Habitat Use and Movement Patterns of Northern Alligator Lizards And

Home , Elgaria, Western skink

HABITAT USE AND MOVEMENT PATTERNS OF NORTHERN ALLIGATOR COLUMBIA BASIN LIZARDS AND WESTERN SKINKS IN FISH & WILDLIFE SOUTHEASTERN BRITISH COLUMBIA COMPENSATION PROGRAM

PREPARED BY Pamela L. Rutherford and Patrick T. Gregory

FOR Ministry of Environment, Columbia Basin Fish & Wildlife Compensation Program Lands & Parks BC Fisheries January 2001

IN PARTNERSHIP WITH Columbia Basin Fish & Wildlife Compensation Program

103 - 333 Victoria Street, Nelson, British Columbia V1L 4K3 Phone: (250) 352-6874 Fax: (250) 352-6178

Habitat use and movement patterns of Northern Alligator Lizards (Elgaria

coerulea principis) and Western Skinks (Eumeces skiltonianus skiltonianus)

in Southeastern British Columbia

Pamela L. Rutherford and Patrick T. Gregory

Department of Biology, University of Victoria, Victoria, British Columbia, Canada. V8W 3N5:

Email: [email protected] HabitatuseandmovementpatternsofNorthernAlligatorLizards(Elgaria

coerulea principis) and Western Skinks (Eumeces skiltonianus skiltonianus)

in Southeastern British Columbia

Pamela L. Rutherford and Patrick T. Gregory

Department of Biology, University of Victoria, Victoria, British Columbia, Canada. V8W 3N5:

Email: [email protected]

ABSTRACT

Many reptiles have different requirements for different activities (e.g. hibernation and nesting/gestation) that may not be satisfied by a single location. Suitable habitat may not only be limiting, it may be fragmented, making it difficult for animals to move between sites. Our first objective in this study was to determine the extent to which Northern Alligator Lizards (Elgaria coerulea principis) and Western Skinks (Eumeces skiltonianus skiltonianus) co-occur, in southeastern British Columbia, near the northern limit of both species’ ranges. Our second objective was to determine the characteristics of hibernation and summer sites for both species.

Our third objective was to determine the extent of movement in both species, particularly whether migration occurs between summer and winter habitats. We used mark-recapture (PIT-tags and toe-clips) to do this. Both lizard species co-occurred at the same study sites and were found in approximately the same locations in spring, summer and fall. Thus, hibernation apparently occurs in the summer habitat and no seasonal migration occurs. In fact, individuals of either species were

1 recaptured within 10 m (on average) of a previous capture. Both lizard species were rarely found in the open and more often under rocks than in vegetation or under logs; they also remained close to shrubs and forest edges. Roads apparently are not a major concern for either lizard species because they have high site-ﬁdelity and do not make large movements between hibernation or summer sites. Their requirement for cover means that any disturbance or removal of rocks from their habitats would be detrimental to both species.

INTRODUCTION

Lack of knowledge of the natural history of a species is one of the greatest constraints in conservation planning. Collecting ecological data on reptile species is particularly important as they have typically attracted less attention than other groups, resulting in limited data on their natural history. To date almost half of the 42 Canadian reptile species (Cook, 1984) are of conservation concern (1 extirpated, 4 endangered, 6 threatened, and 8 species of special concern) according to the Committee on the Status of Endangered Wildlife in Canada (COSEWIC, 2000), although not all taxa have been evaluated. This high ratio indicates the importance of describing the natural history and habitat requirements of all Canadian reptiles.

Many reptiles have different requirements for hibernation and nesting/gestation (Etheridge et al., 1983; Burger and Zappalorti, 1986; Burger et al., 1988; Prior and Weatherhead, 1996;

Litzgus et al., 1999). Description of these sites is of interest to both conservation biologists and population biologists. Identifying hibernation sites is especially important in reptiles that hibernate communally (Gregory, 1984; Litzgus et al., 1999) and return to the same hibernation sites from year to year (Brown and Brooks, 1994; Litzgus et al., 1999). Destruction of communal

2 hibernation sites has occurred in rattlesnakes (Viperidae) as part of ‘rattlesnake round-ups’, resulting in population declines or extirpation from parts of the United States (Galligan and

Dunson, 1989; Warwick, 1990). Hibernation site descriptions are also useful for population biologists as part of determining whether a reptile population is limited by availability of suitable hibernation sites (Gregory, 1984). This is particularly important for northern populations as the absence of available hibernation sites may dictate the northern range limits for a population.

Populations are limited by available nesting/gestation habitat. In animals that are unable to reproduce every year due to energetic limitations (Aldridge, 1979; Luiselli et al., 1996) it is particularly important that pregnant females complete gestation and avoid predation when reproduction is attempted. Oviparous reptiles require nest sites that provide optimal temperatures and moisture content for developing embryos yet protect them from predators. Nest sites that ﬁt this criterion may be limiting (Cooper et al., 1983; Hecnar, 1994). For viviparous reptiles, selection of basking sites is important because basking by gravid females may increase the risk of predation (Huey and Slatkin, 1976; Shine, 1980; Madsen, 1987) due to their reduced mobility

(Vitt and Congdon, 1978; Bauwens and Thoen, 1981; Shine, 1980; Seigel et al., 1987; Brodie,

1989; Cooper et al., 1990; Sinervo et al., 1991).

Because the requirements for hibernating and reproducing are quite different they may not be satisﬁed by a single location and animals may need to travel long distances between these sites

(Weintraub, 1966; Gregory and Stewart, 1975; Brown and Parker, 1976; Brown and Brooks,

1994). Movement between sites may be difﬁcult if the habitat has become fragmented. This has occurred in many terrestrial habitats (Diamond et al., 1987; Saunders et al., 1991). There will be additional difﬁculty if there are barriers between the hibernation habitat and the summer habitat.

Roads are common barriers that isolate habitats, deter the movement of wildlife and cause

3 extensive wildlife mortality (Oxley et al., 1974; Case, 1978; Dalrymple and Reichenbach, 1984;

Garland and Bradley, 1984; Mader, 1984; Bernardino and Dalrymple, 1992; Rosen and Lowe,

1994; Ashley and Robinson, 1996; Trombulak and Frissell, 2000). In addition, paved roads retain heat and many snakes will bask on the pavement increasing their likelihood of being killed

(Bernardino and Dalrymple, 1992; Ashley and Robinson, 1996). The effect of roads on small lizards has not been investigated and it is important to determine if roads represent barriers between habitat patches or if they result in high mortality due to basking, as is the case with snakes.

Hibernation sites, summer habitat, and basic movement biology have not been described for the only two common lizard species found in British Columbia, which comprise two of the

ﬁve native lizard species in Canada: 1) the Northern Alligator Lizard (Elgaria coerulea principis) or 2) the Western Skink (Eumeces skiltonianus skiltonianus). Our ﬁrst objective in this study was to determine the extent to which Northern Alligator Lizards (Elgaria coerulea principis) and

Western Skinks (Eumeces skiltonianus skiltonianus) co-occur, in southeastern British Columbia, near the northern limit of both species’ ranges. Our second objective was to determine the characteristics of hibernation and summer sites for both species. Our third objective was to determine the extent of movement in both species, particularly whether migration occurs between summer and winter habitats. We used mark-recapture (PIT-tags and toe-clips) to do this. In addition to addressing fundamental questions about the biology of these animals, our results also have important implications for their management.

4 METHODS

Species Description

The Northern Alligator Lizard (Elgaria coerulea principis) is a small lizard with a long, slender body and short legs. It is brown in color, and frequently has dark blotches that vary between sexes and populations (Gregory and Campbell, 1984). It is viviparous, having one litter per year; four to six young on average (Vitt, 1974). It is diurnal, thermoregulates by basking, and is active at body temperatures ranging from 20 to 30 ˚ C (Vitt, 1973).

The Western Skink (Eumeces skiltonianus skiltonianus) is a small slender lizard with a pointed head and short legs. It has a broad brownish band down its back, ﬂanked by white stripes.

The young have a bright blue tail tip that fades as they age (Gregory and Campbell, 1984). They are oviparous and lay one clutch per year. Eggs are deposited in excavations dug under rocks or other cover objects. Clutch size varies from two to ﬁve and the female frequently stays with the eggs until they hatch. It is diurnal and thermoregulates by basking (Gregory and Campbell, 1984).

Distribution

Northern Alligator Lizards are found in southern British Columbia, south to the Sierra Nevada of

California, and east to the northern tip of Idaho and northeastern Montana (Fig. 1). In Canada, the

Northern Alligator Lizard (Elgaria coerulea principis) occurs in southern British Columbia, including Vancouver Island and the Gulf Islands. Within this range it is absent only from the southeastern corner of the province (Fig. 2).

The Western Skink (Eumeces skiltonianus skiltonianus) is also located in the southern part

5 of British Columbia, south to Baja, California and northern Arizona and east to central Utah (Fig.

3). In British Columbia it is absent from the southwestern corner of the province, Vancouver

Island and the Gulf Islands (Fig. 4).

Habitat Preference

Northern Alligator Lizards can be found in dry woodland, in grassland, along the banks of creeks, and on ocean beaches up to 1800 m. They are often associated with rocky outcroppings, talus slopes, northern and montane coniferous forests, and streams (Fitch, 1935; Nussbaum et al., 1983;

Cook, 1984; Gregory and Campbell, 1984; Good, 1988). They are widespread in southern British

Columbia, inhabiting all four of the southern Ecoprovinces: Southern Interior Mountains,

Southern Interior, Coast and Mountains and Georgia Depression. Northern Alligator Lizards are not restricted to a speciﬁc habitat. In British Columbia they are a representative species in four of the fourteen biogeoclimatic zones (Meidinger and Pojar, 1991): Coastal Douglas-ﬁr zone (in mixed coniferous and deciduous forests, and Garry Oak - Arbutus forests), Coastal Western

Hemlock zone (in mixed coniferous and deciduous forests), Interior Douglas-fir zone (in riparian areas, wetlands, meadows, and floodplains), and Interior Cedar - Hemlock zone (in riparian areas, wetlands, meadows, and floodplains).

Western Skinks also are found in a variety of habitats, including desert canyons, open woodlands, grassland, forest and on dry hillsides up to 2100 m in elevation (Nussbaum et al.,

1983; Cook, 1984). They are most commonly found in open, rocky areas where there is lots of cover in the form of logs, rocks, leaf litter and vegetation and are especially common along river banks (Rodgers and Fitch, 1947; Tanner, 1957, 1988; Gregory and Campbell, 1984; Morrison et al., 1999). In British Columbia, they are a representative species in three of the fourteen

6 biogeoclimatic zones (Meidinger and Pojar, 1991): Bunchgrass zone (in riparian areas, wetlands, meadows, and ﬂoodplains), Interior Douglas-ﬁr zone (in riparian areas, wetlands, meadows, and

ﬂoodplains), and Interior Cedar - Hemlock zone (in riparian areas, wetlands, meadows, and

ﬂoodplains).

Study Site

This study was conducted during the summers of 1996-1998 from mid-April to mid-September on the west side of the Creston Valley, 10 km west of Creston, British Columbia, Canada (49 ˚ 6’

N, 116 ˚ 31’ W; elevation 597 m; Fig. 5). Mean daily maximum air temperatures during April to

September of 1996 ranged from 6.5 ˚ C to 35.0 ˚ C. Mean daily minimum air temperatures in the same time frame ranged from -0.6 ˚ C to 18.3 ˚ C (Environment Canada, 1996).

The Creston Valley populations of these two species of lizards are located in the very dry warm subzone of the Interior Cedar - Hemlock zone. This subzone occurs in a few areas in extreme southeastern British Columbia, the largest area being the Creston Valley (Meidinger and

Pojar, 1991). The most common vegetation in this subzone is (percentage cover is listed in brackets): Douglas-ﬁr, Pseudotsuga menziesii (26-99); Western Redcedar, Thuja plicata (11-25);

Snowberry, Synphoricarpos albus (6-10); Douglas Maple, Acer glabrum (6-10); Western

Hemlock, Tsuga heterophylla (6-10); Mallow Ninebark, Physocarpus malvaceus (2-5); Beaked

Hazelnut, Carylus cornuta (2-5); Mock Orange, Philadelphus lewisii (2-5); Paper Birch, Betula papyrifera (2-5); Tall Oregon Grape, Mahonia aquifolium (2-5); Thimbleberry, Rubus parviﬂorus

(2-5); Queen’s Cup, Clintonia uniﬂora (2-5); Twinﬂower, Linnaea borealis (2-5); and Utah

Honeysuckle, Lonicera utahensis (0.1-1) (Meidinger and Pojar, 1991).

7 Mark-recapture

We hand-captured and trapped animals at four primary study sites [Pat’s Hill (Fig. 6: Group 2),

Hydro (Fig. 9: Group 1), East Clearing (Fig. 9: Group 2), and Lone Pine Hill (Fig. 6: Group 4)] and hand-captured animals at six secondary sites [Dewdney (Fig. 6: Group 1), Ofﬁce (Fig. 9:

Group 3), Sign Slope (Fig. 9: Group 4), Trail (Fig. 9: Group 5), Junction (Fig. 6: Group 5), and

West Creston (Fig. 6: Group 6)]. In 1998, Pat’s Hill was used to follow animals with PIT-tag implants. All sites were separated from each other by distances of 500 meters or greater.

On average, the primary sites were visited four times a year and the secondary sites were visited two times per year over three years (1996-1998). Upon capture we recorded the following data: site, year, ground temperature in the open ( ˚ C), temperature at the capture site ( ˚ C), lizard’s capture position (open or under cover), distance to nearest rock >10 cm in length (cm), distance to nearest shrub >1 m in base diameter (cm), distance to forest edge to the nearest 5 m, rock area (determined by a scaled down sketch; cm2), and mean rock thickness (cm).

Temperatures were measured using a Smart2 precision indoor - outdoor thermometer to the nearest 0.1 ˚ C. Ground temperature is the exposed temperature in the open, at ground level, of the nearest site to the captured lizard. For lizards captured in the open, it is measured where they were captured. We gave each rock a unique number to determine if they were used by more than one lizard and if lizards show site ﬁdelity.

At each primary site we set up a portable array of traps. All trap numbers, sessions and duration are averages. In 1997, twelve traps were set for three sessions of three days in length. In

1998, thirty traps were set for four sessions of ﬁve days in length. In both years, traps were checked from one to three times a day depending on the weather.

8 The traps were made of wire-mesh. They were 34 cm in length and 10.5 cm diameter. A wire-mesh funnel was sewn into one end using 30 lb braided ﬁshing line. A removable sponge was inserted into the other end. Lizards entered a trap through a 3.5 cm opening in the funnel and were unable to escape. Traps were covered with a cloth in the spring and fall, and a piece of wood in the summer.

PIT-tags

In 1998, we implanted AVID PIT (Passive Integrated Transponder) tags in 13 Northern Alligator

Lizards (3 adult male, 5 adult female, 4 juvenile male, 1 juvenile female) and 6 Western Skinks (5 adult male and 1 adult female) at one site (Pat’s Hill). These tags do not appear to affect growth rates or locomotor performance of neonatal snakes (Keck, 1994; Jemison et al., 1995). Although

Roark and Dorcas (2000) urged caution in use of PIT tags because of their potential to move through the body and be expelled via the gut, we never captured any PIT-tagged lizards that had lost their tags.

The PIT-tags were 14 mm by 2.1 mm and weigh 0.08 g. Each tag has a circuit, coil and capacitor sealed in biocompatible glass. PIT-tags were implanted by making a small incision (2 mm) in the side of a lizard and injecting the tag under skin, using a specially designed needle and syringe. Animals were left to recover for one day in the laboratory before release. All animals fully recovered and later recaptures in the ﬁeld indicated complete healing of the small incision.

The tags were read by passing a reader within 18 cm of the animal. Rock thickness (cm) measures in 1996-97 indicated that on average lizards were under rocks less than 18 cm.

Therefore, we expected to be able to scan cover objects and identify animals sitting under them without disturbing the animals.

9 We implanted PIT-tags from May 4-7 and June 14-17. In the spring session we scanned for 480 minutes over 3 days, but only one (of the seven implanted to date) Northern Alligator

Lizards was detected and two (of the ﬁve implanted to date) Western Skinks were detected.

Therefore, scanning during the remaining three visits to the site was done opportunistically, rather than on a formal schedule.

Mapping Locations

Broad-scale maps were constructed using a Trimble Geo-Explorer II GPS unit. Fine-scale maps of the rocks at each site were constructed by hand using a tape measure and compass.

RESULTS

Species Co-occurrence

Northern Alligator Lizards and Western Skinks co-occurred at seven of ten of the sites (Table 1):

Dewdney (Fig. 7), Pat’s Hill (Fig. 8), Hydro (Fig. 9: Group 1), Sign Slope (Fig. 9: Group 4),

Ofﬁce (Fig. 9: Group 3), West Creston Junction (Fig. 11), and West Creston (Fig. 12). Northern

Alligator Lizards were the only species that occurred at the other three sites (Table 1): Lone Pine

Hill (Fig. 10), East Clearing (Fig. 9: Group 2), and Trail (Fig. 9: Group 5). Both species co-occurred with Northern Alligator Lizards being the predominant species (67% or greater of the captures) at four sites (Table 1): Hydro (Fig. 9: Group 1), Sign Slope (Fig. 9: Group 4), Ofﬁce

(Fig. 9: Group 3) and West Creston Junction (Fig. 11). Both species co-occurred in approximately equal numbers at two sites (Table 1): Dewdney (Fig. 7) and Pat’s Hill (Fig. 8).

10 Western Skinks predominated (79% of the captures) at only one site (Table 1): West Creston (Fig.

12).

At the seven sites where the two species co-occurred (either in equal numbers or where one species dominated) there was no spatial separation of the two species and they were frequently found using the same rocks, although not together (Fig. 7-9, 11, and 12). In three years of capture we never once saw both species under a rock at the same time. In fact, for either species, we found only copulating lizards or newborn (presumed to be from the same litter) together under a single rock.

Hibernation and Summer Sites

Northern Alligator Lizards captured at hibernation sites were near captures made during the summer at the four primary study sites (Fig. 13). A similar pattern existed in Western Skinks at the only primary study site (Pat’s Hill) where they were present (Fig. 14). This suggests that both species were using the same habitat for both hibernation and summer activities.

Most Northern Alligator Lizards and Western Skinks were found under rocks (Table 2).

Northern Alligator Lizards were under larger, thicker rocks than Western Skinks (t = -1.97, P =

0.050, df = 339; t = -3.282, P = 0.001, df = 306). Both lizards stayed similarly close to rocks (t =

-1.243, P = 0.214, df = 495), shrubs (t = 0.318, P = 0.751, df = 494) and forest edges (t = 0.451, P

= 0.653, df = 493; Table 3).

We compared associations with shrub species between the two sites where the two lizard species were abundant (Pat’s Hill and Dewdney). The ﬁve most common shrubs were compared at Pat’s Hill and the top three at Dewdney. Both lizard species were associated with similar shrubs

(Pat’s Hill: χ2 = 2.75, df = 4, P = 0.60; Dewdney: χ2 = 1.40, df = 2, P = 0.50; Table 4).

11 Surrounding substrate associations (the top three) were only compared at Pat’s Hill. Both lizard species were associated with similar surrounding substrate (χ2 = 3.55, df = 2, P = 0.17; Table 5).

All sites were located on forest edges (Fig. 7-12) and the predominant tree species differed between sites. At Pat’s Hill, where Northern Alligator Lizards and Western Skinks were equally abundant, neither lizard species selectively associated with Douglas-ﬁr or Ponderosa Pine

(χ2 = 0.18, df = 1, P = 0.67; Table 6). At the other site where both lizard species were commonly found (Dewdney), the predominant tree species was Douglas-ﬁr (91% of captures for Northern

Alligator Lizards and 100% of captures for Western Skinks). Douglas-ﬁr also predominated at the four sites where Northern Alligator Lizards were most abundant [Hydro (100% of captures),

Ofﬁce (100% of captures), East Clearing (100% of captures) and Lone Pine Hill (99% of captures)]. The most common tree species at the one site where Western Skinks were most abundant was Trembling Aspen (96% of captures for Western Skinks and 71% of captures for

Northern Alligator Lizards). The other tree species found at this site was Ponderosa Pine.

Neither lizard species was commonly found on roads, even though six of the ten sites

(Hydro, Trail, Ofﬁce, East Clearing, and West Creston Junction) were bordered on one side by a road.

Movement Patterns

Distances were not corrected for the time between captures as there was no relationship between distance moved and days between captures (Fig. 15). Therefore, raw straight-line distance was used as the measure of the distance between capture sites.

Twenty-seven percent (90 of 334) of all marked Northern Alligator Lizards were recaptured over the three years and twenty-ﬁve percent (25 of 101) of all Western Skinks were

12 recaptured. Of these recaptures, neither Northern Alligator Lizards nor Western Skinks were caught very far from a previous capture location (Table 7). Only one percent of all Northern

Alligator Lizards that were recaptured moved from one study site to another site over the three-year study. No individual Western Skinks were detected at a second site, although neither of the two main Western Skink sites were within a km of another Skink site.

We compared distances between capture locations within the same year (1996, 1997, or

1998) to those between capture years (1996 to 1997, 1997 to 1998, and 1996 to 1998). There was no signiﬁcant difference in the distances regardless of how far apart in time Northern Alligator

Lizards (F5,84 = 0.6202, P = 0.6848) or Western Skinks (F5,19 = 0.5441, P = 0.7407) were captured (Fig. 16).

Northern Alligator Lizards were as likely to make both short or long distance moves within or between seasons (Fig. 17). This is particularly evident for the 1998 data, as the movement study was more intensive that year. A similar plot of only the within-season data shows that Northern Alligator Lizards did not make long-distance moves from hibernation sites to summer sites (Fig. 18). Western Skinks showed similar movement patterns, both within and between seasons (Fig. 19 and 20)

Adult male Northern Alligator Lizards tended to move greater distances than newborns, juveniles or adult females, but the difference was not signiﬁcant (F = 0.6675, P = 0.5743) 3,84

(Fig. 21a). A similar trend was true for male Western Skinks compared to female Western Skinks but again the difference was non-signiﬁcant (t = 0.677, df = 22, P = 0.506) (Fig. 21b).

13 Site Fidelity

Sometimes individuals of both species were captured repeatedly at the same location (Northern

Alligator Lizards: 9% of 282 captures; Western Skinks: 10% of 92 captures). Some of these repeat captures were of the same animal recaptured at the same location [Northern Alligator

Lizards: 7 of the 26 (26.9%) repeat captures; Western Skinks; 4 of 9 (44.4%) repeat captures]. In all other instances different lizards were captured at different times at the same location.

There was no difference in the area or thickness of rocks used once versus more-than-once for either Northern Alligator Lizards [rock area (t = 0.6117, df = 31.785, P = 0.5451); rock thickness (t = 0.6714, df = 27.326, P = 0.5076)] or Western Skinks [rock area (t = 1.2459, df =

8.823, P = 0.2449); rock thickness (t = 1.0124, df = 9.202, P = 0.3372)]. Similarly, distance to the nearest rock for both Northern Alligator Lizards (t = -0.8735, df = 36.305, P = 0.3881) and

Western Skinks (t = 0.1526, df = 10.945, P = 0.8815); distance to the nearest shrub for both

Northern Alligator Lizards (t = 0.289, df = 26.006, P = 0.7749) and Western Skinks (t = -1.292, df

= 27.579, P = 0.2071) or distance to the nearest forest edge for both Northern Alligator Lizards (t

= -0.8374, df = 32.471, P = 0.4085) and Western Skinks (t = -0.7388, df = 11.269, P = 0.4752) did not differ between single-use or multiple-use rocks.

Response to Disturbance

Western Skinks were more secretive than Northern Alligator Lizards as fewer were seen in the open, either in vegetation or on a hard substrate (χ2 = 43.31, df = 5, P<0.001). Although Western

Skinks were rarely captured or sighted in vegetation compared to Northern Alligator Lizards

(Table 2), when disturbed they typically ran towards a shrub for cover. In contrast, Northern

14 Alligator Lizards typically ran to a nearby rock for cover (personal observation, P. Rutherford).

DISCUSSION

Although Northern Alligator Lizards and Western Skinks are frequently found at the same sites in

Creston, some sites are dominated by one species. Why this should be is not clear because we have no evidence of competitive interactions between the two species, although this question has not been addressed rigorously. Perhaps the pattern of site occupation is due simply to historical reasons.

Northern Alligator Lizards and Western Skinks were captured in the same locations in spring, summer and fall. This suggests that hibernation and reproduction sites are in the same location. This had been previously reported for Northern Alligator Lizards by Stewart (1985), who found most recaptures of individuals within a 10 m radius of the original capture point. This is in contrast to a previous study (Vitt, 1973), in which Northern Alligator Lizards were gregarious around localized dens in early April and then from late April through August they were dispersed away from the den sites. In addition, individuals of either species were recaptured within 10 m (on average) of a previous capture. Both these factors indicate that a population requires a relatively small area for persistence.

Both lizard species were rarely found in the open and more often under rocks than in vegetation or under logs. They rarely strayed far from available cover, remaining closest to rocks but typically within 2 m of a shrub. For reptiles, retreat sites can serve as protection from lethal ground temperatures and predators (Huey et al., 1989; Downes and Shine, 1998). In the summer, maximum air temperatures in Creston can reach 35 ˚ C with ground temperatures exceeding

15 40 ˚ C, lethal for a lizard in the open in midafternoon. Retreat sites also would provide refuge from avian predators. The main predators of either lizard species are unknown but Northern Alligator

Lizard carcasses have been seen on nearby nest boxes; presumably left by avian predators.

It also appears that some retreat sites are more important than others. Although we found no physical differences between these ‘preferred’ locations and ‘single-use’ locations, it is possible that the former locations had optimal thermoregulatory properties in addition to their proximity to available cover. Movement patterns also indicated site ﬁdelity for both species although adult males of both species moved longer distances. This may reﬂect the fact that nesting Western Skinks females guard their eggs (Gregory and Campbell, 1984) and gravid

Northern Alligator Lizards females have reduced mobility (Rutherford, unpublished data).

This dependence on speciﬁc retreat sites may have broad effects on the population biology of these animals. In areas where food is not limiting, the availability of retreat sites may determine the upper limit for species abundance on a local scale (Bustard, 1969, 1970). For retreat-site availability to be limiting retreat sites must be vital to the biology of the animal and there must be a limit on the number of individual lizards able to use each site simultaneously. Use of a rock by more than one Northern Alligator Lizard or Western Skink was rare in this study, regardless of the size of the rock.

This necessity for available cover means that any disturbance or removal of rocks in the area would be detrimental to both species. Rock collecting is thought to negatively impact Velvet

Geckos (Oedura lesueurii) (Schlesinger and Shine, 1994) and Broad-headed Snakes (Shine et al.,

1998) in southern Australia. Northern Alligator Lizards and Western Skinks are similar to these reptiles in that they rely heavily on retreat sites and show some site ﬁdelity. Both of these features make them susceptible to retreat-site disturbance.

16 Although both lizards were most commonly captured under rocks they remained close to nearby shrubs. In addition, disturbed Western Skinks preferentially ran towards shrubs for cover.

Northern Alligator Lizards and Western Skinks were most frequently found nearest four shrub types: Mallow Nine Bark (Physocarpus malvaceus), Ocean Spray (Holodiscus discolor),

Snowberry (Symphorocarpos albus), and Mock Orange (Philadelphus lewsii). There is no difference in the shrub types selected by the two lizard species. Proximity to these shrub types merely reﬂects their availability at the site (Meidinger and Pojar, 1991; Parish et al., 1996). All four of these shrubs are dense and provide cover close to the ground allowing the lizards to disappear easily into the vegetation. Both lizard species are insectivores (Gregory and Campbell,

1984) and also may use the shrubs for foraging. The two lizard species are most often found in grass or moss as surrounding substrate, which may also provide cover. Both shrubs and surrounding substrate appear important to these lizard species.

The association of Northern Alligator Lizards and Western Skinks with forests is unclear.

All sites were in forest clearings but the lizards may not have been utilizing the forests. Northern

Alligator Lizards sometimes are captured within forests (Gregory and Campbell, 1984), but they are most commonly seen in clearings. This may in part be due to the difﬁculty of seeing and capturing a lizard in the forest compared to in an open clearing. The consistent capture and recapture of both species in the clearings suggests that even if they were venturing into the forests they still returned to the clearing. An intensive movement study would need to be conducted to determine their association with forests.

17 Management Recommendations

Both lizard species are widely distributed throughout western Canada and the United States which makes them less vulnerable to extinction. Nonetheless there have been few natural history studies of either species and no studies evaluating whether populations are decreasing in size or disappearing. Both lizards require rock and vegetative cover and disturbance or removal of this cover will make them vulnerable to predation.

Both lizards respond quickly to passersby and run to available cover where they remain for an extended period. Only copulating lizards were unresponsive to human presence, even tolerating being picked up while they remained together. Hiking paths through prime lizard habitat probably would be detrimental to lizard populations as they would not allow animals to bask without disturbance. In particular, gravid female Northern Alligator Lizards would be consistently disturbed while trying to maintain embryos at optimal developmental temperatures.

Roads apparently are not a major concern for either lizard species because they have high site-ﬁdelity and do not make large movements between hibernation or reproduction sites. In addition, they are not attracted to roads as heat sources. However, it is possible that roads serve as barriers between populations. This results in unconnected populations, ultimately limiting gene

ﬂow and eliminating colonization of new areas. This has not been shown in lizards but has been observed in populations of small and medium-sized mammals and carabid beetles (Oxley et al.,

1974; Mader, 1984). Knowledge of the breeding biology and dispersal patterns of these lizards is necessary to determine if this is a concern.

18 Acknowledgments

The authors thank the staff at the Creston Valley Wildlife Management Area (B. Stushnoff, A. de

Jager, G. Cooper, D. Bjarnason, and B. Bruns), Columbia Basin Fish and Wildlife Program (I.

Parﬁtt and J. Krebs) and the Simon Fraser University Field Station (R. Ydenberg) for logistical support. Field assistance was provided by D. Hoysak, J. Rutherford, M. Beaucher and M. Bowen.

This study was ﬁnancially supported by the Columbia Basin Trust and an N.S.E.R.C operating grant to P.T.G.

References

ALDRIDGE, R. D. 1979. Female reproductive cycles of the snakes Arizona elegans and Crotalus viridis. Herpetologica 35:256–261.

ASHLEY, E. P. AND J. T. ROBINSON. 1996. Road mortality of amphibians, reptiles, and other wildlife on the Long Point Causeway, Lake Erie, Ontario. Can. Field Nat. 110:403–412.

BAUWENS, D. AND C. THOEN. 1981. Escape tactics and vulnerability to predation associated with reproduction in the lizard Lacerta vivipara. J. Anim. Ecol. 50:733–743.

BERNARDINO, F. S. AND G. H. DALRYMPLE. 1992. Seasonal activity and road mortality of the snakes of the Pa-hay-okee wetlands of Everglades National Park. Biol. Conserv. 62:71–75.

BRODIE, E. D., III. 1989. Behavioral modiﬁcation as a means of reducing the cost of reproduction. Am. Nat. 134:225–238.

BROWN, G. P. AND R. J. BROOKS. 1994. Characteristics of and ﬁdelity to hibernacula in a northern population of snapping turtles, Chelydra serpentina. Copeia 1994:222–226.

BROWN, W. S. AND W. S. PARKER. 1976. Movement ecology of Coluber constrictor near communal hibernacula. Copeia 1976:225–242.

BURGER, J. AND R. T. ZAPPALORTI. 1986. Nest site selection by pine snakes, Pituphis melanoleucus, in the New Jersey pine barrens. Copeia 1986:116–121.

BURGER, J., R. T. ZAPPALORTI, M. GOCHFEILD, W. I. BOARMANN, M. CAFFREY, V. DOIG, S. D. GARBER, B. LAURO, M. MIKOVSKY, C. SAFINA, AND J. SALIVA. 1988. Hibernacula and summer den sites of pine snakes (Pituphis melanoleucus) in the New Jersey Pine Barrens. J. Herpetol. 22:425–433.

19 BUSTARD, H. R. 1969. The population ecology of the gekkonid lizard Gehyra variegate (Dumerial & Bibron) in exploited forests in northern New South Wales. J. Anim. Ecol. 38:35–51.

BUSTARD, H. R. 1970. The population ecology of the Australian gekkonid lizard Heteronotia binoei in an exploited forest. J. Zool. 162:31–42.

CASE, R. M. 1978. Interstate highway road-killed animals: A data source for biologists. Wildl. Soc. Bull. 6:8–13.

COOK, F. R. 1984. Introduction to Canadian Amphibians and Reptiles, National Museums of Canada, Ottawa.

COOPER, W. E., JR., L. J. VITT, R. HEDGES, AND R. B. HUEY. 1990. Locomotor impairment and defense in gravid lizards (Eumces laticeps): Behavioral shift in activity may offset costs of reproduction in an active forager. Behav. Ecol. Sociobiol. 27:153–157.

COOPER, W. E., JR., L. J. VITT, L. D. VANGILDER, AND J. W. GIBBONS. 1983. Natural nest sites and brooding behavior of Eumeces fasciatus. Herpetol. Rev. 14:65–66.

COSEWIC. 2000. Canadian species at risk, may 2000, Tech. rep., Committee on the Status of Endangered Wildlife in Canada, 23pp.

DALRYMPLE, G. H. AND N. G. REICHENBACH. 1984. Management of an endangered species of snake in Ohio, USA. Biol. Conserv. 30:195–200.

DIAMOND, J. M., K. D. BISHOP, AND S. V. BALEN. 1987. Bird survival in an isolated Javan woodland: Island or mirror. Conserv. Biol. 1:132–142.

DOWNES, S. AND R. SHINE. 1998. Heat, safety or solitude? Using habitat selection experiments to identify a lizard’s priorities. Anim. Behav. 55:1387–1396.

ENVIRONMENT CANADA. 1996. Canadian climate normals. temperature and precipitation: Creston, British Columbia, Tech. rep., Environment Canada Climate Data Services.

ETHERIDGE, K., L. C. WIT, AND J. C. SELLERS. 1983. Hibernation in the Lizard Cnemidophorus sexlineatus (Lacertilia: Teiidae). Copeia 1983:206–214.

FITCH, H. S. 1935. Natural history of the alligator lizards. Trans. Acad. Sci. St. Louis 29:1–38.

GALLIGAN, J. H. AND W. A. DUNSON. 1989. Biology and status of timber rattlesnake (Crotalus horridus) populations in Pennsylvania. Biol. Conserv. 15:13–58.

GARLAND, T. AND W. G. BRADLEY. 1984. Effects of a highway on Mojave desert rodent popultaions. Am. Midl. Nat. 111:47–56.

GOOD, D. A. 1988. Phylogenetic Relationships Among Gerrhonotine Lizards: An Analysis of External Morphology, University of California Press, Berkeley, CA.

20 GREGORY, P. T. 1984. Communal denning in snakes, in SEIGEL, R. A., L. E. HUNT, J. L. KNIGHT, L. MALARET, AND N. L. ZUSCHLAG (eds.), Vertebrate Ecology and Systematics: A Tribute to Henry S. Fitch, Spec. Publ. Nat. Hist., pp. 57–75, Univ. Kansas, Lawrence.

GREGORY, P. T. AND R. W. CAMPBELL. 1984. The Reptiles of British Columbia, The Royal British Columbia Museum, Victoria.

GREGORY, P. T. AND K. W. STEWART. 1975. Long-distance dispersal and feeding strategy of the red-sided gartersnake (Thamnophis sirtalis parietalis) in the Interlake of Manitoba. Can. J. Zool. 53:238–245.

HECNAR, S. J. 1994. Nest distribution, site selection, and brooding in the ﬁve-lined skink (Eumeces fasciatus). Can. J. Zool. 72:1510–1516.

HUEY, R. B., C. R. PETERSON, S. J. ARNOLD, AND W. P. PORTER. 1989. Hot rocks and not-so-hot rocks: Retreat site selection by garter snakes and its thermal consequences. Ecol. 70:931–944.

HUEY, R. B. AND M. SLATKIN. 1976. Costs and beneﬁts of lizard thermoregulation. Quart. Rev. Biol. 51:363–384.

JEMISON, S. J., L. A. BISHOP, P. G. MAY, AND T. M. FARRELL. 1995. The impact of PIT-tags on growth and movement of the rattlesnake, Sistrurus miliarius. J. Herpetol. 29:129–132.

KECK, M. B. 1994. Test for detrimental effects of PIT tags in neonatal snakes. Copeia 1994:226–228.

LITZGUS, J. D., J. P. COSTANZO, R. J. BROOKS, AND R. E. LEE, JR. 1999. Phenology and ecology of hibernation in spotted turtles (Clemmys guttata) near the northern limit of their range. Can. J. Zool. 77:1348–1357.

LUISELLI, L., M. CAPULA, AND R. SHINE. 1996. Reproductive output, costs of reproduction and ecology of the smooth snake , Coronella austiaca, in the eastern Italian Alps. Oecologia 106:100–110.

MADER, H. J. 1984. Animal habitat isolation by roads and agricultural ﬁelds. Biol. Conserv. 29:81–96.

MADSEN, T. 1987. Cost of reproduction and female life-history tactics in a population of grass snakes, Natrix natrix, in southern Sweden. Oikos 49:129–132.

MEIDINGER, D. AND J. POJAR. 1991. Ecosystems of British Columbia, Ministry of Forests, Victoria, BC.

MORRISON, M. L., P. A. AIGNER, AND L. S. HALL. 1999. Habitat characteristics of sympatric Gilbert’s and Western Skinks. Herpetol. Rev. 30:18–20.

NUSSBAUM, R. A., E. D. BRODIE, JR., AND R. M. STORM. 1983. Amphibians and Reptiles of the Paciﬁc Northwest, The University Press of Idaho, Idaho.

21 OXLEY, D. J., M. B. FENTON, AND G. R. CARMODY. 1974. The effects of roads on populations of small mammals. J. Appl. Ecol. 11:51–59.

PARISH, R., R. COUPE, AND D. LLOYD (eds.). 1996. Plants of southern interior British Columbia, Lone Pine Publishing, Vancouver.

PRIOR, K. A. AND P. J. WEATHERHEAD. 1996. Habitat features of black rat snake hibernacula in Ontario. J. Herpetol. 30:211–218.

ROARK, A. W. AND M. E. DORCAS. 2000. Regional body temperature variation in corn snakes measured using temperature-sensitive passive iintegrated transponders. J. Herpetol. 34:481–485.

RODGERS, T. L. AND H. S. FITCH. 1947. Variation in the skinks (Reptilia: Lacertilia) of the Skiltonianus group. Univ. California Publ. Zool. 48:169–220.

ROSEN, P. C. AND C. H. LOWE. 1994. Highway mortality of snakes in the Sonoran Desert of southern Arizona. Biol. Conserv. 68:143–148.

SAUNDERS, D. A., R. J. HOBBS, AND C. R. MARGULES. 1991. Biological consequences of ecosystem fragmentation: A review. Conserv. Biol. 5:18–29.

SCHLESINGER, C. A. AND R. SHINE. 1994. Choosing a rock: Perspectives of a bush-collector and a saxicolous lizard. Biol. Conserv. 67:49–56.

SEIGEL, R. A., M. M. HUGGINS, AND N. B. FORD. 1987. Reduction in locomotor ability as a cost of reproduction in gravid snakes. Oecologia 73:481–485.

SHINE, R. 1980. ‘Costs’ of reproduction in reptiles. Oecologia 46:92–100.

SHINE, R., J. K. WEBB, M. FITZGERALD, AND J. SUMNER. 1998. The impact of bush-rock removal on an endangered snake species, Hoplocephalus bungaroides (Serpentes: Elapidae). Wildl. Res. 25:285–295.

SINERVO, B., R. HEDGES, AND S. C. ADOLPH. 1991. Decreased sprint speed as a cost of reproduction in the lizard Sceloporus occidentalis: Variation among populations. J. Exp. Biol. 155:323–336.

TANNER, W. W. 1957. A taxonomic and ecological study of the western skink (Eumeces skiltonianus). Great Basin Nat. 17:59–94.

TANNER, W. W. 1988. Eumeces skiltonianus. Cat. Am. Amph. Rept. 447:1–4.

TROMBULAK, S. C. AND C. A. FRISSELL. 2000. Review of ecological effects of roads on terrestrial and aquatic communities. Conserv. Biol. 14:18–30.

VITT, L. J. 1973. Reproductive biology of the anguid lizard Gerrhonotus coeruleus principis. Herpetologica 29:176–184.

VITT, L. J. 1974. Reproductive effort and energy comparisons of adults, eggs, and neonates of Gerrhonotus coeruleus principis. J. Herpetol. 8:165–168.

22 VITT, L. J. AND J. D. CONGDON. 1978. Body shape, reproductive effort and relative clutch mass in lizards: Resolution of a paradox. Am. Nat. 112:595–608.

WARWICK, C. 1990. Disturbance of natural habitats arising from rattlesnake round-ups. Environmental Conservation 17:172–174.

WEINTRAUB, J. D. 1966. Winter behavior of the granite spiny lizard Sceloporus orcutti. Copeia 1966:708–712.

23 TABLE 1. Sizes of the ten study sites and total number of captures of Northern Alligator Lizards (Elgaria coerulea principis) and Western Skinks (Eumeces skiltonianus skiltonianus).

Site Size (m2) E. coerulea E. skiltonianus TOTAL (N) (%) (N) (%)

Primary Pat’s Hill 22 500 61 61 39 39 100 Hydro 60 000 51 93 4 7 55 East Clearing 30 000 50 100 0 0 50 Lone Pine Hill 52 500 65 100 0 0 65

Secondary Dewdney 70 000 36 59 25 41 61 Ofﬁce 90 000 47 94 3 6 50 Sign Slope 10 000 3 75 1 25 4 Trail 2 500 6 100 0 0 6 Junction 1 250 4 67 2 33 6 West Creston 22 500 7 21 27 79 34 Total 334 100 100 100 435

24 TABLE 2. Locations of all captured (including recaptures) and sighted (not captured) a) Northern Alligator Lizards (Elgaria coerulea principis) and b) Western Skinks (Eumeces skiltonianus skiltonianus) from CVWMA, Creston, British Columbia collected in 1996-1998.

Location Captured Sighted Total (N) (%) (N) (%) (N) (%)

Under rock 271 61 47 34 318 55 In vegetation 59 13 21 15 80 14 On dirt/rock 27 6 24 18 51 9 Under log 4 1 1 1 5 1 On road 2 0.5 0 0 2 0.3 Unknown 79 18 42 31 121 21 Total 442 100 137 100 579 100

Location Captured Sighted Total (N) (%) (N) (%) (N) (%)

Under rock 112 83 55 60 167 74 In vegetation 2 1 5 5 7 3 On dirt/rock 1 1 2 1 3 1 Under log 0 0 0 0 0 0 On road 0 0 0 0 0 0 Unknown 19 14 29 32 48 21 Total 135 100 91 100 226 100

25 TABLE 3. Summary statistics for proximity to cover, and cover object size of a) Northern Alligator Lizards (Elgaria coerulea principis)and b) Western Skinks (Eumeces skiltonianus skiltonianus) from CVWMA, Creston, British Columbia collected in 1996-1998.

Variable N Min Max Mean SE

Distance to rock (cm) 380 0 520 23.7 3.0 Distance to shrub (cm) 379 0 4400 177.7 14.7 Distance to forest edge (m) 378 0 100 17.3 0.7 Rock size (cm2) 248 82 5500 916.4 42.1 Rock thickness (cm) 248 1 34 8.6 0.3

Variable N Min Max Mean SE

Distance to rock (cm) 117 0 198 16.7 3.1 Distance to shrub (cm) 117 0 3000 184.7 27.3 Distance to forest edge (m) 117 0 80 18.0 1.2 Rock size (cm2) 93 96 3360 756.0 71.0 Rock thickness (cm) 93 1 22 6.7 0.4

26 TABLE 4. Species of nearest shrub of captured Northern Alligator Lizards (Elgaria coerulea principis) and Western Skinks (Eumeces skiltonianus skiltonianus) from a) Pat’s Hill and b) Dewdney on the CVWMA, Creston, British Columbia collected in 1996-1998.

Shrub Type E. coerulea E. skiltonianus (N) (%) (N) (%)

Mallow Nine Bark (Physocarpus malvaceus) 23 28 12 20 Ocean Spray (Holodiscus discolor) 19 23 13 22 Snowberry (Symphorocarpos albus) 15 18 10 17 Mock Orange (Philadelphus lewsii) 9 11 9 15 Rose (various spp.) 8 10 10 17 Other 9 11 6 10 Total 83 100 60 100

Shrub Type E. coerulea E. skiltonianus (N) (%) (N) (%)

Mallow Nine Bark (Physocarpus malvaceus) 4 12 8 38 Ocean Spray (Holodiscus discolor) 6 18 5 24 Mock Orange (Philadelphus lewsii) 6 18 5 24 Snowberry (Symphorocarpos albus) 8 24 1 5 Rose (various spp.) 2 6 2 10 Other 8 24 0 0 Total 34 100 21 100

27 TABLE 5. Species of immediately surrounding substrate of captured Northern Alligator Lizards (Elgaria coerulea principis) and Western Skinks (Eumeces skiltonianus skiltonianus) from Pat’s Hill on the CVWMA, Creston, British Columbia collected in 1996-1998.

Substrate Type E. coerulea E. skiltonianus (N) (%) (N) (%)

Grass (various spp.) 32 40 40 67 Moss (various spp.) 20 25 11 18 Dirt 7 9 6 10 Fern (various spp.) 5 6 2 3 Oregon Grape (Mahonia aquifolium) 8 10 0 0 Needles (various spp.) 7 9 1 2 Other 2 2 0 0 Total 81 100 60 100

TABLE 6. Species of trees in the nearest forest edge of captured Northern Alligator Lizards (Elgaria coerulea principis) and Western Skinks (Eumeces skiltonianus skiltonianus) from Pat’s Hill on the CVWMA, Creston, British Columbia collected in 1996-1998.

Tree Type E. coerulea E. skiltonianus (N) (%) (N) (%)

Ponderosa Pine (Pinus ponderosa) 52 63 34 57 Douglas-ﬁr (Pseudotsuga menziesii) 31 37 25 42 Rocky Mountain Juniper (Juniperus scopulorum) 0 0 1 2 Total 83 100 135 100

28 TABLE 7. Summary of distance (m) between capture locations for Northern Alligator Lizards (Elgaria coerulea principis) and Western Skinks (Eumeces skiltonianus skiltonianus) from CVWMA, Creston, British Columbia collected in 1996-1998.

Statistic E. coerulea E. skiltonianus (All) (Within Site) (All)

Minimum 0 0 0 Maximum 500 53 61.4 Mean 16.1 10.7 8.0 Standard Error 5.56 1.18 2.67 Median 7.0 6.7 3.6 N 90 89 25

29 Elgaria coerulea coeruleus Elgaria coerulea shastensis Elgaria coerulea principis Elgaria coerulea palmeri

FIG. 1. Distribution of Northern Alligator Lizards (Elgaria coerulea principis) in North America (from Stebbins, 1966).

30 FIG. 2. Distribution of Northern Alligator Lizards (Elgaria coerulea principis) in British Columbia (from Orchard, 1988).

31 Eumeces skiltonianus skiltonianus Eumeces skiltonianus utahensis Eumeces skiltonianus interparietalis

FIG. 3. Distribution of Western Skinks (Eumeces skiltonianus skiltonianus) in North America (from Stebbins, 1966).

32 FIG. 4. Distribution of Western Skinks (Eumeces skiltonianus skiltonianus) in British Columbia (from Orchard, 1988).

33 117 15 W 117 00 W 116 45 W 116 30 W

000 e n 00 2 Hooker Pass S A rrys 2 2 Bay 2000 C i 000 0 r

t R

2 e

H 2 k Queens Bay e 0 D k 2 u Y

0 0 u C a 0 m 000 C r h 0 l e 0 a r l e 0 m C k 0 e

r L e e e a l k e G k Balfour Pilot r a y 20 C k e Mount C 00 r Pt Longbeach r g Grohman e Cresent Gray e Procter n C k Bay m Creek i Mt2 r A r d 0 e

Eccles00 e a Sunshine Cape d k k Harrop e e Bay Horn k N R 0 e e Atbar 0 e r a 0 t L L 2 r C r s a C e s r

W o Willow Point c a w A e n n s 2000 c h a Snowcrest a S p r m r e o h K M u C Cr Mtn o l C c e e r F r n C n a 2 G i E r r o F v 0 e s a White Grouse Mallanda e l e 2 L 00 k i

0 Mountain 2 Pass

W 0 0 C 0 0 0 r M 00 i e l 0 e e 2 49 30 N k Taghum Granite 2 y C 0 r 0 0 ra C e 0 0 R o Nelson 0 e V E 2 Haystack n I t k Akokli R Blewett t r M o Mountain F C i 1 n 2 Mtn o w 000 l d r 0 t g 0 o e Boswell t 0 t k o k l i C r K y o K u e A i n d

i a

n n

e Ymir 20 C k 00 u r Creek C r e e k

C Mtn 2 a

r 0 x 00

2 a n C m 2000 0 Ape e r 00 S e e R k e e e k r 0 S a n c a C Copper Sanca C 0 C E

Mtn r 0 l e 2 a e Hall r w 000 2 V

2 2 a e 0 t 000 e 2 Mount k 00 0 2 r iwash 00 C r I 000 Skelly C r Mtn Baldy Mount B a r 2 S r L a i b 000 k e l l y e t 2 R t Mtn 0 k C r e e k McGregor 0 C r Porto Rico e 0 e 2 r 0 000 C 0 2 0 0 e k r e 0 i r C Kuskonook 0 E m 2 Y in r u l t us

i C 00

e 0

Ymir 0 0

0 0 H a 2 l

2 200 l k D e e u C r P n 0 e c o r c u p i C r e e k 0 r 0 k 2 C

C 49 15 N

Sirdar k Kootenay T

r Six e e Duck

Mtn Mile e e 00 C r Lake H 2 r k R i d 0 o t Slough A d m C e n 000 l C E 2 E x k

e V C r O e N 2 I e k 0 R 0 0 0 G 0 0 Meadows Erie 0 0 2 2 Salmo 0 e k Reno20 00 0 Wynndel Three2 0 000 Mtn 0 2 w Ross Spur 2000 o Leach r Sisters r B Lake l A a z k e CVWMA Mount e 2000 d C r e Peak John Bull2 C McCon S 0 r Arrow r h e e p Mtn 00 e Kelly Yellowstone Creek e n 0 h Peak 2 k 1000 c le 00 e e t 0 r K i O 0 C 0 Alice M 2 Nevada 2 Siding

L 0

r Mountain

00 A 2 00 C 00 0 0 Erickson S t m 2 m i Creston Mount u u m c S i C r e e k Thompson l s t 00 L o k l C r e e Canyon 1 00 i 0 0 0 T S 2 0 2 O 00 U U 0 0

P n i T r Lost 2 P o L H r C C E 000 Mountain R 1 p Lister a e P E S l L 0 A 2 R L g 1 0 L 0 I 00 M a 0 0 E 1 0 0 t

R 1 O 0 S

0 1 S Huscroft 0 0 0 0 00 2 k R T e 2 000 B o u e 0 000 2 n d a r y C r Rykerts R 49 00 N

FIG. 5. The Creston Valley Wildlife Management Area (CVWMA), located near Creston, British Columbia

0 10 20 30 40 50 km

Scale 1:500,000 - Projection UTM Zone 11 - Datum NAD83 Columbia Basin Fish and Wildlife Compensation Program GIS -- October 16, 2000

34 5 25 000m E 5 30 000m E

R 6 I 54 45 000m N

00 Group 1 R 1 BC 88001 200 154

1100 r

BC 78142 e

e e k Group 2 v O

L i

800 D N I C K S I S L A N D R 6 K 0 0 O

N Group 3 Y N

A 0

0 A Y N I C K S

1 0

4 t

00 N V

I I S L A N D

A a

V D a v i d C r e e k L E

L o

E M o o Y T r e e e k G s C r

H M Group 4 O c L 54 40 000m N e n A n a n C k M r e e N G A O

R N 0 S E

0 K l 0 H L

0 0 14 0 T 1 200 9 7 e e t 1z 0 k O 1e 0 e 0 l e r C

T l k e

e e e e n

t z e l C r n

1 a

3 h

1 1 C 0 20 1 0 0 00 r e v i R t a 0 o G 0 0 d l O 0 7 0 0 6 k

9 e

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0 r

0 h

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r m m o n s e S i O C n r C r r h

M C p e C r s

C F O 8 s o 0 r t

J 0 C 1 B e t e 1 0 r

o 9 e 1 0 8 k e 0 e m k 0 0 n 0 0 0 e T 0 0 r 54 35 000m N c 9 b 0 C 1 h s 2 n m o 0 S i m C 1 E 0 r 3 k e 0 e 0 e k N

1 e

0 7

r 0 0 n 0 o 0 t s

C m r A U r C S

l BC 88001 o 189 6 u Y 0 g 0 h

l k e 7 e e C r 0 i 0 MT n k o RYKERT t s

m r 9 U 12 1 0 0 00 0 0 1 0 8 5 0

0 0 0 0 0 1 800 1 1 Group 6 R

0 1 I 8 4 1 1 0

D 1 l C 6 0 l r i e FIG. 6. The 10 study sites with the CVWMA: De7 wdney (Group h1), Pat'se Hill (Group 2), Balance Rock (Group 3; contains r t k o 0 0 0 0 P o 54 30 000m N Hydro, East Clearing, Office, Sign Slope, Trail), Lone Pine Hill (Group 4), West Creston Junction (Group 5), and West Creston (Group 6). Locations of Northern Alligator Lizards (Elgaria coerulea principis) and Western Skinks (Eumeces skiltonianus skiltonianus) are shown. Northern Alligator Lizard Capture 0 1 2 3 4 5 km Western Skink Capture Scale 1:75,000 - Projection UTM Zone 11 - Datum NAD83 CVWMA Boundary Columbia Basin Fish and Wildlife Compensation Program GIS -- October 16, 2000

35 5 25 800m E 5 26 000m E 5 26 200m E 5 26 400m E 54 44 600m N

54 44 400m N

54 44 200m N

54 44 000m N

FIG. 7. Locations and numbers of Northern Alligator Lizards ( Elgaria coerulea principis ) and Western Skinks ( Eumeces skiltonianus skiltonianus ) at Dewdney (Group 1 on Fig. 6).

Northern Alligator Lizards (No. captured at location by class) 2 3 1 0 100 200 300 m

Western Skinks (No. captured at location by class) Scale: 1:5000 1 2 3 Map Projection: UTM Zone 11 Datum: NAD 83 Number of Captures: CBFWCP GIS Class 1 = 0-5; Class 2 = 6-10; Class 3 = > 10 October 16, 2000

36 5 25 600m E 5 25 800m E 5 26 000m E 5 26 200m E 54 44 000m N

54 43 800m N

54 43 600m N

54 43 400m N

54 43 200m N

FIG. 8. Locations and numbers of Northern Alligator Lizards ( Elgaria coerulea principis ) and Western Skinks ( Eumeces skiltonianus skiltonianus ) at Pat's Hill (Group 2 on Fig. 6). 54 43 000m N Northern Alligator Lizards (No. captured at location by class) 0 100 200 300 m 1 2 3

Scale: 1:5000 Western Skinks (No. captured at location by class) Map Projection: UTM Zone 11 1 2 3 Datum: NAD 83 CBFWCP GIS Number of Captures: October 16, 2000 Class 1 = 0-5; Class 2 = 6-10; Class 3 = > 10

37 5 26 000m E 5 26 200m E 5 26 400m E 5 26 600m E 5 26 800m E

1 54 42 000m N

54 41 800m N 5 3 4 54 41 600m N

54 41 400m N 2

54 41 200m N

54 41 000m N

54 40 800m N

FIG. 9. Locations and numbers of Northern Alligator Lizards ( Elgaria coerulea principis ) and Western Skinks ( Eumeces skiltonianus skiltonianus ) at Balance Rock (Group 3 on Fig. 6). The following sub-sites are indicated: Hydro, (Group 1); East Clearing, (Group 2); Office, (Group 3); Sign Slope, (Group 4); and Trail, (Group 5) Northern Alligator Lizards (No. captured at location by class) 0 100 200 300 m 1 2 3

Scale: 1:7500 Western Skinks (No. captured at location by class) Map Projection: UTM Zone 11 Datum: NAD 83 1 2 3 CBFWCP GIS Number of Captures: October 17, 2000 Class 1 = 0-5; Class 2 = 6-10; Class 3 = > 10

38 5 26 800m E 5 27 000m E 5 27 200m E 5 27 400m E 54 40 400m N

54 40 200m N

54 40 000m N

54 39 800m N

54 39 600m N

FIG. 10. Locations and numbers of Northern Alligator Lizards ( Elgaria coerulea principis ) and Western Skinks ( Eumeces skiltonianus skiltonianus ) at Lone Pine Hill (Group 4 on Fig. 6).

Northern Alligator Lizards (No. captured at location by class) 2 3 1 0 100 200 300 m

39 5 29 000m E 5 29 200m E 5 29 400m E 5 29 600m E 54 36 600m N

54 36 400m N

54 36 200m N

54 36 000m N

FIG. 11. Locations and numbers of Northern Alligator Lizards ( Elgaria coerulea principis ) and Western Skinks ( Eumeces skiltonianus skiltonianus ) at West Creston Junction (Group 5 on Fig. 6).

Northern Alligator Lizards (No. captured at location by class) 2 3 1 0 100 200 300 m

40 5 31 000m E 5 31 200m E 5 31 400m E 5 31 600m E 54 31 400m N

54 31 200m N

54 31 000m N

54 30 800m N

54 30 600m N

FIG. 12. Locations and numbers of Northern Alligator Lizards ( Elgaria coerulea principis ) and Western Skinks ( Eumeces skiltonianus skiltonianus ) at West Creston (Group 6 on Fig. 6).

Northern Alligator Lizards (No. captured at location by class) 2 3 1 0 100 200 300 m

41 400 150 A B 300 100 200 50 Y Coordinate (m) Y Coordinate (m) 100 0 0

0 50 100 150 0 100 200 300 400

X Coordinate (m) X Coordinate (m)

400 C 400 D 300 300 200 200 Y Coordinate (m) Y Coordinate (m) 100 100 0 0

0 100 200 300 400 0 100 200 300 400

X Coordinate (m) X Coordinate (m)

FIG. 13. Hibernation (closed circle) and summer sites (open circle) for Northern Alligator Lizards (Elgaria coerulea principis) at four primary sites: a) Pat’s Hill, b) Balance Rock (Hydro), c) Balance Rock (East Clearing), and d) Lone Pine Hill.

42 150 100 Y Coordinate (m) 50 0

0 50 100 150

X Coordinate (m)

FIG. 14. Hibernation (closed circle) and summer sites (open circle) for Western Skinks (Eumeces skiltonianus skiltonianus) at Pat’s Hill.

43 800 A 600 400 200 Days between captures 0

0 10 20 30 40 50 60 70

Distance between capture sites (m)

800 B 600 400 200 Days between captures 0

0 10 20 30 40 50 60 70

Distance between capture sites (m)

FIG. 15. Days between capture sites and distance traveled (m) by a) Northern Alligator Lizards (Elgaria coerulea principis) and b) Western Skinks (Eumeces skiltonianus skiltonianus) from CVWMA, Creston, British Columbia collected in 1996-1998. One outlier, an adult male Northern Alligator Lizard who was recaptured more than 500 m from his original capture after 330 days, was omitted from the plot.

44 FIG. dif Skinks in 1996-1998. ferent Distance moved (m) Distance moved (m) 16. ( Eumeces Mean years 0 5 10 15 20 10 20 30 40 50 B A Sample for distance skiltonianus a) 1996 1996 Northern (2) (4) sizes and are standard skiltonianus Alligator gi 1997 1997 (5) (7) v en Capture andRecaptureYears Capture andRecaptureYears error in Lizards brackets. ) bars 1998 1998 from (11) (35) 45 between ( Elgaria CVWMA, 96 &97 96 &97 (2) (9) capture coerulea Creston, 97 &98 97 &98 locations principis (27) (4) British within 96 &98 96 &98 ) Columbia and (8) (1) a b) year W estern collected or in Sept 98 April 98 Sept 97 Date of Second Capture April 97

<10 m 10−25 m 25−50 m Sept 96 >50 m April 96 April 96 Sept 96 April 97 Sept 97 April 98 Sept 98

Date of First Capture

FIG. 17. Distance between location of ﬁrst capture and location of second capture for Northern Alligator Lizards (Elgaria coerulea principis) from CVWMA, Creston, British Columbia collected in 1996-1998.

46 Oct 1 Sept 1 Aug 1 July 1 Date of Second Capture June 1

May 1 <10 m 10−25 m 25−50 m April 1

April 1 May 1 June 1 July 1 Aug 1 Sept 1 Oct 1

Date of First Capture

FIG. 18. Distance between location of ﬁrst capture and location of second capture within one season for Northern Alligator Lizards (Elgaria coerulea principis) from CVWMA, Creston, British Columbia collected in 1996-1998.

47 Sept 98 April 98 Sept 97 Date of Second Capture April 97

<5 m

Sept 96 5−10 m >10 m April 96 April 96 Sept 96 April 97 Sept 97 April 98 Sept 98

Date of First Capture

FIG. 19. Distance between location of ﬁrst capture and location of second capture for Western Skinks (Eumeces skiltonianus skiltonianus) from CVWMA, Creston, British Columbia collected in 1996-1998.

48 Oct 1 Sept 1 Aug 1 July 1 Date of Second Capture June 1

May 1 <5 m 5−10 m >10 m April 1

April 1 May 1 June 1 July 1 Aug 1 Sept 1 Oct 1

Date of First Capture

FIG. 20. Distance between location of ﬁrst capture and location of second capture within one season for Western Skinks (Eumeces skiltonianus skiltonianus) from CVWMA, Creston, British Columbia collected in 1996-1998.

49 FIG. b) British juv female

enile, Distance between captures (m) Distance between captures (m) 21. Columbia

Mean 0 5 10 15 0 10 20 30 40 50 adult and B A male female distance Newborn collected W (9) estern and and adult in standard Skinks Female 1996-1998. male (7) ( Eumeces Juvenile Northern error Sex /AgeCategories (43) Sample bars skiltonianus Alligator 50 between Sex sizes Adult Female are capture Lizards skiltonianus gi (58) v en locations ( in Elgaria Male brackets. (34) ) from coerulea for Adult Male a) CVWMA, (62) ne wborn, principis Creston, ) and