East Orange/Central Irvine Ranch Movement Study

Final Report

Prepared for:

University of Wisconsin

U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY WESTERN ECOLOGICAL RESEARCH CENTER

East Orange/Central Irvine Ranch Mammal Movement Study

By Chris Haas1, Karen Raymond2, Lisa Lyren1, and Robert Fisher3

U.S. GEOLOGICAL SURVEY WESTERN ECOLOGICAL RESEARCH CENTER

Final Report

Prepared for:

University of Wisconsin

1- San Diego Field Station-Corona Office USGS Western Ecological Research Center 1147 East Sixth Street Corona, CA 92879 (909) 735-0774

2 – Department of Wildlife Ecology 219 Russell Labs, University of Wisconsin 1630 Linden Drive Madison, Wisconsin 53706

3 – San Diego Field Station USGS Western Ecological Research Center 5745 Kearny Villa Road, Suite M San Diego, CA 92123

Sacramento, California 2002

ii U.S. DEPARTMENT OF THE INTERIOR GALE A. NORTON, SECRETARY

U.S. GEOLOGICAL SURVEY Charles G. Groat, Director

The use of firm, trade, or brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey.

For additional information, contact:

Center Director Western Ecological Research Center U.S. Geological Survey 7801 Folsom Blvd., Suite 101 Sacramento, CA 95826

iii TABLE OF CONTENTS

Abstract...... 1

Introduction...... 1

Methods...... 3

Results...... 6

Discussion...... 11

Recommendations...... 14

Literature Cited ...... 19

Tables

Table 1: Large and medium-bodied mammal species detected at baited scent stations ...... 25

Table 2: Large and medium-bodied mammal species detected at baited scent stations along Hicks Haul Road and Santiago Canyon Road ...... 26

Table 3: Large and medium-bodied mammal species detected at camera stations located in areas removed from roadways (interior areas) and along drainages bisected by roadways...... 27

Table 4: Large and medium-bodied mammal species detected at camera stations located at underpasses along Santiago Canyon Road...... 28

Figures

Figure 1: Location of study area, East Orange/Central Irvine Ranch, CA ...... 29

Figure 2: Location of track transects and scent stations ...... 30

Figure 3: Location of camera stations...... 31

Figure 4: Location of scent and camera stations along Hicks Hauls Road...... 32

Figure 5: Location of scent and camera stations along Santiago Canyon Road...... 33

Figure 6: Location of proposed underpasses/underpass improvements along Hicks Haul Road and Santiago Canyon Road ...... 34

iv

Appendices

Appendix A: GPS coordinates of scent stations ...... 35

Appendix B: GPS coordinates of camera stations ...... 36

Appendix C: GPS coordinates of underpasses monitored by remotely triggered cameras along Santiago Canyon Road ...... 37

Appendix D: Representative photos of mammal species taken by remotely triggered cameras stationed at interior locations ...... 38

Appendix E: Representative photos of mammal species taken by remotely triggered cameras stationed at underpasses along Santiago Canyon Road...... 39

v ABSTRACT

Surveys were conducted between August and December 2002 to determine mammalian movement routes in relation to two roadways bisecting The Irvine Company’s East Orange/Central Irvine Ranch project area: Hicks Haul Road (future Jeffrey Road extension) and Santiago Canyon Road. Track transects were placed along both roadways; one transect was located along the shoulder of Hicks Haul Road, a private two-lane roadway bisecting Loma Ridge, and another was located along the shoulder of Santiago Canyon Road, a two-lane road paralleling Limestone Creek. Twenty-five remotely triggered cameras monitored wildlife activity in the habitat surrounding the roadways, at existing roadway underpasses, and at drainages bisected by the roadways. A total of nine mammal species were detected by track and camera surveys. In general, the area around Loma Ridge received the highest level of activity by the target species (mountain , mule deer, , and ). Several drainages bisected by Hicks Haul Road and Santiago Canyon Road received relatively high levels of activity by each of these four target species, and we identify these drainages as potential sites for future underpass placement/underpass retrofitting.

INTRODUCTION

The construction of roadways has been one of the principal mechanisms contributing to habitat fragmentation (Noss & Cooperrider 1994; Forman & Alexander 1998). Roadways fragment previously connected areas of habitat, creating a barrier for organisms attempting to move between patches. The isolation of these habitats may lead to changes in community structure, function, and composition. Roadways create edges that would otherwise be absent in undisturbed conditions and have the potential to subject adjacent habitat to increases in light, noise, chemical pollution, microclimate alteration, and non-native invasion (Mader 1984; Murcia 1995; Reed et al. 1996). They may also act as mortality sinks for attempting to negotiate their way from one patch to another (Adams & Geis 1983; Harris & Gallagher 1989; Bruinderink & Hazebroek 1996; Kline & Swann 1998; Mumme et al. 2000; Lyren 2001). If road kill rates exceed that of reproduction and immigration rates, wildlife populations can suffer declines (Beier 1993; Bruinderink & Hazebrook 1996; Moore & Mangel 1996; Forman & Alexander 1998).

Animals can respond by refusing to enter areas that support elevated road densities (Thiel 1985; McLellan & Shackleton 1988) or by shifting their activities away from the habitat immediately adjacent to the road (Reijnen et al. 1995, 1996; Boarman & Sazaki 1996; Mace et al. 1996; Paquet & Callaghan 1996; McLellan & Schackleton 1988). Moreover, some species are willing to cross only certain classes of roads (Brody & Pelton 1989; Lovallo & Anderson 1996), whereas others may change their crossing activity periods in response to varying traffic volumes throughout the day, as increased traffic volume increases noise levels (Reijnen et al. 1995, 1996; Forman & Alexander 1998; Lyren 2001). Particularly at risk from roadway development are wide-ranging, area dependent mammalian carnivores, including grizzly (Gibeau & Herrero 1998; Servheen et al. 1998), black bears (Brody & Pelton 1989), gray (Thiel 1985; Mech 1989; Paquet

1 & Callahan 1996), Florida panthers (Foster & Humphrey 1995; Land & Lotz 1996), mountain (Beier 1996), (Ruediger 1998), and (Tewes & Blanton 1998).

The use of underpasses to facilitate movement through roaded areas may be a potential measure to mitigate the negative impacts of roadways on wildlife populations. In urbanizing landscapes, maintaining or restoring connections between fragmented habitats is particularly challenging due to the dense network of roads. Although underpasses may be especially critical in maintaining connectivity throughout these landscapes, limited effort is typically devoted to identifying the most suitable locations for these types of structures. Furthermore, certain species of carnivores and ungulates are sensitive to various underpass dimensions, thus roadway and underpass design become critical to maintain the movement of these species (Reed et al. 1975; Reed 1981; Foster & Humphrey 1985; Yanes et al. 1985; Rodriguez et al. 1996, 1997; Clevenger & Waltho 2000; Haas 2000; Ng 2000).

Proposed road extension (Jeffrey Road) and road-widening (Santiago Canyon Road) projects within The Irvine Company’s East Orange/Central Irvine Ranch project area has the potential to impact carnivore and ungulate movement patterns. The cumulative impacts of these alterations/modifications represent serious short and long-term impacts on connectivity between the large blocks of habitat that these roadways bisect. Currently, the proposed Jeffrey Road extension follows the general route of an existing two-lane road: Hicks Haul Road, which is a private road that has very low traffic levels; it is used only by dump trucks. Santiago Canyon Road is also a two-lane road, but receives a much higher level of traffic. Therefore, these two projects (extension and widening) represent two levels of impacts to connectivity. The road extension introduces a new roadway through an area that is currently experiencing little or no traffic impacts. Thus, identifying and maintaining adequate connections across the roadway is critical, since present wildlife crossings along Hicks Haul Road are surface crossings (there are currently no underpasses along Hicks Haul Road that are large enough to facilitate the movement of the target species). Alternatively, Santiago Canyon is an existing two-lane road that has several existing underpasses. However, widening this road has the potential to disrupt or impact movement either over the surface or through underpasses since 1) the roadway will be wider, resulting in a greater distance in which animals need to travel through the underpass, 2) traffic volumes will be greater, thus increasing the likelihood of vehicle-induced wildlife mortality, and 3) traffic speeds will be higher, thus increasing noise levels along the roadway, in addition to increasing the likelihood of vehicle- induced wildlife mortality. Each of these impacts may inhibit wildlife movement across the road. Thus underpasses and an effective fencing design to reduce wildlife mortality will play an important role in attempting to maintain or increase the current level of connectivity.

The level of connectivity that could be disrupted by each of these projects can occur on two scales: a local scale and a landscape scale. On a local scale, the Jeffrey Road extension would separate potential movement routes along Loma Ridge and the various side drainages of Limestone Canyon. The Santiago Canyon Road widening would result

2 in an increased barrier effect, could increase road-related wildlife mortality, and could possibly disrupt movement between the Santiago Creek and Limestone Creek drainages. On a landscape scale, these roadways could potentially isolate patches of habitat west of Santiago Canyon Road (principally Limestone Canyon Open Space) from larger blocks of habitat to the east (Santa Ana Mountains and Cleveland National Forest), particularly for larger ranging species such as mountain lions and mule deer.

Furthermore, Santiago Canyon Road is located along an interface between the upland habitat to the north of the road and the riparian habitat of Limestone Creek. Therefore, underpasses along Santiago Canyon Road are critical at providing movement for vertebrates moving a) into Limestone Creek from upland habitats to the north (through dispersal, seasonal movements, acquisition of resources) or b) out of Limestone Creek (dispersal, intraspecific competition, seasonal movements). Given the wealth of biological diversity in this area, further fragmentation could isolate these habitats from each other causing irreversible consequences to the ecological community.

For this study, our specific focus was to identify 1) critical east-west wildlife movement patterns in the vicinity of the proposed extension of Jeffrey Road (along Hicks Haul Road) and 2) critical north-south wildlife movement patterns in the vicinity of Santiago Canyon Road between Silverado Canyon Road and the Irvine Lake area. Surveys were focused on four target species: mountain lion, mule deer, coyote, and bobcat. Several other species whose status and distribution is limited or poorly known also had the potential to be documented throughout this study, including American , spotted , long-tailed , and ringtail.

METHODS

The East Orange/Central Irvine Ranch project area is located in central Orange County in the western foothills of the Santa Ana Mountains (Figure 1). The study area is bisected by Santiago Canyon Road and is bounded on the east by Santiago Creek and on the west by Loma Ridge. The majority of habitat is preserved as part of The Irvine Company’s Open Space Reserve, specifically Limestone Canyon Open Space.

Surveys were established to obtain data on 1) the distribution of mammal species within the habitat surrounding the two roadways and 2) the movement of mammal species through canyons bisected by each of the roadways. The latter survey type was to establish baseline movement data within drainages that had the potential to be impacted by future road construction or road-widening activities. By identifying these movement routes, we could subsequently provide recommendations on which drainages would be best suited for the construction of wildlife underpasses.

Two sampling techniques were used to document the distribution and relative abundance of large across the study area: track surveys and remotely triggered camera surveys. We also conducted opportunistic track and scat surveys while traversing the

3 study area (i.e. walking to camera locations, driving ranch roads, scouting scent and camera stations).

Track Surveys

Scent stations have been widely used as a means to monitor trends in carnivore populations. Following methods developed by Linhardt and Knowlton (1975), track surveys have been shown to be effective measures of distribution and relative abundance of mammalian species (Conner et al. 1983; Sargeant et al. 1998).

To obtain information on the distribution of mammals within habitats surrounding the two roadways, we established four track transects along various dirt roads. Two of the transects were established west of Hicks Haul Road (Loma Ridge and Shoestring Canyon) and two were established east of Hicks Hauls Road (Limestone/Loma Ridge and Limestone Canyon) (Figure 2; Appendix A). Each 1000 m transect consisted of five scent stations at approximately 250 m intervals. Each scent station consisted of a 1 m2 plot of finely sifted gypsum powder and a rock, placed in the middle of the station, baited with two artificial scent lures every other day (Russ Carman's Pro Choice and Canine Call). Stations were checked for visitation for five consecutive mornings. If an animal visited a station, tracks were identified to species and the station was cleared and resifted. Scent stations were surveyed during two sampling periods: summer (August 23-27, 2002) and fall (October 29-November 2, 2002).

To further assess the movement of large and medium-bodied mammals throughout the study area, track transects were also established along Hicks Haul Road and Santiago Canyon Road (Figure 2; Appendix A). Scent stations along these transects (5 scent stations along Hicks Hauls Road; 10 scent stations along Santiago Canyon Road) were established at varying intervals to 1) detect potential surface crossing locations by mammals and 2) compare the relative abundance of mammal species along certain portions of these roadways. Such information would be valuable in determining future crossing structure placement.

To obtain an index of relative abundance, the number of visits by each species was divided by the total sampling effort. This index was calculated using the following equation:

I= {vj/(sjnj)}

where, I = index of carnivore activity at transect j vj = number of stations visited by species at transect j sj = number of stations in transect j nj = number of nights that stations were active in transect j

Any scent station in which tracks were too difficult to read was omitted from the sampling night. Thus, the true sampling effort was:

4

{sjnj} – oj where, oj = number of omits in transect j

This index does not provide data on the absolute number of individuals. Instead, the index is used to compare relative abundance of species across space and time (Conner et al. 1983; Sargeant 1998). Track indices were pooled across seasons to derive a single track index per transect for each individual species. GPS coordinates of scent stations are presented in Appendix A.

Camera Surveys

Remotely triggered cameras have increasingly become a useful tool in recording activity of various wildlife species (Griffiths and Van Schaik 1993; Jacobson et al. 1997; Karanth and Nichols 1998). Cameras provide a relatively low-maintenance means of surveying wildlife populations because visitations to the units are only made to change film and batteries.

Cameras were distributed among three sampling areas: interior locations (removed from Hicks Hauls Road and Santiago Canyon Road), drainages bisected by Hicks Hauls Road, and drainages bisected by Santiago Canyon Road. To obtain information on the distribution of mammals within interior habitats surrounding the two roadways, 7 Camtrak cameras (Camtrak South Inc, 1050 Industrial Drive, Watkinsville, GA 30677) were placed along wildlife trails and dirt roads throughout the study area (Figure 3; Appendix B). Two of these cameras were placed west of Hicks Haul Road (cameras 11 and 12), two were placed east of Hicks Hauls Road (cameras 14 and 15), and three were placed north of Santiago Canyon Road (cameras 26, 27, and 28). GPS coordinates of these cameras are presented in Appendix B. Data from these cameras were used in conjunction with track station data to provide information on those species occupying habitats surrounding Hicks Haul Road and Santiago Canyon Road.

The remaining cameras were placed in either one of two potential locations within drainages bisected by Hicks Haul Road and Santiago Canyon Road. For drainages containing an underpass under the roadway, the camera was secured to a wooden stake driven into the ground and stationed at a distance of 1 m from the underpass entrance. Nine underpasses were monitored by cameras, all of which were located along Santiago Canyon Road (Appendix C). At the request of The Irvine Company, two of the nine cameras stationed at underpasses (cameras 21 and 22) were established south of the East Orange/Central Irvine Ranch project area to monitor locations historically frequented by mountain lions (Beier & Barrett 1993) (see Figure 3 inset). For the remaining two drainages bisected by Santiago Canyon Road and the seven drainages bisected by Hicks Haul Road, cameras were placed along wildlife trails leading up the drainage away from the roadway (Appendix B). Thus, cameras could monitor movement by wildlife species

5 through the canyon in order to determine which drainages were being used by target species.

Each pass of an animal by the infra-red sensor triggered the camera. Date and time of pass were recorded on each print. Cameras were operated between August and December 2002. To obtain an index of relative abundance, the number of visits by each species was divided by the total sampling effort. This index was calculated using the following equation:

I= {vj/nj} where, I = index of carnivore activity at camera j vj = number of passes by species at camera j nj = number of nights that camera j was active

Camera indices were compared among cameras to detect relative activity levels of species across the study area. An index of underpass use was determined by dividing the number of pictures of each species entering or exiting the underpass by the number of nights the camera was active. Representative mammal photos taken by remotely triggered cameras are presented in Appendix D and E.

Additional Surveys

We recorded all incidental road killed large and medium-bodied wildlife along the portion of Santiago Canyon Road between CA 241 and Silverado Canyon Road. Road kill surveys coincided with track survey dates, however additional surveys were conducted between sampling dates due to visits being conducted to change film and batteries in cameras. Although surveys were not conducted systematically, this data represents the minimum rate of road mortality along this stretch of road. Locations were marked with a GPS unit. Date of kill, lane direction (northbound or southbound), and, if possible, sex and age were recorded.

We also conducted opportunistic track and scat surveys while traversing the study area (i.e. walking to camera locations, driving ranch roads, scouting scent and camera stations).

RESULTS

Nine mammal species were detected across the study area. Track surveys detected six species, including 2 species along Santiago Canyon Road, 4 species along Hicks Hauls Road, and 6 species within the open space surrounding Hicks Haul Road and Santiago Canyon Road. Camera surveys detected eight species, including 8 species traveling through drainages bisected by Santiago Canyon Road (including the underpasses), 6 species traveling along drainages bisected by Hicks Haul Road, and 7 species at interior

6 locations. Seven species were documented using the underpasses along Santiago Canyon Road.

Track Surveys

Six species were detected at scent stations within the area surrounding Hicks Hauls Road and Santiago Canyon Road, including mule deer, coyote, bobcat, gray , , and long-tailed weasel (Table 1). Scent stations also documented the presence of several smaller mammal, bird, and herpetofauna species, including squirrels, rabbits, rodents, roadrunners, and lizards. The Limestone/Loma Ridge transect was visited by six species, the Limestone Canyon transect was visited by five species, the Shoestring Canyon transect was visited by four species, and the Loma Ridge transect was visited by three species. and were detected on all four transects, mule deer and striped were detected on three transects, and and long-tailed were detected on two transects. Coyote activity was highest along the Loma Ridge transect and lowest along the Limestone/Loma Ridge transect; gray fox activity was highest along the Limestone/Loma Ridge transect and lowest along the Shoestring Canyon transect. Mule deer activity was highest along the Limestone/Loma Ridge transect. Bobcat and long-tailed weasel indices were similar for each species on the two transects where they occurred (0.020 for each species on each transect).

Four species were detected at scent stations along Hicks Haul Road and Santiago Canyon Road; four species along Hicks Haul Road and two species along Santiago Canyon Road (Table 1). Coyotes and gray fox were first and second, respectively, in order of frequency along each roadway; they were the only two species to visit scent stations along Santiago Canyon Road. Bobcats and striped skunks were only detected along Hicks Haul Road. All five scent stations along Hicks Haul Road were visited with fairly equal frequency (between 8-12 visits/station) (Table 2; Figure 4). Of the 10 stations along Santiago Canyon Road, station 7 was visited the most (10 coyote visits), whereas stations 3 and 9 were never visited (Table 2; Figure 5).

Camera Surveys

Eight species were detected at camera stations, including mountain lion, mule deer, coyote, bobcat, gray fox, striped skunk, , and the non-native Virginia opossum. Three of these species were not detected at scent stations, including the Virginia opossum, raccoon, and mountain lion. The only species that was detected at scent stations and not detected at camera stations was the long-tailed weasel.

Seven species were detected at interior camera stations (Table 3). The three cameras north of Santiago Canyon Road (cameras 26, 27, and 28) only monitored interior locations for a month and it is possible that more species may have been detected if the cameras surveyed for a longer time period. No animals were recorded at camera 26; cameras 27 and 28 each documented one species (coyotes at camera 27; mule deer at camera 28). The four cameras south of Santiago Canyon Road (cameras 11, 12, 14, and

7 15) documented a greater number of species. Camera 11 recorded 6 species, camera 14 recorded 5 species, and cameras 12 and 15 recorded 4 species. Three of these four cameras documented mountain lions (cameras 11, 12, and 14); the highest mountain lion activity was recorded at camera 12. Coyotes were recorded at all four of the cameras south of Santiago Canyon Road; bobcats and mule deer were recorded at three of them (cameras 11, 14, and 15).

Six species were detected moving along drainages leading away from Hicks Haul Road (Table 3). Camera 6 documented the greatest number of species (4), including all four of the target species. Mountain lions were recorded at two of the seven cameras (5 and 6); mule deer were recorded at 5 of the cameras (5, 6, 7, 10, and 13). Coyotes and bobcats were detected at four of the cameras.

All eight mammal species recorded by cameras were documented along Santiago Canyon Road; seven of these species used underpasses (Table 4). The nine underpasses receiving the greatest number of species included numbers 18, 19, and 20 (four species each). Mule deer were documented at two of the underpasses (cameras 16 and 20); a mountain lion was detected using underpass 19 (Table 4). Bobcats used eight of the nine underpasses, whereas coyotes used six underpasses. Other species recorded at underpasses included gray fox, raccoon, and the non-native Virginia opossum.

Additional Surveys

Only one road-killed animal was detected during this study: a raccoon along Santiago Canyon Road. Incidental observations of scat detected no additional species unique to those already detected by track and camera surveys.

Baseline Condition Assessment of Surveyed Drainages Bisected by Hicks Haul Road and Santiago Canyon Road

Five drainages that represent potential connectivity areas were identified along Hicks Haul Road and seven locations were identified along Santiago Canyon Road (Figure 6). Drainages were grouped into high, medium, and low activity areas based on the following criteria:

• drainages that were used by mule deer

Mule deer are very sensitive to underpass dimensions. Therefore, it is critical that underpasses of adequate size be placed in drainages in which they are known to occur (see Underpass Dimensions section below). Furthermore, this species represents the majority of the prey base for mountain lions and maintaining their populations is a critical component in maintaining mountain lion populations within this region.

8 • drainages used by mountain lions

Based on their home range area requirements, drainages in which mountain lions have been recorded will need structures that allow for their safe passage under roadways.

• drainages used by the greatest number of species

From a community perspective, it is important to maintain the movement of multiple species across roadways.

• drainages showing high levels of bobcat and coyote activity

Bobcats and coyotes will require a greater number of potential crossing locations due to their social structure, home range sizes, and dispersal capabilities.

Canyons listed below are identified by the number of the camera stationed in that particular drainage.

High Activity Drainages

1. Canyon 6 – Hicks Haul Road

Monitored by camera 6 (Figure 4). This drainage was used by all four of the target species. Furthermore, of all the drainages along Hicks Haul Road, mountain lions and mule deer had their highest activity level through this drainage. Further indication of the importance of this drainage is the high target species (mule deer, coyote, bobcat, and mountain lion) activity recorded at Camera 11 located along the ridgeline above this drainage.

2. Canyon 5 – Hicks Haul Road

Monitored by camera 5 (Figure 4). This drainage was used by mountain lions and mule deer. Further indication of the importance of this drainage is the high target species (mule deer, coyote, bobcat, and mountain lion) activity recorded at Camera 11 located along the ridgeline above this drainage.

3. Canyon 10 – Hicks Haul Road

Monitored by camera 10 (Figure 4). Canyon 10 was used by three of the target species: mule deer, coyote, and bobcat. This canyon contained the highest levels of bobcat activity, the second highest levels of coyote activity, and the third highest level of mule deer activity recorded in the side drainages to Hicks Haul Road.

9 4. Canyon 7 – Hicks Haul Road

Monitored by camera 7 (Figure 4). This canyon was used by three species, including mule deer and bobcats. Although common at scent stations along Hicks Haul Road, this was the only drainage bisected by Hicks Haul Road that gray fox were documented using.

5. Loma Ridge Saddle – Hicks Haul Road

Monitored by camera 13 (Figure 4). This saddle, located at the crest of Hicks Haul Road, represents an important movement route for several of the target species. Mule deer and coyotes were detected at the camera station (camera 13) and coyotes and bobcats were detected at the scent station. Given the topography in this area (the crest of the hill), an underpass may be difficult to establish in this vicinity. We suggest that a wildlife overpass be considered, which is an alternative to underpasses in these types of situations.

6. Canyon 19 – Santiago Canyon Road

Monitored by camera 19 (Figure 5). This drainage was the site of the only underpass in which mountain lion activity was documented. Although it was the only target species recorded at this underpass, maintaining the movement of this species across Santiago Canyon Road is critical, particularly so that populations west and south of Santiago Canyon Road do not become isolated from those occurring in the larger blocks of habitat to the east and north.

7. Canyon 20 – Santiago Canyon Road

Monitored by camera 20 (Figure 5). This underpass was used by three of the target species: mule deer, coyote and bobcat. Scent station 7 on Santiago Canyon Road is located in close proximity to Canyon 20 and had a high visitation rate by coyotes, possibly indicating that this species is attempting at-grade crossings. In addition, although a mule deer was recorded facing the entrance of this underpass, it is highly unlikely that it used the structure due to the small dimensions. However, this is only one of two underpasses along Santiago Canyon Road where mule deer were detected.

Medium Activity Drainages

1. Canyon 16 – Santiago Canyon Road (Santiago Creek Bridge)

Monitored by camera 16 (Figure 5). This underpass was used by three of the target species: mule deer, coyote, and bobcat. Scent stations 9 and 10 on Santiago Canyon Road were located on either side of this underpass and were rarely visited or not visited at all possibly indicating that this underpass is functioning to effectively facilitate movement of these species across Santiago Canyon Road.

10

2. Canyon 18 – Santiago Canyon Road

Monitored by camera 18 (Figure 5). This underpass was used by two of the target species: bobcat and coyote. Although only two of the target species were recorded, this underpass had the second highest index of bobcat use along Santiago Canyon Road.

Low Activity Drainages

1. Canyon 24 – Santiago Canyon Road

Monitored by camera 24 (Figure 5). Although this underpass was monitored for only a month, two of the target species were recorded using it: bobcat and coyote. The rocks (rip-rap) at the entrances to the underpass may decrease the probability that smaller vertebrates (i.e. lizards, snakes, amphibians) utilize this underpass.

2. Canyon 25 – Santiago Canyon Road

Monitored by camera 25 (Figure 5). Similar to underpass 24, this underpass was only monitored for a month, however two of the target species were recorded: bobcat and coyote.

3. Canyon 17 – Santiago Canyon Road (Limestone Creek Bridge)

Monitored by camera 17 (Figure 5). This large underpass recorded the presence of two target species: bobcat and coyote. It should be noted that there was also high human use compared to all other underpasses, which could potentially affect movement of these species across Santiago Canyon Road. This underpass represents another potential structure that could potentially facilitate mule deer movement, although mule deer were not detected using it.

DISCUSSION

Large mammals represent an excellent group of species as targets for conservation, in that they are wide-ranging, exhibit low population densities, and are large patch or interior dwelling species (Meffe et al. 1997). Further, the disappearance of top predators from fragmented systems may have community-wide implications (Robinson 1953, 1961; Linhart & Robinson 1972; Sargeant et al. 1983; Voight & Earle 1983; Schmidt 1986; Johnson et al. 1989; Sovada et al. 1995; Ralls & White 1995). As a group, carnivores (Order ) are collectively listed as state mammal species of special concern. Furthermore, the mountain lion has been identified as a high priority species of management/monitoring concern within the Nature Reserve of Orange County and the movement of top predators (mountain lions, coyotes, and bobcats) have been the focus of special monitoring efforts within the reserve (Crooks & Jones 1998). Finally, the area surrounding the East Orange/Central Irvine Ranch project area lies at the eastern end of

11 what has been identified as a critical connectivity zone (El Toro linkage) between the Laguna Coast Wilderness and the Santa Ana Mountains (Cleveland National Forest) (Penrod 2000). Large mammals have been identified as one of the key groups of species indicative of the connection.

Data collected from both track and camera surveys suggest that Loma Ridge and its’ eastern drainages are an important movement route for mountain lions. Five of the cameras situated in this vicinity documented mountain lion activity. Based on body size and color patterns, we were able to identify at least 3 different mountain lions traversing this area. Mountain lions possess large body sizes, home ranges, and habitat requirements and hence are the most sensitive predator species to fragmentation effects (Beier 1993; Crooks 2002). Specifically, the Loma Ridge/Limestone Canyon area alone is too small to permanently support resident lion populations with long-term viability, and thus this reserve likely serves as a critical component of one or several mountain lion home ranges that extend much further than the boundaries of the study area. In fact, mountain lion home ranges in this region range from 218 km2 (average female home range) to 767 km2 (average male home range) (Beier & Barrett 1993). Therefore, it is critical that linkages to larger areas of habitat to the east be maintained across Santiago Canyon Road. At least one underpass along Santiago Canyon Road was used by a mountain lion in this study (underpass 19) and other studies have documented numerous crossings by multiple individuals. A small canyon east of the old Hillcrest fire station (the underpass 19 drainage), an area approximately 200 m southeast of the junction of Santiago Canyon Road and Hicks Haul Road, and a location in the vicinity of underpasses monitored by cameras 21 and 22) were all locations where mountain lion activity was documented across Santiago Canyon Road (Beier & Barrett 1993). The use of underpass 19 by a mountain lion suggests that the habitat immediately south of Irvine Lake is being used by mountain lions as they travel between Loma Ridge and points north and east (i.e Fremont Canyon, Black Star Canyon), and appropriate efforts to maintain connectivity across this road in light of potential widening efforts should be addressed. Furthermore, mountain lion activity through two of the drainages bisected by Hicks Haul Road (canyons 5 and 6) indicate that suitable crossing structures will need to be placed along the proposed Jeffrey Road extension so that mountain lions can continue to maintain their travel routes (see Recommendations section below). In the future, monitoring for mountain lions can be best achieved by maintaining long-term camera stations. Although track transects are a cheaper means to document activity, they are only operated quarterly. Thus for large-ranging animals, such as mountain lions, the infrequency of track transects reduces the potential for these species to be detected, particularly where there are a wide variety of travel routes (i.e. no choke points). However, camera stations can be operated daily over much larger time frames, thus increasing the likelihood of detecting the presence of a mountain lion. In this study, camera stations were successful in detecting a relatively high level of mountain lion activity; no mountain lions were detected at scent stations.

Mule deer not only represent a critical component to a functioning ecosystem (in that they are top herbivores), they also comprise the majority of mountain lion diet (Beier &

12 Barrett 1993; Beier 1996). Mule deer activity was highest along Loma Ridge; track indices were highest along the Loma Ridge and Limestone/Loma Ridge transects. Cameras positioned along Loma Ridge (cameras 11 and 14) also recorded the greatest levels of mule deer activity. Of the numerous side drainages bisected by Hicks Haul Road, camera 6 recorded the greatest level of mule deer activity. Camera 16 along Santiago Canyon Road recorded the highest level of mule deer activity along that particular roadway. The only other additional underpass where mule deer activity was recorded was camera 20. Although this underpass was too small to allow mule deer to pass through it, this location represents an excellent opportunity to install a larger underpass (if the road design can accommodate a structure of this type) to facilitate mule deer movement in light of the projected widening of Santiago Canyon Road. Although mule deer appear to be fairly common in this area, the key to maintaining their populations is to provide adequate crossing structures in order for them to successfully pass under roadways (Reed et al. 1975; Foster & Humphrey 1995; Haas 2000). Currently, only two such structures exist along this portion of Santiago Canyon Road (underpasses monitored by cameras 16 and 17). Although traffic densities in this area are relatively low – moderate, future increases in road width and traffic volume should necessitate the need for adequate crossing structures for mule deer. Furthermore, in the event that traffic volumes increase, considerations should be given to providing adequate wildlife fencing (to reduce vehicle-related mortality) and enhancing existing crossing structures (Haas 2000; Lyren 2001). Mule deer have often benefited from fragmentation and have increasingly become problematic in many urbanized localities (Noss and Cooperrider 1994). However, in highly fragmented areas they occur in smaller, more isolated metapopulations that are more at risk to local extinctions and disease outbreaks. Therefore, although mule deer have adapted well to urbanized localities, their long-term persistence may ultimately depend on their ability to disperse successfully between fragmented patches of habitat.

The highest bobcat activity within the study area was also recorded in the Loma Ridge vicinity: along the Limestone/Loma Ridge transect, at the camera placed along the northern slopes of Loma Ridge (camera 11), and at the camera positioned in one of the drainages bisected by Hicks Haul Road (camera 10). Bobcat activity through underpasses along Santiago Canyon Road was fairly common; they were recorded at eight of the nine underpasses surveyed. Underpasses receiving the highest levels of bobcat activity included the underpass along Shoestring Canyon (camera 18), the underpass draining a small side drainage across from the Limestone Spur Road gate (camera 20), and the two underpasses located south of Silverado Canyon Road (cameras 21 and 22). Bobcats are intermediate in their sensitivity to habitat fragmentation (Haas 2000; Crooks 2002); they can still exist in fragmented habitats, but only those that provide adequate movement corridors to other habitat patches. Bobcats in Wisconsin used home ranges with low densities of secondary highways (paved two-lane roadways), and survival of populations may be affected by high levels of road density (Lovallo & Anderson 1996). Bobcat probability of occurrence and abundance in southern California has been negatively correlated with road density (Haas 2000), however they are not as sensitive as mountain lions to habitat fragmentation, primarily due their smaller home

13 range sizes; in the Chino Hills, located 15 km north of the study area, bobcat home ranges vary from 4 km2 – 12 km2 (Lyren 2001). Bobcats are more sensitive to habitat fragmentation than coyotes, which can persist in all but the smallest and most isolated habitat isolates (Crooks & Soulé 2000).

Coyote activity was also highest in the Loma Ridge area, specifically along the Loma Ridge transect at the cameras located along the crest of the ridge (cameras 11 and 14). Movement across Hicks Haul Road was highest at camera 6; cameras 16 and 18 along Santiago Canyon Road contained the highest levels of coyote activity. Although coyotes are widespread and relatively abundant throughout the region, certain populations are vulnerable to localized extinction in habitat fragments that are too small, disturbed, or isolated (Crooks & Soulé 2000).

Due to the fact that road kill mortality plays a significant role at removing juveniles from the population (Beier 1993; Lyren 2001), it is important to ensure that these individuals continue to utilize the underpass. Of particular concern is the movement of juveniles in a north to south direction across Santiago Canyon Road, as these individuals represent (on a regional scale) a potential source population from which genetic diversity south of Santiago Canyon Road depends on. Although the cameras along Santiago Canyon Road documented which species were utilizing the underpass, it was difficult to distinguish the sex, age, and social status of individuals traveling through the underpass. Such information is important in determining the level of interaction between various subsets of the target species populations on either side of Santiago Canyon Road. Information such as the demographic characteristics of target species utilizing the underpass, the dispersal distances and success of juveniles in the population, and the reproductive success of individuals using underpasses could offer more specific information on how these underpasses are being utilized. However, this study did obtain important information on juvenile/yearling activity through the underpasses; “non-adult” individuals were identified at camera 19 (mountain lion) and camera 21 (bobcat).

RECOMMENDATIONS

Future Underpass Locations and Function

The position of the underpass relative to the surrounding landscape in addition to habitat characteristics in the immediate vicinity of the underpass have been identified as critical factors in determining whether or not an underpass will be used by a particular species (Crooks & Jones 1998; Haas 2000). Landscape characteristics that have a negative impact on underpass use include a) for bobcats: high levels of residential/urban landscapes, narrow corridors, high road densities, and high levels of habitat fragmentation, b) for coyotes: high levels of residential/urban landscapes, narrow corridors, and high levels of habitat fragmentation, and c) for mule deer: high levels of residential/urban landscapes and high road densities (Crooks & Jones 1998; Haas 2000). Habitat characteristics in the immediate vicinity of the underpass are also important in predicting the use of underpasses by wildlife. For bobcats and mule deer, the use of

14 native vegetation increases the probability of underpasses use, whereas using non-native, ornamental landscaping decreases the probability of underpass use for bobcats (Crooks & Jones 1998; Haas 2000). The function of the underpass is also important for bobcats, as they are less likely to use underpasses that have a road/trail/paved bike path going through them (Crooks & Jones 1998). There has been increasing evidence that human traffic either directly (animal alters activity when a human is present) or indirectly (animal alters activity after a human has vacated the area) may cause animals to alter their activity patterns or avoid areas altogether (Griffiths & Van Schaik 1993; Clevenger & Waltho 2000).

In general, in order to optimize the probability of underpass use by the target species, we recommend that underpasses be situated along primary travel routes, away from areas containing noise and light pollution, and serve only wildlife needs. Additionally, native vegetation should surround all underpass entrances and replace any proposed rock fill slope protection. Concrete V-ditches and rip-rap should be avoided to allow for natural stream flows, which provide the elements critical for the movement of sensitive reptile and amphibian species. Sound walls should also be considered along portions of the roadways.

Underpass Dimensions

Like the landscape variables identified in determining the probability of underpass use, underpass dimensions are also important in determining whether or not a species will use an underpass as well as how frequently a species will use an underpass (Haas 2000). Haas (2000) found that mule deer (“species of interest” in NCCP/HCP planning and monitoring efforts) never used an underpass less than 4.5 m in height and coyotes never used underpasses less than 1 m in height. Furthermore, Crooks and Jones (1998) found that mule deer used open span bridges more frequently than box or pipe culverts. Thus, a more important variable is the openness of the underpass, which takes into consideration the height, width, and length of the underpass (H*W/L). An openness value greater than 0.6 has been recommended for mule deer (Reed 1981). In fact, Haas (2000) reported that bobcat, coyote, and mule deer frequency of underpass use increased as underpass height, width, and/or openness increased. Although the smaller drainage culverts may receive use by smaller vertebrates (rodents, herpetofauna, and mesopredators), large mammal activity through underpasses less than 1 m in height is highly unlikely. Specific underpasses dimensions (particularly large underpasses to facilitate mule deer movement), however, may be difficult to achieve due to road profile limitations.

Wildlife Fencing Design

In order to prevent attempts in at-grade crossings by the target species, it is critical that fencing be installed to complement the underpasses. It is recommended that fencing occur along the entire roadway/wildland interface, particularly along those stretches of roads that experience mule deer activity. Mule deer, as well as coyotes, are infamous for end runs, which means that they will travel along a fence until it ends and attempt to

15 cross the roadway at that location (Thompson 1978; Roof & Wooding 1996; Lyren 2001). This means they will continue to shift their movements to go around the end of a fence instead of using an underpass. If lengthy stretches of road can not be fenced, we recommend that monitoring take place to 1) identify high activity zones where mule deer mortality is occurring and 2) compare how those activity zones shift in relation wildlife fencing position. If lengthy portions of the road are fenced, it is critical that underpasses of adequate size be provided, so that the fencing does not create a barrier in itself. Within the immediate vicinity of wildlife crossing structures, fencing should be installed to “funnel” the animals towards each underpass.

It is entirely possible that fencing may not be as complete along the certain stretches of the road because of cost or aesthetics. We recommend that the fencing be a neutral color (ex: brown or green) to complement the natural landscape, instead of the startling silver that is standard. Since fencing is so crucial to the success of the underpasses, this would allow it to be installed along lengthy stretches of the roadways, but minimize the interruption of the scenery and maximize both functionality for wildlife and public enjoyment of the landscape. Additionally, native vegetation could be strategically placed along fencing to minimize its intrusiveness. This would be an added benefit because additional vegetation would buffer the additional noise and light that will accompany the increased traffic volume, which appears to suppress frequency of underpass use for coyotes (Lyren 2001). Finally, the fencing should have mesh that is less than 10 cm x 15 cm and be seated at least 15 cm into the ground to prevent the animals from exploiting any weaknesses, which would allow them access to the road.

Post-Construction Monitoring

Based on our experience of conducting wildlife corridor studies, and on our knowledge of similar studies published in the literature, we suggest the following approach to evaluating potential large and medium-bodied mammal crossing locations along a roadway. When faced with a situation such as the road extension of Jeffrey Road and road widening of Santiago Canyon Road, in which the goal is to identify potential crossing locations and evaluate the success of crossing structures after the roadway is widened, there is a need to compare baseline, “pre-impact” conditions to “post-impact” conditions. This approach is termed a before-after-control-impact (BACI) approach. Such an approach allows for a statistical comparison of large mammal activity prior to the widening of a road to large mammal activity after construction has been completed. This study contributes to the baseline (or “before”) knowledge of the distribution and frequency of species within the immediate area of the two roadways.

The track and camera station methodologies followed those that are consistent with the literature and local studies (Hatcher & Shaw 1981; Clark & Campbell 1983; Conner et al. 1983; Woelfl & Woelfl 1997; Sargeant et al. 1998). Perhaps more importantly, scent and camera stations were distributed at all existing and potential crossing locations in order to adequately assess the relative use of drainages, wildlife trails, and other topographical features the wildlife may be using to cross Hicks Haul Road and Santiago Canyon Road.

16 We suggest that an additional period of monitoring occur immediately before construction begins, so as to obtain pre-construction activity levels within the connectivity zones identified in this study. Such information will be more comparable to data collected after construction due to the shorter time frame between the studies. Post- construction monitoring should occur for a minimum of one year after the roadway widening has occurred; however it should be noted that even two-year studies are hardly adequate to determine movement patterns of larger predators. Additionally, mule deer may exhibit reluctance to use underpasses for at least 8 months after installation (Reed 1981; Ward 1982; Haas 2000). Again, these species require longer sampling periods since they operate at larger scales than other species (i.e. larger home ranges, longer life spans, etc.); the sampling strategy should reflect longer response periods to potential impacts. Road kill surveys should continue to determine how effective fencing is and appropriate measures should be taken if road kill levels continue at the rate prior to underpass installation.

When analyzing movement routes, the preferred method is telemetry. Although this method was not employed, it is highly advantageous, albeit costly, because it provides more accurate information on specific movement routes and rates of movement across the roadway. Furthermore, it would provide information on what demographics (underpasses need to be designed so that they facilitate not only home range movements of adults, but more importantly allow for dispersal movements of juveniles) are currently crossing the road, utilizing crossing structures, or avoiding the road. However, given that telemetry efforts were not utilized for this study, track and camera methodologies can still provide information on the relative use of particular crossing locations.

Summary of Recommendations

To summarize, we provide a list of recommendations that are targeted to maximize the level of connectivity relative to the proposed road construction projects:

1. Drainages that were utilized by mountain lions and mule deer should contain underpass large enough to facilitate the movement of these two species where feasible.

2. Fencing should be constructed along portions of the roadways containing underpasses that are used by mountain lions and mule deer and mortality surveys for mule deer should be conducted to determine whether they are making end runs in light of any fencing.

3. To enhance the areas surrounding each underpass, we recommend planting native vegetation so as to provide continuous cover for animals as they utilize these structures. Additional cover will also help in reducing light and noise pollution.

17 4. Another six-month study, focusing on connectivity zones/drainages that have been identified in this study, should occur immediately prior to construction so as to allow for more accurate comparison between pre- and post-construction wildlife activity.

5. Post-construction monitoring should mirror survey efforts conducted in this study so that potential differences in activity can be analyzed. Monitoring should address short-term and long-term impacts, as different species vary in their response to underpass use.

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23 Table 1. Large and medium-bodied mammal species detected at baited scent stations.

Transect Sampling Days 1 Species Detected Number of Detections Track Index Limestone Canyon 50 Canis latrans (Coyote) 18 0.360 cinereoargenteus (Gray fox) 10 0.200 mephitis (Striped skunk) 3 0.060 rufus (Bobcat) 1 0.020 Odocoileus hemionus (Mule deer) 1 0.020

Limestone/Loma Ridge 49 Urocyon cinereoargenteus (Gray fox) 11 0.220 Canis latrans (Coyote) 6 0.122 Mephitis mephitis (Striped skunk) 4 0.080 Odocoileus hemionus (Mule deer) 3 0.061 Felis rufus (Bobcat) 1 0.020 Mustela frenata (Long-tailed weasel) 1 0.020

Loma Ridge 50 Canis latrans (Coyote) 33 0.660 Urocyon cinereoargenteus (Gray fox) 3 0.060 Odocoileus hemionus (Mule deer) 2 0.040

Shoestring Canyon 50 Canis latrans (Coyote) 20 0.400 Mephitis mephitis (Striped skunk) 6 0.120 Urocyon cinereoargenteus (Gray fox) 2 0.040 Mustela frenata (Long-tailed weasel) 1 0.020

Hicks Haul Road 50 Canis latrans (Coyote) 28 0.560 Urocyon cinereoargenteus (Gray fox) 18 0.360 Felis rufus (Bobcat) 4 0.080 Mephitis mephitis (Striped skunk) 2 0.040

Santiago Canyon Road 100 Canis latrans (Coyote) 19 0.190 Urocyon cinereoargenteus (Gray fox) 4 0.040 1 Sampling days is calculated as the number of scent stations per transect x the number of nights the stations were active; any nights in which the station was ommitted was subtracted from the sampling nights total (see pages 4-5). Table 2. Large and medium-bodied mammal species detected at baited scent stations along Hicks Haul Road and Santiago Canyon Road. Locations of track stations are presented in Figures 4 and 5.

Roadway Scent Station # Species Detected Number of Detections Hicks Haul Road 1 Canis latrans (Coyote) 5 Urocyon cinereoargenteus (Gray fox) 2 Felis rufus (Bobcat) 1 Mephitis mephitis (Striped skunk) 1

2 Canis latrans (Coyote) 6 Urocyon cinereoargenteus (Gray fox) 5 Mephitis mephitis (Striped skunk) 1

3 Canis latrans (Coyote) 5 Urocyon cinereoargenteus (Gray fox) 5 Felis rufus (Bobcat) 2

4 Canis latrans (Coyote) 6 Urocyon cinereoargenteus (Gray fox) 2

5 Canis latrans (Coyote) 6 Urocyon cinereoargenteus (Gray fox) 4 Felis rufus (Bobcat) 1

Santiago Canyon Road 1 Canis latrans (Coyote) 1 Urocyon cinereoargenteus (Gray fox) 1

2 Canis latrans (Coyote) 3 Urocyon cinereoargenteus (Gray fox) 1

3 No species detected

4 Canis latrans (Coyote) 1

5 Canis latrans (Coyote) 1

6 Urocyon cinereoargenteus (Gray fox) 2

7 Canis latrans (Coyote) 10

8Canis latrans (Coyote) 3

9 No species detected

10 Canis latrans (Coyote) 1 Table 3. Large and medium-bodied mammal species detected at camera stations located in areas removed from roadways (interior areas) and along drainages bisected by roadways (Figure 3).

Camera Location Camera # Sampling Days Species Detected Number of Detections Camera Index Interior 11 112 Odocoileus hemionus (Mule deer) 28 0.250 Canis latrans (Coyote) 23 0.205 Felis rufus (Bobcat) 9 0.080 lotor (Raccoon) 3 0.027 concolor (Mountain lion) 2 0.018 Urocyon cinereoargenteus (Gray fox) 1 0.009

Interior 12 114 Mephitis mephitis (Striped skunk) 4 0.035 Urocyon cinereoargenteus (Gray fox) 4 0.035 Puma concolor (Mountain lion) 3 0.026 Canis latrans (Coyote) 1 0.009

Interior 14 103 Odocoileus hemionus (Mule deer) 16 0.155 Urocyon cinereoargenteus (Gray fox) 9 0.087 Canis latrans (Coyote) 7 0.068 Felis rufus (Bobcat) 1 0.010 Puma concolor (Mountain lion) 1 0.010

Interior 15 78 Felis rufus (Bobcat) 2 0.026 Canis latrans (Coyote) 1 0.013 Odocoileus hemionus (Mule deer) 1 0.013 Procyon lotor (Raccoon) 1 0.013

Interior 26 28 No species detected

Interior 27 28 Canis latrans (Coyote) 6 0.214

Interior 28 28 Odocoileus hemionus (Mule deer) 2 0.071

Hicks Haul Road 5 129 Odocoileus hemionus (Mule deer) 5 0.039 Puma concolor (Mountain lion) 1 0.008

Hicks Haul Road 6 129 Odocoileus hemionus (Mule deer) 28 0.217 Canis latrans (Coyote) 12 0.093 Puma concolor (Mountain lion) 4 0.031 Felis rufus (Bobcat) 1 0.008

Hicks Haul Road 7 114 Odocoileus hemionus (Mule deer) 2 0.018 Felis rufus (Bobcat) 1 0.009 Urocyon cinereoargenteus (Gray fox) 1 0.009

Hicks Haul Road 8 128 Canis latrans (Coyote) 1 0.008 Felis rufus (Bobcat) 1 0.008

Hicks Haul Road 9 136 Mephitis mephitis (Striped skunk) 1 0.007

Hicks Haul Road 10 97 Canis latrans (Coyote) 7 0.072 Felis rufus (Bobcat) 3 0.031 Odocoileus hemionus (Mule deer) 3 0.031

Hicks Haul Road 13 93 Odocoileus hemionus (Mule deer) 6 0.065 Canis latrans (Coyote) 4 0.043

Santiago Canyon Road 23 20 No species detected

Santiago Canyon Road 29 28 Mephitis mephitis (Striped skunk) 2 0.071 Canis latrans (Coyote) 1 0.036 Urocyon cinereoargenteus (Gray fox) 1 0.036 Table 4. Large and medium-bodied mammal species detected at camera stations located at underpasses along Santiago Canyon Road (Figure 3).

Camera # Sampling Days Species Detected Number of Detections Camera Index 16 117 Canis latrans (Coyote) 13 0.111 Odocoileus hemionus (Mule deer) 5 0.043 Felis rufus (Bobcat) 4 0.034

17 118 Felis rufus (Bobcat) 6 0.051 Procyon lotor (Raccoon) 4 0.034 Canis latrans (Coyote) 1 0.008

18 110 Procyon lotor (Raccoon) 21 0.191 Felis rufus (Bobcat) 14 0.127 Canis latrans (Coyote) 9 0.082 Didelphis virginiana (Virginia opossum) 1 0.009

19 124 Procyon lotor (Raccoon) 17 0.137 Urocyon cinereoargenteus (Gray fox) 9 0.073 Didelphis virginiana (Virginia opossum) 5 0.040 Puma concolor (Mountain lion) 1 0.008

20 131 Felis rufus (Bobcat) 11 0.084 Canis latrans (Coyote) 3 0.023 Odocoileus hemionus (Mule deer) 1 0.008 Procyon lotor (Raccoon) 1 0.008

21 96 Felis rufus (Bobcat) 10 0.104

22 97 Felis rufus (Bobcat) 30 0.309 Procyon lotor (Raccoon) 2 0.021

24 28 Felis rufus (Bobcat) 3 0.107 Procyon lotor (Raccoon) 3 0.107 Canis latrans (Coyote) 2 0.071

25 28 Felis rufus (Bobcat) 2 0.071 Procyon lotor (Raccoon) 2 0.071 Canis latrans (Coyote) 1 0.036

Figure 1. Location of study area, East Orange/Central Irvine Ranch, CA.

Figure 2. Location of track transects (blue line) and scent stations (red circles). All transects contained five scent stations with the exception of Santiago Canyon Road, which contained ten.

Figure 3. Location of camera stations. Cameras 21 and 22 were located 2 km south of camera 16 along Santiago Canyon Road.

Figure 4. Location of scent and camera stations along Hicks Haul Road. Scent stations (red circles; numbered 1-5) were placed along the shoulder of Hicks Hauls Road. Cameras (yellow circles) were placed along wildlife trails in drainages bisected by Hicks Haul Road.

Figure 5. Location of scent and camera stations along Santiago Canyon Road Road. Scent stations (red circles; numbered 1-10) were placed along the shoulder of Santiago Canyon Road. Cameras (yellow circles) were placed along wildlife trails in drainages bisected by Hicks Haul Road. Cameras were also placed at underpasses along Santiago Canyon Road (yellow squares).

Figure 6. Location of proposed underpasses/underpass improvements along Hicks Haul Road and Santiago Canyon Road. Appendix A. GPS coordinates of scent stations.

Transect Scent Station # Degrees N a Degrees W a Limestone Canyon 1 33.74819 117.68804 2 33.74902 117.68550 3 33.74898 117.68300 4 33.75030 117.68552 5 33.75163 117.68418 Limestone/Loma Ridge 1 33.73971 117.69992 2 33.73799 117.69896 3 33.73586 117.69907 4 33.73612 117.69636 5 33.73776 117.69564 Loma Ridge 1 33.74684 117.71221 2 33.74826 117.71445 3 33.74920 117.71668 4 33.75060 117.71909 5 33.75198 117.72015 Shoestring Canyon 1 33.76318 117.71260 2 33.76175 117.71421 3 33.76082 117.71653 4 33.75950 117.71883 5 33.75736 117.72031 Hicks Haul Road 1 33.74285 117.70611 2 33.74552 117.70425 3 33.74729 117.70315 4 33.74930 117.70268 5 33.75157 117.70304 Santiago Canyon Road 1 33.76758 117.72441 2 33.76592 117.71497 3 33.76374 117.71327 4 33.76191 117.70888 5 33.75788 117.69975 6 33.75483 117.69517 7 33.75271 117.68599 8 33.75263 117.68318 9 33.74759 117.67665 10 33.74776 117.67501 a locations obtained in WGS84 datum Appendix B. GPS coordinates of camera stations.

Camera # Degrees N a Degrees W a 5 33.75434 117.70417 6 33.75301 117.70477 7 33.75002 117.70344 8 33.74842 117.70387 9 33.74938 117.70239 10 33.74661 117.70632 11 33.75385 117.71244 12 33.76041 117.71779 13 33.73972 117.70416 14 33.73832 117.69445 15 33.74897 117.68304 16 33.74770 117.67557 17 33.76002 117.70340 18 33.76354 117.71267 19 33.76749 117.72686 20 33.75278 117.68509 21 33.73626 117.65731 22 33.73404 117.65328 23 33.76027 117.70193 24 33.75271 117.68815 25 33.75259 117.69027 26 33.76248 117.69590 27 33.75762 117.68655 28 33.76550 117.69670 29 33.75476 117.69363 a locations obtained in WGS84 datum Appendix C. GPS coordinates of underpasses monitored by remotely triggered cameras along Santiago Canyon Road.

Camera # Degrees N a Degrees W a 16 33.74770 117.67557 17 33.76002 117.70340 18 33.76354 117.71267 19 33.76749 117.72686 20 33.75278 117.68509 21 33.73626 117.65731 22 33.73404 117.65328 24 33.75271 117.68815 25 33.75259 117.69027 a locations obtained in WGS84 datum Appendix D. Representative photos of mammal species taken by remotely triggered cameras stationed at interior locations.

Camera 5: Mountain lion Camera 5: Mule deer

Camera 6: Bobcat with ground squirrel Camera 6: Mountain lion

Camera 11: pair of coyotes Camera 11: pair of mule deer

Camera 11: Mountain lion Camera 12: Mountain lion Appendix E. Representative photos of mammal species taken by remotely triggered cameras stationed at underpasses along Santiago Canyon Road.

Camera 16: Bobcat Camera 16: Coyote

Camera 18: Coyote Camera 18: Bobcat

Camera 19: Mountain lion Camera 20: Bobcat

Camera 21: Bobcat Camera 22: Bobcat