1. The Influence of Vegetation Type on Winter Soil Respiration Rates Scott Clingan Winter Ecology Spring 2014

2. Terrestrial Carbon Cycle Soil respiration estimated to account for 20-38% of annual biogenic CO 2 emissions (Scott 2002) Increased Respiration from global warming = lower carbon sequestration (positive feedback?)

3. How does vegetation type influence soil respiration? Snow depths<1m, vegetation type exerts a signifant influence on landscape level CO 2 respiration (Grogan 2012) Vegetation influences abiotic and biotic factors of respiration Soil moisture, soil temp, litter quantity/quality, litter depth (Fu 2013) AET (Actual Evapotranspiration) good predictor of soil respiration High levels of spatial heterogeneity

4. Questions Q 1 : Does vegetation type influence winter soil respiration? – Hypotheses: H 1 :Vegetation type influences the amount of winter soil respiration H 0 : Winter respiration rates do not differ across vegetation thypes Q 2 : Does soil moisture impact soil respiration rates – Hypotheses: H 1 : High soil moisture content will inhibit soil respiration rates in the winter H 0 : Soil Moisture does not effect soil respiration rates

5. Methods PP Systems SRC-1 Soil CO 2 Flux System – Measured soil CO 2 emissions over 120 seconds 3 Vegetation Types (~100cm snow depth) – Aspen (Populus tremuloides) – Lodgepole Pine (Pinus contorta) – Mixed Grass Meadow (various species) 2 Replicates of each type – 3 Subsamples per replicate Supplemental Data 1 – Soil Moisture (0-4) – Amount of Organic Matter (0-5) Analyzed with “R” statistical software 1 Collaboration with Coin Pettinati

6. Site Characterization Elevation ~9,500 ft. Mean Annual Precipitation: 20 to 40 inches Mean Annual Air Temp 36-39 degrees F Frost-Free Period: 30 to 50 days Soils 1 Aspen: Slight/moderate decomposition to sandy loam Lodgepole: Cobbly silt loam to Very Cobbly Silt Loam Meadow- Organic Layer Cobbly to gravely sandy loam Glacial till and/or alluvium derived from igneous and metamorphic rock 1 R etrieved from: www.websoilsurvey.nrcs.usda.gov 3/6/2014www.websoilsurvey.nrcs.usda.gov

7. Replicate Results

8. Significance Lodgepole-Aspen: p<.001 Lodgepole-Meadow: p<.001 Aspen-Meadow: p=0.5264186 (f-value 119.7) Comparison of Respiration Rates

9. Is soil moisture a good predictor of soil respiration rates? Significance Low-High: p=0.5264186 Moderate-High: p<0.001 Moderate-Low: p<0.001 (fvalue= 119.7) Moisture Values Low: 1&2 Moderate: 3 High:

10. Does Litter Amount influence Soil Respiration Rates? Significance Medium-High: p<0.001 Medium/High-High: p<0.001 Medium/High-Medium: p<0.5265186 (f value 119.7)

11. Summary Vegetation Type does influence soil respiration rates….however – Aspen respiration is lower that other studies Limiting Factor? Litter amount directly influences rates – What about quality? Research litter C:N ratios Problems – High levels of spatial heterogeneity – Highly variable (diurnal, seasonal, interannual time scales)

12. Questions? Special thanks to the following people who contributed to this project: Tim Kittel, Kelly Matheson, Derek Sweeney, Colin Pettinati, Angel Bigas, Evan Esfahani

13. References Fu, Xiaoli, et al. "Soil Respiration as Affected by Vegetation Types in a Semiarid Region of China." Soil Science and Plant Nutrition 59.5 (2013): 715-26. Print. Grogan, Paul. "Cold Season Respiration Across a Low Arctic Landscape: The Influence of Vegetation Type, Snow Depth, and Interannual Climatic Variation." Arctic Antarctic and Alpine Research 44.4 (2012): 446-56. Print. Merbold, Lutz, Nele Rogiers, and Werner Eugster. "Winter CO2 Fluxes in a Sub-Alpine Grassland in Relation to Snow Cover, Radiation and Temperature." Biogeochemistry 111.1-3 (2012): 287-302. Print. Morgner, Elke, et al. "The Importance of Winter in Annual Ecosystem Respiration in the High Arctic: Effects of Snow Depth in Two Vegetation Types." Polar Research 29.1 (2010): 58-74. Print. Scott-Denton, Laura E., Kimberlee L. Sparks, and Russell K. Monson. "Spatial and Temporal Controls of Soil Respiration Rate in a High-Elevation, Subalpine Forest." Soil Biology and Biochemistry 35.4 (2003): 525-34. Print.