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| Titel |
Spatial and Temporal Variability and Non-Monotonic Responses of Landscape-Scale Soil CO2 Efflux |
| VerfasserIn |
Diego Riveros-Iregui, Brian McGlynn, Ryan Emanuel, Howard Epstein |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250055379
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| Zusammenfassung |
| Mountainous landscapes impose strong physical gradients that affect the redistribution of
biophysical resources such as water, energy, and substrate. Further variability is introduced by
the spatial heterogeneity of biological processes responsible for carbon (C) transformation in
the soil. The juxtaposition of physical and biological processes results in high degree of
heterogeneity of soil CO2 efflux at the landscape scale, and complicates the transfer of
understanding gained from point observations to entire landscapes or regions. We analyzed
the role of landscape heterogeneity and structure on the distribution and flux of C to the
atmosphere, based on a suite of field observations performed over three years, detailed terrain
analysis, and process-based modeling. Our findings demonstrate that rates of growing
season soil CO2 efflux vary spatially by almost an order of magnitude within a
small, mountainous watershed (~4 km2), and that this variability is related to water
redistribution and accumulation across the landscape. Furthermore, our results also
indicate that topographically complex landscapes can respond non-monotonically to
changing hydrologic regimes (e.g., ‘wet’ vs. ‘dry’ years). Non-monotonic behavior is a
function of hydrologic influences on biological processes and the emergence of
thresholds in the relationship between physical processes and biological responses.
We suggest that the magnitude of threshold-mediated, non-monotonic landscape
responses is a function of the intersection of landscape structure and biological
activity. Furthermore, these observations should be transferable across different
watershed morphologies (shapes), vegetation structures, and climatic conditions. |
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