SR-152 Pacheco Pass Wildlife Connectivity Study and
Implementation of Wildlife Connectivity Enhancements
Pathways for Wildlife, in collaboration with the Department of Fish and Wildlife and Caltrans, conducted the Wildlife Permeability and Hazards across SR-152 Pacheco Pass Project 2018-2019, and the current SR-152 Pacheco Pass Wildlife Connectivity study (Figure 2).
Within the 2018-2019 monitoring period, multiple species including deer, American badger, coyote, bobcat, gray fox, raccoon, striped skunk, and opossum were recorded consistently traveling under three bridges. Numerous medium-sized mammals such as coyote, bobcat, gray fox, raccoon, opossum, and skunk, were also consistently traveling through the cement box culverts. A total of 3,125 animals were recorded traveling under bridges and through the culverts throughout the duration of the study.
Many of the same species recorded crossing under the bridges and through the culverts, were also found hit on the highway during the study. A total of 128 wildlife-vehicle collisions have been recorded on SR-152 Pacheco Pass. A total of four mountain lions, nine tule elk, and eleven American badgers have been recorded hit on the highway by either PFW, Caltrans, or CDFW.
State Route (SR) 152 creates an ongoing risk of collision and a barrier to movement and full recovery of Tule elk from their near extirpation in the historic era. The mountain lion species also suffer from habitat fragmentation and reproductive isolation due to human encroachment on habitat and constructed barriers to movement (CDFW 2020 California Action Plan Update to the State Wildlife Action Plan).
Based on the project results from the 2018-2019 study and the current study, Pathways for Wildlife have been working with CDFW and Caltrans to develop wildlife connectivity enhancements recommendations that would improve the ability for wildlife to safely cross SR-152 as well as improve highway safety for drivers by reducing wildlife-vehicle collisions.
Pathways for Wildlife co-authored two WCB Wildlife Corridor and Fish Passage Program Grants and were awarded funding to implement the following wildlife connectivity enhancements generated from our wildlife connectivity studies:
1) A Wildlife Overpass Planning grant that will include a feasibility analysis to determine the best location for a wildlife overpass. Pathways for Wildlife is conducting a muti-focal species linkage analysis, in which the camera and roadkill data will be used to validate the model. The focal species include tule elk, mountain lion, bobcat, and American badger.
American badger and bobcat recorded traveling together under a SR-152 bridge.
2) Installation of directional fencing to guide wildlife to existing bridges and culverts where documented successful crossings by multiple species of wildlife have occurred but also include a high rate of wildlife-vehicle collisions in the vicinity of the culverts and bridges.
3) Retrofitting the Pacheco Creek bridge at the Pacheco Creek Preserve to create a walkable pathway over large rip-rap boulders so that wildlife can travel along the bank when the bridge is flooded.
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4) Restoration of Sycamore alluvial woodland habitat to create a visual guide for wildlife to bridges and culverts that have high documented wildlife use.