Mountain Lion Crossing

Read on if you like mountain lions, pumas, cougars, Santa Cruz Mountains, wildlife crossings, the Bay Area Puma Project, Santa Cruz Puma Project and the Land Trust of Santa Cruz County.

by Hanae Armitage

Dec. 13, 2013—Anyone who has driven the too-narrow, snaking lanes of Highway 17 can attest to its reputation as one of California’s most treacherous highways, a Blood Alley of dense traffic, blind corners and tight shoulders. But commuters and vacationers aren’t the only ones who have to brave its perils. On either side of Highway 17, the forest teems with wildlife. The roadway slices through expansive habitats of mammals like black-tailed deer, coyotes and mountain lions, forcing those animals to continuously negotiate treacherous crossings—often with deadly results.

Earlier this summer, a young mountain lion wandered into an aqueduct near downtown Santa Cruz, remaining trapped there until puma researchers tranquilized and relocated it. But five months after its return to the wild, the famous “downtown mountain lion” was struck and killed on Highway 17.

The young lion’s demise highlights one of the main problems with wildlife’s overlap with our world: negotiating the roads. Statewide, an estimated 60 mountain lions are killed on highways each year; roadkill is the second-most common cause of mountain lion deaths (the first is depredation, or the permitted killing of a puma following an attack on livestock). In the Santa Cruz Mountains, five big cats have died on Highway 17 in the last several years.

“Navigating the 17 is dangerous for humans and wildlife,” says Dan Medeiros, Projects Director at the Land Trust of Santa Cruz County. “It causes fatalities for both of us.”

Read UCSC Researchers Have A Mountain Lion Kitten
Read Pumas at PechaKucha

In the case of Highway 17, what makes it safer for humans makes it more perilous for animals. While the tall center median adds a layer of security for commuters rounding curves at 50 mph, it’s the most dangerous part for a mountain lion. Too high for pumas to see the other side, the jump over the divider becomes literally a leap of faith—especially at night.

A local effort is underway to help the big cats. Between the Land Trust of Santa Cruz County, the California Department of Transportation and the Bay Area Puma Project, ideas to facilitate safe critter-crossings are stirring.

Wildlife Crossing Hotspot

There are two wildlife-crossing “hotspots” along Highway 17. The land adjacent to these more frequently crossed areas is fairly underdeveloped, making it ideal habitat for wildlife (aside from the live version of Frogger that bisects it). One of these wildlife-crossing hotspots, Laurel Curve, is the site of a plan to help animals cross safely. It’s also just two or three miles from where the downtown mountain lion met its maker.

“From the Puma Project’s mountain lion tracking data, we see that this is a heavy crossing area for mountain lions, and probably a lot of other types of wildlife,” says Medeiros.

Globally, animal crossing issues have been addressed through underpass or overpass construction and fences that guide wildlife toward safe crossings. “It comes down to two basic things: Is there a place for a passage? And is there wildlife habitat on either side?” explains Medeiros. “For this project, the answer is yes to both.”

Though a plan to funnel wildlife under Highway 17 at Laurel Curve has not been approved by all partners involved, it appears to be in the works. In its fall newsletter, the Land Trust announced it had signed an option to buy a 10-acre property near Laurel Curve and was hoping to secure two larger properties on either side of the highway totaling 340 acres.

The underpass would focus on land connectivity— essentially habitat connection—a priority for the Land Trust. “Santa Cruz is characterized by amazing open spaces,” says Medeiros. “But these spaces are fragmented, and one of the biggest barriers is Highway 17.” These fragmentations cut off territory and lead to isolation of animals, which is exactly the problem the underpass would aim to mitigate.

Other animals, too, would benefit. “Basically we’re looking for not only mountain lion connectivity, but connectivity for all of wildlife,” says Nancy Degran, the Caltrans biologist working on the project.

Mountain lion researchers are hoping for better habitat connectivity not just within the Santa Cruz Mountains but throughout the region. For puma health it's important that the animals be able to roam and connect with other populations. Male mountain lions in particular establish large territories, up to 200 square miles in some cases. Santa Cruz Puma Project Director Chris Wilmers explained at a Dec. 4 lecture hosted by the Land Trust that the Santa Cruz Mountains host 50-100 mountain lions—not quite enough to maintain healthy genetic variability over the long haul. "Ours is already low," said Wilmers, "so it's important to connect to the Hamilton and Gabilan ranges."

Those involved in manifesting the Laurel Curve underpass acknowledge that the path from project infancy to completion is long and complicated, but they’re undeterred. Says Medeiros, “It’s a long way out and could take years, but we’re pretty hopeful.”