Chanet Stevenson, Staff Reporter
March 7, 2012
In an effort to make Snoqualmie Pass safer for animals, Central Washington University biologists and students have been working to document wildlife movement across Interstate-90 (I-90) for the Washington State Department of Transportation (WSDOT).
Central biologists and students have been involved in the I-90 Snoqualmie Pass East Project since 2008 when the project first began. The goal is to build crossing structures, including bridges and underpasses, which will safely and ecologically connect wildlife with both sides of the Interstate.
The project, which spans 15 miles along I-90 between Hyak and Easton, will include a total of 15 wildlife crossing structures when completed.
The WSDOT enlisted help from the Central biology department to document where wildlife resides near I-90. The idea was to track wildlife movement in order to determine where crossing structures should be built so that animals could easily find and use them to cross the Interstate. To accomplish this, biologists have chosen to document specific wildlife and their habitats and movements, including pikas, fish, amphibians, and reptiles.
Kristina Ernest, a terrestrial community ecologist and professor, is one of the professors involved in the project.
“One really great thing about this project is that we have been able to involve students,” Ernest said.
For Ernest and her lab students, researching the ecology of pikas along I-90 has been the main point of focus in the project.
Pikas are small mammals with short tails and limbs, rounded ears. They are related to rabbits and hares.
Ernest said pikas primarily live in shady, rocky patches with crevices that can be used for shelter. Since pikas live in such small, confined areas, it is difficult for them to move from place-to-place, especially with I-90 acting as a barrier.
In order to track the pikas’ movement, the researchers must first trap and tag the animals before releasing them back into their environment.
When an already tagged pika is caught again, it is weighed and processed to determine how much the pika has changed over the course of the year.
By doing this research, Ernest and the students involved can give better recommendations as to where crossing structures should be placed to best benefit pikas since it demonstrates where the animals have moved to and from, and whether or not they are more likely to stay on one side of I-90 or the other.
This same process is used to research and track the movements of fish populations within the streams along I-90. Paul James, an ichthyologist and professor, said each fish is tagged with an assigned number.
When the fish are re-caught, their length is then measured and recorded to show how fast they are growing. Since each fish is tagged with an assigned number, James and his students can also determine where the fish were first caught and compare the location to where they were found the second time to see how far the fish have traveled.
James also explained how constructing bridges allows for water in the streams to flow naturally underneath them, whereas constructing culverts often causes the water to rush too quickly through them making it more dangerous for fish.
Cameras have also been placed along I-90 to capture wildlife movement and allow biologists to see which animals are crossing where.
The cost for the project is $100,000 to $120,000 per year and is contracted through the WSDOT.
According to James, the I-90 Snoqualmie Pass East Project is the first ever project to monitor wildlife movements and populations before, during and after construction of crossing structures.
By collecting data throughout the entire course of the project, biologists hope to accurately determine how effective the crossing structures have been once they are completed.
Because of this, many European countries interested in constructing wildlife crossing structures have been closely following the data collected throughout the project.
Though it is still uncertain when the construction of the wildlife crossing structures will be completed, Central students and biologists continue to research wildlife populations, which they hope will ultimately help make crossing structures a safe and effective way for animals to cross over I-90 at Snoqualmie Pass.