Environmental effects of overland winter access:

Research conducted in the Mackenzie Delta

Julian Kanigan, INACOverland Winter Access Workshop

Inuvik, April 23-24, 2008

Outline1. Define overland winter access2. Short-term & long-term effects on:

– Vegetation– Permafrost

• Ground temperatures• Thaw depths• Thaw settlement

3. Limitations of previous research in the delta

Overland winter access

• Winter roads– Packed snow roads– Processed snow roads– Ice roads

• Seismic lines

Short-term effects (1-4 yrs)• 2006 ESRF study of vegetation changes on seismic lines

Short-term effects (1-4 yrs)

Inuvik snow road 1974

• vegetation• thaw depths• thaw settlement

(Northern Engineering Services Company 1974)

Short-term effects (1-4 yrs)

Inuvik snow road 1974

• vegetation• thaw depths• thaw settlement

(Northern Engineering Services Company 1974)

N

Vegetation: short-term effects

– ↓ total living vegetation

– no species increased as a result of the disturbance

– exposed soil

– soil compaction

– ponding(Northern Engineering

Services 1974, Kemper 2006)

Permafrost: short-term

effects

Shingle Point 1971

• ground temperatures

(Kerfoot 1972)

Permafrost: short-term effects• ↑ Near surface ground temperatures

(Kerfoot 1972)

Near surface temperatures up to 2°C higher

Deeper temperatures the same

Permafrost: short-term effects

Sitidgi Creek 1971

• thaw depths

• thaw settlement

(Kerfoot 1972)

Permafrost: short-term effects

• ↑ Thaw depths

(Kerfoot 1972)

(Kerfoot 1972)

Permafrost: short-term effects

• Thaw settlement

Sitidgi Creek

– Control sites: high ice content

– Disturbed sites: ice content correlated with surface settlement

(Kerfoot 1972)

Long-term effects (≥5 yrs)• Alaskan studies

– Low initial disturbance → no longer visible

– Moderate/high initial disturbance →

visible green trail → brown trail (Felix et al. 1992,

Emers & Jorgenson 1997)

Vegetation – long-term effects, MD• ↑ total vascular vegetation cover

– ESRF upland tundra, 16.5% increase

• Vegetation cover change– ESRF upland tundra, Inuvik snow road ↑ shrubs ↓ lichens ↓ mosses

(Kerfoot 1972, Hardy and Assoc. 1980, Kemper 2006)

Vegetation: long-term effects

• Alaska north coast

Moist shrub-sedge tundra:

– ↓ total vegetation cover

– vegetation community replacement

↑ sedge cover, ↓ shrub cover

(Felix et al. 1992)

Permafrost – long-term effects, MD

• Inuvik snow road , ESRF upland tundra• Thaw depth• Thaw settlement• Organic layer depth

• No statistical difference between disturbed and control sites

(Hardy and Assoc. 1980, Kemper 2006)

Permafrost – long-term effects

• Alaska north coast after 5 yrs (1984-88)

– Moderate/high initial disturbance → increased thaw depths

– ↑ thaw depths in moist shrub-sedge tundra areas

(Felix et al. 1992)

MD Research limitations• Few studies and most > 20 years old

• Mostly short-term studies (1-5 yrs)

• Lack of baseline data and disturbance level

• Qualitative, visual assessment of impacts

Conclusions

• Short-term (1-4 yrs) effects:– Visual indicators

• changes to vegetation, soil, ponding– Vegetation

• ↓total living vegetation – Permafrost

• ↑ nr. surface ground temperatures, • ↑ thaw depths, • thaw settlement

Conclusions

• Long-term (≥5 yrs) effects:– Visual indicators

• none, green trails, brown trails

– Vegetation & Permafrost• Variable effects depending on: Terrain type? Initial disturbance intensity?

• Increased thaw depths & vegetation cover change

Recommendations• Continued monitoring of historic sites for change

• Collection of baseline data, disturbance intensity level, and long-term monitoring at new sites

• Quantitative measures of disturbance

• Collect complementary data

Thanks,

Questions?