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Responses of ecosystem carbon dioxide fluxes to soil moisture fluctuations in a moist Kenyan savanna

Published online by Cambridge University Press:  11 October 2010

D. O. Otieno ,
G. O. K'Otuto ,
J. N. Maina ,
Y. Kuzyakov  and
J. C. Onyango
D. O. Otieno*
Affiliation:
Department of Plant Ecology, University of Bayreuth, 95440 Bayreuth, Germany
G. O. K'Otuto
Affiliation:
Department of Botany & Horticulture, Maseno University, Private Bag Maseno, Kenya
J. N. Maina
Affiliation:
Department of Botany & Horticulture, Maseno University, Private Bag Maseno, Kenya
Y. Kuzyakov
Affiliation:
Department of Agroecosystem Research, BayCEER, University of Bayreuth, 95440 Bayreuth, Germany
J. C. Onyango
Affiliation:
Department of Botany & Horticulture, Maseno University, Private Bag Maseno, Kenya
*
1Corresponding author. Email: denotieno@yahoo.com
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Abstract:

Measurements were conducted within a fence-exclosure between February 2008 and July 2009 to investigate the influence of soil moisture on ecosystem CO2 fluxes in a Themeda triandra-dominated grassland of a humid Kenyan savanna. Rainout shelters were constructed to reduce ambient rainfall by 0%, 10% and 20% respectively to attain variable soil water content (SWC) during plant growth. SWC within the top 30 cm layer, above-ground biomass, soil and plant nitrogen (N) concentrations were assessed monthly alongside CO2 fluxes. Net ecosystem CO2 exchange (NEE) and ecosystem respiration (Reco) were measured with closed chambers while carbon (C) partitioning during the wet and dry seasons were assessed through pulse 13C labelling. There were significant seasonal and between plot differences in SWC, above-ground biomass, canopy light utilization efficiency (α), CO2 fluxes and C allocation pattern resulting from differences in SWC. The ecosystem was a net C sink during the wet and C neutral during the dry seasons. The study showed strong seasonal fluctuations in ecosystem CO2 fluxes and underscores the significant role of the savanna grasslands in regional C balance due to its expansive nature. The savanna grassland is however vulnerable to low soil moisture, with significant reduction in CO2 uptake during drought.

Keywords

δ13CAfricabiomassCO2 chambersecosystem respirationgross primary productionhumid savannanet ecosystem exchangenitrogensoil moistureThemeda triandra
Type
Research Article
Information
Journal of Tropical Ecology , Volume 26 , Issue 6 , November 2010 , pp. 605 - 618
Copyright
Copyright © Cambridge University Press 2010

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References

LITERATURE CITED

ARCHIBALD, S. A., KIRTON, A., VAN DER MERWE, M. R., SCHOLES, R. J., WILLIAMS, C. A. & HANAN, N. 2009. Drivers of inter-annual variability in Net Ecosystem Exchange in a semi-arid savanna ecosystem, South Africa. Biogeosciences 6: 251–266.CrossRefGoogle Scholar
ARDÖ, J., MÖLDER, M., EL-TAHIR, A. B. & ELKHIDIR, H. A. 2008. Seasonal variation of carbon fluxes in a sparse savanna in semi arid Sudan. Carbon Balance and Management 3: 7doi:10.1186/1750-0680-3-7.CrossRefGoogle Scholar
BATES, D. 2005. Fitting linear mixed models in R. R News 5:27–39.Google Scholar
BOMBELLI, A., HENRY, M., CASTALDI, S., ADU-BREDU, S., ARNETH, A., DE GRANDCOURT, A., GRIECO, E., KUTSCH, W. L., LEHSTEN, V., RASILE, A., REICHSTEIN, M., TANSEY, K., WEBER, U. & VALENTINI, R. 2009. An outlook on the Sub-Saharan Africa carbon balance. Biogeosciences 6:2193–2205.CrossRefGoogle Scholar
BRÜMMER, C., FALK, U., PAPEN, H., SZARZYNSKI, J., WASSMANN, R. & BRUGGEMANN, N. 2008. Diurnal, seasonal and interannual variation in carbon dioxide and energy exchange in shrub savanna in Burkina Faso (West Africa). Journal of Geophysical Research 113: G02030, doi:10.1029/2007JG000583.CrossRefGoogle Scholar
CIAIS, P., PIAO, S.-L., CADULE, P., FRIEDLINGSTEIN, P. & CHÉDIN, A. 2009. Variability and recent trends in the African terrestrial carbon balance. Biogeosciences 6:1935–1948.CrossRefGoogle Scholar
DEFRIES, R. S., HOUGHTON, R. A., HANSEN, M. C., FIELD, C. B., SKOLE, D. & TOWNSHEND, J. 2002. Carbon emissions from tropical deforestation and re-growth based on satellite observations for the 1980s and 1990s. Proceedings of the National Academy of Sciences, USA 99: 14256–14261.CrossRefGoogle Scholar
GEBAUER, G. & SCHULZE, E.-D. 1991. Carbon and nitrogen isotope ratios in different compartments of a healthy and a declining Picea abies forest in the Fichtelgebirge, NE Bavaria. Oecologia 87: 198–207.CrossRefGoogle Scholar
GIFFORD, R. M. 2003. Plant respiration in productivity models: conceptualization, representation and issues for global terrestrial carbon-cycle research. Functional Plant Biology 30: 171–186.CrossRefGoogle ScholarPubMed
GILMANOV, T. G., SOUSSANA, J. F., AIRES, L., ALLARD, V., AMMAN, C., BALZAROLO, M., BARCZA, Z., BERNHOFER, C., CAMPBELL, C. L., CERNUSCA, A., CESCATTI, A., CLIFTON-BROWN, J., DIRKS, B. O. M., DORE, S., EUGSTER, W., FUHRER, J., GIMENO, C., GRUENWALD, T., HAZSPRA, L., HENSEN, A., IBROM, A., JACOBS, A. F. G., JONES, M. B., LANIGAN, G., LAURILA, T., LOHILA, A., MANCA, G., MARCOLLA, B., NAGY, Z., PILGAARD, K., PINTER, K., PIO, C., RASCHI, A., ROGIERS, N., SANZ, M. J., STEFANI, P., SUTTON, M., TUBA, Z., VALENTINI, R., WILLIAMS, M. L. & WOHLFART, G., 2007. Partitioning European grassland net ecosystem CO2 exchange into grass primary productivity and ecosystem respiration using light response function analysis. Agriculture Ecosystems and Environment 121:93–120.CrossRefGoogle Scholar
GRACE, J., SAN JOSE, J., MEIR, P., MIRANDA, H. S. & MONTES, R. A. 2006. Productivity and carbon fluxes of tropical savannas. Journal of Biogeography 33: 387–400.CrossRefGoogle Scholar
HANSON, P. J., EDWARDS, N. T., GARTEN, C. T. & ANDREWS, J. A. 2000. Separating root and soil microbial contributions to soil respiration: a review of methods and observations. Biogeochemistry 48: 115–146.Google Scholar
HODGKINSON, K. C., LUDLOW, M. M., MOTT, J. J. & BARUCH, Z. 1989. Comparative responses of the savanna grasses Cenchrus ciliaris and Themeda triandra to defoliation. Oecologia 79: 45–52.CrossRefGoogle ScholarPubMed
HOUGHTON, R. A. 2003. Revised estimates of the annual net flux of carbon to the atmosphere from changes in land use and land management 1850–2000. Tellus 55B: 378–390.Google Scholar
HOUGHTON, R. A. & HACKLER, J. L. 2006. Emissions of carbon from land use change in sub-Saharan Africa. Journal of Geophysical Research 111: G02003, doi:10.1029/2005JG000076.CrossRefGoogle Scholar
IPCC. 2007. Climate Change 2007. The physical science basis: summary for policy markers. IPCC WGI Fourth Assessment Report. IPCC, Geneva.Google Scholar
KÖCHY, M. & WILSON, S. D. 2004. Semiarid grassland responses to short-term variation in water availability. Plant Ecology 174:197–203.CrossRefGoogle Scholar
KUTSCH, W. L., HANAN, N., SCHOLES, R. J., MCHUGH, I., KUBHEKA, W., ECKHARDT, H. & WILLIAMS, C. 2008. Response of carbon fluxes to water relations in a savanna ecosystem in South Africa. Biogeosciences 5:4035–4069.CrossRefGoogle Scholar
KUZYAKOV, Y. & CHENG, W. 2004. Photosynthesis controls of CO2 efflux from maize rhizosphere. Plant and Soil 263:85–99.CrossRefGoogle Scholar
KUZYAKOV, Y. & GAVRICHKOVA, O. 2010. Time lag between photosynthesis and CO2 efflux from soil: a review. Global Change Biology. doi: 10.1111/j.1365-2486.2010.02179.x.CrossRefGoogle Scholar
LLOYD, J. & TAYLOR, J. A. 1994. On the temperature dependence of soil respiration. Functional Ecology 8:315–323.CrossRefGoogle Scholar
MA, S., BALDOCCHI, D., XU, L. & HEHN, T. 2007. Inter-annual variability in carbon dioxide exchange of an oak/grass savanna and open grassland in California. Agricultural and Forest Meteorology 147:157–171.CrossRefGoogle Scholar
MARKERT, B. 1996. Instrumental element and multi-element analysis of plant samples — methods and applications. John Wiley and Sons, New York. 312 pp.Google Scholar
McCULLEY, R. L., BOUTTON, T. W. & ARCHER, S. R. 2007. Soil respiration in sub tropical savanna parklands: response to water addition. Soil Science Society of America Journal 71:820–828.CrossRefGoogle Scholar
MERBOLD, L., ARDÖ, J., ARNETH, A., SCHOLES, R. J., NOUVELLON, Y., DE GRANDCOURT, A., ARCHIBALD, S., BONNEFOND, J. M., BOULAIN, N., BRUEMMER, C., BRUEGGEMANN, N., CAPPELAERE, B., CESCHIA, E., EL-KHIDIR, H. A. M., EL-TAHIR, B. A., FALK, U., LLOYD, J., KERGOAT, L., LE DANTEC, V., MOUGIN, E., MUCHINDA, M., MUKELABAI, M. M., RAMIER, D., ROUPSARD, O., TIMOUK, F., VEENENDAAL, E. M. & KUTSCH, W. L. 2008. Precipitation as driver of carbon fluxes in 11 African ecosystems. Biogeosciences 5:4071–4105.Google Scholar
MICHELSEN, M., ANDERSON, M., JENSEN, M., KYOLLER, A. & GASHEW, M. 2004. Carbon stocks, soil respiration and microbial biomass in fire-prone tropical grassland, woodland and forest ecosystem. Soil Biology and Biochemistry 36:1707–1717.CrossRefGoogle Scholar
OJIMA, D. S., PARTON, W. J., COUGHENOUR, M. B. & SCURLOCK, J. M. O. 1996. Impact of climate and atmospheric carbon dioxide changes on grasslands of the world. Pp. 271–309 in Breymeyer, A. I., Hall, D. O., Mellilo, J. M. & Agren, G. I. (eds.). Global change: effects on coniferous forests and grasslands. Scientific Committee on Problems of the Environment (SCOPE). Wiley, New York.Google Scholar
OTIENO, D. O., WARTINGER, M., NISHIWAKI, A., HUSSAIN, M. Z., MUHR, J., BORKEN, W. & LISHAID, G. 2009. Responses of CO2 exchange and primary production of the ecosystem components to environmental changes in a mountain peatland. Ecosystems 12:590–603.CrossRefGoogle Scholar
PALM, C. A., WOOMER, P. L., ALEGRE, J., AREVALO, L., CASTILLA, C., CORDEIRO, D. G., FEIGL, B., HAIRIAH, K., KOTTO-SAME, J., MENDES, A., MOUKAM, A., MURDIYARSO, D., NJOMGANG, R., PARTON, W. J., RICSE, A., RODRIGUES, V., SITOMPUL, S. M. & VAN NOORDWIJK, M. 1999. Carbon sequestration and trace gas emissions in slash-and burn and alternative land-uses in the humid tropics, alternative to slash-and-burn. Pp. 1–33 in Palm, C. (ed.). Climate change working group Final Report Phase II. Telstra Services, Nairobi.Google Scholar
PARTON, W. J., COUGHENOUR, M. B., SCURLOCK, J. M. O. & OJIMA, D. S. 1996. Global grassland ecosystem modeling; development and test of ecosystem models for grassland ecosystems. Pp. 229–269 in Breymeyer, A. I., Hall, D. O., Mellilo, J. M. & Agren, G. I. (eds.). Global change: effects on coniferous forests and grasslands. Scientific committee on problems of the environment (SCOPE). Wiley, New York.Google Scholar
PATRICK, L., CABLE, J., POTTS, D., IGNACE, D., BARRON-GAFFORD, G., GRIFFITH, A., ALPERT, H., VAN GESTEL, N., ROBERTSON, T., HUXMAN, T. E., ZAK, J., LOIK, M.E. & TISSUE, J. 2007. Effects of an increase in summer precipitation on leaf, soil and ecosystem fluxes of CO2 and H2O in a sotol grassland in Big Bend National Park, Texas. Oecologia 151:704–718.CrossRefGoogle Scholar
PELZER, D. A. & WILSON, S. D. 2001. Variation in plant responses to neighbors at local and regional scales. American Naturalist 157:610–625.CrossRefGoogle Scholar
RAICH, J. W. & SCHLASSINGER, W. H. 1992. The global carbon dioxide flux in soil respiration and its relation to vegetation and climate. Tellus Series B 44:81–99.CrossRefGoogle Scholar
REIS, L. P. & SHUGART, H. H. 2008. Nutrient limitations on understory grass productivity and carbon assimilation in an African woodland savanna. Journal of Arid Environments 72:1423–1430.CrossRefGoogle Scholar
ROBERTS, G., WOOSTER, M. J. & LAGOUDAKIS, E. 2008. Annual and diurnal African biomass burning temporal dynamics. Biogeosciences Discussions 5:3623–3663.Google Scholar
RODRIGUEZ-ITURBE, I., D'ODORICO, P., PORPORATO, A. & RIDOLFI, L. 1999a. On the spatial and temporal links between vegetation, climate and soil moisture. Water Resource Research 35:3709–3722.CrossRefGoogle Scholar
RODRIGUEZ-ITURBE, I., D'ODORICO, P., PORPORATO, A. & RIDOLFI, L. 1999b. Tree-grass coexistence in savannas: the role of spatial dynamics and climate fluctuations. Geophysical Research Letters 26:247–250.CrossRefGoogle Scholar
SALEEM, A., MIRZA, S. N., KHAN, I. A. & FRANKLIN, J. 2009. Effects of diverse ecological conditions on biomass production of Themeda triandra (Kangaroo grass) at various growth stages. African Journal of Biotechnology 8:1233–1237.Google Scholar
SANDARMAN, J., AMUNDSON, R. G. & BALDOCCHI, D. D. 2003. Application of eddy covariance measurements to the temperature dependence of soil organic matter mean residence time. Global Biogeochemical Cycles 17:1061.Google Scholar
SANTOS, A. J. B., QUESADA, C. A., DA SILVA, G. T., JAIR, F. M., MIRANDA, H. S., MIRANDA, A. C. & LLOYD, J. 2004. High rates of net ecosystem carbon assimilation by Brachiara pasture in the Brazilian Cerrado. Global Change Biology 10:877–885.CrossRefGoogle Scholar
SCHOLES, R. J. & WALKER, B. H. 1993. An African savanna: synthesis of the Nylsvley Study. Cambridge University Press, Cambridge. 318 pp.CrossRefGoogle Scholar
TAINTON, N. 1999. Veld management in South Africa. University of Natal Press, Pietermaritzburg. 218 pp.Google Scholar
TANG, J., BALDOCCHI, D. D. & XU, L. 2005. Tree photosynthesis modulates soil respiration on a diurnal time scale. Global Change Biology 11:1298–1304.CrossRefGoogle Scholar
WEBER, U., JUNG, M., REICHSTEIN, M., BEER, C., BRAAKHEKKE, M., LEHSTEN, V., GHENT, D., KADUK, J., VIOVY, N., CIAIS, P., GOBRON, N. & RÖDENBECK, C. 2009. The inter-annual variability of Africa's ecosystem productivity: a multi-model analysis. Biogeosciences 5:4035–4069.Google Scholar
WELTZIN, J. F., LOIK, M. E., SCHWINNING, S., WILLIAMS, D. G., FAY, P. A., HADDAD, B. M., HARTE, J., HUXMAN, T. E., KNAPP, A. K., LIN, G., POCKMAN, W. T., SHAW, M. R., SMALL, E. E., SMITH, M. D., SMITH, S. D., TISSUE, D. T. & ZAK, J. C. 2003. Assessing the response of terrestrial ecosystems to potential changes in precipitation. BioScience 53:941–952.CrossRefGoogle Scholar
WERTH, M. & KUZYAKOV, Y. 2006. Assimilate partitioning affects 13C fractionation of recently assimilated carbon in maize. Plant Soil 284:319–333.CrossRefGoogle Scholar
WILLIAMS, C. A. & ALBERTSON, J. D. 2004. Soil moisture controls on canopy-scale water and carbon fluxes in an African savanna. Water Resources Research 40:1–14.CrossRefGoogle Scholar
WILLIAMS, C. A., HANAN, N. P., NEFF, J. C., SCHOLES, R. J., BERRY, J. A., DENNING, A. S. & BAKER, D. F. 2007. Africa and the global carbon cycle. Carbon Balance and Management 2:3.CrossRefGoogle ScholarPubMed
WILLIAMS, C. A., HANAN, N., SCHOLES, R. J. & KUTSCH, W. 2009. Complexity in water and carbon dioxide fluxes following rain pulses in an African savanna. Oecologia 161:469–480.CrossRefGoogle Scholar
XU, L., BALDOCCHI, D. D. & TANG, J. 2005. How soil moisture, rain pulses and growth alter the response of ecosystem respiration to temperature. Global Biogeochemical Cycles 18:GB4002, doi:10.1029/2004GB002281.Google Scholar
YANG, X., WANG, M., HUANG, Y. & WANG, Y. 2002. A one-compartment model to study soil carbon decomposition rate at equilibrium situation. Ecology Models 151:63–73.CrossRefGoogle Scholar