Wildlife Permeability and Hazards across Highway 152 Pacheco Pass: Establishing a Baseline to Inform Infrastructure and Restoration. February 2020 PREPARED BY PATHWAYS FOR WILDLIFE FOR THE SANTA CLARA VALLEY HABITAT AGENCY. SR-152 Wildlife Permeability Study 2018-2019 Monitoring Study TABLE OF CONTENTS 1.0 EXECUTIVE SUMMARY PGS.2-3 2.0 INTRODUCTION PG. 4 2.1 Background & Purpose PGS.4-6 3.0 STUDY AREA AND MONITORING SITES PG. 7 3.1Study Area PGS.7-9 4.0 STUDY METHODS PG.9 5.0 CAMERA DATA RESULTS PG.10 5.1 Total Detections of Passages by Species PGS.10-12 5.2 Data Results by Study Site PGS.13-18 6.0 WILDLIFE-VEHICLE COLLISION DATA RESULTS PG.19 6.1 Wildlife-Vehicle collision rates by Species PGS.19-21 6.2 Wildlife-Vehicle collision data combined with contributed data PGS.22-23 7.0 STORM EVENTS & SEASONAL VARIATION PG.24 7.1 Storm events in relation to a decrease of wildlife passages PGS.24-26 & an increase of wildlife-vehicle collisions. 8.0 WILDLIFE CONNNECTIVITY ENHANCEMENT PG.27 RECOMMENDATIONS 8.1 Recommendations for improving the permeability of the PGS.27 highway for wildlife passages at locations identified from the analysis. 8.2 Modifications for improving the ability for wildlife to travel PGS.28-32 through bridges and culverts during high water events. 9.0 NEXT STEPS FOR RESEARCH PG.32-33 10.0 ACKNOWLEDGMENTS PGS.33 Appendix A. Study Area in relation to Climate Change PGS.34-37 Resilience & Habitat Connectivity 11.0 LITERATURE CITED PG.38 Page 1 SR-152 Wildlife Permeability Study 2018-2019 Monitoring Study WILDLIFE PERMEABILITY AND HAZARDS ACROSS HIGHWAY 152 PACHECO PASS: ESTABLISHING A BASELINE TO INFORM INFRASTRUCTURE AND RESTORATION. PREPARED BY PATHWAYS FOR WILDLIFE FOR THE SANTA CLARA VALLEY HABITAT AGENCY. 1.0 Executive summary SR‐152 Pacheco Pass bisects the Diablo Range‐Inner Coast Linkage as identified by the Bay Area Critical Linkages Project. Pathways for Wildlife, in collaboration with the Santa Clara Valley Habitat Agency (Habitat Agency), conducted the Wildlife Permeability and Hazards across SR‐152 Pacheco Pass Project (Project), which was funded by the California Department of Fish and Wildlife (CDFW) Local Assistant Grant (LAG) and the Habitat Agency. The purpose of the study was to identify bridges and culverts that wildlife are using to cross under SR‐152 within the study area, and to make wildlife connectivity enhancement recommendations that would improve existing highway infrastructure for wildlife safe passage. The project involved 1) monitoring three bridges and two 5‐foot‐tall dual box culverts for wildlife passage, and 2) conducting routine roadkill surveys along SR‐152 Pacheco Pass within the study area for a twelve‐month monitoring period from August 1, 2018 to July 31, 2019. Within the twelve month monitoring period, multiple species including, deer (Odocoileus hemionus), American badger (Taxidea taxus), coyote (Canis latrans), bobcat (Lynx rufus), gray fox (Urocyon cinereoargenteus), raccoon (Procyon lotor), striped skunk (Mephitis mephitis), and opossum (Didelphis virginiana) were recorded consistently traveling under each of the 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 the bridges and through the culverts throughout the duration of the study. The same species recorded crossing under the bridges and through the culverts were also routinely found dead‐on‐road during scheduled roadkill surveys and were recorded as Page 2 SR-152 Wildlife Permeability Study 2018-2019 Monitoring Study wildlife‐vehicle collision points. A total of 75 wildlife‐vehicle collisions (datum points) were recorded on SR‐152 within the study area. Based on the project results, Pathways for Wildlife recommends four wildlife connectivity enhancements that would improve the ability for wildlife to safely cross SR‐152 as well as improve highway safety for drivers by reducing wildlife‐vehicle conflict. Enhancement recommendations are as follows: 1. Installation of directional fencing to guide wildlife to existing bridges and culverts where documented “successful crossings” by wildlife occur. 2. Increase the ability for wildlife to walk along the rip‐rap at bridge abutments as they act as a barrier to wildlife movement when bridges become flooded and banks are not available for use. 3. Remove dead and invasive vegetation and with restore native vegetation to increase overall bank area available for wildlife to travel along when the creeks associated with the bridges and culverts become inundated with water from storm events. 4. Install “critter crossing” shelving units at culverts that become flooded during storm events to facilitate wildlife safe passage. Given the high number of wildlife‐vehicle collisions recorded on the highway, these proposed wildlife connectivity enhancements and improvements would benefit not just wildlife populations but would also improve highway safety for people driving on SR‐152 Pacheco Pass. Page 3 SR-152 Wildlife Permeability Study 2018-2019 Monitoring Study 2.0 Introduction 2.1 Background & Purpose PROJECT BACKGROUND SR‐152 Pacheco Pass bisects one of the Bay Area Critical Linkages, the Diablo Range to the Inner Coast Linkage (Figure 1). The Bay Area Critical Linkage project was a comprehensive modeling effort to identify important habitat linkages that connect large landscape features such as mountain ranges (Penrod et al. 2012). The project area is also identified as a priority for connectivity by the California State Wildlife Action Plan (CDFW 2015) and the draft Santa Clara County Regional Conservation Investment Strategy. Focal species used to create the Bay Area Critical Linkage Diablo Range to the Inner Coast Linkage Design included mountain lion (Puma concolor), bobcat (Lynx rufus), American badger (Taxidea taxus), San Joaquin kit fox (Vulpes macrotis mutica), tule elk (Cervus canadensis nannodes), black‐tailed deer (sp.), ringtail (Bassariscus astutus), and California quail (Callipepla californica). The SWAP identifies connectivity among communities and ecosystems as a key ecological attribute for the Central California Coast Ranges region and identifies land acquisition and restoration as a conservation strategy (CDFW 2015). The Santa Clara Valley Habitat Conservation Plan/Natural Community Conservation Plan (NCCP) recognizes the importance of landscape linkages, and specifically identifies Pacheco Pass on SR‐152 as a focal area in the Biological Goals and Objectives, Reserve System design, and long‐term monitoring (Santa Clara Valley Habitat Plan 2012) (Figure 2). Page 4 SR-152 Wildlife Permeability Study 2018-2019 Monitoring Study Figure 1. Bay Area Critical Linkage Design: Diablo Range to the Inner Coast Linkage. Page 5 SR-152 Wildlife Permeability Study 2018-2019 Monitoring Study Project Area Figure 2. The Santa Clara Valley Habitat Conservation Plan Landscape Linkages. PROJECT PURPOSE The overall project goal was to help support the implementation of the wildlife connectivity strategies outlined in the Santa Clara Valley Habitat Plan by improving wildlife crossings along SR‐152. To achieve this goal, we developed wildlife connectivity enhancement recommendations to improve wildlife permeability across the highway. These recommendations were developed by data results from monitoring wildlife use of existing crossing structures within the study area, three bridges and two dual box culverts, which were monitored with remote cameras. Roadkill surveys were also conducted to identify locations in which animals were attempting to cross the highway and were hit by vehicles. Page 6 SR-152 Wildlife Permeability Study 2018-2019 Monitoring Study 3.0 Study area and monitoring sites 3.1Study Area The SR‐152 Pacheco Pass study area includes a 13 mile stretch of the highway beginning at Casa de Fruta on the west side of Pacheco Pass to the South Fork of Pacheco Creek on the east side of the Pass (Figure 1). SR‐152 is built upon a south facing hillslope with the upland and lowland habitats on either side of SR‐152 consisting of primarily undeveloped lands with a few rural residential parcels and cattle grazing operations. The upland habitat consists almost entirely of oak woodland savanna, while the lowlands consist of the Pacheco Creek riparian corridor. There are several protected lands on both sides of the highway. On the north side and upslope from the highway, protected lands include Henry Coe State Park and the Cañada de los Osos Ecological Reserve (Figure 1). On the south and downslope side of the highway, protected lands include the Habitat Agency’s Pacheco Creek Reserve. Pacheco Creek is perennial, making it important habitat for wildlife. The creek provides year‐round resources such as water, food, and vegetation cover. The study area also provides a significant amount of climate change resilience, which is important as the upland habitats become hotter and drier (Appendix A). Please see Appendix A for a discussion on climate change resilience in relation to the study area and the benefits that provides in relation to wildlife connectivity. STUDY SITES Three bridges and two dual box culverts where selected for monitoring within the study area (Table 1 & Figure 3). The three bridges include a bridge by the fire station, the Pacheco Creek bridge at the Pacheco Creek Reserve, and the Cedar Creek Bridge (Table 1 & Figure 3). The two dual box culverts included the Elephant Head Creek culvert and the Pacheco Creek Reserve culvert (Table 1 & Figure 3). Three additional bridges in the study area were not monitored due to access issues. These bridges may be monitored in future project phases (Figure 3). The two dual box culverts are both 5 feet height and 5 feet wide cement box culverts. Each of the three bridges are large open span bridges that have three sections with a creek running through the middle section. The bridge by the Fire stations spans 59 meters long and 25 meters wide, the Pacheco Creek bridge spans 67 meters long and 54 meters wide, and the Cedar Creek bridge spans 54 meters long and 50 meters width.