Phenology of Plant Production in the Northwestern Great Plains: Relationships with Carbon Isotope Discrimination, Net Ecosystem Productivity and Ecosystem Respiration
This chapter represents a case study of seasonal and annual variation in above-ground biomass production in a northern temperate grassland during a 9 year period (1998–2006). I describe the relationship between variation in biomass production and the major environmental factor controlling this variation, precipitation inputs. Annual peak biomass production and leaf δ13C values were negatively correlated, and this relationship was consistent with lower biomass production being predominantly controlled by reduced water availability. Two patterns in the relationship between peak above-ground biomass and annual net ecosystem productivity (NEP) were observed. First, there was a strong linear relationship between biomass and NEP in 4 years when peak leaf area production was held significantly below the maximum by low water availability. Second, among 4 years with similar maximum LAI values, there was wide variation in NEP largely due to differences in the length of time leaf tissue was photosynthetically active. Water availability also had a significant effect on ecosystem respiration because it controlled grassland phenology. The product of plant biomass and soil water content was a good proxy for estimating ecosystem respiration because of relationships with both autotrophic and heterotrophic activities. Seasonal variation in grassland respiration was more strongly linked to carbon substrate availability and soil moisture than to shifts in temperature.
KeywordsNormalize Difference Vegetation Index Leaf Area Index Carbon Isotope Composition Ecosystem Respiration Enhance Vegetation Index
Financial support was provided by grants from the Natural Sciences and Engineering Research Council of Canada and the University of Lethbridge. Peter Carlson, Chera Emrick, Nicole Geske, Bruce Johnson, Francine May, Ngaire Nix and Linda Wever provided excellent technical assistance. Stewart Rood kindly allowed my associates and I to work on his land.
- Chapin, F.S., Matson, P.A. and Mooney, H.A. (2002) Principles of Terrestrial Ecosystem Ecology. Springer, New York.Google Scholar
- Ciais, P., Reichstein, M., Viovy, N., Granier, A., Ogee, J., Allard, V., Aubinet, M., Buch-mann, N., Berhofer, Chr., Carrara, A., Chevallier, F., De Noblet, N., Friend, A.D., Friedlingstein, P., Grunwald, T., Heinesch, B., Keronen, P., Knohl, A., Krinner, G., Loustau, D., Manca, G., Matteucci, G., Miglietta, F., Ourcival, J.M., Papale, D., Pile-gaard K., Rambal, S., Seufert, G., Soussana, J.F., Sanz, M.J., Schulze, E-D., Vesala, T. and Valentini, R. (2005) Europe-wide reduction in primary productivity caused by the heat and drought in 2003. Nature 437, 529–533.CrossRefGoogle Scholar
- Ehleringer, J.R. (1993a) Carbon and water relations in desert plants: an isotopic perspective. In: J.R. Ehleringer, A.E. Hall, G.D. Farquhar (Eds.), Stable Isotopes and Plant Carbon-Water Relations. Academic, San Diego, CA, pp. 155–172.Google Scholar
- Ehleringer, J.R. (1993b) Gas-exchange implications of isotopic variation in arid-land plants. In: J.A.C. Smith, H. Griffiths (Eds.), Water Deficits: Plant Responses from Cells to Community. BIOS Scientific Publishers Ltd, Oxford, pp. 265–284.Google Scholar
- Ostlie, W.R., Schneider, R.E., Aldrich, J.M., Faust, T.M., McKim, R.L.B. and Chaplin, S.J. (1997) The Status of Biodiversity in the Great Plains. The Nature Conservancy, Arlington, VA.Google Scholar
- Ponton, S., Flanagan, L.B., Alstad, K.P., Johnson, B.G., Morgenstern, K., Kljun, N., Black, T.A. and Barr, A.G. (2006) Comparison of ecosystem water-use efficiency among Douglas-fir forest, aspen forest and grassland using eddy covariance and carbon isotope techniques. Global Change Biol. 12, 294–310.CrossRefGoogle Scholar
- Running, S.W., Thornton, P.E., Nemani, R.R. and Glassy, J.M. (2000) Global terrestrial gross and net primary productivity from the earth observing system. In: O.E. Sala, R.B. Jackson, H.A. Mooney, R.W. Howarth (Eds.), Methods in Ecosystem Science. Springer, New York, pp. 44–57.Google Scholar
- Savage, C. (2004) Prairie: a Natural History. Greystone Books, Douglas & McIntyre Publishing Group, Vancouver.Google Scholar
- Xu, L., Baldocchi, D.D. and Tang, J. (2004) How soil moisture, rain pulses, and growth alter the response of ecosystem respiration to temperature. Global Biogeochem. Cycles 18, doi: 10.1029/2004GB002281.Google Scholar