Posts Tagged ‘Arizona Game and Fish Department’
Reducing Roadkill: Safe Passages for Wildlife on Interstate-10 East
By Jessica Moreno, Conservation Science Director
One of the best things about doing roadkill surveys is watching the sunrise. During the monsoons, the sun breaks across the eastern horizon and lights up the moisture laden air and morning cloud cover with light and throws the foothills into brilliant color. The sun feels hopeful and the day new. The second-best thing is knowing that every datapoint is helping us make things better.
The 20-mile stretch of Interstate-10 (I-10) between Vail and Benson, east of Tucson, Arizona, divides the regionally important Rincon-Santa Rita-Whetstone Mountains Wildlife Linkage. This wildlife pathway is one of only a few – somewhat safe – crossing points across I-10 found between Tucson and New Mexico, and it encompasses several protected areas and important waters, including Davidson Canyon and Cienega Creek, making it critically important for desert wildlife in the face of climate change.
This wildlife pathway is protected partially by federally protected lands including Saguaro National Park, Rincon Wilderness, and Las Cienegas National Conservation Area. Pima County has invested in securing additional conservation lands in this linkage as mitigation under the Multi-Species Conservation Plan (MSCP), including Bar V Ranch, Cienega Creek Natural Preserve, Rancho Agua Verde, and Colossal Cave Mountain Park, which are managed under the Cienega Creek Management Plan.
However, I-10 cuts through this area of wildlife movement, resulting in more wildlife-vehicle collisions for large animals such as black bear, mule deer, whitetail deer, javelina, coyote, and mountain lion, as well as smaller species like box turtles, opossum, Antelope jackrabbit, white-nose coati, raccoon, badger, and bobcat. It also serves as a potential movement area for jaguars and ocelots. Existing culverts and right of way fencing are not currently adequate at reducing wildlife-vehicle collisions or ensuring safe wildlife passage in this area. Future growth and increases in traffic volumes will only worsen the frequency of vehicle-wildlife collisions.
Since 2006, several qualitative assessments and reports have been produced that highlight the area’s importance for wildlife movement, but there has not been a study that has collected data to build a high accuracy model of wildlife movements and roadkill locations along this corridor. With the lack of such a product, nothing has been done on the ground to reduce wildlife-vehicle collisions and to improve safe wildlife passage by employing effective mitigation structures like winged highway fencing or wildlife overpasses. The Coalition for Sonoran Desert Protection, in conjunction with partners, is spearheading the effort to collect data to provide the information necessary to make this stretch of I-10 a safer passage for both wildlife and people in this important corridor.
In the spring of 2017, CSDP conducted comprehensive assessments and wildlife surveys of the nearly 80 existing concrete box culverts and metal plate pipe structures between milepost 277-302 (Houghton Road to SR90), with participants from several government, nonprofit, and community partners, including the Arizona Game and Fish Department, Cochise County, Pima County, Tucson Audubon Society, Sky Island Alliance, Defenders of Wildlife, and the Wildlands Network. Our results indicated that this wildlife linkage could be made safer for wildlife and motorists by 1) installing wildlife funnel-fencing to keep animals off the highway and to direct wildlife toward existing crossing points; 2) retrofitting and widening existing drainage culverts located in high volume areas; and 3) construction of an additional wildlife crossing between Cienega Creek and the railroad underpass near Empirita Rd Exit 292.
Roadkill surveys were part of the next phase of this effort: to gather data on roadkill hotspots, together with wildlife passage rates using wildlife cameras in the best existing culverts. We hope this data will inform State and County highway and wildlife officials on where to focus mitigation efforts to improve highway safety and minimize wildlife-vehicle collisions with site-specific wildlife funnel-fencing installation, existing culvert retrofits, and new wildlife crossing structures. Our results illustrate the need to implement changes and provides baseline information to evaluate the success of future mitigation measures.
Our Desert Roadies project began with a team of volunteers to help collect wildlife-vehicle mortality data on Interstate-10 between SR83 and SR90, east of Tucson. Desert Roadies volunteers worked in teams of 2-4 people, including myself, to conduct driving roadkill surveys. Observations were recorded by our notetaker with the GPS coordinates. Surveys were conducted in the morning, starting up to 30 minutes before sunrise, every week for 6 weeks during the monsoon season in 2019 and 2020, beginning in July, except when conditions were bad for visibility or driving such as rain, dust storms, or other low visibility weather. In addition to these formal roadkill surveys, we collected other data on iNaturalist.org from community members and personally investigated reports about black bear mortalities. We also requested ADOT records on reported animal-vehicle crashes in the study area. This data was analyzed separately.
Due to the onset of the Covid-19 pandemic in March 2020, carpooling with volunteers was no longer a safe option. So, we adapted as best we could by canceling the planned spring 2020 survey and having another monsoon season survey instead, which was conducted by myself and my family, Eddie Moreno (who is also a biologist experienced in roadkill surveys) and my two toddlers munching on donuts and “helping” look for animals from the backseat. This survey was done when the state was under curfew and lockdown, resulting in reduced traffic volumes. This likely was one reason for fewer observations of roadkill during this survey window.
Walking surveys are the ideal method for complete and accurate data. But safety concerns eliminated that option because we are using volunteer participation and this is a busy interstate highway with narrow right of ways. Therefore, the roadkill survey portion of this project was designed to be a broad-brush stroke only and we anticipated a small sample size. Recording categories of small, medium, large animals and/or by clade (reptile, bird, small/med/large mammal) are adequate for our purpose. Because of the project design, we have near zero detectability of small animals, and instead our target species are deer, bear, coyote, bobcat, gray fox, javelina, and those larger animals that the Arizona Department of Transportation consider most hazardous to drivers. The data will hopefully serve to provide a preliminary look at potential roadkill hotspot areas. For best accuracy 1) our GPS units had a one-button click to mark points quickly, 2) volunteers could also use maps and mileposts to confirm locations, 3) we analyzed the data in 1-mile segments, which better informs the fencing solution strategy and somewhat addresses imprecise location information, and 4) a staff biologist was always present to provide corroborating identification.
We completed two monsoon survey seasons for roadkill observations in 2019 and 2020, resulting in 78 data points of at least 14 different species. We were able to detect animals as small as a rock squirrel or cottontail rabbit. Skunks, raptors, and deer were not identified to specific species. All of our deer mortality observations (n=2) occurred between mileposts 296-297, near the Pima-Cochise County line. A hotspot of roadkill observations occurred between mileposts 291-295 (between Cienega Creek and Empirita Rd), in an area that coincides with a gap in available culverts and crossing points, and near several culvert locations between mileposts 283-287.
I-10 has been identified as a significant barrier to black bears in southern Arizona. In 2011, Todd Atwood et al published a study describing I-10 as a more significant barrier to functional gene flow for black bears than the U.S.-Mexico border, identifying I-10 as the dividing line between the Border subpopulation of black bears to the south, and the White Mountain subpopulation to the north. In our study area, these subpopulations meet and Romeo and Juliet romances unfold, ensuring healthy black bear populations in Arizona and in Mexico. For black bears, I-10 may be a barrier to gene flow as well as a “population sink” due to wildlife-vehicle deaths. This could pose a significant issue for the Border subpopulation, which additionally faces barriers to movement at the U.S.-Mexico border due to the construction of the border wall and other border-related infrastructure such as roads and lighting. Without safe passage both north of I-10 or south of the border, our southern Arizona black bears are at risk of genetic isolation and disappearing all together (what we call extirpation).
We have gathered four records of black bear mortalities in recent years, and three of these are verified with photos. These records indicate that the bears attempted to cross I-10 by following higher elevation ridgelines closely associated with the two largest underpass structures at Davidson Canyon and Cienega Creek. We also have animal track and camera trap data showing successful passage under I-10 at a few specific culverts. Most of our observations show bears moving south. April-May and August-September appear to be peak periods of activity for black bears in this area according to our data.
Black bears are just one example of the impact I-10 is having on native wildlife. In addition to large animals like bear, deer, and jaguar, smaller animals are at risk as well. Saguaro National Park has been monitoring a disturbing decline in “lost carnivores” over the last decade, including skunks, foxes, and badgers. Biologists are also concerned about the local disappearance of smaller range habitat specialist species affected by habitat fragmentation, including box turtles, Antelope jackrabbits, skunks, kit foxes, badgers, and white-nose coati. Increasing wildlife connectivity conditions for black bears and deer should allow struggling populations to repopulate from connected habitat areas and also benefit a wide array of other species.
With the data we’ve collected, we have solid evidence to back up the need for funding wildlife funnel fencing where it is most needed and make the case for new or improved wildlife crossings.
Read CSDP’s final project report to Arizona Game and Fish Department here.
(Please note: Photos of roadkill animals are included in the report)
Want to help?
Although collecting information on roadkill is not for the faint of heart, the data it provides is valuable. In the future, CSDP will be looking to continue our Desert Roadies program in more areas. In the meantime, folks can also document sightings of wildlife on roads in Pima County at https://www.inaturalist.org/projects/csdp-safe-passages.
This work was made possible thanks to the time, effort, and skill of the following volunteers: Matt Clark, Sami Hammer, Bruce Jacobsen, Ken Lamberton, Eduardo Moreno, D’angelo Padilla, Raynor VanDeven, Althea Weeks, and Daisy Weeks.
We also want to thank Scott Sprague, Jeff Gagnon and Brit Oleson of the Arizona Game and Fish Department, and give special thanks to our collaborating partners: Myles Traphagen with The Wildlands Network and Brian Powell with Pima County Natural Resources, Parks and Recreation.
This project was funded in part by the Arizona Game and Fish Department Heritage Fund.
Avra Valley Fence Removal Volunteer Day a Big Success!
On December 11, 2021, a group of local organizations and state/federal agencies came together to celebrate National Public Lands Day by holding a Fence Removal Volunteer Day in Avra Valley. It was a wonderfully cool day with volunteers in high spirits to accomplish something tangible and positive for wildlife.
A few fun stats from this great event:
- Over 65 volunteers, a group from the American Conservation Experience (ACE) program, and staff from Arizona Game and Fish Department and the National Park Service joined together for the project.
- 3 miles of fence were removed from the landscape in one morning.
- 3 tons of metal, including fence posts and wire fencing, were hauled away.
This is a fantastic start to improving the permeability of the landscape for wildlife movement between the Tucson Mountains, Ironwood Forest National Monument, Pima County open space lands, and more. And a big thanks to the Coalition volunteers that came out and volunteered their time – we are so thankful for you.
This is the first of a few Fence Removal Volunteer Days – we plan to hold one to two more this winter and spring so keep your eye out for more details. We’d love to have you join in on the next event!
Thank you to all the organizations that helped make this event possible, including Friends of Ironwood Forest, Coalition for Sonoran Desert Protection, Saguaro National Park/National Park Service, Arizona Game and Fish Department, American Conservation Experience, Pima County, U.S. Bureau of Reclamation, and the Mule Deer Foundation.
Photos below are courtesy Carolyn Campbell and Lee Pagni.
Oracle Road wildlife crossings featured on FOX10 Drone Zone segment
The Oracle Road wildlife crossings were recently featured on TV station FOX10’s Drone Zone segment in Phoenix. Check out this 3+ minute segment to see some amazing drone footage of both the Oracle Road wildlife underpass and overpass, along with a great interview of our partner Jeff Gagnon with the Arizona Game and Fish Department (click on the image/link below to access the full TV segment).
Monitoring results from the Tangerine Road wildlife crossings
Did you know that there are now five wildlife underpasses under Tangerine Road?
As part of a larger project to improve Tangerine Road, five existing drainage structures were enhanced and improved to better accommodate safe wildlife movement across this popular roadway. This is a cost-effective way to increase connectivity across roadways that is less visible to the general public (as compared to a wildlife bridge) but still very important. Construction was completed on these wildlife underpasses in Spring 2018 with the cooperation of the Town of Marana, Pima County, the Regional Transportation Authority (RTA), Arizona Game and Fish Department (AGFD), the Coalition for Sonoran Desert Protection, and other members of the RTA’s Wildlife Linkages Sub-Committee.
Starting in 2010, the AGFD completed pre-construction monitoring using roadkill surveys. After the underpasses were completed in Spring 2018, the AGFD started a 3-year post-construction monitoring project, including roadkill surveys and monitoring wildlife use of the crossings using wildlife cameras. According to an April 2019 progress report from AGFD:
Between May and September 2010 5,152 road mortalities representing 88 species were documented, helping to identify hot spots for future implementation of fencing and wildlife crossing structures.
[Using this data], the objectives of this construction project were to:
- Increase the size of five drainage structures and modify inlets/outlets to accommodate medium-sized mammals.
- Add funnel fencing at the crossings.
- Conduct habitat establishment evaluations, for three seasons, beginning one year after project completion, to determine whether any adaptive management measures are necessary to improve the effectiveness of the wildlife crossing structures.
Post-construction roadkill surveys began in Spring 2019. An April 2019 progress report primarily includes data from wildlife cameras installed on the underpasses and can be found HERE. A few data points and photos from the report are highlighted below:
Data has been analyzed to January 7th, 2019, this represents two full months of monitoring data for all five structures. A combined total of 1049 crossings by 17 wildlife species have been documented across all 5 structures to date. Coyote, javelina, and bobcat constitute the most commonly recorded species with 475, 365, and 130 crossings respectively, representing 93% of all documented crossings.
This is exciting news for wildlife in the Tortolita Fan and motorists along Tangerine Road. With the inclusion of wildlife fencing on either side of these five underpasses, wildlife are now being funneled to cross Tangerine Road under the roadway, leading to increased safety for wildlife and motorists.** We will share new monitoring results from AGFD when they release their next progress report on this project sometime in the next year.
Thank you for supporting connected wildlife linkages and wildlife habitat!
**Some observant community members have noted that this wildlife fencing is shorter than the wildlife fencing along Oracle Road. Why is this? The Tangerine Road wildlife fencing was designed for the medium-sized mammals that are most likely to use these smaller culvert wildlife crossings.