Behavioral responses of bobcats and coyotes to habitat fragmentation and corridors in an urban environment

Biological Conservation 108 (2002) 299–306 www.elsevier.com/locate/biocon

Behavioral responses of bobcats and coyotes to habitat fragmentation and corridors in an urban environment Lourraine A. Tigasa,*, Dirk H. Van Vurena, Raymond M. Sauvajotb a

Department of Wildlife, Fish, and Conservation Biology and Ecology Graduate Group, One Shields Avenue, University of California, Davis, CA 95616, USA b US National Park Service, Santa Monica Mountains National Recreation Area, 401 W. Hillcrest Drive, Thousand Oaks, CA 91360, USA Received 15 December 2001; received in revised form 21 February 2002; accepted 9 March 2002

Abstract We examined the behavior of bobcats and coyotes in a fragmented urban area northwest of Los Angeles, California, from July 1998 to October 1999. Activity patterns of bobcats and coyotes were crepuscular with no apparent shift to nocturnality, but activity was somewhat lower during daylight hours than in an unfragmented reference area, implying some avoidance of humans. Home ranges were not significantly larger in fragmented than in unfragmented habitat, probably because unproductive development within a home range may have been balanced by availability of human-related food, such as fruit, garbage, and pets. Female bobcat home ranges were generally within a single fragment, while male bobcats and coyotes of both sexes included more than one fragment. Both species tended to cross over roads rather than use culverts. Culverts were more likely to be used earlier in the night, during heavier traffic, and if they contained less water. Bobcats and coyotes used corridors as habitat and, less often, for travel. Both species also crossed development to move between fragments, but seemed to prefer corridors when available. Our results indicate that bobcats and coyotes persisting in an urban environment adjust behaviorally to habitat fragmentation and human activities, in part through temporal and spatial avoidance. Both species appeared willing to cross well-travelled roads despite the availability of culverts; consequently, vehicular collision is an important cause of mortality (50%) and needs attention. # 2002 Elsevier Science Ltd. All rights reserved. Keywords: Habitat fragmentation; Wildlife corridor; Bobcat; Coyote; Activity; Movement; Home range

1. Introduction Habitat fragmentation is currently one of the major threats to biodiversity, especially to large carnivores because of their large area requirements (Wilcox and Murphy, 1985; Noss et al., 1996; Crooks and Soule´, 1999; Crooks, in press). Fragmentation leaves pieces of habitat that may be too small to maintain a viable population or even a single carnivore’s home range. Carnivores may become extirpated, or they may persist in small home ranges within a single fragment or by incorporating several fragments into a larger home range. Moving through a hostile matrix between fragments, however, may be problematic because individuals may be unwilling or because they may be killed in * Corresponding author. Present address: ENTRIX, Inc., 2601 Fair Oaks Boulevard, Suite 200, Sacramento, CA 95864, USA. Tel.: +1916-923-1097; fax: +1-916-923-6251. E-mail address: [email protected] (L.A. Tigas).

the attempt. Corridors may enhance connectivity by providing safe passage between fragments (Beier, 1993; Noss et al., 1996; Beier and Noss, 1998). However, little is known about whether animals use corridors to move between fragments (Beier and Noss, 1998). In areas where roads are barriers to movement, culverts may serve as corridors to traverse roads. The effects of roads in hindering animal movement and the potential for culverts to mitigate those effects are a growing conservation topic (Foster and Humphrey, 1995; Noss et al., 1996; Clevenger and Waltho, 2000; Trombulak and Frissell, 2000). Urbanization is a major cause of habitat fragmentation threatening carnivore survival around the world (Ferreras et al., 1992; Vila et al., 1995; White et al., 1996; Adkins and Stott, 1998), but fragmentation is especially severe in southern California where large areas of natural habitat are annually converted to roads, houses, and businesses. The two most common large carnivores in southern California are the bobcat

0006-3207/02/$ - see front matter # 2002 Elsevier Science Ltd. All rights reserved. PII: S0006-3207(02)00120-9

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(Felis rufus) and the coyote (Canis latrans), species which are likely to be sensitive to fragmentation because of their size, trophic needs, and low numbers. Both species are able to persist to some degree in fragmented habitat (Crooks, in press; Tigas 2000), but it is unknown how bobcats and coyotes respond behaviorally to habitat fragmentation and human disturbance. Habitat fragmentation and disturbance from human activities are likely to affect both temporal and spatial habitat use. Bobcats and coyotes in undeveloped areas are crepuscular (Andelt and Gipson, 1979; Bekoff, 1982; McCord and Cardoza, 1982; Anderson, 1987; Shivik et al., 1997); however, some carnivores are able to change the timing of their activity in response to human presence (Ayres et al., 1986; Van Dyke et al., 1986; Larivie`re et al., 1994; Samson and Raymond, 1995; Vila et al., 1995; Doncaster and MacDonald, 1997). Further, individuals might be able to expand their home range to include several fragments that together provide adequate resources (Redpath, 1995; Collins and Barrett, 1997; Little and Crowe, 1998). However, traversing such a home range requires movement through the urban matrix, which has been little studied for coyotes (Shargo, 1988; Quinn, 1997b; Romsos, 1998), and not at all for bobcats. Similarly, use of culverts and corridors by bobcats and coyotes has received little attention (Foster and Humphrey, 1995; Romsos, 1998). We investigated the effect of habitat fragmentation on circadian activity, home range size and location, and movement patterns of bobcats and coyotes in a southern California residential area by comparing animals in our fragmented study area to those in an adjacent reference area of continuous habitat. We expected that individuals in fragmented habitat would shift to nocturnal activity and locate their home ranges away from development, and that home ranges would be larger due to the presence of unusable developed land within the home range perimeter. We determined the paths taken by individuals in fragmented habitat to determine if corridors are used to traverse the urban matrix and if culverts are used to cross roads.

2. Methods 2.1. Study area Southern California is exhibiting rapid growth, yet there are still many natural areas interspersed among human development. Our study was conducted in an area in the Simi Hills and Conejo Valley in western Los Angeles and eastern Ventura counties (34
100 0000 N, 118
500 000 W) in and around the communities of Oak Park, Agoura Hills, Westlake Village, Thousand Oaks, and Newbury Park. Between 1960 and 1980, much of this area was converted from native vegetation (mixed

chaparral, coastal sage scrub, annual grassland, oak woodland, oak savanna, and riparian woodland; Holland, 1986) into roads, housing developments, shopping centers, and business complexes. Building density in housing developments averaged ca. 140/km2. Most fragments of native vegetation were located on steep hills, canyons, and riparian areas that were unsuitable for development or were set aside as open space easements. Fragments ranged 4–560 ha in size and were 10– 200 m from the nearest fragment or potential corridor. Potential corridors were any linear fragments of vegetation. Some were set aside as wildlife corridors, others included golf courses and riparian habitat that were situated in development between fragments. The reference area consisted of continuous habitat to the north and east containing similar vegetation and managed by the Santa Monica Mountains National Recreation Area, US National Park Service. The area has a Mediterranean type climate with distinct dry (June–November) and wet (December–May) seasons. Average annual rainfall is 30 cm. Summer temperatures average 15–25
C but can reach 45
C, and winters are typically mild averaging 10–20
C. 2.2. Animal capture and telemetry We trapped animals with padded leg-hold traps or neck snares with stops to prevent strangulation. Bobcats were chemically restrained with a ketamine hydrochloride/xylaxine mixture, while coyotes were physically restrained by hobbling and muzzling. Sex and age class (adult or juvenile) were determined for each animal. Animals were tagged with uniquely colored ear tags, fitted with motion-sensitive radio-transmitter collars that transmitted for about 2 years, then released at the capture site within 1 h. 2.3. Activity patterns Hand testing of collars and observation of collared animals indicated that motion-sensing switches were especially sensitive; therefore, measurements of animal inactivity should be considered conservative. Activity patterns were obtained by scanning for all animals once every 30 min for 2- to 12-h sessions distributed throughout the 24-h day. Additional activity data were obtained during radio-location to determine home range size and movements. Animals were scored as active if activity was detected during > 10 s of a 60-s interval. For each season (wet and dry), > 25 observations were obtained for every hour of the 24-h day and a minimum of five coyotes and eight bobcats contributed to each hour’s observations. We attempted to spread observations as evenly as possible among study animals, time periods, seasons, and environmental conditions, such as weather and moon phase, that may affect activ-

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ity. An index of activity was calculated by dividing the number of active observations by the total number of observations for each 2-h period of the 24-h day (Pacific Standard Time, PST). Activity patterns in the reference area were obtained through regular locations of eight coyotes and nine bobcats in a separate study using the same protocol (Sauvajot et al., 2000). 2.4. Home ranges Animals were radio-located on average twice a week with locations at least 24 h apart. Due to an extensive road network and relatively small fragment area, observers were almost always within 1 km of collared animals and usually within 500 m. Three to four bearings were obtained within 20 min by one observer, or two bearings were obtained simultaneously by two observers. Observer locations were determined using a global positioning system (GPS, Trimble Navigation Limited, Sunnyvale, California) with an accuracy of within 1 m. To minimize error, triangulations for home range analysis were limited to those with bearing differences of 30–120
for sequential bearings by one observer and 70–110
for simultaneous bearings by two observers. We attempted to obtain at least 20 locations each season for each animal. Animal locations were determined using LOCATE II (version 1.6, Pacer, Truro, Nova Scotia, Canada, 1990– 1994), which produced a universal transverse mercator (UTM) coordinate for all locations. Locations with large error polygons, diverging lines, or of low observer confidence were subjectively eliminated from analysis. Annual home ranges were calculated based on a 95% minimum convex polygon using CALHOME (version 1.0, US Forest Service Pacific SW Research Station and California Department of Fish and Game, 1994). Home range sizes were compared with those of nine bobcats and eight coyotes in the reference area in a separate study (Sauvajot et al., 2000). Home range size was compared between sexes and between fragmented and unfragmented habitat using two-way analysis of variance (ANOVA).

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Movement paths were mapped on a GIS for analysis (Animal Extension Software, version 2, Alaska Biological Center, USGS, Anchorage, Alaska). The night was broken into three time periods: dusk (1 h before to 1 h after sunset), evening (1 h after sunset until 23:00), and night (23:00 until 1 h before sunrise); after about 23:00, human activity in the study area decreased markedly. Focal locations were classified as fragment interior (> 100 m from development), edge ( < 100 m from development), or development. We chose 100 m arbitrarily as the boundary between fragment edge and interior. We identified five corridors prior to the onset of the study. We recorded the number of times animals were present in these corridors and the number of times animals travelled through them to move from one fragment to another during focal sessions. We determined the number of locations that fell within the corridors and the fraction of these locations when the animal was travelling and not travelling. We defined travelling as movement rate > 1 km/h from the previous location to the subsequent location and without a reversal of direction (modified from Laundre´ and Keller, 1981). Mortality rate for each species was calculated by dividing the number of deaths for the entire year of the study by the total number of collared animals.

3. Results 3.1. Activity patterns We recorded 1976 activity pattern observations of 11 bobcats (five adult males, four adult females, and two juvenile females) and 1198 observations of 13 coyotes (six adult males, two juvenile males, three adult females, and two juvenile females) from June 1998 to October 1999. The activity patterns of bobcats and coyotes were generally similar (Fig. 1). Both species showed a bimodal pattern with crepuscular activity peaking around sunrise and sunset. Both bobcats and coyotes were less active during the day in fragmented than in unfragmented habitat (about 30% compared to about 50%, respectively).

2.5. Movement patterns 3.2. Home range size and location Animal movements were determined by focal-animal telemetry, with consecutive locations obtained every 30 min for 2- to 12-h telemetry sessions, with an average of three focal sessions per animal. Animals in the vicinity of developed areas were monitored particularly closely with continuous monitoring and visual observation when possible. Crossings of roads were observed visually when possible, and the following variables were recorded: time, method (over the road or through a culvert), road width, traffic (number of cars passing in 5 min), culvert diameter, and depth of water within the culvert.

We obtained a mean of 43.3 radio-locations (range=37–50) for bobcats in fragmented habitat, 20.2 (range=20–22) for bobcats in unfragmented habitat, 28.3 (range 18–47) for coyotes in fragmented habitat, and 21.0 (range 20–24) for coyotes in unfragmented habitat. We doubt that variation in number of radiolocations unduly influenced our home range estimates because number of locations explained almost none of the variation in home range size for either bobcats (r2=0.06, P=0.27) or coyotes (r2=0.04, P=0.48).

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Annual home ranges of bobcats were not significantly larger in fragmented than in unfragmented habitat (F=1.73, P=0.15, one-tailed test; Table 1). Males tended to have larger home ranges than females, although the difference was not significant (F=3.51, P=0.11). Like bobcats, annual home ranges of coyotes were not significantly larger in fragmented than in unfragmented habitat (F=0.97, P=0.18, one-tailed test). Unlike bobcats, female coyote home ranges tended to be larger than those of males, a difference that approached significance (F=4.84, P=0.06). For analysis of home range location, we included four bobcats and seven coyotes that we excluded from home range size because of age (subadult) or because of radiolocations that were too few for home range calculation (n=13–17) but sufficient to describe home range location. Eight of 14 bobcats had home ranges entirely within a single fragment. Two bobcats (both adult males) encompassed more than one fragment in their home ranges and crossed over four-lane roads even during heavy traffic. The remaining four bobcats had home ranges that encompassed part of the reference area and one or two fragments. Two of these ventured into fragments mainly at night and spent the day in the reference area. The third often spent the day within fragments. The fourth bobcat, an adult female, moved from the reference area into fragments, crossing US Highway 101, a heavily traveled 8- to 10-lane highway. Only 2 of 12 coyotes had home ranges entirely within a single fragment. Four coyotes had home ranges that

included more than one fragment; two of these frequently crossed major roads. The remaining six coyotes spent time in both the reference area and in fragments and were located in fragments day or night. 3.3. Movement patterns Of 57 focal sessions conducted on 13 bobcats and nine coyotes, four were eliminated from analysis because the animals moved a total of < 100 m during the session. In 23 of 32 bobcat sessions, the bobcat never left the fragment in which it was first detected. In 16 of these, the bobcat was never within 100 m of development. Of the nine sessions in which bobcats left the initial fragment, two crossed roads but not development, and seven crossed both roads and development. In 9 of 21 coyote sessions, the animal never left the fragment in which it was first detected. In four of these, the coyote was never within 100 m of development. Of the 12 that left the fragment, three crossed roads but not development, and nine crossed both roads and development. The maximum straight-line distance moved through development was 342 m for bobcats and 721 m for coyotes. Eighty-six road crossings were documented, 36 by bobcats and 50 by coyotes. Of the 77 road crossings in which method was discernible, 68 (28 by bobcats and 40 by coyotes) were over the road. Seven individual bobcats and nine individual coyotes crossed roads but crossings were not evenly distributed among individuals; for example, one adult male bobcat crossed roads 21 times and one adult male coyote crossed roads 16 times. There were 33 crossings (13 bobcat and 20 coyote) where culverts were available within 100 m, and in 24 method was discernible. Fifteen (five bobcat and 10 coyote) of the 24 crossings were over the road and nine (two bobcat and seven coyote) were through culverts. Road crossings averaged about 1.5 h later at night than did culvert crossings (Table 2). Culverts were used more Table 1 Home range sizes (95% MCP home ranges, in ha), by sex, of bobcats and coyotes in fragmented and unfragmented habitat in southern California, 1998–1999 Sex Bobcats Fragmented

Mean St. Sample Minimum Maximum Dev. size

Male 271.8 Female 124.9

93 6 58.7 4

151 71.8

361 193

67 21

281 469

32.2 3 72.8 2

90 273

153 376

Unfragmented Male 131.8 73.6 4 Female 198.5 130.3 4

59 63

234 376

Unfragmented Male 149.8 93.7 4 Female 125.2 192.9 5 Coyotes Fragmented Fig. 1. Annual average bobcat and coyote activity patterns in fragmented and unfragmented habitat, northwest of Los Angeles, California, June 1998 to October 1999. Activity patterns from the unfragmented habitat are incomplete due to insufficient data.

Male 125.2 Female 324.2

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often during heavier traffic, and culverts used for crossings contained about half the water depth of culverts not used. Culvert diameter and road width did not appear to influence road crossing behavior. The distribution of focal locations of bobcats and coyotes among interior habitat, edge habitat, and development changed as dusk progressed to evening and then night (Fig. 2). Bobcats were mainly in interior habitat at dusk, but ventured more into edge and development during evening and night (P< 0.005; w2=23.5; df=4). In contrast, coyote locations were mainly in edge habitat at dusk, but increasingly moved into development with evening and night (P=0.009; w2=9.3; df=4). Animals were located within corridors at least once during 36% (n=53) of focal sessions; 39% of focal bobcats and 56% of focal coyotes occurred in corridors at least once. Bobcats, coyotes, or both were located in all five corridors. Animals used a corridor to travel from one fragment to another in 21% of 19 sessions when an animal was within a corridor, all of them involving coyotes. Three of five corridors were used for travelling between fragments. Coyotes used corridors for travelling more than did bobcats (w2=6.80, P < 0.01, df=1); 42% of coyote locations in corridors involved travelling (n=36), compared with only 16% of bobcat locations (n=49). The remainder likely involved other activities such as resting or foraging. Two bobcats died during the study (14%); one death was caused by vehicle collision (a yearling female), whereas the cause of the other (an adult male) was unknown. Four coyotes died (29%); two deaths were caused by vehicle collisions (adult males) and two were unknown (an adult male and an adult female).

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areas at dusk, foraging and rest during the night, and travelling to resting areas at dawn (Laundre´ and Keller, 1981; Shargo, 1988). Human activity in our study did not alter the bimodal nature of this circadian pattern because both bobcats and coyotes in fragmented habitat were active most during the evening and morning. However, both species were less active during the day in fragmented habitat than in unfragmented habitat, suggesting some behavioral avoidance of human activities. Few other studies have explored the effects of humans on bobcat and coyote activity in urban areas. Some studies have found activity shifts in response to humans (Romsos, 1998; Kitchen et al., 2000; McClennen et al., 2001), while others have not (Bradley and Fagre, 1988; Shargo, 1988). 4.2. Home ranges For both bobcats and coyotes, home range sizes in fragmented habitat were not significantly larger than those in unfragmented habitat, contrary to our expectation. We suspect that the presence of unproductive development within home ranges in fragmented habitat may have been balanced by high productivity in other parts of the home range. Urban landscapes often have high numbers of rodents and rabbits, the main prey of

4. Discussion 4.1. Activity patterns The general pattern of activity for both bobcats and coyotes is rest during the day, travelling to foraging Table 2 Characteristics of road crossings where culverts were available within 100 m, for bobcats and coyotes in fragmented habitat in urban southern California, 1998–1999 Characteristic

Over the road (n=15)

Through culvert (n=9)

Time of day Traffic level Average diameter of culvert Depth of water in culvert Road width

x=22:35 PST x=0.8 cars/min x=4.1 m x=8.2 cm x=2.7 lanes

x=20:02 PST x=2.1 cars/min x=3.3 m x=4.5 cm x=3.1 lanes

Some individual animals made several crossings, precluding statistical comparison because of lack of independence among observations.

Fig. 2. Distribution of bobcat and coyote locations in relation to development at different times of the night in an urban area northwest of Los Angeles, California, 1998–1999. Time is divided into dusk (1 h before to 1 h after sunset), evening (1 h after sunset until 23:00), and night (23:00 until 1 h before sunrise). Location is divided into interior ( >100 m from development), edge ( <100 m from development), and development (roads, residential, commercial, or manicured landscapes such as golf courses and community parks).

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bobcats and coyotes in southern California, as well as human-related food such as fruit, garbage, and household pets (MacCracken, 1982; Shargo, 1988; Harrison, 1993; McClure et al., 1996; Oehler and Litvaitis, 1996; Quinn, 1997a; Fedriani et al., 2000). Food may have been sufficiently abundant to allow some animals to maintain a small home range within a single fragment, as has been suggested for other species (Coman et al., 1991; Wauters et al., 1994; Andreassen and Ims, 1998). The only previous study on the effect of development on bobcat home ranges reported smaller range sizes for males and females in urban areas compared to rural areas (Riley, 1999). Previous studies on coyote home ranges have generally reported smaller ranges in developed or fragmented areas than in natural areas (Bradley and Fagre, 1988; Shargo, 1988; Atkinson and Shackleton, 1991; Bounds and Shaw, 1997; Grinder and Krausman, 1998; Romsos, 1998). Indeed, the smallest home range known for coyotes (x=56 ha) was in an urban environment (Shargo, 1988). Bobcats are generally considered relatively intolerant of humans (Bradley and Fagre, 1988; Turbak, 1994; Harrison, 1998), thus we were surprised to find that some of our bobcats, mostly males, occurred in development between fragments, even crossing major roads. However, home ranges of over half of the bobcats were entirely within fragments, suggesting sensitivity to human development. In urban northern California, male bobcats were more likely than females to approach the urban–wildland interface (Riley, 1999). However, unlike our study, both males and females seldom crossed roads and never left continuous habitat (Riley, 1999). In contrast to bobcats, coyotes in our study area appeared to be relatively tolerant of human development. Both males and females tended to incorporate more than one fragment into their home ranges and frequently crossed even major roads. Several studies of coyotes in urban, suburban, and agricultural landscapes have reported a similar tolerance for human development (Bradley and Fagre, 1988; Shargo, 1988; Atkinson and Shackleton, 1991; Bounds and Shaw, 1997; Grinder and Krausman, 1998; Romsos, 1998), although some coyotes preferred vegetated areas and continuous habitat nearby (Shargo, 1988; Romsos, 1998). Such tolerance helps explain why coyotes and humans have come into conflict in some urban areas of southern California (Baker and Timm, 1998).

sessions, and were never within 100 m of development in only 19% of focal sessions. Further, the maximum distance moved through development was over twice as far for coyotes as for bobcats. Coyotes appear to be more willing to cross roads (50 crossings in 21 sessions) than bobcats (36 crossings in 32 sessions). When a culvert was available, 63% of crossings were over the road, suggesting a slight avoidance of culverts. Greater use of culverts earlier in the evening, when traffic volume was higher, suggests that animals used culverts to avoid vehicles. Culvert suitability appears to be unaffected by diameter, but is diminished by deep water. Both species, but especially bobcats, tended to venture into developed areas mostly late at night. The majority of bobcat focal locations at dusk were in interior habitat, and locations in development were mostly at night. Coyotes showed less sensitivity to humans than did bobcats, with dusk locations mainly in edge habitat, but locations in development were still mainly at night. Therefore, although both species venture into development, they are less likely to do so during times of high human activity. Both bobcats and coyotes occurred frequently in corridors, including all five corridors in our study area, but use of corridors as travel routes occurred much less often, and only coyotes were observed to use corridors to travel from one fragment to another. Our focal sessions may have been insufficient to detect some movements between fragments; alternatively, perhaps animals view corridors as habitat fragments instead of travel routes. Bobcats may have used corridors less than coyotes because they were more likely to confine their movement to one fragment, presumably due to their greater sensitivity to human development. Animals seemed to preferentially travel through corridors when they were available. Only one bobcat crossed through development rather than use a nearby corridor, and on only three occasions did an animal approach but not use a corridor; in all three cases, the animal was separated from the entrance to the corridor by a major four-lane road. Vehicular collision was a significant source of mortality (at least 50% of mortalities) for both species, as reported in other studies in developed and semideveloped areas (Wassmer et al., 1988; Gese et al., 1989; Ferreras et al., 1992; Romsos, 1998).

4.3. Movement patterns 5. Conclusion Bobcats appear to avoid human development during movement more than do coyotes. Bobcats remained entirely within a single fragment in 72% of focal sessions and were never within 100 m of development in 50% of focal sessions. In contrast, coyotes remained entirely within a single fragment in only 44% of focal

Bobcats and coyotes persisting in an urban environment show behavioral adjustments to habitat fragmentation and human activities. Both species reduce their daytime activity and show avoidance of developed areas during times of high human activity. Some individuals,

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mostly female bobcats, restrict their home range to a single fragment, while other individuals frequent several fragments. Home ranges, however, are not enlarged in fragmented habitat, perhaps due to abundant resources in other parts of the home range. Individuals take a variety of routes between fragments, occasionally using corridors but also crossing through development, including crossing over roads rather than using culverts. Although corridors were not always used for travelling between fragments, they were used often enough to suggest that they may serve an important role in maintaining connectivity. Frequent road crossing leads to high mortality due to vehicle collision and may be an important problem in urban fragmented areas. Preventing collisions with vehicles might be enhanced by designing open space to minimize the need for animals to cross major roads, by identifying frequent crossing points and reducing speed limits and posting warning signs at these points, and by educating the residents, who in our study displayed a general interest in the wellbeing of bobcats and coyotes. Culverts were used to cross under roads, thereby avoiding vehicles, but we found no clear evidence of preference for culverts. Carnivores such as bobcats and coyotes may be able to persist in fragmented habitat, but movement between fragments needs to be maintained by providing connectivity and preventing vehicular collision.

Acknowledgements This project would not have been completed if not for the assistance and support of L.A.T.’s family and good friends and field assistants Giar-Ann Kung and Gary Haught. Special thanks to all who assisted in fieldwork: N. Athearn, D. Jones, E. York, and all NPS employees and interns. NPS of SMMNRA, Conejo Park and Recreation District, Rancho Simi Park and Recreation District, and residents of the communities within our study area, especially the North Ranch Country Club Estates, kindly granted access to study sites. D. Dierkes, L. Lee, D. Kamradt, S. Riley, and B. Sacks provided logistical support and advice. Funding, supplies, and logistical support were provided by NPS of SMMNRA. Additional funding was provided by the University of California, Davis. M. Johnson and D. Kelt provided valuable advice on this manuscript.

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