The Land Trust’s campaign to build a wildlife crossing began three years ago – with the death of a mountain lion on Highway 17.
We had just finished our Conservation Blueprint and knew that providing safe passage for wildlife across the highway was critical to the long-term survival of the county’s mountain lion population.
News of the latest death of a lion trying to cross led to a meeting with Chris Wilmers, who heads the UCSC Puma Project and was a member of the Blueprint Steering Committee. Within a few weeks we met CalTrans officials to see what could be done. We returned from the meeting knowing that this was a long-term project involving a massive government agency – so we got to work right away!
We are still amazed at how quickly this project has come together. In February we were able to purchase a critical 10-acre property in the best possible location for a wildlife tunnel. In July we signed an option to buy an adjoining 280-acre undeveloped property.
The wildlife crossing area
Our goal is to protect 470 acres of land on either side of Highway 17 at the Laurel Curve (see map). The land must be protected from development before CalTrans will build a wildlife crossing.
If you Google images for wildlife tunnels you’ll find pictures of all sorts of wildlife in lots of places – mountain lions, deer, coyotes, bears, alligators, badgers, buffalos. We’re not reinventing the wheel and neither is CalTrans, which has built similar tunnels (or bridges) on Highways 1, 68, 101, 152, and 280.
They work! A variety of wildlife species have been documented using these crossing structures on a consistent basis, and there have been very few animal-vehicle collisions where they’ve been built.
Short and long-term protection for wildlife
The wildlife crossing will protect wildlife and motorists from the immediate dangers of collisions – and is critical to addressing the longer term danger of geographic isolation. There is no doubt of the immediate dangers – because the area is routinely used by mountain lions and other wildlife. Since 2008, the Santa Cruz Puma Project has collared and tracked 46 pumas in the Santa Cruz Mountains. This data shows that pumas routinely attempt to cross Highway 17 at the Laurel Curve study site, with seven documented crossings by three different individuals. Four pumas have been hit by cars in the Laurel Curve study area since the inception of the Puma Project study in 2008. Only one survived.
A wildlife crossing under Highway 17 will effectively breach what one observer called “the Berlin Wall” dividing the extensive natural lands of our county. This is especially important for wide-ranging species like the mountain lions in the Santa Cruz Mountains, which are becoming increasingly isolated by habitat fragmentation. Fragmentation has inhibited the genetic flow that is essential to maintaining a healthy and sustainable population of mountain lions.
The best place for a crossing
Highway 17 is only 55 feet wide at Laurel Curve. The scientific literature and various case studies suggest that a 10 by 20-foot box culvert would be sufficient for large mammals such as deer and pumas to be persuaded to cross under the highway, The cost of box culverts is modest compared to open-span bridges, bridge extensions, or wildlife overpasses.
Santa Cruz Puma Project Director, Chris Wilmers, has called Laurel Curve “the best opportunity for maintaining puma connectivity across Highway 17 in Santa Cruz County.” Wildlife biologist Tanya Diamond, of Pathways for Wildlife, made a study of every possible crossing culvert site between Scotts Valley and the summit of Highway 17. Most weren’t big enough, many were located in heavily developed areas. Her conclusion was that Laurel Curve is the most suitable location—by a long-shot—for a wildlife crossing.
A three-phase project
The Land Trust is seeking to protect three properties adding up to 470 acres. We protected the first critical 10-acre property in February – and are working to sell it with an easement that protects the wildlife corridor.
This property was identified in our Conservation Blueprint as having the highest development potential in the Santa Cruz Mountains – with the potential for dozens of homes to be built. Our plan is to allow one or perhaps two homes and ensure that the vast majority of the property remains wild.
We are already talking with the owners of a third 190-acre property on the east side of the highway and hope to have it protected by 2016. We have been talking with CalTrans since that first meeting three years ago and the project is moving steadily through their process.
Gifts of $1,000 or more will be doubled by a generous challenge from Pam and Allen Rozelle – up to a total of $150,000.
The first $600,000 in gifts will be matched by a grant from the Gordon and Betty Moore Foundation.
Header photo by Paul Zaretsky. Aerial photo © Steve Mandel