Does soil moisture overrule temperature dependence of soil respiration in Mediterranean riparian forests?
| Autor: | Francesc Sabater, Dominik Sperlich, C. T. Chang, Sílvia Poblador, Carles Gracia, Santiago Sabaté |
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| Přispěvatelé: | Universitat de Barcelona |
| Rok vydání: | 2014 |
| Předmět: |
Soil physics
lcsh:Life Q10 Soil science Forests Mediterrània (Regió) Carbon cycle Soil respiration lcsh:QH540-549.5 Riparian forest Water content Ecology Evolution Behavior and Systematics Ecologia fluvial Earth-Surface Processes geography geography.geographical_feature_category Boscos Moisture Mediterranean Region lcsh:QE1-996.5 Física dels sòls Stream ecology lcsh:Geology lcsh:QH501-531 Carbon dioxide Environmental science lcsh:Ecology Diòxid de carboni Soil fertility Groundwater |
| Zdroj: | Recercat. Dipósit de la Recerca de Catalunya instname Biogeosciences, Vol 11, Iss 21, Pp 6173-6185 (2014) Dipòsit Digital de la UB Universidad de Barcelona |
| ISSN: | 1726-4189 |
| Popis: | Soil respiration (SR) is a major component of ecosystems' carbon cycles and represents the second largest CO2 flux in the terrestrial biosphere. Soil temperature is considered to be the primary abiotic control on SR, whereas soil moisture is the secondary control factor. However, soil moisture can become the dominant control on SR in very wet or dry conditions. Determining the trigger that makes soil moisture as the primary control factor of SR will provide a deeper understanding on how SR changes under the projected future increase in droughts. Specific objectives of this study were (1) to investigate the seasonal variations and the relationship between SR and both soil temperature and moisture in a Mediterranean riparian forest along a groundwater level gradient; (2) to determine soil moisture thresholds at which SR is controlled by soil moisture rather than by temperature; (3) to compare SR responses under different tree species present in a Mediterranean riparian forest (Alnus glutinosa, Populus nigra and Fraxinus excelsior). Results showed that the heterotrophic soil respiration rate, groundwater level and 30 cm integral soil moisture (SM30) decreased significantly from the riverside moving uphill and showed a pronounced seasonality. SR rates showed significant differences between tree species, with higher SR for P. nigra and lower SR for A. glutinosa. The lower threshold of soil moisture was 20 and 17% for heterotrophic and total SR, respectively. Daily mean SR rate was positively correlated with soil temperature when soil moisture exceeded the threshold, with Q10 values ranging from 1.19 to 2.14; nevertheless, SR became decoupled from soil temperature when soil moisture dropped below these thresholds. |
| Databáze: | OpenAIRE |
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