SPECIAL: Savana Patterns of Energy and Carbon Integrated Across the Landscape

Beringer, Jason, Hacker, Jorg, Hutley, Lindsay B., Leuning, Ray, Arndt, Stefan K., Amiri, Reza, Bannehr, Lutz, Cernusak, Lucas A., Grover, Samantha, Hensley, Carol, Hocking, Darren, Isaac, Peter, Jamali, Hizbullah, Kanniah, Kasturi, Livesley, Stephen, Neininger, Bruno, U, Kyaw Tha Paw, Sea, William, Straten, Dennis, Tapper, Nigel, Weinmann, Richard, Wood, Stephen, and Zegelin, Steve (2011) SPECIAL: Savana Patterns of Energy and Carbon Integrated Across the Landscape. Bulletin of the Amercian Meteorological Society, 92 (11). pp. 1467-1485.

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View at Publisher Website: http://dx.doi.org/10.1175/2011BAMS2948.1
 
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Abstract

Savannas are highly significant global ecosystems that consist of a mix of trees and grasses and that are highly spatially varied in their physical structure, species composition, and physiological function (i.e., leaf area and function, stem density, albedo, and roughness). Variability in ecosystem characteristics alters biophysical and biogeochemical processes that can affect regional to global circulation patterns, which are not well characterized by land surface models. We initiated a multidisciplinary field campaign called Savanna Patterns of Energy and Carbon Integrated across the Landscape (SPECIAL) during the dry season in Australian savannas to understand the spatial patterns and processes of land surface–atmosphere exchanges (radiation, heat, moisture, CO2, and other trace gasses). We utilized a combination of multiscale measurements including fixed flux towers, aircraft-based flux transects, aircraft boundary layer budgets, and satellite remote sensing to quantify the spatial variability across a continental-scale rainfall gradient (transect). We found that the structure of vegetation changed along the transect in response to declining average rainfall. Tree basal area decreased from 9.6 m2 ha−1 in the coastal woodland savanna (annual rainfall 1,714 mm yr−1) to 0 m2 ha−1 at the grassland site (annual rainfall 535 mm yr−1), with dry-season green leaf area index (LAI) ranging from 1.04 to 0, respectively. Leaf-level measurements showed that photosynthetic properties were similar along the transect. Flux tower measurements showed that latent heat fluxes (LEs) decreased from north to south with resultant changes in the Bowen ratios (H/LE) from a minimum of 1.7 to a maximum of 15.8, respectively. Gross primary productivity, net carbon dioxide exchange, and LE showed similar declines along the transect and were well correlated with canopy LAI, and fluxes were more closely coupled to structure than floristic change.

Item ID: 30286
Item Type: Article (Refereed Research - C1)
ISSN: 1520-0477
Funders: Australian Research Council (ARC)
Projects and Grants: ARC (DP0344744 and DP0772981)
Date Deposited: 20 Nov 2013 09:33
FoR Codes: 06 BIOLOGICAL SCIENCES > 0607 Plant Biology > 060705 Plant Physiology @ 100%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960806 Forest and Woodlands Flora, Fauna and Biodiversity @ 100%
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