Wood turtle (Glyptemys insculpta) COSEWIC assessment and status report: chapter 11

Technical Summary

Glyptemys insculpta

Wood Turtle – Tortue des bois

Range of Occurrence in Canada:

Ontario (ON), Quebec (QC), New Brunswick (NB), Nova Scotia (NS)

Extent and Area Information

Extent of occurrence (EO) (km²)

500 000 km². Based on range maps from M. Amato (Fig. 2) and Conant and Collins, 1998.

Specify trend in EO

Apparently stable

Are there extreme fluctuations in EO?

No

Area of occupancy (AO) (km²)

4380 ha or 1051-1752 km²) Estimated based either on studies with areas occupied by Wood Turtles given, and using only the areas of inhabited rivers that are critical to their survival or based on the 2x2km² method. See Canadian range.

Specify trend in AO

Unknown

Are there extreme fluctuations in AO?

No

Number of known or inferred current locations

438 element occurrences (see Canadian Range and Population Sizes and Trends)

Specify trend in #

Are there extreme fluctuations in number of locations?

Specify trend in area, extent or quality of habitat

Decreasing (see Habitat trends)

Population Information

Generation time (average age of parents in the population)

35 yr

Number of mature individuals based on estimates submitted by current researchers across Canada. May be significantly overestimated in some cases, but there may also be undiscovered populations

N/A (very rough estimate of ~6,000-12,000) see Population Sizes and Trends

Total population trend:

% decline over the last/next 3 generations (~100+ years)

Unknown, but likely substantial in parts of Ontario and Quebec

Are there extreme fluctuations in number of mature individuals?

No

Is the total population severely fragmented?

Yes. Fragmentation is likely “natural”, to some extent, but has been increasing because of loss of habitat and population

Specify trend in number of populations

Decreasing?

Are there extreme fluctuations in number of populations?

No

List populations with number of mature individuals in each:

Too numerous to list.

  • Ontario: ~13 watersheds
  • Quebec: ~16 watersheds
  • N.B.: unknown but several watersheds
  • N.S.: ~12; numbers uncertain, ~ 12 watersheds

Threats (actual or imminent threats to populations or habitats)

Commercial collection for the pet trade; increased mortality of adults caused by road traffic, offroad vehicles and modern agricultural machinery; predation of adults, eggs and all other life stages by  increased populations of raccoons and perhaps coyotes and other mammals; habitat loss and modification; degradation of stream habitat by dams, channelization, and sedimentation; and destruction of nests by humans, in vehicles such as ATVs; road mortality, especially on logging roads, casual collection for “pets”. Flooding of streambank nest sites due to deforestation, increased access to habitat via logging and ATV access roads; long-lived life history=late maturity, low reproductive rate, low recruitment.

Rescue Effect (immigration from an outside source)

Status of outside population(s)?

USA: Declining; listed as S1, S2 or S3 in 13 of 16 states (and SH in a 17th)

Is immigration known or possible?

No

Would immigrants be adapted to survive in Canada?

Yes

Is there sufficient habitat for immigrants in Canada?

Yes

Is rescue from outside populations likely?

No

Quantitative Analysis

n/a

Current Status

  • COSEWIC: Threatened (November 2007)
  • COSEWIC: Special Concern (1996)
  • IUCN: Vulnerable
  • Ontario: Endangered – regulated
  • CITES: Appendix II
  • Nova Scotia: Yellow
  • Québec: Menacé

Status and Reasons for Designation

Status: Threatened

Alpha-numeric code: B2ab(iii,v), C1+2a(i)

Reasons for Designation: This species is declining across much of its range, and occurs in small, increasingly disjunct populations. It is more terrestrial than other freshwater turtles, which makes it extremely vulnerable to collection for the pet trade. It has a long-lived life history typical of turtles, so that almost any chronic increase in adult and juvenile mortality leads to a decrease in abundance. Such increased mortality is occurring from increased exposure to road traffic, agricultural machinery and off-road vehicles, collection for pets, commercial collection for the pet trade, and, perhaps, for exotic food/medicines. Increased level of threat is associated with new or increased access to the species’ range by people.

Applicability of Criteria

Criterion A: (Declining Total Population): Not applicable.
Criterion B: (Small Distribution, and Decline or Fluctuation): Applies to Threatened. Small AO (<2000km²), usually occurs in small populations that are increasingly isolated by anthropogenic activity, and there is decline in area and quality of habitat and in number of mature turtles.
Criterion C: (Small Total Population Size and Decline): There are likely fewer than 10,000 adults and there is little doubt that they are declining currently at a rate > 10% in 3 generations (100 years). Only 1 population is likely to have > 1000 individuals.
Criterion D: (Very Small Population or Restricted Distribution): Not applicable.
Criterion E: (Quantitative Analysis): Not applicable.

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