Small-scale variation in ecosystem CO2 fluxes in an alpine meadow depends on plant biomass and species richness
- 350 Downloads
Characterizing the spatial variation in the CO2 flux at both large and small scales is essential for precise estimation of an ecosystem’s CO2 sink strength. However, little is known about small-scale CO2 flux variations in an ecosystem. We explored these variations in a Kobresia meadow ecosystem on the Qinghai-Tibetan plateau in relation to spatial variability in species composition and biomass. We established 14 points and measured net ecosystem production (NEP), gross primary production (GPP), and ecosystem respiration (Re) in relation to vegetation biomass, species richness, and environmental variables at each point, using an automated chamber system during the 2005 growing season. Mean light-saturated NEP and GPP were 30.3 and 40.5 μmol CO2 m−2 s−1 [coefficient of variation (CV), 42.7 and 29.4], respectively. Mean Re at 20°C soil temperature, Re20, was −10.9 μmol CO2 m−2 s−1 (CV, 27.3). Re20 was positively correlated with vegetation biomass. GPPmax was positively correlated with species richness, but 2 of the 14 points were outliers. Vegetation biomass was the main determinant of spatial variation of Re, whereas species richness mainly affected that of GPP, probably reflecting the complexity of canopy structure and light partitioning in this small grassland patch.
KeywordsEcosystem CO2 flux Ecosystem structure and functioning Spatial heterogeneity Species richness Qinghai-Tibetan plateau
We thank Professor Jingyun Fang and Associate Professor Wei Wang at the Peking University for providing fieldwork support and technical assistance. This study was part of a joint research project between the National Institute for Environmental Studies, Japan, and the Northwest Institute of Plateau Biology, China, as part of the “Integrated Study for Terrestrial Carbon Management of Asia in the 21st Century Based on Scientific Advancements” and “Early Detection and Prediction of Climate Warming Based on the Long-Term Monitoring of Alpine Ecosystems on the Tibetan Plateau” projects. This study was supported by the One Hundred Talent Project (0429091211), by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS; No. 18710017), and by the JSPS-KOSEF-NSFC A3 Foresight Program (Quantifying and Predicting Terrestrial Carbon Sinks in East Asia: Toward a Network of Climate Change Research).
- Canadell JG, Mooney HA, Baldocchi DD, Berry JA, Ehleringer JR, Field CB, Gower ST, Hollinger DY, Hunt JE, Jackson RB, Running SW, Shaver GR, Steffen W, Trumbore SE, Valentini R, Bond BY (2000) Carbon metabolism of the terrestrial biosphere: a multitechnique approach for improved understanding. Ecosystems 3:115–130CrossRefGoogle Scholar
- Gilmanov TG, Soussana JF, Allards AL, Ammann C, Balzarolo M, Barza Z, Bernhofer C, Campbell CL, Cescatti A, Clifton-Brown J, Dirks BOM, Dore S, Eugster W, Fuhrer J, Gimenco C, Gruenwald C, Haszpra L, Hensen A, Ibrom A, Jacobs AFG, Jones MB, Laurila G, Lohila A, Manca G, Marcolla B, Nagy Z, Pilegaard K, Pinter K, Pio C, Raschi A, Rogiers N, Sanz MJ, Stefani P, Sutton M, Tuba Z, Valentini R, Williams ML, Wohlfahrt G (2007) Partitioning European grassland net ecosystem CO2 exchange into gross primary productivity and ecosystem respiration using light response function analysis. Agric Ecosyst Environ 121:93–120CrossRefGoogle Scholar
- Grime JP (2001) Plant strategies, vegetation processes, and ecosystem properties, 2nd edn. Wiley, LondonGoogle Scholar
- IPCC (2007) Climate change 2007: the physical science basis. Cambridge University Press, CambridgeGoogle Scholar
- Li W, Zhou X (eds) (1998) Ecosystems of Qinghai-Xizang (Tibetan) Plateau and approach for their sustainable management. Series of studies on Qinghai-Xizang (Tibetan) Plateau. Guangdong Science & Technology Press, GuangdongGoogle Scholar
- Loreau M, Naeem S, Inchausti P (eds) (2002) Biodiversity and ecosystem functioning synthesis and perspectives. Oxford University Press, OxfordGoogle Scholar
- Raich JW, Schlesinger WH (1992) The global carbon dioxide flux in soil respiration and its relationship to vegetation and climate. Tellus 44B:81–90Google Scholar
- Sims PL, Risser PG (2000) Grasslands. p. 323–356. Grasslands. In: Barbour MG, Billings WG (eds) North American terrestrial vegetation, 2nd edn. Cambridge University Press, New YorkGoogle Scholar
- Thornley MN, Johnson IR (1990) Plant and crop modeling; a mathematical approach to plant and crop physiology. Clarendon, OxfordGoogle Scholar
- Uchida M, Kishimoto M, Muraoka H, Nakatsubo T, Kanda H, Koizumi H (2009) Seasonal shift in factors controlling net ecosystem production in a high Arctic terrestrial ecosystem J Plant Res. doi: 10.1007/s10265-009-0260-6