and do not capture all crossings. This can provide a false confidence that an entire corridor is monitored when there are large gaps in monitored space.
• Camera placement is highly influential on results.
  • One study showed large variation in capture rates from cameras placed 20 meters apart in the same habitat at the same height.
  • The same study showed some variation in capture rates was due to variation in effective detection distance of cameras based on factors such as landscape slope, habitat conditions, and placement on a trial.
• Capture rates can be independent of the species density. Studies have shown density can vary despite no change in capture rates, and vice versa. This results from changes in likelihood of photo capture across areas and cameras.
• Numbers of individuals can be elusive to estimate. The same individuals can appear multiple times and inflate numbers and/or some individuals may not be captured.
• Misses information about the likelihood of collisions. Cameras along roadways may not provide information on intent/attempts to cross roads and cannot determine if animals are near the road or if the location is a safe crossing site.
• GPS tracking data may be more valuable for modeling. Analyzing elk collar data can provide information for a detailed habitat analysis to determine how elk are using the landscape (traveling along roadways or open grass feeding) and identify likely/existing crossing locations.

Participant Discussion Highlights