Five-Lined Skink (Eumeces Fasciatus), Belongs to the Family Scincidae and Is Known As Le Scinque Pentaligne in French
COSEWIC Assessment and Update Status Report
on the
Five-lined Skink Eumeces fasciatus
Carolinian population Great Lakes/St. Lawrence population
in Canada
Carolinian population - ENDANGERED Great Lakes/St. Lawrence population - SPECIAL CONCERN 2007
COSEWIC COSEPAC COMMITTEE ON THE STATUS OF COMITÉ SUR LA SITUATION ENDANGERED WILDLIFE DES ESPÈCES EN PÉRIL IN CANADA AU CANADA COSEWIC status reports are working documents used in assigning the status of wildlife species suspected of being at risk. This report may be cited as follows:
COSEWIC 2007. COSEWIC assessment and update status report on the Five-lined Skink Eumeces fasciatus (Carolinian population and Great Lakes/St. Lawrence population) in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vii + 50 pp. (www.sararegistry.gc.ca/status/status_e.cfm).
Previous report:
COSEWIC 2001. COSEWIC assessment and status report on the Five-lined Skink Eumeces fasciatus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 1-41 pp.
Seburn, C.N.L. 1998. COSEWIC status report on the Five-lined Skink Eumeces fasciatus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 1-41 pp.
Production note: COSEWIC would like to acknowledge Briar J. Howes and Stephen C. Lougheed for writing the update status report on the Five-lined Skink Eumeces fasciatus (Carolinian population and Great Lakes/ St. Lawrence population) in Canada, prepared under contract with Environment Canada, overseen and edited by Dr. Ronald Brooks, Co-chair (Reptiles), COSEWIC Reptiles Species Specialist Subcommittee.
For additional copies contact:
COSEWIC Secretariat c/o Canadian Wildlife Service Environment Canada Ottawa, ON K1A 0H3
Tel.: 819-953-3215 Fax: 819-994-3684 E-mail: COSEWIC/[email protected] http://www.cosewic.gc.ca
Également disponible en français sous le titre Ếvaluation et Rapport de situation du COSEPAC sur le scinque pentaligne (Eumeces fasciatus) (population carolinienne et population des Grands Lacs et du Saint-Laurent) au Canada – Mise à jour.
Cover illustration: Five-lined Skink — Photograph by ©Ryan M. Bolton.
©Her Majesty the Queen in Right of Canada 2007 Catalogue No. CW69-14/530-2007E-PDF ISBN 978-0-662-46025-1
Recycled paper COSEWIC Assessment Summary
Assessment Summary – April 2007
Common name Five-lined Skink – Carolinian population
Scientific name Eumeces fasciatus
Status Endangered
Reason for designation The species is the only lizard in Eastern Canada. The Carolinian population occurs in only 4 or 5 small, completely isolated populations on the shores of lakes Erie, St. Clair and Huron. Threats to this skink include loss and degradation of microhabitat, illegal collecting, increased depredation by racoons, coyotes, dogs and cats, and increased mortality on roads. If any population is extirpated, because of isolation there is no chance of natural recolonization.
Occurrence Ontario
Status history The species was considered a single unit and designated Special Concern in April 1998. Split into two populations in April 2007. The Carolinian population was designated Endangered in April 2007. Last assessment based on an update status report.
Assessment Summary – April 2007
Common name Five-lined Skink – Great Lakes/St. Lawrence population
Scientific name Eumeces fasciatus
Status Special Concern
Reason for designation The species is the only lizard in Eastern Canada. This small and secretive species is known from about 84 local populations, but has a small geographic distribution. Threats to the skink include loss and degradation of habitat, alteration of microhabitat, illegal collection, increased depredation by cats and dogs and increased mortality on roads. Increasing development in the species’ range will make populations more isolated and more susceptible to stochastic events of small sites.
Occurrence Ontario
Status history The species was considered a single unit and designated Special Concern in April 1998. Split into two populations in April 2007. The Great Lakes/St. Lawrence population was designated Special Concern in April 2007. Last assessment based on an update status report.
iii COSEWIC Executive Summary
Five-lined Skink Eumeces fasciatus
Carolinian population Great Lakes/St. Lawrence population
Species information
Eastern Canada’s only lizard, Eumeces fasciatus, is a secretive, small-bodied animal that reaches a maximum size of approximately 86 mm snout-vent length. Juveniles have five cream-coloured stripes on their black bodies and prominently display the species’ most characteristic feature, a bright blue tail. Body colouration fades with age in both sexes, although females retain more of the original colour pattern. In the breeding season, males develop orange colouration around the jaws and chin. The scales are unkeeled, giving the animal a smooth, shiny appearance.
Distribution
The geographic range of E. fasciatus roughly coincides with the deciduous hardwood forests of eastern North America, making it the most widely distributed lizard in eastern North America. The species’ range extends from the Atlantic seaboard west to Texas and Minnesota and from southern Ontario south to the Gulf of Mexico. In Canada, the species is restricted to two disjunct series of populations in Ontario: 1. the Great Lakes/ St. Lawrence populations which occur on the southern Canadian Shield (from Georgian Bay east to the St. Lawrence River); and 2. the Carolinian populations which occur in Southwestern Ontario (near the shores of Lakes Erie, St. Clair, and Huron).
Habitat
The species’ habitat varies throughout its range and includes rocky outcrops, sand dunes, and open deciduous forests. It primarily inhabits early successional habitat with low to moderate canopy cover. Individuals spend the majority of their time under rocks, woody debris and other forms of cover; thus suitable microhabitats are of great importance to the species. The two series of populations in Ontario occur in distinct habitats, within which individuals use specific cover elements for refuge. Great Lakes/ St. Lawrence populations occur on the Canadian Shield on rock outcrops embedded in a matrix of coniferous and deciduous forest, and individuals in these populations seek
iv refuge under rocks overlaid on open bedrock. Carolinian populations occur in Carolinian forest with a sandy substrate, and individuals within these populations have a strong association with woody debris as refuge.
Biology
In Ontario, the active season of E. fasciatus is from mid-April to late September or early October. Individuals are sexually mature after they emerge from their second hibernation, at 21 months of age. Several weeks after mating, the female locates a suitable nest site, excavates a nest cavity and lays a clutch of approximately 9 eggs, which she will brood and defend. Females often nest communally. Eumeces fasciatus is an active forager and consumes mainly invertebrates. Predators of the species include snakes, small mammals and predatory birds. Skinks will often autotomize their tails to escape predators. Although males are aggressive toward each other during the breeding season, the species is not territorial and individuals do not have strictly defined home range boundaries.
Population sizes and trends
Approximately 84 populations have been reported on the Shield within the last decade, while only five Carolinian populations have been confirmed in this same period. Carolinian populations have been declining and disappearing since at least 1984. Data on population trends exist for only one Carolinian Population. As a result of microhabitat destruction and removal, this population suffered a three-fold to five-fold decline in numbers from 1990-1995. Population density varies greatly throughout the year, and cohort structure can vary among years depending on weather conditions and other factors. Any particular adult cohort can be reduced by at least half within a year for a variety of reasons.
Limiting factors and threats
Eumeces fasciatus has a strong association with particular microhabitat elements that provide refuge. Destruction or removal of this microhabitat (e.g. cover rock or woody debris) can cause a decline in population abundance. Illegal collecting has been documented in at least one Carolinian Population, and is likely facilitated by the social nesting behaviour displayed by females. Alteration of microhabitat and illegal collecting have been identified as threats to Carolinian populations; the impact of these threats to populations on the Shield is less clear. Other threats include dogs, cats and high numbers of raccoons (Procyon lotor) and road mortality.
Special significance of the species
Eumeces fasciatus is eastern Canada’s only lizard, and occurs exclusively within two distinct habitat types. The skink is a charismatic animal that may inspire the public to elevate their appreciation of Canadian reptiles.
v Existing protection
Although listed as Secure in most of its southern U.S. jurisdictions, several northern jurisdictions consider the species to be imperiled or extirpated. The species has been assessed as Special Concern by COSEWIC in 1998; it is also listed as Special Concern by the Ontario Ministry of Natural Resources.
vi COSEWIC HISTORY
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.
COSEWIC MANDATE
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.
COSEWIC MEMBERSHIP
COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.
DEFINITIONS
Wildlife Species A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years. Extinct (X) A wildlife species that no longer exists. Extirpated (XT) A wildlife species no longer existing in the wild in Canada, but occurring elsewhere. Endangered (E) A wildlife species facing imminent extirpation or extinction. Threatened (T) A wildlife species likely to become endangered if limiting factors are not reversed. Special Concern (SC)* A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats. Not at Risk (NAR)** A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances. Data Deficient (DD)*** A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.
* Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990. ** Formerly described as “Not In Any Category”, or “No Designation Required.” *** Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” (insufficient scientific information on which to base a designation) prior to 1994. Definition of the (DD) category revised in 2006.
Environment Environnement Canada Canada Canada Canadian Wildlife Service canadien Service de la faune
The Canadian Wildlife Service, Environment Canada, provides full administrative and financial support to the COSEWIC Secretariat.
vii
Update COSEWIC Status Report
on the
Five-lined Skink Eumeces fasciatus
Carolinian population Great Lakes/St. Lawrence population
in Canada
2007
TABLE OF CONTENTS
SPECIES INFORMATION...... 4 Name and classification...... 4 Morphological description ...... 4 Genetic description...... 5 Designatable units ...... 9 DISTRIBUTION...... 11 Global range ...... 11 Canadian range ...... 12 HABITAT ...... 14 Habitat requirements ...... 14 Habitat trends ...... 17 Habitat protection/ownership ...... 18 BIOLOGY ...... 19 Life cycle and reproduction...... 20 Predation ...... 26 Physiology ...... 27 Movement and dispersal...... 28 Interspecific interactions ...... 29 Adaptability ...... 29 POPULATION SIZES AND TRENDS...... 30 Search effort ...... 30 Abundance ...... 31 Fluctuations and trends ...... 33 Rescue effect...... 34 LIMITING FACTORS AND THREATS ...... 35 Habitat alteration...... 35 Microhabitat alteration ...... 35 Illegal collecting ...... 36 Depredation by raccoons...... 36 Road mortality ...... 36 SPECIAL SIGNIFICANCE OF THE SPECIES ...... 36 EXISTING PROTECTION OR OTHER STATUS DESIGNATIONS ...... 37 TECHNICAL SUMMARY – Carolinian population ...... 39 TECHNICAL SUMMARY – Great Lakes/St. Lawrence population...... 41 ACKNOWLEDGEMENTS AND AUTHORITIES CONSULTED...... 43 Acknowledgements...... 43 Authorities consulted ...... 43 INFORMATION SOURCES ...... 45 BIOGRAPHICAL SUMMARY OF REPORT WRITERS...... 50
List of figures Figure 1. Distribution and mitochondrial lineage groupings of Eumeces fasciatus...... 6 Figure 2. The relation between a population’s location within the species’ range and its intra-population genetic diversity (Average allelic richness) based on six microsatellite loci for Eumeces fasciatus ...... 7 Figure 3. Comparison of the relationship between population pairwise genetic distance (based on FST ) and geographic distance among north, west, east and central populations in Eumeces fasciatus based on six microsatellite loci...... 8 Figure 4. Neighbor-joining dendrogram based on Nei’s (1978) genetic distance among populations of Eumeces fasciatus as determined by six microsatellite loci...... 10 Figure 5. Map of the faunal provinces of terrestrial amphibians, reptiles, and molluscs in Canada (COSEWIC, 2004)...... 11 Figure 6. Distribution of Eumeces fasciatus in Ontario based on records from the Ontario Herpetofaunal Summary Atlas...... 12
List of tables Table 1. Summary of recorded populations of Eumeces fasciatus in Ontario based on the Ontario Herpetofaunal Summary that began in 1984...... 13 Table 2. Summary of recorded populations of Eumeces fasciatus in southwestern Ontario based on records from the Ontario Herpetofaunal Summary...... 14 Table 3. Summary of extant (recorded or confirmed since 1995) populations of Eumeces fasciatus in Ontario that exist in Federal Land (National Parks or Indian reserves), Provincial Land (Provincial Parks, Provincial Park Reserves, Nature Reserves), a Conservation Area (CA), or an ANSI (Area of Natural and Scientific Interest) based on the Ontario Herpetofaunal Summary...... 18 Table 4. Comparison of reproductive events between a Great Lakes/St. Lawrence and Carolinian population...... 23 Table 5. Estimates of effective population size for nine populations of Eumeces fasciatus in Ontario based on six microsatellite loci and maximum likelihood analysis...... 32 Table 6. NatureServe rank for Eumeces fasciatus for all jurisdictions within its global range...... 38
SPECIES INFORMATION
Name and classification
Eastern Canada’s only lizard, the five-lined skink (Eumeces fasciatus), belongs to the family Scincidae and is known as le scinque pentaligne in French. The Family Scincidae is the largest family of squamate reptiles and is distributed worldwide (Pough et al., 2004). The genus Eumeces is also broadly distributed across North and Central America, North and Southeast Asia, and North Africa (Fitch, 1954). The first comprehensive examination of the genus revealed no less than fifty recognized species that share a relatively conserved morphology (Taylor, 1936). Recent genetic work suggested that Eumeces is not a monophyletic group and that the genus should be split into multiple genera. Taxonmists have recommended that all Eumeces species in North America adopt the genus name Plestiodon (Schmitz et al., 2004; Brandley et al., 2005). Following Crother et al. (2000), the genus name Eumeces will be retained for this report.
Within the genus Eumeces, several species groups have been identified including the fasciatus group that has three North American representatives (E. fasciatus, E. laticeps and E. inexpectatus). Allozyme data suggested that these three species are each other’s closest relatives (Murphy et al., 1983), but more recent genetic evidence based on multiple mitochondrial genes suggests the fasciatus species group is not monophyletic (Schmitz et al., 2004; Richmond and Reeder, 2002). Based on this work, the sister species of E. fasciatus is E. septentrionalis. Eumeces septentrionalis occurs in Canada but is limited to two discrete areas in southwestern Manitoba, and the species is listed federally as Endangered (COSEWIC, 2004a). A third species of Eumeces (E. skiltonianus) has its Canadian range limited to southcentral British Columbia. Eumeces skiltonianus is listed federally as Special Concern (COSEWIC, 2002).
Despite the expansive geographic range of E. fasciatus and the variety of habitat and environmental conditions it occupies, there are no recognized subspecies. Wherever possible, this report supplements information gathered from throughout the species’ range with information specific to populations within its Canadian range. The term “population” is used throughout this report and is generally defined as a group of individuals within 1-2 km (e.g. Fitch, 1954; Seburn, 1993; Hecnar 1994; Hecnar and M’Closkey, 1998; Howes et al., 2006). This designation is consistent with the definition of an “Element Occurrence” employed by the Natural Heritage Information Centre (NHIC, 2006).
Morphological description
Newly hatched E. fasciatus are approximately 25 mm in snout-vent length (SVL) and have five cream stripes on their green-black bodies. The species’ characteristic bright blue tail is most obvious in hatchlings and juveniles. Body and tail colouration fades with age to become a solid bronze in both sexes, although females generally retain more of the juvenile colouration pattern than males. During breeding season,
4 adult males develop bright orange colouration around the jaws and chin, and very large females may show some pink colouration around the chin. The scales are unkeeled, giving individuals a smooth, shiny appearance and perhaps explaining why the species is often misidentified as a salamander by the general public (Fitch, 1954; B. Howes, pers. obs.).
Individuals reach a maximum of approximately 86 mm in SVL and have a wedge- shaped head, and a slender, elongated body ending with a tail that can be autotomized and regenerated. Their laterally flattened bodies and moderately developed limbs make them adept burrowers, and enable them to find refuge under a variety of cover objects while their well developed toes and strong claws provide them with agility over a variety of substrates (Fitch, 1954).
Previous research suggested that males and females have similar body sizes (Fitch, 1954; Vitt and Cooper, 1986a; Seburn, 1990), and that sexual dimorphism is apparent in head size only, with males having larger heads than females (Vitt and Cooper, 1986a; Seburn, 1990). Males probably have larger relative head sizes than females because of sexual selection rather than resource partitioning (Vitt and Cooper, 1986a). Both males and females are capable of eating larger prey than they typically ingest based on their gape limit (Vitt and Cooper, 1986a), and males exhibit intrasexual aggression (e.g. Fitch, 1954; Cooper and Vitt, 1987).
Recent work indicates that some populations differ in the degree of sexual size dimorphism in head size as well as body size. Morphological data collected from populations throughout the species’ range showed that male-biased sexual size dimorphism in SVL significantly increased with latitude (Howes and Lougheed, unpublished data). Mean male SVL for individuals from nine Ontario populations (75.2 ± 5.3 mm, n=50) was significantly greater (P<0.0001) than mean female SVL for individuals from nine Ontario populations (70.5 ± 5.8 mm, n=97).
Genetic description
Range-wide
A recent phylogeographic study spanning the entire range of E. fasciatus revealed six major mitochondrial lineages within the species. Similar to other eastern North American herpetofauna, E. fasciatus is structured in a manner that reflects divergence from east to west (longitudinal phylogeographic structure). Phylogeographic patterns are consistent with fragmentation due to refugial and post-glacial dynamics, but deep divergences among some lineages imply historical fragmentation that predates the Pleistocene (Howes et al., 2006, see Fig. 1).
The species has three broadly distributed (East, Central, and West), and three geographically restricted lineages (Carolinas, Oklahoma, and Wisconsin). The most broadly distributed is the East lineage. It spans from the Mississippi River east to the Atlantic Ocean, and includes all Ontario populations. The West lineage extends from the
5 Mississippi River west to Texas and Minnesota, while the narrowly distributed Central lineage includes populations in northeast Texas, southeast Louisiana, northwest Mississippi, and a population in central Wisconsin (Fig. 1).
The Carolinas lineage consists of two populations in the Atlantic coastal plain, and the Oklahoma lineage consists of one population located at the extreme western periphery of the species range. The Wisconsin lineage consists of one disjunct population (Fig. 1).
Figure 1. Distribution and mitochondrial lineage groupings of Eumeces fasciatus (range distribution based on Conant and Collins, 1998). States and provinces are indicated by abbreviations and sampling sites are marked with circles. Species’ range borders are marked with thick lines and include three disjunct series of populations (MN, WI, and IA). Based on analysis of 769 bp (base pairs) of the mitochondrial DNA and include three main lineages (East, Central, West) and three geographically isolated lineages (Carolinas, Oklahoma, Wisconsin). A simplified phylogeny from Howes et al. (2006) in the lower right of this figure shows the relationships among these different lineages. Adapted from Howes et al. (2006).
Genetic characteristics of Ontario populations
Ontario populations of E. fasciatus may have inherent genetic characteristics that make them more at risk of local extinction because they are peripheral populations
6 located at the northern margin of the species’ range. For instance, northern peripheral populations of a variety of species may carry relatively low levels of genetic diversity possibly due to rapid post-glacial expansion and founder effect (see Hewitt, 1996). Peripheral populations may also be smaller and more genetically isolated relative to more central populations (abundant centre hypothesis; e.g. Brown, 1984).
Howes and Lougheed (in review) found that northern (including Ontario populations) and western peripheral populations had significantly lower intra-population genetic diversity relative to central populations and peripheral populations to the east and south (bordered by the Atlantic Ocean) (Fig. 2). This lower genetic diversity can increase the level of homozygosity of a population and may result in reduced individual fitness (e.g. Shaffer, 1981; Milligan et al. 1994; Lande and Shannon, 1996). Reduced intra-population genetic diversity may also limit the potential for populations to adapt to future changes (e.g. climate change, novel parasites or disease), as a population’s evolutionary potential is proportional to its additive genetic variance (Fisher, 1958). Genetic variation can be a major determinant in the long-term persistence of a population, and Ontario’s populations of E. fasciatus may ultimately face a greater risk of local extinction relative to more southern populations. It should be noted that this finding is based on neutral genetic markers (microsatellite loci), and that it is assumed these neutral genetic markers reflect total genomic variability in E. fasciatus.
Figure 2. The relation between a population’s location within the species’ range and its intra-population genetic diversity (Average allelic richness) based on six microsatellite loci for Eumeces fasciatus. Eastern, western, northern, and southern populations are located within 200 km of the species’ range border and are defined according to their most proximate border. Central populations are defined as any population occurring more than 200 km within the species’ range border. Mean diamonds are drawn for each group, where the vertical span of the diamond represents the 95% confidence interval, and the middle line represents group mean. The horizontal line indicates the grand mean for all groups. From Howes and Lougheed (in review).
7 Although northern populations (e.g. Ontario’s populations) have lower intra- population genetic diversity, estimates of their effective population size (Ne) were not significantly reduced compared to other populations across the range (Howes and Lougheed, unpublished data). Reduced population size could negatively impact intra- population genetic diversity by promoting inbreeding, and increase the impact of genetic drift. It is often assumed that peripheral populations are smaller (and therefore have smaller effective population sizes) than more geographically central populations. The mean Ne in nine surveyed Ontario populations (273) was lower than the mean for 21 other populations across the range (339), but this difference was not significant (Howes and Lougheed, unpublished data).
Northern and western populations were more genetically differentiated from each other across all distances than were central and eastern populations (Fig. 3). The degree of genetic differentiation between population pairs can be used as a surrogate measure for the degree of genetic isolation of a population. Mean values of FST (a standard measure of pairwise population differentiation) for northern and western populations (0.18 and 0.21 respectively) were significantly less than those of central and eastern populations (0.069 and 0.037 respectively). These low values imply that genetic connectivity among Ontario’s populations is reduced relative to levels elsewhere in the range, which in turn indicates that the likelihood of natural recolonization following a local extinction event would be low in Ontario populations (Howes and Lougheed, unpublished data).
Figure 3. Comparison of the relationship between population pairwise genetic distance (based on FST ) and geographic distance among north, west, east and central populations in Eumeces fasciatus based on six microsatellite loci. Northern populations (blue) and western populations (green) show significant isolation by distance (p=0.001, n=67 and p=0.021, n=7 respectively). Central populations (orange) and eastern populations (red) do not show significant isolation by distance.
8 In summary, it is often assumed that peripheral populations possess a variety of genetic characteristics that may threaten their persistence. In this light, Ontario’s northern peripheral populations of E. fasciatus do not appear to be at risk because of low effective population size. However, results do suggest that they have reduced intra- population genetic diversity (Howes and Lougheed, unpublished data) and that they are more genetically isolated relative to more southern populations (Howes and Lougheed, unpublished data). This reduction in genetic diversity and increase in genetic isolation could elevate the likelihood of local extinction in Ontario populations.
Designatable units
Canadian populations of Eumeces fasciatus can be split into two designatable units based on genetic evidence, range disjunction, and biogeographic distinction. The first unit is distributed along the southern Canadian Shield in Ontario (hereafter called Great Lakes/St. Lawrence population) and the second is found within the Carolinian region of southwestern Ontario (hereafter called Carolinian population)
Genetic evidence
Although Ontario’s Carolinian and Great Lakes/St. Lawrence populations belong to the same mitochondrial lineage, they show considerable genetic divergence based on more rapidly evolving microsatellite markers.
Pairwise genetic differences in allele frequencies among thirty populations from across the species’ range were estimated using Nei’s standard genetic distance (Nei, 1978). An unrooted neighbour-joining tree was constructed based on these pairwise genetic distances among populations and support for each cluster of the tree was based on bootstrapping genotypes among populations and is indicated as a percent (Fig 4). Great Lakes/St. Lawrence populations (n=7) form an exclusive cluster, whereas Carolinian populations (n=2) form another cluster with a population from eastern Michigan (Howes et al., 2006).
Genetic differentiation (based on FST) between all pairs of Ontario populations was calculated to determine if average genetic differentiation between Great Lakes/ St. Lawrence and Carolinian populations exceeded that within each series of populations. FST (Wright, 1969) is a standard measure of genetic differentiation between two populations and values can range from 0 (no genetic differentiation) to 1 (complete genetic differentiation). Mean genetic differentiation within Great Lakes/St. Lawrence populations was 0.10 (n=21), and the genetic differentiation between the only pair of Carolinian populations was also 0.10 (Howes and Lougheed, unpublished data). In contrast, the mean genetic differentiation between Great Lakes/St. Lawrence and Carolinian populations was higher at 0.15 (n=14). All pairwise comparisons were highly significant (Howes and Lougheed, unpublished data), suggesting that Great Lakes/ St. Lawrence and Carolinian populations in Ontario show highly significant genetic isolation from each other.
9
Figure 4. Neighbour-joining dendrogram based on Nei’s (1978) genetic distance among populations of Eumeces fasciatus as determined by six microsatellite loci. Bootstrap values (>50%) from 1,000 replicates are shown. The state (U.S.A.) or county (Ontario) where each population was sampled is indicated.
Range disjunction
The nearest Great Lakes/St. Lawrence and Carolinian populations are separated by approximately 250 km. Perhaps more importantly, the two series of Ontario populations are separated by Canada’s most dense urban area (Greater Toronto Area) and expansive agricultural land, rendering exchange of individuals and genetic material between the two regions virtually impossible (Figs. 5,6).
10 Biogeographic distinction
Great Lakes/St. Lawrence and Carolinian populations are biogeographically distinct based on the map of faunal provinces of terrestrial amphibians, reptiles, and molluscs in Canada (Fig. 5; COSEWIC, 2004b). Shield populations occur in the northern portion of the Great Lakes /St. Lawrence faunal province (7), whereas southwestern Ontario populations occur in the Carolinian faunal province (8) (Fig. 5).
Figure 5. Map of the faunal provinces of terrestrial amphibians, reptiles, and molluscs in Canada (COSEWIC, 2004). The distribution of each province is indicated by a unique pattern that corresponds to the legend in the upper right. Populations of Eumeces fasciatus on the Canadian Shield occur in the northern portion of the Great Lakes/St. Lawrence faunal province (7), whereas southwestern Ontario populations occur in the Carolinian faunal province (8).
DISTRIBUTION
Global range
The geographic range of E. fasciatus roughly coincides with the deciduous hardwood forests of eastern North America (Fitch, 1954), making it the most widely distributed species in its genus (Taylor, 1936) and the most widely distributed lizard in eastern North America (Conant and Collins, 1998). The species’ range extends from the Atlantic seaboard west to Texas and Minnesota and from southern Ontario south to the Gulf of
11 Mexico (Fig. 1). The range is approximately square-shaped and spans roughly 1,600 km from north to south and from east to west (Fitch, 1954; Conant and Collins, 1998)
Canadian range
Within Canada, E. fasciatus is limited to two disjunct regions in south central and southwestern Ontario. The Great Lakes/St. Lawrence populations are distributed along the southern margin of the Canadian Shield from Georgian Bay eastward to Leeds and Grenville County. The Carolinian populations are primarily found near the shores of Lakes Erie, St. Clair, and Huron (Fig. 6).
Figure 6. Distribution of Eumeces fasciatus in Ontario based on records from the Ontario Herpetofaunal Summary Atlas (Oldham and Weller, 2000).
12 As of May 2006, a total of 1,406 records existed in the Ontario Herpetofaunal Summary (OHS; Oldham and Weller, 2000). These records identify 229 populations recorded from 1881 to 2005, of which 184 were confirmed to be present after 1984 (the beginning of the Ontario Herpetofaunal Summary; Table 1). A recent summary report based on OHS records indicated that 27% of Ontario’s verified skink populations are considered either historic (not verified in last 20 years) or extirpated. All of the populations considered extirpated are Carolinian populations including all those on the Niagara Peninsula (NHIC, 2006, Fig. 6).
Estimates of area of occupancy were calculated for Great Lakes/St. Lawrence and Carolinian populations by counting the number of 2 x 2 km (4km2) grid cells that were intersected by observations from 1995 to present (A. Filion, pers. comm.).
Table 1. Summary of recorded populations of Eumeces fasciatus in Ontario based on the Ontario Herpetofaunal Summary that began in 1984 (Oldham and Weller, 2000). Populations are classified according to region (Great Lakes/St. Lawrence vs. Carolinian populations) and county. Population numbers reflect the total number of identified populations within each time category: pre-1984, 1984-1994, and 1995- present. The total number of populations identified for each time category is indicated for both Great Lakes/St. Lawrence and Carolinian populations. No. Recorded Pop's No. Recorded Pop's No. Recorded Pop's County Pre-1984 1984-1994 1995-Present Great Lakes/St. Lawrence populations Frontenac 13 11 9 Grey 0 0 1 Haliburton 2 3 2 Halton 0 1 0 Hastings 2 8 4 Lanark 1 1 2 Leeds 2 2 1 Lennox & Addington 6 3 7 Muskoka 20 33 19 Parry Sound 10 20 16 Peterborough 10 13 15 Simcoe 3 12 4 Victoria 2 8 4 Total 71 115 84 Carolinian populations Chatham-Kent 1 2 1 Essex 5 5 2 Kent 2 0 0 Lambton 2 1 2 Middlesex 3 0 0 Niagara 4 0 0 Total 17 8 5
13 Great Lakes/St. Lawrence populations
Estimated extent of occurrence for Great Lakes/St. Lawrence populations is 29,842 km2. Estimated area of occupancy is 484 km2.
Carolinian populations
Estimated extent of occurrence for Carolinian populations is 3,946 km2. Estimated area of occupancy is 88 km2.
In southwestern Ontario, ten populations have been recorded since 1984 (OHS; Oldham and Weller, 2000). Only five of these populations have recorded sightings of E. fasciatus since 1995 (Table 2). Although no post-1995 records for Walpole Island exist in the OHS, skinks have been incidentally observed there during the period 2002- 2004 (C. Jacobs, pers. comm.).
Table 2. Summary of recorded populations of Eumeces fasciatus in southwestern Ontario based on records from the Ontario Herpetofaunal Summary (Oldham and Weller, 2000). Only populations that have been identified or confirmed since 1984 are listed. Populations that have been identified or confirmed since 1995 are indicated in bold. Observed 1984- Observed 1995- County General Location 1994 present Chatham-Kent Rondeau Provincial Park X X Chatham-Kent Wheatley Provincial Park X Essex Dolson Creek Area X Essex Kopegaron Woods Conservation Area X Essex Oxley Poison Sumac Swamp X Essex Point Pelee National Park X X Essex Springarden Road Prairie X Essex Tilbury Northside Conservation Area X Lambton Pinery Provincial Park X Lambton Walpole Island X X
HABITAT
Habitat requirements
Habitat of E. fasciatus varies throughout its distribution and includes rocky outcrops, sand dunes, riparian forests, open deciduous forests, and cut-over woodlots (Fitch, 1954; Seburn, 1990). The species is found in a variety of habitat conditions with different climates and plant associations, although the species is limited to climates of relatively higher humidity and generally occurs in early successional habitats. Within forest habitats, the species is most abundant in well-drained, open, rocky areas. In northeastern Kansas, individuals prefer woods with low to moderate canopy cover, which allows for sunlight to reach the forest floor, where individuals are usually found
14 under rocks or decaying logs. Towards the southern extent of its range, the species is found in more heavily wooded habitats, whereas in northerly parts of its range, the species is found in increasingly open habitats (Fitch, 1954).
Suitable microhabitats are of vital importance to E. fasciatus, as individuals spend most of their time in refuges under cover shelter, while making short foraging trips from a heavily used core area (Fitch and von Achen, 1977). Individuals are prone to desiccation stress (Fitch, 1954) and extreme temperatures, thereby making shelter an essential microhabitat element (Hecnar and M’Closkey, 1998). Furthermore, shelter with suitable thermal properties allows individuals to maintain a body temperature close to their preferred optimal temperature, while providing them with concealment from predators (Quirt et al., in press).
The particular shelter element (e.g. cover rock, wood debris, standing snags, tree cavities) used by individuals varies across the range of the species and is dependent on habitat type and available shelter elements (B. Howes, pers. obs.). The particular shelter element used also varies throughout the year as individuals adjust microsite selection based on thermoregulatory, foraging, predator concealment, nesting and hibernation needs (Hecnar, 1991; Seburn, 1993). Throughout the range, individuals also use artificial cover elements including scrap tin and wood piles, stone and wood fences, boardwalks, picnic shelters, and buildings such as park Visitor Centres and maintenance yards (B. Howes, pers. obs.).
In Ontario, individuals of E. fasciatus in both Great Lakes/St. Lawrence and Carolinian populations show a strong association with particular microhabitat elements (e.g. Hecnar and M’Closkey, 1998; Howes and Lougheed, 2004). Based on such specific microhabitat requirements, the species could be classified as a habitat specialist in Ontario. It should be noted that habitat research performed in northeastern Kansas (Fitch, 1954), southwestern Ontario (Seburn, 1993; Hecnar, 1994) and on the Shield in Ontario (Howes and Lougheed, 2004; Quirt et al., 2006) populations are based on diurnal surveys throughout the active season. Little is known about nocturnal microhabitat use or hibernation microsite selection.
Great Lakes/St. Lawrence populations
Great Lakes/St. Lawrence populations are distributed along the southern edge of the Canadian Shield on rocky outcrops embedded within a matrix of coniferous and deciduous forest. Potential habitat is patchy due to the natural fragmentation and patchiness of open rock outcrops within the region. Exposed rock outcrops are covered with loose rock of variable sizes that provide cover to individuals of E. fasciatus. Nearly all observations of E. fasciatus on the Shield indicate an association with rocky microhabitat (Oldham and Weller, 2000; Howes and Lougheed, 2004). Skinks in these populations use loose rock on open rock faces as cover elements and are rarely observed outside of this cover element (Howes and Lougheed, 2004; B. Howes, pers. obs.).
15 The best predictor of diurnal presence of skinks in seven Great Lakes/ St. Lawrence populations was the proportion of available cover rock at a microsite (Howes and Lougheed, 2004). More intensive research within two of these populations revealed that individuals of E. fasciatus exhibited a preference for longer than average available cover rocks located in exposed outcrop areas with few trees. Cover rocks used by skinks were on average 55.2 cm in length whereas cover rocks that were not used by skinks were on average 33.5 cm in length. Compared to other microsites available in the Shield habitat, rocks lying on a bedrock substrate provided the best opportunities for skinks to achieve their preferred body temperatures (determined to be 28ºC-36ºC; Fitch, 1954) (Quirt et al., 2006). The diurnal mean absolute deviation from preferred body temperature range was 1.99ºC under cover rocks that were occupied by skinks, and 4.33ºC under cover rocks that were unoccupied by skinks. Other cover elements available in this habitat (logs on bedrock, logs in forest, rocks in forest) seldom reached the species’ preferred body temperature range (Quirt et al., 2006).
Carolinian populations
Carolinian populations are found on or near the shores of Lakes Erie, St. Clair, and Huron in Carolinian forest. Remaining potential habitat is extremely patchy due to anthropogenic fragmentation (agricultural lands and urban areas). Individuals are generally found under woody debris in clearings within stabilized sand dunes, open forested areas and wetland areas (Seburn, 1993; Hecnar, 1994). The population of E. fasciatus at Point Pelee National Park (PPNP) is the longest-studied population in the species’ Canadian range. Research performed in PPNP has shown that individuals in this population have a strong association with woody debris as a cover element (Seburn, 1993; Hecnar, 1994; Hecnar and M’Closkey, 1998). Almost all cover material used by skinks within PPNP is woody debris (Seburn, 1990). The importance of woody debris has also been observed for the population of Rondeau Provincial Park. Numbers of skinks observed here seemed to increase following the 1998 wind storm that resulted in more fallen debris in the park (S. Dobbyn, pers. comm.). Other materials used by southwestern Ontario skinks include artificial materials such as building materials, utility poles (Seburn, 1990a) and wooden boardwalks (Hecnar and M’Closkey, 1998).
Individuals of E. fasciatus in PPNP prefer large (logs that are >17 cm diameter and boards that are > 1,700 cm2 in area), moderately decayed woody debris over small woody debris possibly because a larger surface area may offer more suitable substrate moisture levels (Hecnar, 1991; Seburn, 1993). Along with the surface area of a cover element, Seburn (1993) also showed that thickness is an important microhabitat feature. Cover elements that were <10 cm in thickness were preferred by individuals, possibly because a thinner cover element allows for an individual to reach a more optimal temperature more quickly than a thicker cover element (Seburn, 1993). The temperature under woody debris cover elements occupied by skinks ranged from 21.6-24.9ºC (Hecnar, 1991). Microsites selected by nesting females in PPNP were a subset of microsites selected by all individuals throughout the season (Seburn, 1993). Nest microsites tended to be under logs rather than artificial boards, and soil moisture in these microsites was higher than in other selected microsites (16.6-67.3% and 2.2-24.6% respectively) or than the ambient environment (Hecnar, 1994).
16 Habitat trends
Undoubtedly, E. fasciatus has incurred range-wide habitat loss and fragmentation. However, because the species inhabits early successional habitats and because it will use a variety of anthropogenic debris and structures as cover material, it can exist in areas that have been slightly modified by humans throughout much of its range, especially in the southern portion of its range (B. Howes, pers. obs.).
Both series of populations of E. fasciatus in Ontario have incurred habitat loss and fragmentation over the last century due to increased human settlement and disturbance. The Great Lakes/St. Lawrence populations exist in a region that has less human disturbance relative to other regions in southern Ontario, but increased cottage development and outdoor recreation are increasing threats to skink habitat in the Shield region. Carolinian populations have incurred considerable threats from human disturbance and have experienced considerable declines in habitat and number of populations based on observations from the OHS (Oldham and Weller, 2000; see Table 1).
Great Lakes/St. Lawrence populations
The rate of habitat change in Great Lakes/St. Lawrence populations appears to be relatively low. Loss of open rock outcrop habitat due to successional processes is relatively slow compared to natural succession in Carolinian populations (Seburn and Seburn, 1998), therefore the natural rate of change in Shield habitat is a relatively low threat. Because the region is characterized by thin soil overlaying rock substrate, conversion of natural habitat into agricultural land has been minimal and is unlikely to become a threat. Finally, human settlement and development within the region is primarily limited to rural areas and cottages. Such development may become a threat to some populations if encroachment of natural areas by cottage development continues.
Carolinian populations
The rate of habitat change in Carolinian populations has historically been much more severe than in Great Lakes/St. Lawrence populations, and undoubtedly it is this rate of habitat change (primarily anthropogenic) that has contributed to the decline in populations within this region over the last few decades (see Tables 1 and 2). The Carolinian forest ecosystem in southwestern Ontario is a particularly biologically diverse region, but agriculture and urban development have drastically altered the region and these pressures continue to threaten remaining habitat. Only 10% of original Carolinian forest in southwestern Ontario remains, and it harbours approximately 40% of Canada’s species at risk (CWS, 2006).
The rate of natural succession of habitat is a concern in Carolinian populations. It has been suggested that in some areas, fire suppression and other management activities may limit the amount of open habitat available for use by E. fasciatus. Prescribed burning is being used in some Carolinian populations (e.g. Rondeau Provincial Park and Pinery Provincial Park – S. Dobbyn, pers. comm.). Habitat in some
17 Carolinian populations is also altered by continuous deposition and erosion of sand within the stabilized dunes of Lake Erie (East, 1976 in Hecnar, 1994).
Habitat protection/ownership
Great Lakes/St. Lawrence populations
A summary of extant populations in Ontario that occur in Federal Land, Provincial Land, Conservation Areas and Areas of Natural and Scientific Interest (with varying degrees of protection) is provided in Table 3. This summary is based on OHS records. As the number of Great Lakes/St. Lawrence populations located in Provincial Land is likely underestimated by OHS records (M. Oldham, pers. comm.), it should be noted that the number of Great Lakes/St. Lawrence populations located in Provincial Land may also be underestimated in Table 3.
Table 3. Summary of extant (recorded or confirmed since 1995) populations of Eumeces fasciatus in Ontario that exist in Federal Land (National Parks or Indian reserves), Provincial Land (Provincial Parks, Provincial Park Reserves, Nature Reserves), a Conservation Area (CA), or an ANSI (Area of Natural and Scientific Interest) based on the Ontario Herpetofaunal Summary (Oldham and Weller, 2000). Populations are classified according to region (Great Lakes/St. Lawrence vs. Carolinian populations) and county. The total number of populations within each selected land type and within each county is listed. % Extant Observed Populations 1995- Federal Provincial in Classified County Present Land Land CA ANSI Total Land Types Great Lakes/St. Lawrence populations Frontenac 9 0 1 0 0 1 11% Grey 1 0 1 0 0 1 100% Haliburton 2 0 1 0 0 1 50% Hastings 4 0 0 1 0 1 25% Lanark 2 0 0 0 0 0 0% Leeds 1 1 0 0 0 1 100% Lennox & Addington 7 0 2 1 0 3 43% Muskoka 19 5 3 0 0 8 42% Parry Sound 16 0 8 0 0 8 50% Peterborough 15 0 2 0 0 2 13% Simcoe 4 0 1 0 0 1 25% Victoria 4 0 1 1 0 2 50% Total GL/St.L 84 6 20 3 0 29 31%
Carolinian populations Chatham-Kent 1 0 1 0 0 1 100% Essex 2 1 0 0 1 2 100% Lambton 2 1 1 0 0 2 100% Total Carol. 5 2 2 0 1 5 100%
18 Approximately 30% of extant (reported or confirmed since 1995) Great Lakes/ St. Lawrence populations are located in Federal Land, Provincial Land, Conservation Areas or Areas of Natural and Scientific Interest (Table 3). Extant populations occur on the following Federal lands: Georgian Bay Islands National Park (contains four recorded island populations), St. Lawrence Islands National Park, and Moose Point 79 Indian Reserve. A population was also reported on Magnetawan 1 Indian Reserve, although no records of this population have been made since 1988 (Oldham and Weller, 2000). Other Indian Reserves within the species’ Shield distribution that have suitable skink habitat but have not been listed in the OHS (Oldham and Weller, 2000) include Chippewa Island, Christian Island 30A, Curve Lake First Nation 35, Henvey Inlet 2, Islands of the Trent Waters 36A, Mnjikaning, Naiscoutaing 17A, Parry Island First Nation, Shawanaga 17, Shawanaga 17B, and Wahta Mohawk Territory (COSEWIC, 2006). Extant Great Lakes/ St. Lawrence populations also occur in many Provincial Lands including Provincial Parks, Conservation Reserves, and Nature Reserves.
Carolinian populations
All five extant (reported or confirmed since 1995) Carolinian populations are located within Federal Land, Provincial Land, Conservation Areas or Areas of Natural and Scientific Interest (Table 3). Point Pelee National Park and Walpole Island occur on Federal Land. The three remaining extant Carolinian populations occur on Provincial Land (Rondeau Provincial Park and Pinery Provincial Park), or in an Area of Natural and Scientific Interest (ANSI – Oxley Poison Sumac Swamp).
BIOLOGY
The biology of E. fasciatus has been studied by several authors throughout the species’ range. Henry Fitch reported on the life history of the species (including annual cycle of reproduction and growth, food habits, movements, and recruitment) on a population in northeastern Kansas (Fitch, 1954). Laurie Vitt and William Cooper have produced numerous accounts of the species biology that describe reproductive biology, odour detection, and tail autotomy (e.g. Cooper and Vitt, 1985; Vitt and Cooper, 1985; Vitt and Cooper, 1986a; Vitt and Cooper, 1986b; Cooper and Vitt, 1987; Cooper and Vitt, 1988). Carolyn Seburn, Stephen Hecnar and Robert M’Closkey have performed research in one Carolinian population that illuminates various aspects of the species’ biology including microhabitat and nest site selection, movement patterns and population trends (Seburn, 1993; Hecnar, 1994; Hecnar and M’Closkey, 1998; Hecnar et al., 2002). Habitat research has been performed in Great Lakes/St. Lawrence populations (Howes and Lougheed, 2004; Quirt et al., 2006), and fine-scale genetic research has also been performed in Great Lakes/St. Lawrence populations (Wick, 2004; Wick and Bogart, unpublished data; Howes and Lougheed, unpublished data). The majority of the information on species’ biology discussed below comes from these sources.
19 Life cycle and reproduction
Reproduction
Age of sexual maturity is 21 months based on research performed in Kansas (Fitch, 1954) and South Carolina (Vitt and Cooper, 1986a), although size at sexual maturity differed between the two sites (60 mm and 52 mm respectively; Fitch, 1954, Vitt and Cooper, 1986a). Fitch (1954) suggested that sexual maturity varies across the species’ range so that some individuals in southern parts of the range may achieve breeding size in their first summer while some individuals in northern parts may not achieve breeding size until their third summer. However, some individuals in a Carolinian population achieved minimum breeding size in their first summer, although it is unlikely that these individuals successfully reproduced until their second summer (Seburn and Seburn, 1998). This suggests that the average age at sexual maturity is relatively similar throughout the range of E. fasciatus.
In sexually mature males, breeding colours develop following emergence from hibernation and peak during the breeding season that lasts approximately two weeks (Fitch, 1954). These breeding colours can be induced during other parts of the year with testosterone treatments (Edgren 1959), and head colouration likely evolved as a consequence of sexual selection (Cooper and Vitt, 1988). Males use this head colouration along with chemical stimuli to identify the sex of conspecifics (Vitt and Cooper, 1986a; Cooper and Vitt, 1987; Cooper and Vitt, 1988). Although individuals do not defend territories, aggression between males during the breeding season has commonly been observed and reported (Fitch, 1954; Cooper and Vitt, 1987; Seburn, 1993). Vitt and Cooper (1985) showed that in E. laticeps, adult males with larger body size and larger relative head size were more likely to win intrasexual aggressive encounters and were more likely to be observed with females during breeding season (Vitt and Cooper, 1985).
In the spring, males spend the greater part of their time searching for females by visual and chemical stimuli and track females using a scent trail (Fitch, 1954). A variety of cloacal glands and other structures in both sexes produce pheromones (Madison, 1977; Simon, 1983), and although both males and females can detect conspecific odours, females show lower responsiveness to these chemical stimuli than males (Duvall et al., 1980).
When a male approaches a female, he attempts to bite any part of her body or tail. Once he restrains her with his bite, he adjusts his grip so that his jaw is grasping the loose skin on the dorsal side of the female’s neck. The male then thrusts his tail beneath the female’s tail, establishes cloacal contact and copulation begins. Immediately following copulation, the female will struggle to be free from the male’s grasp. When the male releases his grip, the female moves away, often pressing her cloacal region against the ground (Fitch, 1954). The male may follow behind her for a short time, and he may even remain with her for a short period of time to guard her against other males (Vitt and Cooper, 1985). Based on genetic data, multiple paternity
20 was evident in 4/9 nests examined in a Great Lakes/ St. Lawrence population (Wick, 2004).
The ova of sexually mature females begin developing following emergence from hibernation and reach their full size after copulation has occurred (Fitch, 1954). As eggs develop within the female, she becomes less active. She will eventually stop foraging (Cooper et al., 1990), and locate a suitable microsite in which to excavate a nest chamber (Fitch, 1954; Hecnar, 1994). In a Carolinian population, three females were observed to move 23-68 m prior to oviposition, and then return to their pre-oviposition site following hatching of their eggs (Seburn, 1993).
Females of E. fasciatus use a wide range of nesting sites relative to other North American lizards (Fitch, 1954), although they are all generally located within or beneath a cover element. Nest sites include beneath or within decaying logs, trees or stumps (Fitch, 1954; Vitt and Cooper, 1986a; Seburn, 1990; Hecnar, 1991), and beneath rocks (Fitch, 1954; Wick, 2004). In Great Lakes/St. Lawrence populations, nest sites are found beneath cover rock in small depressions of soil over rock substrate. Based on 16 located nest sites in one Great Lakes/St. Lawrence population, the average dimension of nest site cover rock was 39.3 ± 3.1 cm in length, 33.3 ± 4.5 cm in width, and 15.6 ± 1.0 cm in thickness (Wick, 2004). In Carolinian populations, nest sites are commonly found on sandy substrate beneath woody debris (Seburn, 1993; Hecnar, 1994) and are a subset of all microsites used by individuals throughout the year (Seburn, 1993; Hecnar, 1994).
Females were highly aggregated throughout the summer in a Carolinian population (Seburn, 1993), and accounts from across the species’ range suggest that aggregation behaviour in females may be most prevalent during the nesting season (Cagle, 1940; Fitch, 1954; Seburn, 1993; Hecnar, 1994). Communal nests are commonly found throughout the range and Hecnar (1994) showed that communal nesting was not a result of limited nesting sites in one Carolinian population (Hecnar, 1994). Another explanation for communal nesting could be that it allows for more continuous egg guarding by females (Fitch, 1954), as females will brood their own eggs as well as eggs from other females (Noble and Mason, 1933; Fitch, 1954; Vitt and Cooper, 1989; Seburn, 1993; Hecnar, 1994). Even eggs from E. laticeps were brooded by female E. fasciatus, although eggs from other more distantly related species or egg models were discarded from the brood (Noble and Mason, 1933). Brooding females will defend the eggs from predators (Fitch, 1954), and Hecnar (1991) has suggested that communal nesting may be a response to predation pressure in one Carolinian population.
Several weeks after mating, females lay one clutch of 9-10 eggs (Fitch, 1954; Seburn, 1990; Hecnar, 1994). Clutch size within a northeastern Kansas population and a Carolinian population was related to size, age and condition of the female (Fitch, 1954; Hecnar and Hecnar, 2005 respectively). Body size, running speed and some growth measures of E. fasciatus hatchlings appear to be influenced by clutch origin (Goodman, 2006), although it is undetermined whether this is due primarily to
21 environmental or genetic effects. Deposition of a clutch probably occurs over a day or two at most (Fitch, 1954).
Eggshells are thin and easily punctured (Fitch, 1954), and it has been suggested that in skinks, the most vulnerable stage in the life cycle is the egg (Fitch and Fitch, 1967). Important physical variables affecting egg development in reptiles, E. fasciatus included, are temperature, moisture, and gas exchange (Packard and Packard, 1988, in Hecnar, 1994). At low moisture levels, eggs are susceptible to desiccation whereas as at high moisture levels eggs may become infected with microbes or gas exchange may be arrested (Fitch, 1954; Fitch and Fitch, 1967).
Despite the vulnerability of this life stage, eggs show relatively high tolerance for moisture, and normal young have successfully hatched from apparently unhealthy or irregularly shaped eggs (Fitch, 1954). Further, embryos of E. obsoletus remained viable after 30-minute exposures to a maximum temperature of 42.4°C and a minimum temperature of -4°C (Fitch, 1964). In E. fasciatus, eggs probably have a temperature tolerance range comparable to that of an adult, although temperature most certainly affects incubation time (Fitch, 1954). For instance, gravid females in a Carolinian population retained their eggs longer than females in a Kansas population (52 days versus 30-44 days respectively) but brooded them for less time (13 days versus 11-32 days, respectively (Fitch, 1954; Seburn and Seburn, 1998). This difference may reflect a behavioural compensation for a shorter active season in more northern populations (Seburn and Seburn, 1998).
Females rarely leave their eggs unattended (Fitch, 1954) and aid in the successful development of their eggs in a variety of ways (Groves, 1982). First, females rotate the eggs in the nest and tend to keep their eggs in a cluster, with most of the egg exposed to air (Fitch, 1954). Frequent moving of the eggs probably ensures that no part of an egg is touching the substrate long enough for rotting to occur, and helps to prevent the eggs from asymmetrical drying or stretching that could lead to irregularly shaped eggs (Fitch, 1954). Females also defend the nest from predators such as mice, other lizards and small snakes, and retrieve eggs that have fallen outside the nest cavity (Noble and Mason, 1933; Vitt and Cooper, 1989). Finally, females relocate nests following a disturbance or a change in environmental conditions (Fitch, 1954; Vitt and Cooper, 1989), possibly to maintain the eggs at a suitable moisture level.
In a Carolinian population, Hecnar (1994) observed that during dry weather, nests were deeper in the soil than in wet weather, and on three occasions nests under logs disappeared during dry conditions and reappeared during wetter conditions, implying that females vertically move eggs according to moisture levels within the nest. Vitt and Cooper (1989) observed nest relocations in South Carolina after heavy rainfall further supporting the notion that females relocate eggs vertically according to soil moisture levels.
Females also vary their brooding position to alter the degree of contact with eggs according to soil moisture (Hecnar, 1994). High contact during low moisture levels likely
22 reduces transpirational losses from the eggs (Somma and Fawcett, 1989; Hecnar, 1994). It has even been suggested that females may void water in the nest during dry conditions to enhance moisture levels (Fitch, 1954; Seburn, 1990; Hecnar, 1990). Female brooding clearly influences nest moisture levels in E. fasciatus, and eggs that were brooded by a female had higher survivorship across all moisture levels than eggs that were unattended (Somma and Fawcett, 1989).
Females maintain an olfactory interest in their eggs throughout incubation (Noble and Mason, 1933; Fitch, 1954). This may help them to locate and retrieve their eggs and to identify addled (spoiled) eggs. Experimental research using brooding females of E. fasciatus indicates that they ingest eggs within 24 hours of the egg showing signs of addling (Groves, 1982). Vitt and Cooper (1986a) suggested that ingestion of live eggs may occur to satisfy the hunger of the brooding female, but Groves (1982) found that brooding females fed ad libitum in a laboratory experiment still ingested eggs, the large majority of which were addled. Ingestion of addled eggs may help to protect the female and her remaining viable eggs (Groves, 1982), as many predators of skinks locate their prey by olfactory cues (Fitch, 1954; Groves, 1982).
Initiation of incubation and duration of incubation vary across the species’ range and even within a population (Noble and Mason, 1933; Fitch, 1954). Generally, hatching occurs in Kansas by mid-July (Fitch, 1954). In Carolinian populations, hatching occurs from late July to early August (Seburn, 1990), and hatching in Great Lakes/ St. Lawrence populations seems to be at a similar time (Seburn and Seburn, 1989), although it may be slightly later due to a later general emergence date (S. Wick, pers. comm.). A comparison of reproductive events between Great Lakes/St. Lawrence and Carolinian populations was made based on intensive research performed within a Great Lakes/St. Lawrence population in 2002 (Wick, 2004; S. Wick, pers. comm.), and a Carolinian population in 1989 (Seburn, 1990; Seburn and Seburn, 1998). Where uncertainty in timing of the events in the Carolinian population exists due to lack of data, maximal time periods are assumed (Seburn and Seburn, 1998).
Table 4. Comparison of reproductive events between a Great Lakes/St. Lawrence (Wick, 2004; S. Wick, pers. comm.) and Carolinian population (Seburn, 1990; Seburn and Seburn, 1998). GL/St.L Population Carolinian Population General emergence from hibernation Early May to ? April 15 to April 28 Males show breeding colours Late May to early July April 28 to May 25 Females gravid Mid-June to mid-July June 8 to July 17 Females oviposit Early July to mid-July July 12 to July 17 Eggs hatch Early August to ? July 25 to Aug 25 Presumed hibernation (general Late September August 25 to September 16 disappearance or observed burrowing behaviour)
23 Individuals hatch by using an egg tooth over a period of 45 minutes to several hours (Fitch, 1954) and the hatching of an entire clutch is usually completed within 24 hours (Cagle, 1940). Once hatching is complete, the female and hatchlings will disperse within a short time, with the female at times dispersing before the hatchlings (Fitch, 1954). Females and hatchlings have been observed in the nest or nest vicinity a day or two after hatching (Fitch, 1954; Seburn, 1990). Over the incubation period, females lose considerable mass (Seburn, 1990) and, on average, weigh less than a yearling of even smaller SVL. Often, their tails are noticeably thinner because of depleted lipid reserves, and there may even be kinks in the tail as a result of this loss of tail mass (Fitch, 1954).
Growth and survivorship
Hatchlings were measured to be 23-27 mm in SVL in Kansas (Fitch, 1954). The most rapid growth phase of an individual’s lifetime occurs from hatching until first hibernation. During this phase, hatchlings with accelerated growth rates can achieve a maximum growth rate of about 0.5 mm a day to become ~50 mm in SVL upon entering their first hibernation. One Kansas individual with delayed growth emerged from its first hibernation at only 34 mm SVL (Fitch, 1954). In a Carolinian population, the average growth rate for hatchlings was 0.26 mm/day and the maximum SVL achieved by a hatchling before entering its first hibernation was 48 mm (Seburn, 1990). One individual with delayed growth emerged from its first hibernation with an SVL of only 36 mm. In this same population, the average growth rate for yearlings was found to be 0.18 mm/day, while adult males and females had an average of 0.02 mm/day and 0.08 mm/day respectively (Seburn, 1990).
Most yearlings grow to small adult size during the growing season following their first hibernation, and once this size is attained, growth slows abruptly (Fitch, 1954). In Kansas, once an individual’s SVL reaches approximately 75 mm, growth virtually stops in females, and slows for males, who can attain a maximum size several mm larger than that of females. As individuals age and grow, their colour pattern also changes, and the alteration of the colour pattern is more rapid in males than in females.
The most significant period of mortality (excluding egg mortality) occurs between hatching and emergence from first hibernation (Seburn and Seburn, 1998). Even when individuals reach adulthood, they still face a relatively high probability of mortality. Approximately one hatchling per clutch survives to reproduce (Fitch, 1954). Although Fitch (1956) reported a 10-year-old individual, life expectancy is generally five years. Eumeces fasciatus has a much longer life expectancy relative to similarly sized small mammals that often exist in similar habitats (Fitch, 1954).
True sex ratios are difficult to estimate because of the different behaviours exhibited by males and females throughout the active season. However, Seburn (1990) found that the sex ratio of a Carolinian population during breeding season was not significantly different from 1:1.
24 Hibernation
The ability to overwinter successfully may influence the northern range limit of some reptiles (e.g. St. Clair and Gregory, 1990; Rosen, 1991) and can have a large effect on the survivorship of individuals and the subsequent persistence of a population. Fitch (1954) showed that although individuals of E. fasciatus can survive brief exposures to temperatures below freezing, they do not survive prolonged exposures to such temperatures.
In E. fasciatus, a variety of hibernation sites are used, and knowledge of specific physical characteristics (e.g. moisture level, temperature range) of hibernacula is lacking. Across the species’ range, hibernation sites include locations under logs (Conant, 1951), under rocks, and in decaying stumps and fallen timber (Neill, 1948). Hibernation sites have been found up to approximately 2.5 m below ground (Tihen, 1937 in Fitch, 1954). Southwestern Ontario individuals may hibernate underground under wood debris in sand dune habitat (S. Hecnar, pers. comm.).
Skinks show significant aggregation behaviour within sex and age classes and within the general population throughout the year (Hecnar, 1991; Seburn, 1993; Hecnar, 1994), and this behaviour is especially prevalent during hibernation (Fitch, 1954; Cooper and Gartska, 1997). Small groups of hibernating individuals have been observed across the range (e.g. Hamilton, 1948; Neill, 1948; Fitch, 1954). In 1986 and 1987, spring aggregations of 25 individuals and 27 individuals, respectively, were found in a Carolinian population suggesting that aggregations of hibernating skinks also occur in Ontario’s populations (Weller and Oldham, 1988). Aggregation in hibernation sites could reflect a lack of suitable hibernation sites, but this explanation seems unlikely. Experimental research on E. laticeps showed that individuals had a tendency to aggregate despite the presence of multiple artificial hibernation sites. It was also found that aggregation was more likely to occur during periods of low temperatures, implying that there may be a thermal benefit to aggregation behaviour during hibernation (Cooper and Gartska, 1987).
Food habits
Eumeces fasciatus is mainly insectivorous (Fitch, 1954). The diet includes insects, insect larva, arachnids, earthworms, and occasionally small crustaceans and vertebrates (Taylor, 1936; Fitch, 1954). Newborn mice, bird’s eggs, and smaller lizards are possible prey items (Netting, 1939 in Fitch, 1954), but the smallest newborn mice are near the maximum size of prey that could possibly be swallowed by the largest adults of E. fasciatus (Fitch, 1954). Individuals often consume their shed skin, and will sometimes cannibalize other individuals of E. fasciatus. Stomach content and scat analysis on individuals in Kansas revealed that the diet consisted of arachnids (49%), insects (43%), and very small amounts of sloughed skin, skink eggs, and skink hatchlings (under 1% each) (Fitch, 1954). Scat analysis in one Carolinian population (Rondeau Provincial Park) revealed that crickets were the most common food item. Other prey included snails, spiders, cockroaches, sow bugs and caterpillars (Judd,
25 1962). More recent scat analyses performed in another Carolinian population (PPNP) indicated that the most common prey of skinks were arachnids (Hecnar et al., 2002).
Eumeces fasciatus is an active forager and locates prey by chemical perception and visual stimuli (Fitch, 1954; Burghardt, 1964). When presented with odours of known prey species, individuals displayed elevated tongue-flick rates, oriented to the odour source and sometimes even bit the odour source (Burghardt, 1964). Individuals feeding on crickets were observed to catch the cricket, shake it laterally often causing the cricket to be released from the skink’s grip, and then retrieve it and repeat the process (Fitch, 1954; B. Howes, pers. obs.). Burghardt (1964) found that individuals preferred larger, moving prey relative to smaller, non-moving prey. Individuals can ingest crickets that are almost the size of their own body diameter (Fitch, 1954; B. Howes, pers. obs.).
The amount of food ingested by individuals varies with age and throughout the season (Fitch and von Achen, 1977), and according to temperature and activity of the individual (Fitch, 1954). Food consumption by males was found to increase through the early summer and then decrease suddenly in mid-September. Females showed a similar pattern in food consumption, except that even non-brooding females typically decreased food consumption during the brooding period. The average food consumption by juveniles decreased gradually in the autumn (Fitch, 1954). Adult skinks in captivity ate roughly 3% of their body weight per day (0.195 g), whereas juvenile skinks ate 6.11% of their body weight per day (Fitch and von Achen, 1977). Scats of E. fasciatus are roughly 10-20 mm long, 2-4 mm in diameter, straight, cylindrical and capped at one end with uric acid. Typically, they primarily consist of the chitinous fragments of arthropod prey (Fitch, 1954; Judd, 1962; Hecnar et al., 2002).
Predation
Identified predators of E. fasciatus include raccoons, hawks, foxes, minks, weasels, skunks, opposums, armadillos, snakes, moles, and shrews. Based on scat analysis and experimental predation observations, Fitch (1954) suggested that short- tailed shrews were one of the major predators of skinks in his Kansas study site. Cats and dogs are also predators of skinks (Fitch, 1954; Oldham and Weller, 2000; B. Howes, pers. obs.). Cooper (1990) showed that individuals of E. laticeps can distinguish between predator and prey odours, and that they can also distinguish between odours of snake species that do and do not prey on them.
The reactions of E. fasciatus to predators vary greatly depending on the individual and the circumstances. Most often, individuals rely on concealment rather than escape tactics or aggression and respond to a potential predator by “freezing” (Fitch, 1954). Their movements become even more erratic and jerky when they are frightened, and they are especially elusive during warmer temperatures. Although they are primarily terrestrial, they are also adept at burrowing and climbing. Tree-climbing is a common escape tactic for individuals of both sexes and all ages (Fitch, 1954; S. Hecnar, pers. obs.). Individuals have even been observed to take refuge in water (Parker, 1948 in Fitch, 1954), and pull themselves through submerged vegetation (B. Howes, pers. obs.).
26 Tail autotomy
When harassed by a potential predator, individuals of E. fasciatus can autotomize their tails as a defence mechanism. Once severed, the tail will thrash for up to several minutes, distracting the predator so that the lizard can escape (Fitch, 1954). The vivid blue colour of the tail is an attractant for potential predators (Cooper and Vitt, 1985), and because tail colouration fades with age, it is thought that the risk of predation is highest during the juvenile life stage (Vitt and Cooper 1986b). Vitt and Cooper (1986b) suggested that a high proportion of predation attempts are directed to the tail because of its colouration and movement behaviour. They exposed juvenile E. fasciatus to snake attacks, and found that attacks at the base of the tail were more frequent on juveniles with complete tails than on juveniles who had their tails removed or painted black. They also showed that juveniles lash their tails more frequently than adults. Attacks directed at the tail caused the skink to autotomize it and subsequently escape, while attacks directed at the body resulted in a successful predation event (Vitt and Cooper, 1986b).
Although tail autotomy may be an effective predator avoidance mechanism, it may also be costly, as it could impair locomotion, result in loss of social status, and reduce growth or reproduction (Goodman, 2006). Two of these potential costs of tail autotomy in E. fasciatus have been examined. Tail loss in hatchling skinks was not associated with sacrificed growth in body mass or SVL (Vitt and Cooper, 1986b; Goodman, 2006). Juvenile E. fasciatus that underwent full tail autotomy regenerated tails at an average of 6.11 mm/week, a faster growth rate than that observed in juveniles that had only partial tail autotomy. Full tail autotomy was associated with significantly decreased maximum sprint speed in juveniles; however, this effect disappeared within four weeks after tail loss (Goodman, 2006). Costs of tail autotomy have not yet been examined in adults, although it is known that the tail contains over half of the standing lipid content in females and almost half of the standing lipid content in males (Vitt and Cooper, 1986b).
Fitch (1954) measured the incidence of tail loss in his Kansas study population. He found that tail loss had occurred in approximately 25% of 1-month old juveniles, 50% of 1 to 3 month olds, and 75% of 1 year olds. Incidence of broken or regenerated tails in adult females is slightly higher than in adult males, perhaps because of nest guarding and sluggishness resulting from nesting period. Only 16.5% of adult females had their complete original tail (Fitch, 1954).
Physiology
Like other reptiles, individuals of E. fasciatus thermoregulate by adjusting their microhabitat use to maintain core body temperature within an optimal range. By using a terrarium that had extremes of temperatures at each end, Fitch (1954) determined that the preferred temperature range of E. fasciatus was 28-36°C, although their temperature tolerance range is much broader. Individuals were found to survive temperatures as high as 42°C, but it should be noted that during periods of high temperatures skinks are observed less frequently and may become more fossorial (Fitch, 1954; Seburn and Seburn, 1998; B. Howes, pers. obs.). Individuals were also
27 found to survive temperatures as low as –1°C for short periods of time (less than 30 minutes), and are mobile at temperatures below those at which most North American reptiles are capable of moving (Fitch, 1954). The species’ relative cold tolerance compared to other reptiles is likely associated with its status as one of the most northerly lizard species and its classification as a primary herpetological invader following the most recent glacial retreat (Holman, 1995).
Temperatures in Great Lakes/St. Lawrence populations are generally far from the optimum for reptiles (Row and Blouin-Demers, 2006), possibly making microhabitat selection especially important in these northern populations. In two of these populations, during late May and early June, individuals of E. fasciatus selected rocks as cover elements that provided them with thermal conditions that most closely matched their preferred body temperature range. Presumably, this allows them to maximize time at temperatures that optimize physiological processes (Quirt et al., 2006).
Movement and dispersal
Eumeces fasciatus is not territorial, but individuals tend to limit their activities to small, familiar areas. Individuals do have home ranges, although boundaries are not strictly defined. The size of a home range depends on the sex and age of an individual as well as the type of habitat, but was estimated to be between 270 m2 and 578 m2 for individuals in a Kansas population (Fitch, 1954). Within these ranges, individuals often follow natural travel routes, moving along rock faces or fallen logs (Fitch, 1954). If any homing instinct exists within E. fasciatus, it is likely very weak. Fitch (1954) found that the composition of his Kansas study populations differed from year to year, presumably because individuals tended to shift their home ranges. Mark-recapture experiments have revealed that, although individuals have been found up to 208 m from the original point of capture, they are generally recaptured within a short distance of the previous capture (Fitch, 1954). The average movement between captures recorded for 323 recaptured individuals in Kansas was 18 m (Fitch, 1954). Individuals moved an average of 5.1 m per day (Fitch and von Achen, 1977), although activity levels have been shown to differ between males, females, and juveniles (Fitch and von Achen, 1977; Seburn, 1993).
The average movement between captures of Kansas individuals throughout a season was 21 m for males, 14 m for females, and 19 m for juveniles (Fitch, 1954). The maximum distance between any two captures was 119 m for males and 99 m for females (Fitch and von Achen, 1977). In a Carolinian population, the maximum hatchling movement recorded was at least 107 m, while the maximum yearling movement was at least 25 metres (Seburn, 1993).
Adult males tend to undertake longer movements outside of their home range during the breeding season, while adult females tend to make longer movements outside their home range to find a suitable nest site (Fitch, 1954; Seburn, 1993). Females make small movements during the breeding and nesting periods, but become more active following the nesting period (Fitch and von Achen, 1977), and tend to return to their original home range after their eggs have hatched (Seburn, 1993). Juveniles are
28 more active than adults throughout the season (Fitch and von Achen, 1977) and tend to shift to new areas more frequently than adults (Fitch, 1954). Genetic research performed in one Great Lakes/St. Lawrence population revealed that no age or sex class tended to disperse more than another, but because females may leave their home range to nest, hatchlings are born outside of the maternal home range and could therefore be considered the “dispersers” of the species (Wick, 2004).
Interspecific interactions
Eumeces fasciatus is host to several endoparasites and ectoparasites. Small nematodes and flukes have been observed in the feces and small white cysts have been observed in several dissected individuals (Fitch, 1954). Two previously unidentified species of endoparasites (Eimeria fasciatus and Isospora scinci) that were found in the intestine of E. fasciatus could be specialists on the species (Upton et al., 1991). The most common ectoparasites of E. fasciatus are chiggers (Trombicula spp.; Wharton and Fuller, 1952, in Fitch, 1954), which commonly attach themselves to the skin of the limb axes (Seburn and Seburn, 1998; B. Howes, pers. obs.). Chiggers have been observed on individuals in a Carolinian population where the frequency and level of infection seemed to increase throughout the summer. Periodic shedding of the skin for growth seems to reduce the frequency and level of infection (Seburn and Seburn, 1998).
Adaptability
Eumeces fasciatus is intolerant of unsuitable humidity levels and a permanent body of water is a requirement in any habitat (Fitch, 1954). It appears to be relatively tolerant to a wide range of temperatures, although unusually cool weather conditions can delay oviposition or hatching. This could result in delaying sexual maturity in a large proportion of young, drastically reducing the reproductive potential of a population. The percentage of such delays in attainment of sexual maturity is likely to increase in more northerly populations (Fitch, 1954), and may be of particular concern in Great Lakes/ St. Lawrence populations. These populations exist in more extreme climatic conditions than the Carolinian populations. For instance, the mean daily January and July temperatures were noted for seven Great Lakes/St. Lawrence populations and two Carolinian populations based on records from the nearest weather stations (Howes and Lougheed, in review). The mean daily January temperature was -9.5°C for Great Lakes/ St. Lawrence populations, and -4.1°C for Carolinian populations. The mean daily July temperature was 20.3°C for Great Lakes/St. Lawrence populations, and 22.3°C for Carolinian populations (Howes and Lougheed, in review; Environment Canada, 2006).
Fluctuating water levels could increase genetic connectivity among populations that are normally isolated by water in a heterogeneous environment (Wick, 2004). High lake levels may contribute to overwintering losses, especially in Carolinian populations that exist on the shores of Lakes Erie and Huron (Hecnar and Hecnar, 2005). Eumeces fasciatus is intolerant of natural succession processes that alter its early successional habitat. Indeed, the populations that Fitch (1954) studied intensively have now virtually disappeared because of succession (H. Fitch, pers. comm.). Infrequent fires can help to
29 maintain the early successional habitat required by the species, but can also cause a large decline in numbers at a particular site. A fire within a Connecticut population may have eliminated an entire cohort (Gruner, pers. comm. in Seburn and Seburn, 1998). Mushinsky (1992) showed that individuals of E. inexpectatus in Florida were more common on sites that had not been burned for 20 years or were burned on a 5-7 year cycle compared to sites that were burned on a 1-2 year cycle. Less frequently burned sites had significantly more leaf litter, which likely provides more suitable habitat to secretive skinks (Mushinsky, 1992).
Skinks can exist in anthropogenically altered habitats, and may actually thrive in these situations by making use of artificial objects, such as wood piles, and scrap tin and plywood boards. However, this capacity is mainly restricted to areas that retain some aspects of natural habitat (e.g. maintenance yards within protected parks, rock gardens surrounding a house in a rural area). Skinks are not found in urbanized areas. Although skinks are likely relatively resilient to short-term minor disturbances, their tolerance may be greatly reduced during the nesting period (Hecnar and M’Closkey, 1988). Brooding females that are disturbed can abandon their nest (Hecnar and M’Closkey, 1988), possibly resulting in high egg mortality (Hasegawa, 1985). In one Carolinian population (PPNP), E. fasciatus has been shown to be intolerant to loss of microhabitat structures (Hecnar and M’Closkey, 1988).
As previously mentioned, northern populations of E. fasciatus have significantly reduced levels of intra-population genetic diversity relative to central, eastern, and southern populations of the species (Howes and Lougheed, in review). This reduction in genetic diversity could inhibit the evolutionary potential and adaptability of Ontario’s populations.
POPULATION SIZES AND TRENDS
Search effort
Great Lakes/St. Lawrence and Carolinian populations
Estimating population occurrence in Ontario is greatly aided by the OHS database, which contains over 1,200 sightings of the species (Oldham and Weller, 2000). This database is an invaluable resource to aid in identifying the presence of the species, although population occurrence is likely to be disproportionately reported in areas that are more frequented by humans, and overall submission of data to the OHS has declined since 1995 (M. Oldham, pers. comm.). Species misidentification is unlikely because E. fasciatus is the only lizard species in Ontario.
Estimating population abundance in E. fasciatus is extremely difficult. Individuals are secretive and spend the greater part of their day under cover elements. As well, activity patterns change throughout the year. While adult males and females are most abundant in May, yearlings are most abundant in June (Fitch, 1954). After the breeding season,
30 males become much less active (Fitch, 1954; Seburn, 1993) and may become more fossorial in hotter months (Seburn, 1990). Finally, individuals may shift their home range throughout the active season, resulting in over- or underestimates of the true population size. Because the habits and activity patterns of individuals change with sex and age, census data should be sorted into categories of male, female, and young (Fitch, 1954). Young are more likely to be observed than adults because of their increased numbers, increased activity throughout the season, increased movement patterns on a daily basis, and increased conspicuousness due to their brightly coloured tail.
Accurate estimates of population abundance require active searching and intensive study over the course of an appropriate time period in Ontario. In a Carolinian population in PPNP, Hecnar and M’Closkey (1998) measured activity density, which is strongly correlated with true density (see Hecnar and M’Closkey, 1998). Alternatively, Seburn (1993) and Wick (2004) used mark-recapture methods throughout the active season in a Carolinian and Great Lakes/St. Lawrence population, respectively. In both studies, marking was achieved through toe-clipping (Seburn, 1993; Wick, 2004). Although application of paint to the skin of animals is another possible marking method, this technique allows only short-term monitoring as the paint wears quickly (within 24 hours for some individuals – S. Hecnar, pers. obs.) and individuals will shed their skin throughout the active season. Active searching involves flipping or moving cover elements (woody debris or cover rock) that should always be replaced to their original position.
It should be noted that active searching in Great Lakes/St. Lawrence populations can result in skink fatalities, especially when performed by novice surveyors. Appropriate caution is necessary to avoid crushing individuals in the pivot point of the cover rock as it is being lifted. To minimize this risk, smaller rocks should be lifted entirely from the surface insofar as possible. When this is not possible, one surveyor should partially lift a corner of the rock, while another surveyor looks underneath the rock to check for the presence of a skink (B. Howes, pers. obs.).
Abundance
Based on records from the OHS, there are 84 Great Lakes/ St. Lawrence populations and five Carolinian populations reported since 1995 (Oldham and Weller, 2000; see Table 1). An estimate of effective population size (Ne) was generated for nine Ontario populations based on six microsatellite loci, maximum likelihood analyses (Beerli and Felsenstein, 1999; Beerli and Felsenstein, 2001), and the assumption of a typical vertebrate microsatellite mutation rate of 10-4 per locus per generation (Table 5). The average Ne for each designatable unit was then calculated and multiplied by the population occurrence within each unit. The total Ne estimate for Ontario (and consequently Canada) is 23,839 (Howes and Lougheed, unpublished data). This approach has several sources of error: 1. estimates of population occurrence (based on the number of populations recorded in the OHS since 1995) may be inaccurate, 2. the calculated mean of Ne for sampled Great Lakes/St. Lawrence and Carolinian populations may not reflect Ne of unsampled extant populations, and 3. the likelihood method of estimating Ne may be inaccurate (e.g. Zaid et al., 2004).
31
Table 5. Estimates of effective population size for nine populations of Eumeces fasciatus in Ontario based on six microsatellite loci and maximum likelihood analysis. Populations are categorized according to the two disjunct areas of occurrence in Ontario (Great Lakes/St. Lawrence and Carolinian).
Population County Ne estimate (95% confidence interval) GL/St.L. populations Tadenac Muskoka 229 (205, 256) Swift Rapids Simcoe 270 (239, 307) Towerline Simcoe 240 (213, 271) Feeney Lennox & Addington 328 (292, 370) Burke Frontenac 342 (302, 390) Honey Harbour Muskoka 177 (156, 200) Ardoch Frontenac 273 (243, 308)
Carolinian populations Point Pelee National Park Essex 306 (273, 346) Rondeau Provincial Park Chatham-Kent 291 (259, 329)
Estimates of Ne produced below cannot be directly compared to estimates of census population size, because neither method has been simultaneously employed within a single population. In fact, the only population for which a census estimate exists is the population in PPNP. Seburn and Seburn (1989) roughly estimated that this population was composed of between 1,000-2,000 individuals in 1989. Accurate estimates of Ne are certainly less than the census size (Frankham, 1995). While the ratio of Ne to census population size varies among species, estimates of Ne are typically 11% of census estimates (Frankham, 1995).
Great Lakes/St. Lawrence populations
The average Ne for Great Lakes/St. Lawrence populations is 266, and the population occurrence is estimated to be 84 (Table 1) based on records from the OHS since 1995 (Oldham and Weller, 2000). Thus, the total Ne in the Great Lakes/ St. Lawrence faunal province is approximately 22,300 individuals (Howes and Lougheed, unpublished data).
Carolinian populations
The average Ne for Carolinian populations is 299 individuals, and the population occurrence is estimated to be 5 (Table 1, Table 2). Thus, the total Ne in the Carolinian faunal province is approximately 1,495 individuals (Howes and Lougheed, unpublished data). However, this total Ne estimate for the Carolinian populations is based on the assumption that the estimated average Ne for PPNP and Rondeau Provincial Park are representative of the Ne for remaining Carolinian populations. This assumption is not accurate, because the other Carolinian populations are much smaller than populations in PPNP and Rondeau Provincial Park.
32 Fluctuations and trends
Population density varies within a year and among years according to a variety of factors including weather conditions and successional processes. Population density was estimated at 125-250 individuals/ha (excluding hatchlings) for a Kansas population that had typical natural habitat. Population density in one area in PPNP ranged from 21 individuals/ha in 2003 and 2004 to 85 individuals/ha in 2001 (Hecnar and Hecnar, 2005). Within a year, numbers are lowest in mid-summer, just before hatching occurs. Following hatching, population density can double as it reaches a maximum (Fitch, 1954).
Cohort structure can vary greatly from year to year depending on weather conditions and various other factors. For instance, in one of his Kansas study populations, Fitch (1954) found that the two-year old cohort made up 70% of the breeding population in 1951, whereas the corresponding cohort comprised only 36% in 1950 and 58% in 1952. Any given adult cohort can be reduced by at least half within a season (Fitch, 1954).
Great Lakes/St. Lawrence populations
The occurrence of Great Lakes/St. Lawrence populations appears to fluctuate moderately based on population occurrence data in the OHS. The number of recorded populations prior to 1984 was 71. From 1984-1994, the number of recorded populations increased to 115, and from 1995-present, this number declined to 84 (Table 1; Oldham and Weller, 2000). It is difficult to assess if the recent apparent decline in occurrence of Great Lakes/St. Lawrence populations since 1995 is biologically meaningful, as the overall submission of data to the OHS has also declined during this time period (M. Oldham, pers. comm.).
Carolinian populations
The number of populations of skinks in southwestern Ontario has declined since at least 1984. Prior to 1984, 17 populations were recorded. From 1984-1994, this number declined to eight populations, and only five populations have been recorded or confirmed since 1995 (Table 1; Oldham and Weller, 2000; C. Jacobs, pers. comm.). In 2000, locations of 16 historical Carolinian populations were surveyed for E. fasciatus. Of the 16 populations surveyed, skinks were found only at PPNP, Rondeau Provincial Park and Pinery Provincial Park (Hecnar and Hecnar, 2000 in Hecnar and Hecnar 2005; S. Hecnar, pers. comm.). Several of the 16 locations no longer had suitable habitat owing to development and other anthropogenic disturbance. None of the locations on the Niagara Peninsula had skinks.
Although skink abundance within Rondeau Provincial Park appears to be stable (S. Dobbyn, pers. comm.), abundance at Pinery Provincial Park appears to have dwindled to quite low levels (S. Hecnar, pers. comm.), and this population is certainly much smaller than at PPNP or Rondeau based on surveys performed from 2002 to
33 2004 (B. Howes, pers. obs.). Very little information on the extant Oxley Poison Sumac Swamp population is known. The Nature Conservancy of Canada acquired the habitat in which skinks are present in 2004, and has since enhanced skink habitat by laying down artificial cover boards throughout the site (H. Arnold, pers. comm.). The amount of suitable skink habitat within Oxley Poison Sumac Swamp is small and skink sightings remain low despite considerable inventory work performed at the site (M. Oldham, pers. comm.).
The only data on a population trend available for an Ontario population are based on a population in the Carolinian population (PPNP). From 1990-1995, this population suffered a three-fold to five-fold decline in numbers. The age structure of this population appeared to be adult-biased in all five study years, suggesting that recruitment was insufficient to maintain population size (Hecnar and M’Closkey, 1998). Further investigation into this population decline indicated that a lack of suitable microhabitat (woody debris) was responsible for the absence of skinks in areas heavily used by humans. A microhabitat restoration experiment indicated that artificially placed cover elements are used by skinks and can enhance skink habitat (Hecnar and M’Closkey, 1998). The population was not only threatened by microhabitat loss, but also by systematic illegal collecting. The attractive colouration of juvenile five-lined skinks has made them desirable pets, and large-scale collecting has probably occurred in the park since at least 1989 (Hecnar and M’Closkey, 1998). Microhabitat restoration has increased skink abundance within the park since 1996, but continued active management is needed for the persistence of the species within PPNP (Hecnar and Hecnar, 2005).
Rescue effect
Great Lakes/St. Lawrence populations
Great Lakes/St. Lawrence populations separated by as little as 3-5 km showed significant genetic distinction (Wick, 2004; Howes and Lougheed, unpublished data). Wick (2004) also showed that water is an effective barrier to gene flow in the species, and that an island subpopulation in their study site had reduced genetic diversity relative to neighbouring populations that were within approximately 2 km or less. Clearly, rescue from a neighbouring population or recolonization following a local extinction event is unlikely in these populations. Rescue from United States’ populations is not possible.
Carolinian populations
The remaining Carolinian populations are extremely isolated from one another. Rondeau Provincial Park and PPNP display significant genetic differentiation, which is not surprising given the geographic distance that separates them. Natural rescue from a neighbouring population or natural recolonization following a local extinction event is virtually impossible in Carolinian populations. Rescue from the United States’ populations would not be possible owing to distance, and lack of suitable habitat to get to Ontario (e.g., they would have to cross the Great Lakes or their associated rivers).
34 LIMITING FACTORS AND THREATS
Habitat alteration
Like most species at risk, E. fasciatus in Ontario is threatened by habitat loss, fragmentation, and degradation caused by increased human settlement and recreation. This is most evident in southwestern Ontario where skink populations have undergone considerable decline, largely due to increased urban settlement and agriculture which have proliferated in many places where skinks occurred 2-3 decades ago (Hecnar pers. comm.). Habitat alteration is a less serious threat in the Shield region, and the skinks are much more widespread. Nevertheless, loss and degradation of habitat is still a real threat in the Shield region. For instance, one Great Lakes/St. Lawrence population appears to have suffered a decline in individuals because of habitat degradation caused by ATV and dirt bike trails (B. Howes, pers. obs.). The site (located on Crown Land underneath a large power line) was an excellent example of reptile habitat in the southern Shield area, with large rock outcroppings in a matrix of low-lying vegetation and mixed deciduous and coniferous forest. Within four years, most of the vegetation surrounding the outcrops has been turned into barren sand, and cover rocks on outcrops have been removed to facilitate “trailing” on bald rock (B. Howes, pers. obs.). Similar local losses of populations have been observed at other locations on the Shield (R. Brooks, pers. comm.).
Microhabitat alteration
Hecnar and M’Closkey (1998) showed that loss of microhabitat elements in a Carolinian population (PPNP) resulted in a three-fold to five-fold decline in skink abundance between 1990-1995. Loss of microhabitat is clearly the most severe form of microhabitat alteration, but repeated disturbance can also negatively impact a population’s abundance. Significantly fewer skinks were found in areas that had high levels of human disturbance relative to areas of low human disturbance (Hecnar and M’Closkey, 1998; see Fluctuations and Trends section). A single alteration to a microhabitat element could result in a decline of its quality. For instance, a cover rock or log that is flipped and not replaced exactly to its original position may alter the particular microclimate conditions it provides. Even when replaced to its original position, substrate elements (e.g. soil, lichen) may be disturbed.
Even Carolinian populations within protected areas are still at risk of microhabitat alteration, as woody debris may be cleared from beaches for aesthetic reasons or may be removed for firewood (Hecnar and M’Closkey, 1998). Although microhabitat requirements appear to be equally important in Great Lakes/St. Lawrence populations (Howes and Lougheed, 2004; Quirt et al., 2006), the threat of microhabitat alteration in this series of populations appears to be lower. However, evidence of disturbance in the form of recently flipped rocks has been observed, whether by humans or black bears (K. Prior, pers. comm.; B. Howes, pers. obs., R. Brooks, pers. comm.). Furthermore, removal of rock from Shield habitat for urban landscaping has also been observed (e.g. Manitoulin Island, Kawartha Lakes (M. Oldham, pers. comm.).
35 Illegal collecting
Illegal collecting of the species in Ontario was first noticed in a Carolinian population (PPNP) in 1989. Four of eight monitored clutches disappeared, and their disappearance coincided with the movement or destruction of the nesting microsite that consisted of woody debris (Seburn and Seburn, 1998). In 1990, large-scale disturbances to microsites occurred and these disturbances corresponded with the disappearance of gravid females or clutches (Hecnar and M’Closkey, unpublished data in Seburn and Seburn, 1998). In 1989, prior to these microsite disturbances, hatchlings represented 45% of all individuals sampled (Seburn, 1990). Following the disturbances (from 1990-1995), hatchlings represented only 1% to 21% of individuals captured (Hecnar and M’Closkey, 1998).
Hecnar and M’Closkey (1998) found that four out of four local pet stores interviewed were willing to fill orders for five-lined skinks, and one employee actually suggested collecting skinks directly from PPNP. The potential threat of illegal collecting is enhanced by the social behaviour displayed by gravid and brooding females (Hecnar and M’Closkey, 1998). It is possible that illegal collecting is also occurring in Great Lakes/ St. Lawrence populations, but this has yet to be documented.
Depredation by raccoons
Recent observations in one Carolinian population (PPNP) suggest that considerable predation of skinks by raccoons is occurring (Hecnar and Hecnar, 2005). This notion is supported by research that indicates the raccoon density within this park is four-fold higher than the average raccoon density in rural Ontario (Phillips and Murray, 2005, in Hecnar and Hecnar, 2005).
Road mortality
Further research performed in PPNP revealed that road mortality of skinks is occurring. A recent road mortality study indicated that 14 skinks were killed on the park road in 11 days (V. McKay, pers. comm. in Hecnar and Hecnar, 2005). While road mortality has long been identified as a threat to amphibians and reptiles in Ontario (e.g. Ashley and Robinson, 1996), this threat has perhaps been underestimated for skinks in southwestern Ontario. The threat of road mortality to five-lined skinks has been identified elsewhere in the species’ range (Florida – Aresco, 2003), and evidence of road mortality has also been observed elsewhere in the species’ range (Illinois – B. Howes, pers. obs.).
SPECIAL SIGNIFICANCE OF THE SPECIES
Eumeces fasciatus is the only lizard that occurs east of Manitoba in Canada. This makes it not only Ontario’s, but also eastern Canada’s, only lizard. It is widespread and apparently secure in the majority of its geographic range; however, its abundance in the
36 northern part of its range is less secure. Like so many of Canada’s species at risk, Canadian populations of E. fasciatus are northern peripheral populations that may have unique genetic and ecological characteristics. These populations may have an increased risk of local extinction simply because they are geographically peripheral.
Within Ontario, the species exists exclusively in two unique habitat types: 1. open bedrock in a matrix of mixed boreal/deciduous forest (Great Lakes/St. Lawrence populations), and 2. Carolinian forest (Carolinian populations). The habitat in the Great Lakes/St. Lawrence populations is unique because it holds the highest number of animal species within the entire geological area of the Canadian Shield (Moon, 1970). The habitat in the Carolinian populations is unique because it is comprised of Carolinian forest. Carolinian forest habitat holds the greatest variety of life in Canada, and harbours 40% of Canada’s species at risk (CWS, 2006). By conserving the skink’s occurrence and abundance, we will also help to conserve a disproportionate number of other species that co-occur in these diverse habitats.
From a more anthropocentric perspective, the skink provides people with an increased appreciation of the diversity of Canadian fauna. Most people in Ontario are unaware that a lizard species exists in their province, as many people tend to associate lizards with much more southern climates. In general, people are intrigued by the skink’s attractive colouration, small size, and speed. In this regard, the skink is a “charismatic” reptile. If we work to increase public interest and respect for the skink, we may, in turn, help to enhance interest in and respect for all Canadian reptiles.
EXISTING PROTECTION OR OTHER STATUS DESIGNATIONS
Eumeces fasciatus received its COSEWIC status as Special Concern in April 1998 (COSEWIC, 1998) and as a single designated unit. In Ontario, the species is listed as Special Concern by the Ontario Ministry of Natural Resources (OMNR, 2005), and is a Specially Protected Reptile under Ontario’s Fish and Wildlife Conservation Act. In Canada, it has a NatureServe rank of vulnerable (N3), while in the U.S. and globally it is listed as secure (N5 and G5 respectively; NatureServe Explorer, 2006). The species is listed as secure in the majority of jurisdictions across its range. However, in most of its more northerly jurisdictions it is listed as apparently secure, vulnerable, or imperiled (Table 6).
37
Table 6. NatureServe rank for Eumeces fasciatus for all jurisdictions within its global range. SX=presumed extirpated, S1=critically imperiled, S2=imperiled, S3=vulnerable, S4=apparently secure, S5=secure, SNR=unranked, SU=unrankable. State/Province SX S1 S2 S3 S4 S5 SNR SU Massachusetts X Connecticut X Nebraska X Vermont X Michigan X Minnesota X New Jersey X New York X Ontario X District of Columbia X Indiana X Iowa X Pennsylvania X Wisconsin X Alabama X Arkansas X Delaware X Georgia X Illinois X Kansas X Kentucky X Louisiana X Maryland X Mississippi X North Carolina X Oklahoma X Tennessee X Texas X Virginia X West Virginia X Florida X Missouri X Ohio X South Carolina X South Dakota X
38 TECHNICAL SUMMARY
Eumeces fasciatus – Carolinian population Five-lined skink Scinque pentaligne Range of Occurrence in Canada: Southwestern Ontario
Extent and Area Information • Extent of occurrence (EO)(km2) 3,946 km2 • Specify trend in EO Declining • Are there extreme fluctuations in EO? No • Area of occupancy (AO) (km2) 88 km2 • Specify trend in AO Declining • Are there extreme fluctuations in AO? No • Number of known or inferred current locations 5 • Specify trend in # Declining • Are there extreme fluctuations in number of locations? No • Specify trend in area, extent or quality of habitat Decline Population Information • Generation time (average age of parents in the population) 2 years • Number of mature individuals 1,495 (based on estimates of Ne) • Total population trend: Declining • % decline over the last/next 10 years or 3 generations. Unknown • Are there extreme fluctuations in number of mature individuals? Unknown • Is the total population severely fragmented? Yes • Specify trend in number of populations Declining • Are there extreme fluctuations in number of populations? No • List populations with number of mature individuals in each: Point Pelee National Park, Rondeau Provincial Park, Pinery Provincial Park (?), Oxley Poison Sumac Swamp (?), Walpole Island (?) Threats (actual or imminent threats to populations or habitats) - habitat alteration and loss - microhabitat alteration - illegal collecting - depredation by high populations of raccoons and coyotes and by dogs and cats - road mortality Rescue Effect (immigration from an outside source) • Status of outside population(s)? USA: Secure. Variable among U.S. jurisdictions but less secure among northern jurisdictions. • Is immigration known or possible? No • Would immigrants be adapted to survive in Canada? Unknown • Is there sufficient habitat for immigrants in Canada? Unknown • Is rescue from outside populations likely? Unlikely Quantitative Analysis N/A Current Status COSEWIC: Special Concern (1998) Carolinian population: Endangered (2007)
39
Status and Reasons for Designation
Status: Endangered Alpha-numeric code: B1+2ab(i,ii,iii,iv,v) Reasons for Designation: The species is the only lizard in Eastern Canada. The Carolinian population occurs in only 4 or 5 small, completely isolated populations on the shores of lakes Erie, St. Clair and Huron. Threats to this skink include loss and degradation of microhabitat, illegal collecting, increased depredation by racoons, coyotes, dogs and cats and increased mortality on roads. If any population is extirpated, because of isolation there is no chance of natural recolonization.
Applicability of Criteria Criterion A: (Declining Total Population): Decline of ~60% but occurred over more than 3 generations. Criterion B: (Small Distribution, and Decline or Fluctuation): EO and AO are small, and there are 4 or 5 widely separated, highly fragmented populations, declines in Area of Occupancy, Extent of Occurrence,, habitat, locations and numbers. Criterion C: (Small Total Population Size and Decline): Small total population size and documented declines in population occurrence, but there is/are populations over 250 adults and a 20% decline in 5 years has occurred but only one population could be monitored. Criterion D: (Very Small Population or Restricted Distribution): Could meet Threatened D2. Criterion E: (Quantitative Analysis): Not applicable.
40 TECHNICAL SUMMARY
Eumeces fasciatus – Great Lakes/St. Lawrence population Five-lined skink Scinque pentaligne Range of Occurrence in Canada: south central Ontario
Extent and Area Information • Extent of occurrence (EO)(km2) 29,842 km2 • Specify trend in EO Stable or slight decline • Are there extreme fluctuations in EO? No • Area of occupancy (AO) (km2) 484 km2 • Specify trend in AO Stable or slight decline • Are there extreme fluctuations in AO? No • Number of known or inferred current locations 84 • Specify trend in # Slight decline • Are there extreme fluctuations in number of locations? No • Specify trend in area, extent or quality of habitat Some decline Population Information • Generation time (average age of parents in the population) 2 years • Number of mature individuals 22,300 (based on estimates of Ne) • Total population trend: Stable or slight decline • % decline over the last/next 10 years or 3 generations. Unknown • Are there extreme fluctuations in number of mature individuals? Unknown • Is the total population severely fragmented? No • Specify trend in number of populations Stable or slight decline • Are there extreme fluctuations in number of populations? No • List populations with number of mature individuals in each: see Tables 1 and 5 Threats (actual or imminent threats to populations or habitats) - habitat alteration and loss - microhabitat alteration and destruction - illegal collecting - road mortality - incresing fragmentation Rescue Effect (immigration from an outside source) • Status of outside population(s)? • USA: Secure. Variable among U.S. jurisdictions but less secure among northern jurisdictions. • Is immigration known or possible? Not possible from USA (unlikely to occur beyond 3 km) • Would immigrants be adapted to survive in Canada? Unknown • Is there sufficient habitat for immigrants in Canada? Unknown • Is rescue from outside populations likely? Unlikely Quantitative Analysis N/A Current Status COSEWIC: Special Concern (1998) Great Lakes/St. Lawrence population: Special Concern (2002)
41
Status and Reasons for Designation
Status: Special Concern Alpha-numeric code: None Reason for Designation: The species is the only lizard in Eastern Canada. This small and secretive species is known from about 84 local populations, but has a small geographic distribution. Threats to the skink include loss and degradation of habitat, alteration of microhabitat, illegal collection, increased depredation by cats and dogs and increased mortality on roads. Increasing development in the species’ range will make populations more isolated and more susceptible to stochastic events on small sites.
Applicability of Criteria Criterion A: (Declining Total Population): No data on decline. Criterion B: (Small Distribution, and Decline or Fluctuation): No clear evidence of decline. Criterion C: (Small Total Population Size and Decline): Total population is greater than 10,000. Criterion D: (Very Small Population or Restricted Distribution): Not applicable. Criterion E: (Quantitative Analysis): Not applicable.
42 ACKNOWLEDGEMENTS AND AUTHORITIES CONSULTED
Acknowledgements
Dr. Stephen Hecnar, Carolyn Seburn and David Seburn kindly shared their expertise and insight into the species. Carolyn and David Seburn also provided valuable comments on an earlier version of this report. Thanks to the many authorities (see below) that generously provided knowledge of the species’ occurrence and biology, and to Alain Filion for the updated Canadian distribution map and EO and AO calculations. Thanks to Dr. Ron Brooks for his guidance and to members of the COSEWIC Reptile and Amphibian Subcommittee for their support.
Funding for this report was provided by the Canadian Wildlife Service, Environment Canada.
Authorities consulted
Heather Arnold Alain Filion Science and Stewardship Coordinator Assessment Section London Office COSEWIC Secretariat The Nature Conservancy of Canada Species at Risk Division 1017 Western Road Canadian Wildlife Service London, ON N6G 1G5 Ottawa, ON K1A 0H3
Alan Dextrase Dr. Henry Fitch Senior SAR Biologist Department of Ecology and Species At Risk Section, Ontario Parks Evolutionary Biology Ontario Ministry of Natural Resources University of Kansas P.O. Box 7000 2041 Haworth Hall Peterborough, ON K9J 8M5 1200 Sunnyside Avenue The University of Kansas Tammy Dobbie Lawrence, KS 66045 Ecosystem Management Coordinator Point Pelee National Park Gloria Goulet 407 Monarch Lane, R.R.#1 Coordinator Leamington, ON, N8H 3V4 Aboriginal Traditional Knowledge COSEWIC Secretariat Sandy Dobbyn Canadian Wildlife Service Zone Ecologist Environment Canada Ontario Parks, Southwest Zone Ottawa, ON K1A 0H3 659 Exeter Rd, London, ON N6E 1L3 Dr. Stephen Hecnar Associate Professor Department of Biology Lakehead University 955 Oliver Road Thunder Bay, ON P7B 5E1
43 Clint Jacobs Dr. Jonathan Richmond Natural Heritage Coordinator Department of Ecology and Walpole Island Heritage Centre Evolutionary Biology RR 3 Corson Hall E237 Wallaceburg, ON N8A 4K9 Cornell University Ithaca, NY 14853-2701 USA Deb Jacobs Species at Risk Biologist Ken Schmidt Ontario Ministry of Natural Resources Essex Region Conservation Authority P.O. Box 1168 360 Fairview Avenue West Chatham, ON N7M 5L8 Essex, ON N8M 1Y6
Jim Mackenzie Carolyn Seburn Ontario Natural Heritage Information Recovery Science Specialist Centre Canadian Wildlife Service Ontario Ministry of Natural Resources Environment Canada 300 Water Street, 2nd Floor, North Tower 351 St-Joseph Boulevard Peterborough, ON K9J 8M5 Gatineau, QC K1A 0H3
Vicki McKay David Seburn Eastern Prickly Pear Cactus / Seburn Ecological Services Lake Erie Sand Spit Savannas 2710 Clarenda St., Recovery Team Ottawa, ON, K2B 7S5. Species at Risk Biologist Point Pelee National Park Valerie Towsley 407 Monarch Lane, R.R.1 Resource Technician Leamington, Ontario Lower Thames Valley Conservation N8H 3V4 Authority 100 Thames St., Michael Nelson Chatham, ON N7L 2Y8 Species at Risk Biologist Essex Region Conservation Authority Ken Tuininga 360 Fairview Avenue West, Suite 311 Ontario Region Essex, ON N8M 1Y6 Canadian Wildlife Service Environment Canada Paul Pratt 4905 Dufferin Street Naturalist Downsview, ON M3H 5T4 Ojibway Nature Centre 5200 Matchette Road Sara E. Wick, M.Sc. Windsor, ON N9C 4E8 c/o Jim Bogart Department of Integrative Biology Dr. Kent Prior University of Guelph Senior Advisor, Critical Habitat Guelph, Ontario, N1G 2W1 Parks Canada 25 Eddy St, 4th floor Gatineau, QC K1A 0M5
44 Allen Woodliffe District Ecologist Ontario Ministry of Natural Resources Aylmer District P.O. Box 1168 870 Richmond Street West Chatham, ON N7M 5L8
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BIOGRAPHICAL SUMMARY OF REPORT WRITERS
Briar J. Howes
Briar Howes completed her B.Sc. (H) in Zoology at the University of Guelph in 2001. She then completed her Ph.D. in Biology at Queen’s University in 2006. For her Ph.D. research, she investigated range-wide patterns of genetic structuring in the five- lined skink, and tested evolutionary hypotheses for why species’ ranges are geographically restricted. Her research interests include biogeography, range limit theory, conservation genetics, conservation biology, and habitat selection.
Stephen C. Lougheed
Stephen Lougheed is an Associate Professor of Biology at Queen's University. His interests include phylogeography, phylogenetics and population genetics of vertebrates particularly reptiles, amphibians and birds of the New World. Many of the taxa that he works on both in Canada and eslewhere are of conservation concern, and much of his and his students' work focuses on providing explicit inputs into conservation strategies.
50