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?