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Impact of Vegetation on Winter Soil Respiration Rates

Explore how different vegetation types affect soil respiration rates during winter in subalpine forests. Results and implications for carbon balance discussed.

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Impact of Vegetation on Winter Soil Respiration Rates

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  1. Differences in soil respiration rates based on vegetation type Maggie Vest Winter Ecology 2013 Mountain Research Station

  2. Introduction • Estimated 20% of the annual soil respiration occurs during the winter. • Estimates range from 3% to 50% (Hobbie et al. 2000). • High variability across small spatial scales (Scott-Denton et al. 2002). • Lack of understanding of the controlling factors in mid- and high-latitude systems (Hobbie et al. 2000). • Soil temperature is the best predictor for soil respiration (Scott-Denton et al. 2002).

  3. Vegetation and Soil Respiration • Connection between vegetation type and soil respiration at the landscape scale (Grogan 2012). • Total CO2 flux ranged from 34 to 126g CO2/C m^2 for various vegetation types in the low arctic tundra in Canada. • Ecosystem-specific interactions between snow depth, vegetation cover, moisture, and litter production also affect CO2 flux • Different decomposition rates between evergreens and deciduous trees (Hobbie et al. 2000).

  4. Hypothesis • The aim of this study is to determine the degree of significance that surrounding vegetation has on soil respiration during wintertime. • Question: Does the surrounding vegetation significantly impact soil respiration rates in the subalpine forests? • Hypothesis: Deciduous trees are likely to have higher rates of soil respiration than conifers.

  5. Methods • 3 vegetation types • Aspen • Lodgepole • Spruce • 3 Replicates for each site • Trees with 30cm< snow depth • Measured CO2 concentrations over a 2 minute period • Recorded site features: temperature of soil surface, snow depth, soil moisture, amount of organic litter, litter composition

  6. Results Aspen-Lodgepole P Value: 0.11 Aspen-Spruce P Value: 0.46 Lodgepole-Spruce P Value: 0.10

  7. Other Factors Affecting Soil RespirationSnow Depth

  8. Other Factors Affecting Soil RespirationSoil Temperature

  9. Other Factors Affecting Soil RespirationGround Litter

  10. Results • Overall results were insignificant • Aspen CO2 flux and snow depth were only significant data • Results suggest expected trends of aspens having higher soil respiration than the evergreens

  11. Discussion • Vegetation potentially impacts the rate of soil respiration • Errors • Short time scale of project • Small sample size • Further research is needed in order to determine the degree of significance that vegetation has on soil respiration rates.

  12. Summary • Winter time soil respiration has the potential to significantly impact the annual net carbon balance (Grogan 2012). • Results suggest expected trends of aspens having higher soil respiration than the evergreens. • Further research is needed in order to determine the degree of significance that vegetation has on soil respiration rates.

  13. Acknowledgements • Thank to Rob for being a field partner • Thanks to Tim, Derek, and the CU Mountain Research Center The End

  14. References • Brooks, Paul D., S. K. Schmidt, and M. W. Williams. 1997. Winter production of CO2 and N2O from alpine tundra: environmental controls and relationship in inter-system C and N fluxes. Oecologia110: 403-413. • Grogan, Paul. 2012. Cold season respiration across a low arctic landscape: the influences of vegetation type, snow depth, and interannual climatic variation. Arctic, Antarctic, and Alpine Research 44:446-456. 1938-4246-44.4.446. • Hobbie, Sarah E., J. P. Schimel, S. E. Trumbore, and J. R. Randersons. 2000. Controls over carbon storage and turnover in high-latitude soils. Global Change Biology6:196-210. • Scott-Denton, Laura, K. L. Sparks, R. K. Monson. 2003. Spatial and temporal controls of soil respiration rate in a high-elevation, subalpine forest. Soil Biology and Biochemistry 35: 525-534. • Schadt, Christopher, M. P. Martin, D. A. Lipson, S. K. Schmidt. 2003. Seasonal Dynamics of previously unknown fungal lineages in tundra soils. Science 302: 1359-1361. • Tuomi, M, T. Thum, H. Jarvinen, S. Fronzek, B. Berg, M. Harmon, J. A. Trofymow, S. Sevanto, J. Liski. 2009. Leaf litter decomposition-estimates of global variability based on Yasso07 model. Ecological Modeling 220: 3362-3371.

  15. Appendix CO2 Flux

  16. AppendixResults

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