Fulltext

Soil CO2 Emissions Associated with Termitaria in Tropical Savanna: Evidence for Hot-Spot Compensation

Risch, Anita ; Anderson, T. ; Schütz, Martin

In: Ecosystems, 2012, vol. 15, no. 7, p. 1147-1157

Zum persönliche Liste hinzufügen
    Titel
    • Soil CO2 Emissions Associated with Termitaria in Tropical Savanna: Evidence for Hot-Spot Compensation
    Autor
    • Risch, Anita. Research Unit Community Ecology, Research Group Plant-Animal Interactions, Swiss Federal Institute for Forest, Snow and Landscape Research, Zuercherstrasse 111, 8903, Birmensdorf, Switzerland
    • Anderson, T.. Department of Biology, Wake Forest University, 206 Winston Hall, 27109, Winston-Salem, North Carolina, USA
    • Schütz, Martin. Research Unit Community Ecology, Research Group Plant-Animal Interactions, Swiss Federal Institute for Forest, Snow and Landscape Research, Zuercherstrasse 111, 8903, Birmensdorf, Switzerland
    Dokumententyp
    • Postprint
    OAI-PMH-ID
    • oai:doc.rero.ch:322195
    Summary
    Our understanding of carbon (C) dynamics within savannas is very limited, especially how source/sink dynamics are influenced by the resident biota. Previous measurements of epigeal termite mounds (termitaria), ubiquitous in many savannas, have shown that they are considerable point sources of soil carbon dioxide (CO2), whereas CO2 measurements collected outside the mounds were generally assumed to be independent of termite activity. However, no measurements were conducted along gradients away from the mounds to confirm this. We quantified daytime soil CO2 emissions (soil respiration) along gradients from the center to 20m from the mound edge in Serengeti National Park, and measured soil temperature/moisture, macro-invertebrate abundance, and vegetation height as variables potentially influencing these emissions. Further, we quantified how far into the savanna termitaria impact CO2 emissions. As in other studies, we found the highest soil CO2 fluxes at the termitaria-center and considerably lower fluxes in the surrounding savanna. Macro-invertebrate abundance was associated with the differences in emissions measured, whereas the other variables were not. The analysis of spatial autocorrelation revealed significantly lower fluxes between the termitaria edge and up to 9m from the edge compared to the values measured at the termitaria-center and between 10 and 20m from the termitaria edge. When extrapolating the emissions across the landscape our results suggest that the lower CO2 emissions found between the edge and 9m fully compensate for the high fluxes measured at the termitaria center. Consequently, our findings provide evidence that termitaria might influence the savanna C source-sink dynamics differently than previously thought